Sex steroid receptors in colorectal cancer: implications for tumor progression, therapeutic opportunities, and sex-specific outcomes.

Introduction
Colorectal cancer (CRC) presents a major challenge in oncology, ranking globally as the second leading cause of cancer-related deaths and the third most prevalent cancer. Approximately 1.93 million new CRC cases were diagnosed in 2020, resulting in around 0.94 million deaths. With an estimated 3.2 million new cases expected by 2040, these projections indicate a substantial increase[1].
A highly processed Western diet, tobacco use, and obesity continue to play a pivotal role in CRC development[2]. In contrast, nonmodifiable risk factors, like gender, have also been associated with varying susceptibility to colorectal polyps and tumors, with males exhibiting a higher risk for both[3]. This gender disparity has prompted the hypothesis that sex hormones may contribute to observed differences in CRC risk, especially when comparing premenopausal and postmenopausal women[4,5]. Epidemiological evidence indicates that premenopausal women have a lower risk of CRC compared to age-matched men. Among postmenopausal women, those using hormone replacement therapy (HRT) show reduced incidence of CRC; however, findings across studies remain heterogeneous, with some reporting inconsistent protective effects depending on age, tumor location, and study design[2,6,7]. Additionally, female CRC patients aged 18–44 years tend to have a more favorable prognosis compared to women over 50 years and men of the same age[8].
While the gonads are the principal source of sex steroid hormones, various peripheral tissues, such as the colon, are also capable of hormone biosynthesis. These tissues express enzymes needed to generate progesterone (P4), testosterone, and 17β-estradiol (E2)[9–11]. They also contain receptors that mediate hormone signaling, including estrogen receptors (ERs) estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ), the progesterone receptor (PGR), and the androgen receptor (AR)[12–20]. Current evidence indicates that E2 acting through ERβ[12–15] and P4 via PGR[15,16] may function as tumor suppressors. Conversely, E2-induced ERα activation[12–15] and testosterone-mediated AR signaling[17–20] are thought to promote the initiation and progression of colon neoplasia[21].
This study aims to explore and compile existing research on the effects of estrogen, P4, and androgens on CRC, the molecular mechanisms of sex hormone-mediated chemoprotection, and the clinical implications of sex hormones in CRC. Better prognostic markers and alternative hormonal therapies for CRC can be provided if we understand the role of sex steroid hormones in colon oncogenesis.

Literature search and selection
A comprehensive literature search was performed using PubMed, Web of Science, and Google Scholar for studies published from 1970 to 2025. Keywords included “colorectal cancer,” “estrogen receptor,” “progesterone receptor,” “androgen receptor,” “sex differences,” and related terms. Studies were included if they reported original data on sex steroid receptor expression in CRC patients. Reviews, case reports, animal studies, and non-English articles were excluded. Titles and abstracts were screened for relevance, and full texts of eligible studies were retrieved for detailed evaluation. This narrative review was conducted in accordance with the TITAN Guidelines 2025.

Role of ER in colorectal carcinoma
CRC shows variable expression in men and women, while postmenopausal women do not exhibit this variability[3,4]. Postmenopausal women taking HRT show a lower risk for CRC. This variable incidence of CRC is attributed to estrogen and the variable expression of ERs in the colonic mucosa. Estrogens take three different forms: estrone (E1), estradiol (E2), and estriol (E3), whose roles are mostly mediated by two nuclear receptors (ERα and ERβ) and a membrane-associated G-protein [GPR30 or G-protein coupled estrogen receptor (GPER)]. ERβ mainly functions in maintaining epithelial structure, regulating gastrointestinal physiology, and mediating immunological responses[22,23]. ERα promotes cellular growth and proliferation, while ERβ inhibits cellular proliferation by downregulating proto-oncogenes and upregulating tumor suppressor genes[24]. Estrogen response through signaling by ERα and ERβ depends on the ERα/ERβ ratio in a cell, as ERβ inhibits the activity of ERα[25,26]. While ERα predominantly influences reproductive tissues, ERβ has a broader tissue distribution, extending its influence beyond reproduction.
HIGHLIGHTS
ERβ declines in CRC, inhibiting tumors; ERα and GPER show context-dependent roles.

P4 shows antitumor effects in CRC, but its human prognostic value is unclear.

Nuclear AR drives CRC progression; membrane ARs suppress tumor growth.

Hormone receptor levels vary by sex, age, and tumor site, affecting CRC outcomes.

The distribution and expression of these receptors vary in normal and cancerous colon tissues. According to Xie et al, the expression of ERβ is higher in normal colonic tissue (91.7%) than in CRC tissue (83.3%), while the expression of ERα is higher in CRC tissue (25%) than in normal colonic mucosa (16.6%)[27,28]. These contradicting effects of ERα and Erβ are evidenced by the use of selective estrogen receptor modulators (SERMs); ERα agonists increase the risk of colon cancer, while ERβ agonists decrease the risk[29,30]. Expression of ERβ decreases as the stage of cancer increases[26].
Stimulation of these ERs affects gene transcription by interacting with EREs and multiple transcription factors like c-Jun and c-Fos of the AP1, Sp1, and NFκB[26,31]. These interactions regulate genes linked to angiogenesis (VEGF), cell adhesion (cadherins, laminins), and apoptosis. ERα activation typically promotes proliferation. ER is stimulated via phosphorylation through the activated kinase pathway[26]. ERα has a monoubiquitination site that mediates the PI3K/Akt pathway. Mutations in this site prevent phosphorylation of ERα[29,32]. As shown in Figure 1, mitogen-activated protein kinase (MAPK) pathway and PI3K/Akt signaling pathways play significant roles in tumorigenesis by increasing cellular growth and invasion[29,33].

On the other hand, ERβ has been repeatedly shown to exert antitumorigenic effects by regulating the cell cycle, enhancing DNA repair capacity, and downregulating oncogenes such as MYC and PROX1. Its expression correlates with increased p53 signaling and apoptosis, reducing proliferation. However, ERβ expression patterns are not uniform across studies. Some show protective ERβ expression, while others report variable associations depending on stage and tumor location, which likely reflect heterogeneity influenced by immunohistochemistry (IHC) protocols, antibody specificity, and cutoff definitions. While most show loss of ERβ with advancing stage, others report site-specific variation (proximal vs. distal tumors), again highlighting methodological and biological heterogeneity[34]. The concentration of ERβ in the colon could serve as a prognostic factor for CRC. As shown in Figure 2, ERβ levels are denser in normal colonic mucosa and significantly reduced with the progression of tumor staging[29,30]. Expression of ERβ decreases as the stage of cancer increases[26].

ERβ counteracts tumorigenesis through enhancement of tumor suppressor pathways. The ESR2-CA microsatellite in the ERβ gene is associated with CRC risk. A shorter allele increases risk in older women but decreases risk in younger postmenopausal women. In postmenopausal women, ESR2-CA genotypes and ERβ expression impact cancer characteristics based on age, location, and mismatch repair protein status. Noncancerous tissue from older women with specific genotypes exhibits higher ERβ expression. These findings suggest that germline ESR2-CA genotypes influence ERβ expression and may contribute to the clinical characteristics of colon cancer[27]. Chronic inflammation of the colon increases CRC risk, and hormone-replacement therapy with ERβ has protective effects.
A study by Ibrahim et al investigated how intestinal ERβ influences the gut microbiota using mouse models of colitis-induced CRC. Loss of ERβ intensified the reduction in microbiota diversity caused by colitis-induced CRC. The Prevotellaceae_UCG_001 genus of Bacteroidetes was overrepresented in CRC mice, particularly in females and those lacking ERβ[35].
Estrogen regulates the expression of the ATM gene through GPER, which is more pronounced in hypoxic conditions. GPER is a transmembrane receptor that exerts many cellular functions, like proliferation, apoptosis, endoplasmic reticulum stress, angiogenesis, and immune response[36]. Expression of GPER is markedly less in cancerous tissue compared to adjacent normal tissue. GPER activation leads to decreased proliferation, increased endoplasmic reticulum stress, G2/M phase arrest, and apoptosis in cancerous cells[37]. According to Jacenik et al, GPER stimulation inhibits CRC cell migration in normoxic conditions and promotes migration in hypoxic conditions. GPER stimulation plays a role in colonic motility, suggesting that decreased stimulation could cause constipation[34]. Roberts et al found a direct relationship between the risk of both benign and malignant colon cancer and the severity of constipation[38].
Overall, ERβ contributes to a more favorable microbiome that could mitigate CRC development by influencing metabolic functions and immune responses. Thus, this beneficial effect of estrogen on colonic tissue via ERs represents a potential therapeutic option for reducing the morbidity associated with CRC. Plant-derived estrogens, such as phytoestrogens, have already been shown to have beneficial effects on CRC.

Role of PGR in colorectal carcinoma
The role of PGR in CRC remains controversial, with studies reporting divergent findings. While some evidence links low PGR expression to poor prognosis and enhanced malignant progression, other studies fail to establish a clear correlation. PGR is less frequently expressed in CRC compared to breast or gynecologic tumors, and overall receptor content in colonic tumors is low. Importantly, heterogeneity in results likely reflects differences in staining protocols, cutoff thresholds, and tumor site sampled (colon vs. rectum)[39]. Some authors have found that the amount of PGRs differs in the colon and rectum, with higher content in the colon tumor cells[39,40]. This can in no way be compared to the receptors and content in breast carcinoma, which is much higher, even though both tumors suggest similar etiologic factors related to a high-fat and protein diet[41].
In a study conducted by Zhang et al, low levels of PGRs were associated with a poor prognosis in CRC. Experimental studies demonstrate that P4 treatment can inhibit CRC cell proliferation in vitro and in vivo, in part via upregulation of the JNK/GADD45α pathway, which induces apoptosis and reduces malignant progression[17,42]. However, the precise mechanisms remain unclear, with evidence varying depending on hormone concentration, receptor subtype assessed, and cellular model.
P4 can attach to nuclear or membrane receptors via classical or nonclassical pathways, thereby regulating tumor growth. In a nonclassical pathway, the P4 response elements bind to proto-oncogene tyrosine-protein Src, protein kinase B, and MAPK, with subsequent actions on effector targets such as wingless-type MMTV integration site family member 1, cyclin D1, epidermal growth factor receptor, and transcription of p21. The classical pathway leads to the decomposition of heat shock proteins, PGR dimerization, and P4 response elements, initiating effector targets like cyclin D1 and p4 mediator receptor activator of nuclear factor κB ligand[43]. Another study suggests an inverse association between cancer recurrence and the PR pathway. The PR pathway was significantly associated with advanced cancer stages and response to adjuvant chemotherapy[44].
Other studies report no prognostic association between PGR and CRC outcomes, underscoring the inconsistent nature of the literature[45,46]. These discrepancies may reflect methodological issues, including differences in tissue collection, IHC antibodies, thresholds for positivity, and tumor site analyzed, emphasizing the urgent need for standardized protocols[47].

Role of ARs in colon carcinoma
Androgens act on colonic tissue primarily through two pathways: nuclear ARs, which regulate gene transcription, and membrane-bound ARs (mARs), which mediate rapid nongenomic signaling. AR expression is minimal in normal colonic tissue but increases significantly in malignant transformation. According to Albasri et al, increased AR expression correlates with increased tumor size [size greater than 4 cm showed higher AR expression than size below 4 cm (P-value = 0.026)], poorer cell differentiation, advanced stage, lymph node involvement, and distant metastasis[25,43,48]. AR expression acts as a prognostic indicator, with increased expression shown to have decreased survival[48].
Gender- and age-specific differences have been described. For instance, AR expression is higher in right-sided early stage CRC in men compared to women, while expression in left-sided tumors is more balanced. Among women, AR expression increases with age, being higher in postmenopausal than premenopausal cases. These patterns suggest hormonal and life-stage influences on AR biology in CRC[25].
mARs exert tumor-suppressive effects, contrasting with the oncogenic role of nuclear ARs. Activation of mARs by nonpermeable testosterone-albumin conjugates (TAC) promotes cytoskeletal reorganization and apoptosis via caspase-3, independent of classical AR pathways[49]. Notably, anti-androgens do not block these effects, underscoring distinct therapeutic implications. mAR expression is absent in normal mucosa but upregulated in CRC tissue. Activation through TAC leads to inhibition of survival pathways (PI3K/Akt, c-Src, β-catenin) and induction of apoptotic signaling (e.g., GSK-3β phosphorylation)[50,51]. However, these antitumor responses may be offset by concurrent upregulation of anti-apoptotic factors in CRC cells, which partially limits therapeutic efficacy[49].

Cross-talk and interplay of receptors

ER and CRC
Cross-talk between signaling cascades represents a key mechanism shaping CRC development and therapeutic response. ERs engage in both genomic (direct DNA binding and gene regulation) and nongenomic (rapid signaling via membrane ERs) pathways, influencing proliferation, apoptosis, and motility. By forcing ERs to interact with DNA, estrogen binding modifies gene expression and protein synthesis in the genomic route. Membrane-bound ERs in the nongenomic pathway initiate a swift intracellular signaling cascade that affects cell functions such as motility and signaling[52,53]. Convergence of these pathways, through interactions with MAPK and PI3K/Akt cascades, creates redundancy that may underlie therapeutic resistance to receptor-targeted approaches.
Besides genomic and nongenomic pathways, there is a building awareness of convergent pathways that include both components. Two mechanisms for “cross-talk” have been found. In one, estrogen-bound nuclear ER complexes dimerize and translocate to the nucleus, where they interact with phosphorylated transcription factors activated by GPER1 signaling. Second, interactions between GPER1 and ERα/ERβ at the plasma membrane activate protein kinase cascades, resulting in the phosphorylation of transcription factors, including ERs. These phosphorylated factors can then interact with DNA sequences, regulating transcription[54].
Therapeutic resistance remains a major barrier. Cross-talk among ERα, ERβ, AR, and PGR with downstream PI3K/Akt and MAPK pathways generates compensatory signaling that may blunt single-agent efficacy. This suggests that combination or sequential strategies (e.g., ERβ/PGR activation with concurrent ERα/AR inhibition) may overcome resistance. However, most evidence derives from preclinical models, and there is a lack of randomized clinical trials evaluating combined receptor-based strategies in CRC. According to Francesco Caiazza et al, E2 promotes ERβ mRNA translation in the near term (2 and 4 hours after stimulation), followed by late increased transcription (24 hours after stimulation). E2-induced sustained and palmitoylation-dependent p38/MAPK activation was necessary for both processes. The findings also point to a highly tuned control of diverse cellular and molecular activities by fast signals, which is necessary for E2’s protective actions against colon cancer progression. The interplay between these subtypes affects processes like cell proliferation and survival, with implications for diseases such as breast cancer and even CRC[55,56].
A study by Edvardsson et al also suggests that estrogen’s protective role against colon cancer is primarily mediated by ERβ. ERβ expression inhibits CRC growth in xenografts. Reintroducing ERβ in three cancer cell lines led to cell-specific gene regulation, impacting apoptosis, cell differentiation, and cell cycle regulation. Notably, ERβ downregulated IL-6 and associated networks, impacting inflammation in colon cancer development. ERβ and the nuclear receptor co-regulator PROX1 share target genes, while ERβ also enhances DNA-repair capacity, indicating antitumorigenic effects. Enhancing ERβ action could offer a promising therapeutic avenue for colon cancer prevention and treatment[35].

AR and CRC
ARs play a complex part in the regression of CRC, either independently or in conjunction with other sex hormones. According to Roshan et al, the activation of ARs is notably more prevalent in CRC tissue when compared to normal colon tissue. Activation of AR by testosterone-HSA conjugates triggers apoptosis, offering a protective mechanism against CRC. The invasiveness of CRC is under the control of Akt kinases, which are activated by testosterone-HSA, thereby curbing tumor invasion.
The number of CAG repeats in the AR gene is linked to survival rates, with longer repeats associated with less favorable outcomes. The CARM1 protein, which is required for cell proliferation and survival, is overexpressed in CRC; however, its exact role is unknown[38].
Additionally, Xia et al discovered a significant association between hypomethylation at specific sites (cg17964359 and cg18156601) in the AR gene and an increased risk of CRC. This hypomethylation in peripheral blood leukocytes may even serve as a potential biomarker for CRC[57].

PR and CRC
Studies have also shown that P4 has strong anti-cancer properties in the setting of colon cancer. When used as a monotherapy, P4 has been shown to inhibit the proliferation of colon cancer cells in both in vitro and xenograft models. This anti-proliferative activity is connected with the arrest of the cell cycle at the G0/G1 phase, which reduces cell division and tumor formation. Furthermore, P4 has been shown to trigger apoptosis in colon cancer cells, which is a programmed cell death mechanism that effectively controls cancer cell proliferation. Moreover, P4 inhibits cell proliferation and promotes death in colon cancer cells by activating the JNK pathway and increasing the production of GADD45α, an antiproliferative and DNA-damage-inducible protein. The potential of P4 as a promising therapeutic agent in the treatment of colon cancer is highlighted by these collective findings[58].
Kamińska et al found considerable downregulation of PGR, membrane PGRs (mPRβ and mPRγ), and PGRMC2 in CRC tissues compared to normal tissues. This decreased expression of PGR is related to a poorer prognosis for CRC. In contrast, the high expression of PGRMC1 in later stages of CRC suggests a potential role in cancer growth. Furthermore, their findings demonstrate that P4 therapy can reduce the proliferation of numerous CRC cell lines by halting the cell cycle at the G2/M phase and triggering apoptosis. These findings highlight the intricate link between PGRs and CRC, and the potential utility of P4 in limiting the proliferation and advancement of CRC cells[59].
Zhang et al propose that P4’s capacity to impede the S and G2/M stages of the cell cycle, downregulate specific cell cycle-related proteins, and induce apoptosis underscores its therapeutic potential. Notably, the study emphasizes the variability in research outcomes, which can be attributed to differences in cell lines, P4 concentrations, and PGR expression. P4 seems to exert its effects through both classical and nonclassical pathways, with classical pathways involving interactions with various signaling molecules such as MAPKs, and nonclassical pathways involving interactions with cyclin D1 (see Fig. 3) and other downstream effectors. The induction of apoptosis by P4 is intricately linked to GADD45 and the activation of the MAPK pathway, further highlighting its potential to inhibit the growth of colorectal carcinoma (CRC)[17]. Furthermore, research suggests that the P4 (PGR) and ERβ pathways interact in CRC, with PGR’s antitumorigenic actions dependent on ERβ activity in malignant tissues[42].

Methodology and design
This section details the methodologies employed in two cohort studies conducted by Giralda Topi et al and Refaat et al. It describes the patient populations, sample collection methods, IHC techniques, and study aims.
Topi et al used random selection to investigate female patients between January 2008 and June 2012 who underwent primary CRC surgery. The study included 333 female patients who were diagnosed with primary CRC between 2008 and 2012[60]. The research comprised female patients with a primary diagnosis of CRC who were both physically and psychologically capable of participating. Tissue microarrays were performed on 320 original CRC tumor samples using a monoclonal anti-ERβ antibody. An IHC procedure was conducted to assess the intensity of staining. Their research aimed to determine the relationship between ERβ expression and overall survival, disease-free survival, hormone status, lifestyle, and their effects[60,61].
Comparatively, the study conducted by Refaat et al utilized archived paired normal and malignant colon specimens that were collected from 120 patients (Saudi males and females) between January 2019 and December 2021. The specimens were formalin-fixed paraffin-embedded. The study included patients who were either over 18 but under 50 years old or over 60 years old. All participants had been diagnosed with primary sporadic cancer and had not received neoadjuvant chemotherapy or radiotherapy before their surgery. IHC was employed to quantify the levels of ERα, ERβ, PGR, and AR proteins[25].
IHC was performed using primary mouse monoclonal IgG antibodies to identify ERα, ERβ, PGR, and AR in 5-µm slices of both benign and cancerous tissue. Endogenous peroxidases were inhibited by immersing the sample in a BLOXALL solution for 15 minutes. The sections were thereafter placed in an incubator and left overnight in the presence of the primary antibodies. Following the washing process, the sections were subjected to treatment with ImmPRESS HRP Horse Anti-Mouse IgG Plus Polymer Peroxidase Kiss, according to the instructions provided by the manufacturer. The same technique was used for the nonmalignant regions. The quantification of protein expression was conducted using the IHC Image Analysis Toolbox. Regions of interest were identified, and the intensity of staining, along with the proportion of stained areas, was quantified. Subsequently, IHC scores were calculated for each receptor. These IHC scores were compared between matched normal and malignant tissues from each patient. Further analyses included comparisons across different clinical stages [early (I/II) vs. late (III/IV)], genders (male vs. female), tumor locations [right-sided colon (RSC) vs. left-sided colon (LSC)], and age groups (≤ 50 vs. ≥60 years).
This analysis was conducted on a total of 31 patients, with findings categorized by gender, age, clinical stage, and anatomical site (right: RSC vs. left: LSC). The research also aimed to evaluate the impact of hormone proteins on the cell cycle and apoptosis in male and female CRC cell lines SW480 and HT29. Hormone levels were assessed both individually and in combination with their respective inhibitors: ERα (MPP dihydrochloride), ERβ (PHTPP), PGR (mifepristone), and AR (bicalutamide)[25].
Both included cohort studies (Topi et al and Refaat et al) provide valuable data, yet highlight major methodological limitations that complicate interpretation. Patient selection criteria were not always transparent, and IHC protocols varied considerably – including differences in fixation, antibody specificity, scoring systems, and cutoff thresholds for positivity. Such variability likely explains conflicting findings across studies regarding ERβ and PGR expression. Moreover, sample characteristics (sex distribution, menopausal status, tumor site) differed substantially between cohorts, further limiting comparability.

Effects of the hormone receptor blockers
A significant increase in the number of SW480 male and HT29 female colon cancer cell lines in the sub-G1 phase was found after single treatments of E2 and P4 hormones compared to untreated cells. There was a significant increase in the percentage of cells relative to nontreated cells in the sub-G1 phase with the ERα blocker (MPP). In contrast, there was a remarkable decline of SW480 and HT29 cell lines in the sub-G1 phase compared with cells treated with E2 and P4 monotherapies alone, with the addition of ERβ blocker (PHTPP) and PGR blocker (mifepristone)[25].

Cellular apoptosis
There was an increase in the number of early and late apoptotic cells relative to untreated cells on single treatment with E2. ERα blocker enhanced the pro-apoptotic effects of E2, whereas ERβ blocker inhibited the pro-apoptotic effects of E2 in both cell lines. The numbers of viable SW480 and HT29 cells were significantly enhanced with testosterone monotherapy, while the addition of bicalutamide showed increased apoptosis in both cell lines[25].

Gender-specific variations
ERβ and PGR IHC scores correlated indirectly with N stage, M stage, number of positive lymph nodes, and advanced cancer stage in both males and females. PGR, but not ERβ, correlated indirectly with older age and T stage in malignant female specimens[25].
It has been indicated in many studies that ERT (estrogen replacement therapy) reduces colon cancer risk in postmenopausal women. Comparative reverse transcription-PCR and Southern analysis were done in a study to detect the level of mRNA expression for ER subtypes in paired samples of colon tumors and normal mucosa. In female patients, ERβ steady-state levels were significantly decreased in colon tumors compared with normal mucosa. Levels of both ERβ1 and ERβ2 isoforms were significantly decreased in tumors from female patients, with a more remarkable decline in ERβ1 mRNA levels. ERα mRNA levels were much lower than ERβ levels in both genders. In some colon cancer cell lines (Caco-2, T84, and SW1116), ERβ mRNA was detected, while all other cell lines were negative for ERα mRNA. The study showed ERβ as the predominant ER subtype in the human colon, which suggests that decreased levels could be associated with the development of colonic tumors in females[62].
In almost all samples, analysis of AR in neoplastic and surrounding healthy tissues showed specific binding for DHT, demonstrating the presence of AR. Hence, no significant difference was observed between males and females and between healthy and neoplastic tissues[63]. Using western blot, AR was further characterized, and both AR isoforms, AR-B and AR-A, were detected in healthy mucosa, while only the AR-A isoform was detected in neoplastic mucosa[64–66].

Menopausal status
Studies have shown that colon cancer risk in postmenopausal women is affected by the ERβ gene (ESR2) cytosine-adenine (CA) repeat polymorphism (ESR2-CA) in the germline[67]. A different pathogenic role of this polymorphism is seen with age, as a shorter allele of this polymorphism is associated with a higher risk in older women, but a lower risk in younger postmenopausal women. ESR2-CA is a microsatellite region[68].
A close relation was found between right-sided tumors and the level of ERβ positivity and E2 concentration in women above the age of 70. On the other hand, a reduction in ERβ compared to noncancerous counterparts was only observed in left-sided tumors in women below the age of 70 years[55]. Studies have reported that the germline ESR2-CA repeat polymorphism of the ERβ gene has an effect only on colon cancer risk in postmenopausal women but not on rectal or colon cancer risk in either men or premenopausal women[55]. The expression of ARs was significantly higher in RSC and LSC malignant specimens obtained from postmenopausal women relative to premenopausal women[55].
In general, ERα expression increased significantly in malignant vs. nonmalignant specimens. However, left-sided cancers have higher ERα expression than right-sided colon cancers. Concerning the clinical stage, markedly higher IHC scores were seen in the late-stage right and left cancers than in their corresponding early stage cancerous tumors[25]. In noncancerous tissues, PGR expression was significantly higher in the left-sided compared to right-sided tumors, whereas in cancerous tissues, PGR expression declined remarkably, with left-sided tumors showing the highest decline relative to the right-sided tissues. While AR expression increased significantly in cancerous colonic tissues as compared to noncancerous tissues, its expression was equal between proximal and distal cancers[25].

Implications of sex steroid receptor profiles
Estrogens have been implicated in different nonendocrine-related cancer types such as lung and gastrointestinal cancers[60]. Activation of beta-mediated processes in the superficial colonic epithelium may play a role in the preventive effects observed in females and ERT users[62]. AR expression is related to the clinical stage of colon cancer[48]. Despite sex differences in tumor location and aggressiveness, most scientific researchers do not consider sex specificity in their study design and interpretation. CRC screening guidelines do not distinguish females from males, which may explain the higher frequency of more advanced neoplasia when tumors are first detected and false-negative results in colonoscopy in females[66].

Clinical implications and hormonal therapy
Estrogenic pathways, particularly via ERβ, remain a promising therapeutic avenue in CRC. Phytoestrogens and SERMs show potential to mimic protective ERβ signaling while avoiding ERα-driven proliferation. However, results vary markedly between populations (e.g., Asian vs. Western dietary patterns) and across study designs, limiting generalizability. Importantly, clinical implementation requires better biomarkers to identify patients most likely to benefit, as well as trials stratified by sex, menopausal status, and tumor site[27,69,70].
There is a huge difference in the intake and metabolism of isoflavones among Asian and Western populations. On average, the Asian population consumes >30 mg of isoflavone per day, while the Western population takes <1 mg/day[69]. Phytoestrogens do not produce any side effects associated with estrogen intake as they have a greater binding capacity to ERβ than ERα[70]. Intestinal flora metabolizes phytoestrogens to secondary metabolites that have a high binding capacity to ERβ. According to Grosso et al, dietary intake of isoflavones does not lower the risk of CRC in prospective studies, but the risk is reduced in case-control studies[71]. This heterogeneity is due to the difference in the duration of isoflavone intake.
According to a Women’s Health Initiative study published in 2002, there was a significant decrease in the incidence of CRC in women using estrogen plus progestin. The study indicated a reduction of CRC risk by 33% in women taking HRT[72,73]. According to Newcomb and colleagues’ study, there was a significant reduction in CRC risk among women using postmenopausal hormone therapy, and the risk reduction was more pronounced in women with prolonged use of HRT[73]. Though there are good advantages of HRT in reducing the risk of CRC, this comes with the adverse effects of HRT in postmenopausal women. Obesity and smoking mask the benefit of HRT in lowering the risk of CRC, as obesity produces a state of hyperinsulinemia that activates PI3K and increases the risk of CRC, and smoking increases the risk of MSI-linked colon cancer.

Future directions
Based on our study, we suggest that targeting sex hormones, either individually or in combination, holds significant potential for both the treatment and diagnosis of CRC. Future management possibilities for CRC related to estrogen and its receptors involve the development of pharmacological agents that selectively target ERβ, harnessing the potential of SERMs to tailor therapies, investigating the role of the gut microbiome in CRC prevention and considering interventions like diet and probiotics, exploring HRT with ERβ for postmenopausal women to reduce CRC risk, utilizing ERβ concentration as a prognostic biomarker for CRC, researching the role of ERβ in mitigating chronic inflammation, examining the relationship between estrogen, oxygen levels, and hypoxia in CRC development, studying GPER stimulation and its impact on colonic motility and constipation[16]. There is some heterogeneity found in many studies about the relationship between HRT and colon cancer risk reduction. This area needs to be addressed. Cytokines within the tumor microenvironment can also interact with estrogen signaling, creating a complex feedback loop. Moreover, ERβ’s influence on the gut’s microbiota composition, altering local inflammation and tumorigenesis, adds another layer of intricacy. Collectively, these findings paint a dynamic picture wherein estrogen, ERs, inflammation, and immune responses intersect, influencing CRC development and gender-associated immune variations[35].
Phytoestrogens (plant-derived heterocyclic phenols) and xenoestrogens (synthetic compounds) have similar binding capacity as estrogen. Xenoestrogens like industrial chemicals, dioxins, and pesticides have disruptive and negative impacts on humans. Phytoestrogens preferentially bind to ERβ, thus having a therapeutic effect on colon carcinoma[27]. Isoflavones (genistein, daidzein, glycitein, biochanin A, and formononetin), lignans (pinoresinol, lariciresinol, secoisolariciresinol, matairesinol, and enterolignans), and coumestans (coumestrol, wedelolactone, plicadin) are different types of phytoestrogens, with isoflavones being a common source of phytoestrogens in the Asian population and lignans being a common source in the Western population[69,70]. Based on a dose–response analysis of isoflavones, the risk of CRC is decreased by 8% by increasing the intake by 20 mg/day in the Asian population[70].
Mahbub et al propose that the simultaneous activation of ERβ and PGR by their respective ligands may trigger a series of events with anticancer properties. This includes inhibiting cancer growth through the AR and ERα pathways, as well as promoting anti-proliferative and pro-apoptotic effects in CRC. They propose that employing E2 and/or P4 as therapeutic agents could provide alternate approaches to combating CRC, and the efficacy of these therapies may be dependent on the expression patterns of ERs and PGR in malignant colonic tissues. Furthermore, they propose that a sequential hormone therapy involving E2 followed by P4 could be an effective regimen for early stage CRC. In contrast, their concurrent combination may be more appropriate for advanced or metastatic colon cancer[16].
It is also noteworthy that activation of AR through testosterone-HSA conjugates induces apoptosis, providing a safeguard against CRC. Directing efforts towards modulating this pathway may hold the potential to improve the efficacy of therapeutic interventions for CRC patients[38]. Investigating the role of ER targeting in CRC treatment entails investigating how distinct gene alterations within tumors affect the response to estrogen-based therapies. Certain alterations may make tumors more or less responsive to these treatments, necessitating customized approaches to maximize their efficacy. Furthermore, it is critical to consider the involvement of ERs in MSI-high CRC patients. Investigating how MSI status impacts estrogen therapy response can help guide decisions about its use in specific patient populations, perhaps unlocking more effective treatment regimens.
Personalized medicine provides the most effective approach for patients. All of the targeted therapy plans provided for CRC allude to the link of essential genes with the central mechanisms of disease progression, all of which could be inhibited by targeted medications to prevent proliferation and invasion. However, further study is needed to investigate medication resistance mechanisms in varied groups of CRC to determine the likely prognosis in different categories of patients. Chemotherapy formulations have been viewed as increasingly challenging in recent years. Because CRC patients’ prognosis is currently confined to limited information based on the high or low frequency of MSI, the patient’s MSS status, and mutations in BRAF or PIK3CA genes, all of which influence the identification of the potential tumors’ invasion rate and differentiation, good or poor prognosis, the degree of progression, and, in some cases, the tumor’s location. Understanding how ER targeting responds differently depending on tumor location can assist in establishing the appropriate treatment methods for distinct anatomical locations, hence improving therapeutic outcomes[64]. Table 1 summarizes the roles of sex steroid receptors in CRC.

Furthermore, there is an urgent need to discover new biomarkers that predict responsiveness to estrogen-based therapy. Developing biomarkers for ER function or estrogen responsiveness can improve treatment planning, allowing for more precise prognosis and customized therapeutic actions.

Conclusion
In conclusion, the cohort study provides crucial insights into the role of sex steroid receptors in CRC. Altered expression patterns of ERα, ERβ, PGR, and AR in malignant specimens highlight their dynamic functions that regulate cell cycle, apoptosis, and tumor progression. Gender-specific variations and the influence of menopausal status further underscore the complexity of hormonal receptor dynamics. Associations with clinical stage and tumor location suggest potential implications for cancer screening and treatment strategies. These findings emphasize the importance of incorporating sex-specific considerations into CRC research and clinical guidelines, opening avenues for personalized interventions based on receptor profiles.
Estrogen’s modulation of gene transcription through ERα, ERβ, and GPER in CRC highlights the dynamic interplay of these receptors in tumorigenesis. The opposing effects of ERα and ERβ, coupled with the regulatory role of GPER, emphasize the complexity of estrogen signaling. The PGR’s contradictory role in colorectal carcinoma adds a layer of intricacy with potential therapeutic implications. Conflicting findings from PGR studies emphasize the need for standardized methodologies in assessing and clarifying its impact on CRC prognosis.
Finally, the exploration of ARs and P4’s therapeutic potential in CRC provides additional insight into hormonal signaling in CRC. AR activation, particularly its association with testosterone-HSA and the role of CAG repeats, offers clues into possible protective mechanisms and survival outcomes. P4 may become a promising monotherapy, with evidence of inhibiting cell proliferation, inducing apoptosis, and modulating key pathways like JNK and GADD45α. Together, these findings underscore important clinical implications, suggesting new opportunities for targeted therapies in CRC treatment. This research enhances our understanding of hormonal influences in CRC, paving the way for refined clinical strategies and stimulating further exploration into tailored interventions and prognostic markers.