Evaluation of the relation of CD133 expression measured by immunohistochemistry assay with the survival of the colorectal cancer patients: a retrospective cohort study.

[BACKGROUND] Colorectal cancer (CRC) is a prevalent and deadly malignancy, often characterized by cellular heterogeneity and resistance to therapy. CD133, a proposed cancer stem cell marker, has been implicated in poor clinical outcomes, but its prognostic value remains controversial, particularly in diverse populations.

[OBJECTIVE] This study aimed to evaluate the relationship between CD133 expression and overall survival (OS) in patients with colorectal adenocarcinoma treated at Mousavi Hospital in Zanjan, Iran.

[METHODS] This retrospective cohort study analyzed 55 patients who underwent surgical resection for histologically confirmed colorectal adenocarcinoma between 2012 and 2017. CD133 expression was assessed using immunohistochemistry (IHC) and categorized as positive or negative. Associations with clinicopathological features and 5-year survival were examined using logistic regression and Cox proportional hazards (PH) models.

[RESULTS] CD133 expression was detected in 47.3% of tumors. It was significantly more prevalent in high-grade tumors (83.1% vs 18.7%, p = 0.001) and in female patients (66.7% vs 32.2%, p = 0.015). Five-year survival was significantly lower in CD133-positive patients (19.2%) compared to CD133-negative individuals (75.9%, p < 0.001). In multivariable Cox regression adjusted for tumor grade and age, CD133 positivity was associated with increased hazard of death (adjusted hazard ratio(HR) = 5.03; 95% confidence interval (CI) 1.66-15.25; p = 0.004). Because of the modest sample size and wide confidence intervals, this association should be considered preliminary. In crude analyses, tumor grade impacted survival; in the adjusted model, only CD133 remained remarkable, while age, sex, and tumor location showed no significant associations.

[CONCLUSIONS] CD133 expression is significantly associated with high tumor grade and poor survival in Iranian CRC patients, but findings should be interpreted with caution, given the small cohort. Its evaluation could aid in identifying high-risk individuals and guiding personalized treatment strategies in larger confirmatory studies.