Hierarchical clustering defines hypermethylated RSPO2 as early-stage potential biomarker in colorectal cancer.

[BACKGROUND] Early-stage diagnosis, absence of specific reliable biomarkers, and better clinical management of colorectal cancer (CRC) remain major challenges. The Rspondin2 (RSPO2) gene is one of the most potent enablers of Wnt signaling, having contrasting aspects in tumor development and progression.

[AIM] We aimed to identify the role of RSPO2 as a molecular biomarker by evaluating its methylation and expression profiles in CRC tissue samples to identify biomarker potential.

[METHODOLOGY] Combined bisulfite restriction analysis CoBRA) and quantitative reverse transcription polymerase chain reaction (qRT-PCR) were used to access the change in methylation pattern and expression profile of RSPO2 in 52 CRC tissue samples. DNA methylome and transcriptome profiling of CRC samples were hierarchically clustered, and prognostic utility was measured using a Kaplan-Meier (K-M) plot and univariate analysis.

[RESULTS] RSPO2 was hypermethylated (33/52; 63.46 %) and significantly associated with early-stage (I+II, p = 0.04) CRC tissue and exhibited low RSPO2 expression (42/52; 80.76 %). Hierarchical clustering stratified the samples into two distinct clusters that share some significant clinical and molecular factors specific for cluster 1 such as LN status (p < 0.0001) and lymphovascular invasion (p = 0.0013) while staging (p < 0.0001) and RSPO2 methylation (p = 0.0402) in cluster 2, which are valuable for personalized medicine. K-M plot analysis showed that patients with low RSPO2 expression have poor disease-free survival but could not be a risk factor.

[CONCLUSION] RSPO2 may be a potential biomarker for early-stage detection and provide valuable insight into the diagnosis of patients with CRC.