Differences in the expression of CMTM3 and SSTR2 genes in right and left colon tumors: A molecular insight into colorectal cancer.

Colorectal cancer (CRC) is a prevalent and lethal malignancy influenced by genetic, epigenetic, and environmental factors, with diverse molecular subtypes and varying incidence rates across different populations. The anatomical, histological, morphological, and genetic differences between the right and left colons contribute to disparities in tumor incidence, clinical presentation, prognosis, and therapeutic responses, depending on the tumor's localization. We aimed to investigate the expression patterns of the CMTM3 and SSTR2 genes both of which are hypermethylated and potentially involved in the development and progression of colorectal tumors in tumors originating from the right and left colon. The study consisted of 89 histopathologically diagnosed tumour tissue samples, 42 from the right colon and 47 from the left colon, and 89 healthy tissue samples from the same individuals adjacent to the tumour tissue. The expression of the CMTM3 and SSTR2 genes was analysed using the comparative CT (ΔΔCT) method in real-time PCR. Our findings demonstrated a significant upregulation of CMTM3 and SSTR2 expression in tumor tissues compared to adjacent normal tissues (p < 0.05). Notably, CMTM3 expression was significantly higher in left-sided colon tumors (2 = 20.95) compared to those originating from the right colon (2 = 14.13) (p = 0.027). This study is the first to suggest that elevated CMTM3 expression may be associated with the increased incidence and distinct molecular behavior of left-sided colorectal tumors. Results provide novel insights into the molecular heterogeneity of colorectal cancer, emphasizing the importance of tumor localization in understanding disease mechanisms and informing targeted therapeutic strategies.