Promoter methylation analysis of Suppressor of Cytokine Signaling-1 (SOCS1) gene in Colorectal cancer patients and its association with Clinicopathological characteristics

Abstract

Colorectal cancer (CRC) is the third most common cancer worldwide with 1.3 million new cases each year. In India, it is the fourth most common cancer in males and the third most common cancer in females. By the advent of molecular biology techniques, new biomarkers such as methylation of DNA, miRNAs resulted and used for early diagnosis as well as personalized therapies. Tumor suppressor gene(s) promoter methylations are one of such biomarkers in identifying the tumor aggressiveness, metastasis and the survival outcome after the surgery. Suppressor of cytokine signaling-1 (SOCS1) gene is a tumor suppressor gene, reported to be silenced in several types of cancers including CRC. However, the role of SOCS1 promoter methylation as a marker remains understudied, not completely established in CRC. We investigated the promoter methylation status of SOCS1 gene in stage II and III CRC samples, find its prognostic significance and association with clinicopathological characteristics. We analyzed 56 CRC samples for SOCS1 promoter methylation and found, 24 samples (42.9%) methylated whereas 32 samples (57.1%) unmethylated. The pathological investigations revealed that SOCS1 promoter methylations were associated with poor differentiation of tumor tissue (P less than 0.017), and decreased the overall survival rate (22.5 months). Further, we also found that promoter methylations are not associated with other clinicopathological characteristics such as lymph node metastasis, tumor stage, and dietary habits.