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<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.