SOMATOSTATIN (SST) PROMOTER HYPERMETHYLATION IN ASSOCIATION WITH COLORECTAL CANCER

Abstract

Colorectal cancer (CRC) is one of the most common diagnosis malignancies with different risk factors, including environmental and genetic. Several genes, called tumor suppressor genes, play an essential role in inhibiting these risk factors by preventing tumor development. One of these genes is somatostatin (SST). Somatostatin is an antiproliferative peptide with pro-apoptotic effects that enhance cell death to prevent tumor growth. This study aimed to investigate the association relationship between DNA methylation in SST promotor and colorectal cancer progression. After DNA bisulfite conversion, SST promoter methylation was examined using quantitative methylation‐specific PCR (qMSP) in 71 cases (19 metastasis CRC, 28 early-stage CRC, and 24 healthy controls). Quantitative methylation‐specific PCR (qMSP) is a real-time PCR method used to determine the unmethylated and methylated cytosine residues using a specific set of primers. The percentage of hypermethylation in SST promoter was 17%, 60%, and 79% for healthy controls, early-stage, and metastasis CRC groups. The results showed a significant association between DNA hypermethylation of SST promoter and CRC progression. P-values were 0.0364 for the early-stage group and 0.0138 for the metastasis group. The results also supported that the DNA hypermethylation block the expression of SST, which in turn induce carcinogenesis. The detection of SST promoter hypermethylation at early stage of cancer could be used as a biomarker for screening and prognosis of CRC.