MS-MLPA reveals progressive age-dependent promoter methylation of tumor suppressor genes and possible role of IGSF4 gene in colorectal carcinogenesis of microsatellite instable tumors.

In 43 MSI-H colorectal cancers we searched for new targets of promoter methylation, inspected the nature of methylation process, and the influence of methylation at specific CpG site on gene expression. CpG methylation was detected in 12 tumor suppressor genes. Our findings suggest a potential role of IGSF4 gene in the development of colorectal tumors. According to the detected methylation pattern, two groups of tumors, significantly differing in age, exist in MSI-H colorectal cancers. Our study also suggests that methylation at a specific CpG island in the promoter could be the representative for gene silencing and therefore serve as a biomarker.