Immunoprofiles and DNA Methylation of Inflammatory Marker Genes in Ulcerative Colitis-Associated Colorectal Tumorigenesis.

Immunological and epigenetic changes are interconnected and contribute to tumorigenesis. We determined the immunoprofiles and promoter methylation of inflammation-related genes for colitis-associated colorectal carcinomas (CA-CRC). The results were compared with Lynch syndrome (LS)-associated colorectal tumors, which are characterized by an active immune environment through inherited mismatch repair defects. CA-CRCs ( = 31) were immunohistochemically evaluated for immune cell scores (ICSs) and PDCD1 and CD274 expression. Seven inflammation-associated genes (, , , , , , and ), the repair gene , and eight standard marker genes for the CpG Island Methylator Phenotype (CIMP) were investigated for promoter methylation in CA-CRCs, LS tumors ( = 29), and paired normal mucosae by multiplex ligation-dependent probe amplification. All but one CA-CRCs were microsatellite-stable and all LS tumors were microsatellite-unstable. Most CA-CRCs had a high ICS (55%) and a positive CD274 expression in immune cells (52%). revealed frequent tumor-specific hypermethylation in CA-CRC and LS. When compared to LS mucosae, normal mucosae from patients with CA-CRC showed significantly higher methylation of and most CIMP markers. In conclusion, CA-CRCs share a frequent ICS/CD274 expression pattern with LS tumors. Elevated methylation in normal mucosa may indicate field cancerization as a feature of CA-CRC-associated tumorigenesis.