The role of CCR5 polymorphism in colorectal cancer and liver metastasis in the Tunisian population

Chemokines and their receptors are involved in cancer initiation and progression, including colorectal cancer (CRC) and liver metastasis formation. Our aim was to elucidate C-C chemokine receptor type 5 (CCR5) gene polymorphism (CCR5?32) impact on CRC and colorectal cancer liver metastases (CRLM) occurrence risk. We analyzed the CCR5 gene mutational status in 108 primary CRC cases, 35 CRLM and 248 healthy individuals, and evaluated CCR5 expression in healthy tissue and tumors. Rare allele ??32? was more frequent in controls (7.2% vs 2.8% in CRC). All 35 metastases had wild-type CCR5. Our analysis showed that CCR5 wild type has a significant risk of 2.73-fold (95% CI=1.22-7.31) to cause CRC while ?32 reduced the risks 0.36-fold (95% CI=0.13-0.82). For CRC, CCR5 correlated with left-sided tumors and liver metastases (P=0.040 and P= 0.039 respectively). As for CRLM, no correlation was found. Immunohistochemical profile analysis of CCR5 revealed a significant association with the male gender (P=0.049) and non-mucinous carcinomas (P< 0.001) in primary CRC. CCR5 expression revealed an association with the degree of tumor differentiation for both CRC and CRLM (P < 0.001). CCR5?32 might be a protective factor against CRC development and dissemination.