Prognostic value of CXCL17 and CXCR8 expression in patients with colon cancer.

C-X-C motif chemokine ligand 17 (CXCL17) is a mucous chemokine and its expression is highly correlated with that of G protein-coupled receptor 35 (GPR35), which has been confirmed as its receptor and named C-X-C motif chemokine receptor 8 (CXCR8). CXCL17 is upregulated in several types of cancer. However, the biological role of this chemokine in colon cancer remains unknown. In the present study, the expression levels of CXCL17 and CXCR8 were examined using immunohistochemistry in 101 colon cancer tissues and 79 healthy tumour-adjacent tissues. CXCL17 and CXCR8 expression levels were increased in the colon cancer samples compared with tumour-adjacent samples. Patients with high CXCL17 expression had longer overall survival (OS) compared with patients with low expression of CXCL17 (log-rank test; P=0.027). However, CXCR8 expression, but not CXCL17, was an independent prognostic factor for OS in patients with colon cancer. The expression of CXCR8 correlated positively with that of CXCL17 in colon cancer samples (ρ=0.295; P=0.003). Furthermore, the combined high expression of CXCL17 and CXCR8 was a significant independent prognostic factor for OS in patients with colon cancer (P=0.001). In subgroups with a TNM stage of I-II, the patients with combined high expression of CXCL17 and CXCR8 had a longer survival compared with those without combined high expression (P=0.001). However, this difference was not observed in subgroups with a TNM stage of III-IV. Collectively, these findings suggest that CXCL17/CXCR8 signalling may be involved in colon cancer and contribute to improved patient outcomes.