OBJECTIVETo investigate the association between receptor-interacting kinase protein 4 (RIPK4) relative copy number (RCN) and prognosis of stage III( colorectal cancer (CRC) patients treated with oxaliplatin-based chemotherapy.

METHODSRIPK4 RCN was determined by real-time PCR and then dichotomized into high RIPK4 RCN group(n=35) and low RIPK4 RCN group (n=104) using the third quartile as the cut-off point. Overall survival (OS) and recurrence-free survival (RFS) were compared between high and low RIPK4 RCN groups. The subgroup prognostic analysis was also conducted based on tumor site.

RESULTSThe median follow-up period was 49 months (ranged 4 to 98 months). Patients with high RIPK4 RCN had poorer OS than those with low RIPK4 RCN, which reached marginal significance(median OS, 43.0 months vs. 53.5 months, P=0.074). Meanwhile there was no significant difference of RFS between two groups (P=0.352). In colon cancer subgroup, high RIPK4 RCN was significantly associated with poor OS (median OS, 31.5 months vs. 56.6 months, P=0.015) but not with RFS (P=0.135). In rectal cancer subgroup, RIPK4 RCN was not associated with both OS and RFS (P=0.981, P=0.738). Multivariate analysis revealed that high RIPK4 RCN was an independent prognostic factor of OS in stage III( CRC patients treated with oxaliplatin-based chemotherapy (HR=2.903, 95% CI: 1.275 to 6.610).

CONCLUSIONRIPK4 RCN is significantly associated with OS in stage III( colon cancer patients receiving oxaliplatin-based chemotherapy and may be a novel biomarker that can predict the efficacy of oxaliplatin in colon cancer patients.