Short article: Influence of regulatory NLRC5 variants on colorectal cancer survival and 5-fluorouracil-based chemotherapy

Background NLRC5 is an interferon γ-inducible protein, which plays a role in immune surveillance with a potential influence on cancer survival. Objective We aimed to evaluate the effect of potential regulatory variants in NLRC5 on overall survival and survival after 5-fluorouracil (5-FU)-based therapy of colorectal cancer (CRC) patients. Patients and methods We carried out a case-only study in a Czech population of 589 cases; 232 received 5-FU-based therapy. Eleven variants within NLRC5 were selected using in-silico tools. Associations between polymorphisms and survival were assessed by Cox regression analysis adjusting for age at diagnosis, sex, and TNM stage. Survival curves were derived using the Kaplan-Meier method. Results Two variants showed a significant association with survival. All patients and metastasis-free patients at the time of diagnosis (pM0) who were homozygous carriers of the minor allele of rs27194 had a decreased overall survival (OS all and OS pM0) and event-free survival (EFS pM0) under a recessive model (OS all P=0.003, OS pM0 P=0.005, EFS pM0 P=0.01, respectively). OS was also decreased for all patients and for pM0 patients who carried at least one minor allele of rs289747 (OS all P=0.03 and OS pM0 P=0.003, respectively). Among CRC patients, who underwent a 5-FU-based adjuvant regimen, rs12445252 was associated with OS all, OS pM0 and EFS pM0, according to the dosage of the minor allele T (OS all P=0.0004, OS pM0 P=0.0001, EFS pM0 P=0.008, respectively). Conclusion Our results showed that polymorphisms in NLRC5 may be used as prognostic markers of survival of CRC patients, as well as for survival in response to 5-FU treatment.