Long non-coding RNA polymorphisms and prediction of response to chemotherapy based on irinotecan in patients with metastatic colorectal cancer.

Background: Colorectal cancer is the fourth cause of cancer related death. Drug resistance and toxicity remain major clinical issues. HOTAIR and MALAT1 are long non-coding RNAS that affect cellular proliferation, apoptosis and drug resistance; their up-regulation has been linked with a poor prognosis.

Objective: Investigation of the association between rs4759314 HOTAIR and rs3200401 MALAT1 polymorphisms and irinotecan-based chemotherapy in terms of drug efficacy and toxicity.

Methods: Samples from 98 patients receiving different regimens of irinotecan-based therapy were included. Efficacy and toxicity were evaluated. KRAS mutation, rs3200401 HOTAIR and rs4759314 MALAT1 polymorphisms genotyping in the tumors and peripheral blood respectively were performed with PCR.

Results: Neither rs3200401 MALAT1 nor rs4759314 HOTAIR polymorphism are associated with response to treatment regimens. Rs4759314 was also not associated with increased toxicity in patients receiving irinotecan-based regimens. CT genotype of rs3200401 was associated with significantly reduced overall survival. An association between KRAS mutation and AG/GG genotypes in the rs4759314 was detected.

Conclusions: CT genotype of rs3200401 MALAT1 polymorphism could serve as a toxicity biomarker. Carriers of the G allele of the rs4759314 HOTAIR are more likely to be carriers of KRAS mutations too. However, further studies in larger patient populations are required.