MIR27A rs895819 TC genotype increases risk of fluoropyrimidine-induced severe toxicity independently of DPYD variations.

ABSTRACT

Aim: MicroRNA 27a (miR-27a) regulates post-transcriptionally DPD activity. We have analyzed the association of MIR27A rs895819T>C variation, that modulates miR-27a expression, with fluropyrimidine-induced toxicity. Materials & methods: MIR27A rs895819T>C genotyping was conducted by TaqMan® allelic discrimination assay in 313 FP-treated cancer patients. Results: In overdominance (TC vs TT + CC), TC genotype was associated with grade 3-4 toxicity (p = 0.002), any grade toxicity (p = 0.052), and delayed drug administration or therapy discontinuation (p = 0.038). Odds of grade 3-4 toxicity were increased by both DPYD deficiency (OR 8.923; p = 0.006) and MIR27A rs895819 TC genotype (OR 3.865; p = 0.002). Conclusion: MIR27A rs895819 TC genotype is an independent risk factor for fluoropyrimidine-associated toxicity in the Greek population. Thus, MIR27A rs895819TC patients can be closely monitored for fluoropyrimidine-induced severe toxicity.

What is this summary about? To date, for cancer patients treated with fluoropyrimidines (capecitabine and 5-fluorouracil), analyzing DPYD gene can be used to guide the optimal dose of treatment in order to reduce the incidence of severe, even life threatening toxicity and thus, increase drug safety. However, the frequency of clinically significant DPYD variants is rare, below 5%, and there is therefore an urgent medical need to identify additional genes that can help in predicting response to fluoropyrimidines. Apart from changes in DPYD gene, noncoding RNAs modulate DPD enzymatic activity. MiR-27a is such a modulator. MIR27A rs895819 polymorphism affects miR-27a expression and is a potential candidate of fluoropyrimidine response. In this study, we have analyzed the association of MIR27A rs895819T>C polymorphism with fluoropyrimidine-induced toxicity in cancer patients. What were the results? MIR27A rs895819 TC genotype is associated with fluoropyrimidine-induced grade 3­4 toxicity, any grade toxicity and delayed drug administration or therapy discontinuation. Carrying MIR27A rs895819 TC genotype leads to over of threefold increased risk for grade 3­4 toxicity and can improve sensitivity of DPYD genotyping alone. What do the results mean? MIR27A rs895819 TC carriers should be closely monitored for fluoropyrimidine-induced severe toxicity. Fluoropyrimidine pharmacogenomics can help in improving drug safety and patient response.