5-Fluorouracil toxicity-attributable IVS14 + 1G > A mutation of the dihydropyrimidine dehydrogenase gene in Polish colorectal cancer patients.

DPYD gene encodes dihydropyrimidine dehydrogenase which is the initial and rate-limiting enzyme in the metabolism of 5-fluorouracil (5-FU). The aim of our study was PCR-RFLP based-genetic testing for the most common 5-FU toxicity-attributable IVS14 + 1G > A DPYD mutation (DPYD()2A) in 252 Polish colorectal cancer (CRC) patients treated with this adjuvant chemotherapeutic regimen after surgery. The DPYD()2A allele was identified only in one patient: a male who was one of 4 CRC patients suffering from grades 3-4 myelotoxicity upon 5-FU chemotherapy. We conclude that IVS14 + 1G > A DPYD (DPYD(*)2A) variant occurs in the Polish population and is responsible for a significant proportion of life-threatening toxicity of 5-FU.