RESUMEN
Consensus guidelines for genotype-guided fluoropyrimidine dosing based on variation in the dihydropyrimidine dehydrogenase (DPYD) gene before treatment have been firmly established. The prior pharmacogenetic report avoids the serious toxicity that inevitably occurred in a non-negligible percentage of the treated patients. The precise description of the allelic distribution of the variants of interest in our reference populations is information of great interest for the management of the prescription of these antineoplastic drugs. We characterized the allelic distribution of the UGT1A1*28 variant (rs3064744), as well as the DPYD*2A (rs3918290) variant, c.1679T>G (rs55886062), c.2846A>T (rs67376798) and c.1129-5923C>G (rs75017182; HapB3) in series of 5251 patients who are going to receive treatment with irinotecan and fluoropyrimidines, representative of Valencian, Aragonese and Western Andalusian populations.