“…Regarding the pretreatment group, 2.5% of the patients presented DPYD gene variants, a value somewhat inferior to that described in other European populations, in which the four variants combined were detected in about 5-10% of the patients in a pretherapeutic screening setting [20,29,31,32]. The frequency of DPYD variants can differ among populations, as previously described for the c.1905 + 1G>A variant, for which the incidence among European populations ranges from 0.7-3.5% [4,10,17,20,26,29,[31][32][33][35][36][37]. Likewise, the frequency of the c.2846A>T and c.1129-5923C>G variants also varies between populations, ranging from 0.4-3% to 2.4-6.2% in European populations, respectively [4,10,17,20,29,[31][32][33].…”