RESUMEN
BACKGROUND: CYP2D6 is an important cytochrome P450 enzyme. These enzymes catalyse the oxidative biotransformation of about 25% of clinically important drugs as well as the metabolism of numerous environmental chemical carcinogens. The most frequent null allele of CYP2D6 in European populations, CYP2D6*4, has been studied here in order to elucidate whether a relationship exists between this allele and the risk of developing breast cancer in a Spanish population. MATERIALS AND METHODS: Ninety-six breast cancer Spanish patients and one hundred healthy female volunteers were genotyped for the CYP2D6*4 allele using AmpliChip CYP450 Test technology. RESULTS: Homozygous CYP2D6*4 frequency was significant lower in breast cancer patients than in the control group (OR=0.22, p=0.04). The heterozygous CYP2D6*4 group also displayed lower values in patients than in controls but the difference was not significant (OR=0.698, p=0.28). Therefore, the presence of the CYP2D6*4 allele seems to decrease susceptibility to breast carcinoma in the selected population. CONCLUSIONS: A possible decreased transformation of procarcinogens by CYP2D6*4 poor metabolisers could result in a protective effect against carcinogens (AU)