Purpose: The aim was to verify the potential association between CYP19A1 genetic polymorphisms and clinical outcome of hormone therapy in hormone receptor (HR)-positive early breast cancer.
Methods: Genotyping for CYP19A1 rs4646 (C/A) polymorphism was performed on 287 women with HR-positive early breast cancer. Associations were evaluated between CYP19A1 rs4646 genotypes and disease-free survival (DFS).
Results: Totally, women with the minor allele (AA or AC) had an improved DFS when compared with those carrying the homozygous common allele (CC) (AA or AC vs. CC: 62.7 months versus 55.6 months; Hazard ratio (HR), 0.745; 95% CI, 0.562-0.988; P=0.04). The difference was further demonstrated by multivariate analyses (HR, 0.681; 95% CI, 0.506-0.917; P=0.011). In premenopausal women, AA genotype was associated with a prolonged DFS (AA versus CC or AC: 98.2 months versus 56.2 months; HR, 0.425; 95% CI, 0.198-0.914; P=0.024). In addition, women with the A allele had an improved DFS when compared with those carrying the homozygous C allele (AA or AC vs. CC: 62.7 months versus 55.6 months; HR, 0.709; 95% CI, 0.516-0.975; P=0.033). These findings were further confirmed by the Cox regression model (HR, 0.336, 0.670; 95% CI, 0.160-0.836, 0.479-0.938; P=0.017, 0.019). In postmenopausal women, rs4646 genotypes were significantly associated with DFS (AA versus AC versus CC: 32.7 months versus not reached versus 56.3 months; P=0.011). Women carrying AA variant had a poorer DFS than those with CC or AC genotypes (32.7 months versus 70.6 months; HR, 3.613; 95% CI, 1.380-9.457; P=0.005). Furthermore, being adjusted by the patients features in multivariate analyses, AA genotype remained an independent prognostic factor for DFS (HR, 3.614; 95% CI, 1.308-9.991; P=0.013).
Conclusions: The homozygous minor allele (AA) of CYP19A1 rs4646 is significantly associated with improved clinical outcome of hormone therapy in premenopausal HR-positive early breast cancer patients, but with a worse impact on postmenopausal women. The findings are novel, if confirmed, genotyping for CYP19A1 rs4646 polymorphism may provide predictive information for better selection of endocrine treatment.
Keywords: Breast cancer; aromatase; genetic polymorphisms; predictive role.