Pairwise analysis showed that combinations of the ERalpha G allele with the homozygous Trp genotype of CYP19A1 codon 39 (rs2236722), the methionine (Met) allele of COMT codon 158 (rs4680) or Pro allele of p53 codon 72 (rs1042522) were more frequent in ER-positive than ER-negative breast cancer, especially in patients less than 50-year old.