UBE2I and breast cancer: We observed a strong association between breast cancer occurrence and the G/A genotype (OR 5.03; 95 % Cl 3.05–8.28), A/A genotype (OR 11.3; 95 % Cl 4.24–30.3) and A allele (OR 6.86; 95 % Cl 4.43–10.6) of the c.73G>A polymorphism of the UBC9 gene.