Polymorphisms of HER2 Ile655Val and cyclin D1 (CCND1) G870A are not associated with breast cancer risk but polymorphic allele of HER2 is associated with nodal metastases.

The HER2 codon Ile655Val and Cyclin D1 (CCND1) G870A polymorphisms were analyzed in a hospital-based Malaysian population using PCR-RFLP method. Peripheral blood samples were collected from 230 breast cancer patients, and 200 normal and healthy women who had no history of breast disease or breast cancer. We evaluated the association between HER2 or CCND1 polymorphisms and breast cancer risk, and clinico-pathological parameters in the population. The genotype and allele frequencies of HER2 (P=0.163 vs P=0.0622) and CCND1 (P=0.377 vs P=0.284) polymorphisms were not significantly different between the breast cancer cases and normal subjects, respectively. Women who were Ile/Val heterozygotes (OR=1.48; 95% CI, 0.91-2.43), Val/Val homozygotes (OR=1.93; 95% CI, 0.51-7.77) and carriers of Val allele genotype (OR=1.53; 95% CI, 0.95-2.45) were not significantly associated with increased breast cancer risk. Similarly, women who were homozygous (OR=1.34; 95% CI, 0.77-2.34) or heterozygous (OR=0.98; 95% CI, 0.60-1.60) for A allele, or carriers of A allele genotype (OR=1.10; 95% CI, 0.70-1.73) were not associated with breast cancer risk. Analysis on clinico-pathological parameters showed that Val allele genotype was significantly correlated with nodal metastases but A allele genotype was not associated with any of the variables. Our findings suggest that the polymorphic alleles of HER2 and CCND1 may not play an important role as genetic markers for breast cancer risk, but presence of Val allele may be useful for tumor prognosis.