HLA-DRB1,-DQA1 and -DQB1 allele and haplotype frequencies in female patients with early onset breast cancer.

Based on the reports, few HLA class II alleles are associated with susceptibility or protection in breast cancer. Here we investigate the association between HLA class II alleles and breast cancer in Iranian women. 100 patients with pathologically proven breast cancer who referred to Cancer Institute were randomly selected and compared with a group of 80 healthy blood donor subjects. The patients were studied in two groups, group 1 includes patients aging 40 years or younger and group 2 include patients aging over 40 years. HLA class II alleles were determined by amplification of DNA followed by HLA-typing using sequence-specific primer (SSP) for each allele. In group 1, the most frequent alleles were HLA-DQA1*0301 (P = 0.002, OR = 3.3) and HLA-DQB1*0302 (P = 0.04, OR = 2.8). In group 2, the following alleles increased significantly than those in controls including HLA-DQA1*0301 (P = 0.001, OR = 3.4) and HLA-DRB1*0301 (P = 0.04, OR = 2.3). In complete group of patients, the frequency of HLA-DQA1*0301 (P = 0.001, OR = 3.4) and HLA-DRB1*1303 (P = 0.02, OR = 2.3) increased significantly than those in control group. HLA-DQA1*0505, HLA-DQA1*0101, HLA-DRB1*1301and HLA-DRB1*0101 alleles showed negative association with breast cancer. Our findings suggest that HLA-DQA1*0301 allele is mainly associated with increased risk of breast cancer including early-onset of the disease. HLA-DQA1*0505 and HLA-DRB1*1301 are involved in protection. We conclude that specific alleles of HLA class II influence breast cancer risk.