RESUMEN
The study aimed to examine the association between human leukocyte antigen [HLA] class II allele frequencies and breast cancer in Iranian women. A total of 100 patients with pathologically proven breast cancer who referred to Cancer Institute were randomly selected and compared with a group of age matched healthy blood donors [n = 80]. HLA class II alleles were determined by amplification of DNA followed by HLA-typing using sequence-specific primer [SSP] for each allele. The frequency of HLA-DQA1 0301 [P=0.001, OR=3.4] and HLA-DRB11303 [/M].02, OR=2.3] among breast cancer patients was significantly higher than those in control group. HLA-DQA 10505 [/M].003, OR=0.4], HLA-DRB11301 CP=0.002, OR=0.12] and HLA-DQA10101 [P=0.01, OR=0.21] alleles showed negative association with breast cancer. The findings suggest that HLA-DQA10301 allele is mainly associated with increased risk of breast cancer in Iranian female patients. HLA-DQA 10505 and HLA-DRB11301 alleles are suggested as protective genetic factors against breast cancer. The findings confirm that specific alleles of HLA class II influence breast cancer risk