To analyze ATM and CHEK2 genes for the presence of SNPs and their association with breast cancer. Breast cancer is a malignant tumour that starts in the cells of the breast. 10-15% of breast cancer cases have some family history of the disease, only 5% can be explained by rare, highly penetrant mutations in genes such as BRCA1 and BRCA2 (First-degree relatives of breast cancer patients have a 2- fold increase in risk over the general population). Breast cancer can be separated into different types based on the way the cancer cells look under the microscope. Risk factors could be genetic or environmental, or in most cases, a combination of the two. The higher rate of most breast cancers in monozygotic twins of case patients than in dizygotic twins or siblings suggests that most familial clustering is the result of inherited genetic factors rather than lifestyle or environmental factors. Some of this clustering can be explained by mutations in specific genes that confer high risk of disease. However, such susceptibility alleles are rare in the population.