Abstract: Most common cancer among the women is breast cancer, it contributes about 30% all the cancer patients. Amazingly it very rare in men, it effects only 1% of all cancers in men. About 10% of breast cancers are genetically inherited, due to inherited germ-line mutations in high penetrance moderate penetrance and low penetrance breast cancer susceptibility genes. The remaining 90% of breast cancers are due to acquired somatic genetic and epigenetic alterations. There are many genes that are responsible for the breast cancer. For analyzing whether common variants linked to differential allelic expression, a list of genes are established on the basis of their involvement in cancer related pathways and mechanisms.