Breast cancer (BC) is one of the common malignant tumors of women in the world.The incidence rate of this cancer increased in frequency in the last years in Iraq. Many etiological agents are proposed to play a role inBC pathogenecity, one of these factors is genetic map of the patient. This is a study was carried out to investigate the possibleassociation of some gens like BRCA1 P53, KRAS AND HER-2in the pathogenesis of the disease. A total of 36 female patients with BC were studied, their ages range from 31-80 years with maximum age are between (50-59) years. Family history is positive in 31%of patients, and 77% of total breast cancer are infiltrative breast carcinoma. Two control groups were included in this study for comparison. •First group included (14) of dead female breast in which DNA were extracted from formalin soaked specimen for PCR-MULTIPLEX gene study. •Second control group, serum samples were bought from SIGMA (MILAN-ITALY) company for biosensor technique to determine HER- 2 concentration. DNA was extracted, and the gene study showed 8.3% have BRCA1 mutation of both axon (2, 20), and 30% of them have mutated P53 (P=0.012) and16% are mutated Kras axon (1, 2) and p value=0.0103. The different parameters of the assay were optimised and a first calibration was produced in buffer with good sensitivity (1.7 ng/mL) and reproducibility (average CV% = 7%). The reached sensitivity was comparable to the sensitivity of some commercial ELISA kit for HER2 (1.5 ng/mL) and it was adequate for the analysis of serum samples since 15 ng/mL was defined as the appropriate cut-off between normal and elevated serum HER-2 protein levels. For Her-2 concentration in bio sensor technique in serum 30% of the tested sample has elevated level (more than 15ng/ml).