The objective of this work was also to investigate the expression patterns of the most clinically critical molecules for breast cancer such as ER, PR and HER2, as well as others involved in cell cycle, angiogenesis and cellular migration of invasive breast cancer cells, frequently expressed in neoplastic cells with metastatic properties and enzymes that play a key role in the metabolism of drugs and environmental chemicals. The gene discussed is ERBB2; the disease is breast cancer.