Currently, cancer becomes world’s problem including in Indonesia. Breast cancer is a disease that commonly diagnosed among women aÑ–er cervical and ovary cancer. South-East Asia, Indonesia places the first rank for breast cancer incident with 16.6 died per 1.000.000 cases. Breast cancer is ferocity in breast tissue that can origin from epithelium duct or lobulus. НLs disease is caused by multiple risk factors and early detection is an easy way to prevent women from this disease such as self-examination of the breast. Many research have focused on breast cancer mainly to find the cause, the drug for the curing, and biomarkers for its diagnosis. Нe status of breast cancer can be determined by status of molecular marker expressed on its plasma membrane such as Estrogen Receptor (ER), Progesteron Receptor (PR) and Human Epidermal Growth Factor 2 (HER2). HER2/neu is family of EerbB protein or alternative named CD340. НLs gene located on chromosome 17 (17q11.12) and have function in control breast cells development. НLs protein was expressed on membrane plasma of epitel cells and in the normal condition this protein regulate the population of breast cells. Defect in this protein can induce abnormality of breast cells proliferation that lead to carcinogenesis.