To determine whether lysosomotropic agents are cytotoxic to breast cancer cells alone or in combination with chemotherapeutic agents, MDA MB-231 cells (triple negative breast cancer cell line) were treated with siramesine, cytotoxic agents (etoposide, cisplatin and taxol), anti-estrogen therapy (tamoxifan), and targeted chemotherapy, lapatinib (tyrosine kinase inhibitor against ErbB1/2), respectively. This evidence concerns the gene EGFR and breast cancer.