Loss of TRPML1 impairs the growth of melanoma18 and reduces cell proliferation, cell viability and tumor growth in the MDA-MB-231 breast cancer cell line, a highly aggressive, invasive and poorly differentiated triple-negative breast cancer (TNBC) cell line lacking estrogen and progesterone receptor expression as well as HER2 (human epidermal growth factor receptor 2) amplification18. The gene discussed is ERBB2; the disease is breast cancer.