We next investigated TOM1L1 role in breast cancer by manipulating its expression level in ERBB2+/ER+/TOM1L1− SKBR3 cells (by overexpression) and in ERBB2+/ER+/TOM1L1+ BT-474 cells (by short interfering RNA (shRNA)-mediated silencing). The gene discussed is ERBB2; the disease is breast cancer.