To confirm our findings, we examined FOXD1 expression levels in a panel of breast cancer cell lines, including three luminal lines (MCF7, T47D, and YMB1), four HER2-amplified lines (BT474, SKBR3, MDA-MB-361, and MDA-MB-453), and six basal lines (BT549, Hs578T, MDA-MB-231, BT20, HCC1954, and HCT1937). The gene discussed is ERBB2; the disease is breast cancer.