In the present study, we have addressed this issue by silencing podocalyxin expression in the highly aggressive triple-negative basal-like human breast cancer cell line, MDA-MB-231, or overexpressing it in a well-differentiated, ER-positive and PgR-positive, luminal-like human breast cancer cell line, MCF7 [23]. The gene discussed is ESR1; the disease is breast carcinoma.