Briefly, the surface pool of Integrin β1 on the luminal breast cancer (BRCA) cell line, MCF7, was labeled on ice with an Alexa 488–conjugated antibody, and allowed to internalize for 15 min at 37°C, prior to fixation and immunolabeling of endogenous ErbB3. The gene discussed is ERBB3; the disease is breast carcinoma.