EGF and non-small cell lung carcinoma: To clarify pEGFR internalization, confluent NSCLC cell lines were cultured in serum-free medium for 3 h, and then EGFR phosphorylation was induced by incubation with EGF (100 ng/ml) for 15 min on ice in a binding medium (1 mg/ml bovine serum albumin (BSA) in RPMI medium).