EGFR and non-small cell lung carcinoma: To explore the effects of Ca2+ on EGFR protein expression, NSCLC cell lines PC-9 (harboring an EGFR activating mutation, EGFR exon 19 del) or H1975 (harboring a TKI-resistant mutation, EGFRL858R/T790M) were treated with or without CaCl2.