EGFR and lung adenocarcinoma: Western blot analysis revealed the protein expression of epidermal growth factor receptor (EGFR) and pan-CK in Penl1 cells compared with HCC827 and H460 (lung adenocarcinoma cell lines; HCC827 was used as a positive control, and H460 was used as a negative control for EGFR-overexpression [16]) (Figure 2a).