EGFR and non-small cell lung carcinoma: Gefitinib at 16 μmol/L had no effect on PC-9/AB2 cell viability; however, the combination of PD 0332991 at 8 μmol/L and gefitinib at 16 μmol/L inhibited the growth of PC-9/AB2 cells (Figure 1D), suggesting that PD 0332991 has the potential to reverse EGFR-TKI resistance in NSCLC cells.