Immunohistochemical analysis showed that lower EZH2 expression and higher LC3 expression were found in the resistant tumor tissues compared to parental sensitive cells, and the combined treatment of SAHA with gefitinib could reverse the decrease in EZH2 and increase in LC3 caused by gefitinib, which was consistent with the in vitro results (Figure 5C, Supplementary Figure S2B). This evidence concerns the gene EZH2 and neoplasm.