Then, we knockdown TROY by siRNA, and the results showed that TROY siRNA can effectively reduce TROY protein expression (Figure 4B), and cell growth was significantly reduced in TROY knockdown HCC827/GR cells when treated with gefitinib (Figure 4C), indicating that TROY is one of the reasons for gefitinib acquired resistance in NSCLC. This evidence concerns the gene TNFRSF19 and non-small cell lung carcinoma.