On the other hand, down‐regulation of H19 combined with Gefitinib treatment significantly increased the levels of PTEN and PDCD4, while decreased the expression of NFIB when compared with down‐regulation of H19 alone treatment, which suggested that Gefitinib might inhibit PTEN signalling pathway in NSCLC in vivo. This evidence concerns the gene NFIB and non-small cell lung carcinoma.