Gefitinib and Erlotinib (first-generation TKIs) exhibited no efficacy in lung adenocarcinoma patients with KRAS mutations, which could have been due to downregulation of VEGFR-2 in H2170-ER cells compared to H358-ER cells when both cell lines were exposed to Erlotinib (Figure 2) [42]. This evidence concerns the gene KRAS and lung adenocarcinoma.