In recent years, with the improvement of molecular biology technology and the further understanding of tumor pathogenesis at the molecular level of cell receptors and proliferation regulation, people have started to target cell receptors, key genes and regulatory molecules, and call it “molecular targeted therapy”. Compared with conventional chemotherapy, which does not selectively kill cells, molecularly targeted therapy works on tumor cells and improves the precision of tumor treatment. Instead of targeting tumor cells, molecularly targeted drugs target molecules specifically or highly expressed on tumor cell membranes or within cells, which can not only act more specifically on tumor cells to block their growth, metastasis or induce apoptosis, but also reduce the killing effect on normal cells. In recent years, novel molecular targeted drugs targeting signal transduction, growth factors and their receptors in lung cancer treatment have shown promising efficacy. I. EGFR-targeted lung cancer therapy Epidermal growth factor receptor is the expression product of the proto-oncogene C-erbB-1. 40%-80% of non-small cell lung cancers overexpress EGFR. EGFR forms dimer with ligand to activate tyrosine kinase, causing tumor cell proliferation, division and immortalization, therefore, EGFR-targeted therapy is widely used in lung cancer treatment. Gefitinib Gefitinib is an orally available small molecule inhibitor of EGFR TK that primarily blocks cancer cells in the G1 phase. Gefitinib is used to treat NSCLC with rapid onset of action and objective results. However, the clinical study of gefitinib also brings us many questions: why is it effective and particularly effective in only some patients? Why does it work only for a short period of time? What patients are suitable for gefitinib? What kind of biological indicators can predict the efficacy and usefulness? It is worthwhile to continue to study this in depth in the future. Erlotinib Erlotinib is an effective, reversible, selective HER1/EGFR TK inhibitor. A large phase III clinical trial showed that patients with advanced NSCLC treated with erlotinib monotherapy had significantly longer median survival, disease-free progression, and disease remission compared to the placebo group; 1-year survival and remission rates were significantly higher. This phase III trial brought to light the value of oral erlotinib monotherapy in the treatment of refractory advanced NSCLC. Is erlotinib combined with chemotherapy for first-line treatment equally effective? Two phase III clinical studies, the former with carboplatin and paclitaxel and the latter with cisplatin and gemcitabine based in combination with erlotinib compared to the placebo group, suggest that the combination regimen did not show superiority in terms of remission rates and survival. The combination regimen is not currently recommended as first-line treatment. The most common adverse reactions after erlotinib treatment are rash and diarrhea, and the most serious one is ILD, which is life-threatening in severe cases. If ILD is diagnosed, erlotinib treatment should be interrupted and treated accordingly. Imatinib Imatinib is a TKc-kit inhibitor. A recent phase II randomized clinical trial containing 68 patients investigated the role of imatinib in combination with chemotherapy in the first-line treatment of progressive small cell lung cancer. Carboplatin + irinotecan + imatinib was used in the tested patients, resulting in a remission rate of 66%, PFS of 5.7 months, median survival of 6.3 months, and granulocyte deficiency of 10% and 6% in 3rd and 4th degree, respectively, suggesting that imatinib in combination with chemotherapy is safe and effective for extensive-stage small cell lung cancer. Cetuximab Cetuximab is an EGFR monoclonal antibody. In a randomized phase II clinical trial, Rosell et al. divided 62 patients with stage IIIB and IV EGFR+ NSCLC who had not received prior chemotherapy into two groups and gave NP regimen (cisplatin + vincristine) chemotherapy and NP regimen combined with cetuximab, respectively, and the results showed that the efficiency of the chemotherapy and combination groups were The results showed that the efficiency of the chemotherapy group and the combination group were 32% and 59% respectively, and the phase III clinical study is underway. Vascular endothelial growth factor plays an important role in the growth of primary tumors, the formation of metastatic tumors and the growth of blood vessels. In most human tumor tissues (including lung cancer), the expression of VEGF is considerably higher than that of other normal tissues. Bevacizumab Bevacizumab is a recombinant humanized anti-VEGF monoclonal antibody. in a phase III randomized clinical trial reported by the American Society of Clinical Oncology in 2005, patients with NSCLC were randomized to receive first-line chemotherapy drugs in combination with or without bevacizumab. The results found that the group treated with bevacizumab had significantly better efficiency, PFS and stability than the control group, with overall survival improving from 10.2 months to 12.5 months. As a result, the U.S. FDA approved a new two-drug regimen of bevacizumab combined with platinum-containing agents as the standard first-line treatment option. The results of this study have changed the standard first-line treatment regimen for NSCLC and are far-reaching, drawing widespread attention. Zactima ZD6474 is a synthetic anilinoquinazoline compound with high solubility and bioactive effects that selectively inhibits VEGFR-1, VEGFR-2, VEGFR-3, and also inhibits EGFR to some extent. The recommended oral dose of this drug in clinical phase II trials is 100-300 mg/d. Sunitinib Sunitinib is a small molecule TK inhibitor that binds to VEGFR tyrosine residues after phosphorylation and inhibits signaling. It is primarily metabolized by the liver and has a long half-life without cumulative effects. Currently, the recommended oral dose in clinical phase II trials is 50 mg/d for 4 weeks with a 2-week off period. Sorafenib Sorafenib inhibits both Raf kinase and VEGFRs, including VEGFR-2, VEGFR-3, PDGFR, and c-Kit. Vascular endothelial inhibitors Vascular inhibitors and endothelial inhibitors are newly discovered highly potent and specific vasopressors. To verify the role of recombinant human vascular endothelial inhibitor in combination with chemotherapy in advanced NSCLC, a randomized, double-blind, placebo parallel-controlled, multicenter phase III clinical trial was conducted by Sun Yan and other Chinese scholars from April 2003 to June 2004 to evaluate the efficacy and safety of NP regimen combined with vascular endothelial inhibitor versus NP combined with placebo in the treatment of advanced NSCLC. The results suggest that the combination of vascular endothelial inhibitor and NP regimen can improve the response rate and median time to tumor progression in advanced NSCLC with better safety, and has better clinical application prospects. At present, most of the anti-angiogenic therapeutic measures are still in experimental studies or clinical trials, and there are still many problems. For example, after anti-angiogenic treatment, tumor cells can develop tolerance, and after stopping the drug, the tumor will start to grow again, and the comprehensive evaluation of its efficacy also needs to be confirmed by long-term clinical observation. Although anti-angiogenic therapy is still in the early stage of trial, with the in-depth research on the mechanism of angiogenesis and tumor development, we can optimistically expect that anti-angiogenic therapy will receive more and more attention in lung cancer treatment and become one of the important measures in the comprehensive treatment of lung cancer. Reviewing the progress of targeted therapy for lung cancer, many questions need to be solved: how can targeted therapeutic drugs act only on tumor cell targets, but not on the same targets of normal cells? How to understand the effect of “targeted drugs” on lung cancer by testing some indicators in clinical practice? How to select the combination of “targeted drugs” and other therapies to produce additive or synergistic effects? How to determine the optimal biological dose of “targeted drugs”? Due to the slow progress of chemotherapy and radiotherapy for advanced lung cancer, people are increasingly concerned about targeted therapy for lung cancer, which is a new field of lung cancer treatment.