Non-small cell lung cancer component exists in small cell lung cancer Non-small cell lung cancer can convert to small cell lung cancer after TKI resistance Inactivation of Rb1 and TP53 may lead to eventual conversion of adenocarcinoma to small cell lung cancer Alveolar type II cells have the potential to develop into small cell lung cancer and EFGR mutated non-small cell lung cancer As two major histological subtypes of lung cancer, non-small cell and small cell lung cancer, due to their biological and However, just as the Taoist thought of yin and yang, I have you and you have me, some recent studies have shown that there is no insurmountable gap between non-small cell and small cell. The key points are excerpted and shared in this article. In recent years, the emergence of EGFR TKI has revolutionized the treatment of non-small cell lung cancer, but TKI resistance often occurs after about 1 year, and some of these patients are found to have a small cell component after biopsy. For the former, the article points out that in the current study, it can be determined that small cell lung cancer can be combined with other histological types of lung cancer (including large cell, adenocarcinoma, and squamous carcinoma), and for the latter, the article mentions that patients who are resistant to TKI therapy and have a histological conversion to small cell lung cancer. In the latter article, it was mentioned that the chance of drug resistance after TKI treatment and histologic conversion to small cell lung cancer was up to 14%, and it was found that this conversion occurred in EGFR mutant lung cancer, which still retained the EGFR positive mutation, but several studies found that their EGFR positive small cell lung cancer had low EGFR protein expression levels and EGFR was also in a low amplification state, so the efficacy of using EGFR TKI was The article points out that two studies on small cell lung cancer gene sequencing found that inactivation of Rb1 and TP53 may lead to conversion of adenocarcinoma to small cell lung cancer and that the MYC gene may be the driver gene of small cell lung cancer. In addition to genetic alterations in the conversion between non-small cell lung cancer and small cell lung cancer, is there also a common starting cell between the two? This question is also clearly answered in the article. The current study found that alveolar type II cells have the potential to develop into small cell lung cancer and EFGR mutated non-small cell lung cancer. The article concludes by stating that the treatment strategy should not neglect the treatment of small cell lung cancer, either in combination with adenocarcinoma or in transformation of adenocarcinoma into small cell lung cancer, as long as the small cell lung cancer component is present. Comment: At present, there are few reports on the transformation between non-small cell lung cancer and small cell lung cancer from clinical studies, and there are still many questions that need to be addressed, such as why EGFR is low in EGFR-positive small cell lung cancer and which subtype of non-small cell lung cancer is more likely to transform into small cell lung cancer. The era of targeting is no longer indistinct.