Dear Editor, COVID-19 associated with SARS-CoV-2 virus is an ongoing global pandemic. 1 Although great efforts have been made, the COVID-19 situation is still very serious due to the rapid mutation rate of SARS-COV-2 and the increase of drug resistance. 2 Patients with lung cancer are more susceptible to COVID-19 because of their immunosuppressed state and fragile lung tissue. 3,4 angiotensin converting enzyme 2 (ACE2) has been confirmed to be the key entry site for the SARS-CoV-2 virus 5 ; however, the roles of ACE and TMEM27, the other two genes in ACEs gene family (ACEs) with high homology to ACE2, in lung cancer and COVID-19 have not been entirely clarified.As shown in Figure 1, data related to ACEs, SARS-CoV-2 and lung cancer were obtained from several databases. The relationship among the three was analyzed to provide ideas for prevention and control of SARS-CoV-2 infection of lung cancer patients. The transcriptional levels of ACEs in 20 cancers were compared to transcription profiles in normal tissues. The dates showed that the transcriptional level of ACE was downregulated in four studies, whereas transcriptional levels of ACE2 and TMEM27 were only one study elevated in patients with lung cancer (Figure S1, Table S1). And we further revalidated the transcription level of ACEs in lung cancer patients in UALCAN database. It was found that ACE was dramatically downregulated in lung tumor tissues (Figure S2A,B), whereas ACE2 was at a high transcriptional level in lung tumor tissues (Figure S2C,D). TMEM27 was overexpressed in lung adenocarcinoma (LUAD), while it was downregulated in lung squamous carcinoma (LUSC) (Figure S2E,F). We further checked the protein expression levels of ACEs in lung cancer (Figure S3A-C).Then, the relationship between transcriptional levels of ACEs and the clinicopathological parameters of lungThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.