ACE2 and COVID-19: Considering the crucial role of ACE2, TMPRSS2, and AAK1 in the SARS-CoV-2 invasion of target cells and intracellular transmission, performing an analysis of the expression and distribution characteristics and related biological processes of ACE2, TMPRSS2, and AAK1 in cancer patients can help us better understand the pathogenesis of their susceptibility to COVID-19 and better explore potential novel treatment strategies.