ACE2 and cancer: We first confirmed that the top 100 central genes of the activated and repressed TopNets of the same cell line were disjoint, with a few exceptions: out of 100 genes, 1 is common in Calu3 cell line, 2 in A549, 3 in A549 with high ACE2 expression, and 5 in the Vero cell line, suggesting dual activation and repressive roles of certain key genes; for instance, ATM, a protein kinase which plays key roles in many processes such as cell cycle progression, cell metabolism and growth, oxidative stress and chromatin remodeling, and is upregulated as well as downregulated in different cancers (41).