Indeed, staining for SARS-CoV-2 N protein in different anatomical regions of the gastrointestinal tract of COVID-19 patients revealed positive signals in the glandular epithelium of the stomach, duodenum, and rectum, but not in the esophagus, which correlated with ACE2 expression of the respective tissue (Xiao et al., 2020). This evidence concerns the gene ACE2 and COVID-19.