CDH1 and COVID-19: Immunofluorescence analyses identified increased nuclear expression of the cyclin-dependent kinase inhibitor p21, a marker of senescence, in vascular endothelium and hyperplastic and metaplastic E-cadherin–labeled epithelial cells in lung tissue from patients with COVID-19 compared to endothelial and epithelial cells in normal lungs (Fig. 7, A and B).