At the experimental level, Choong and colleagues analyzed the expression of ACE2, TMPRSS2, and NRP1 proteins in RCC by immunohistochemistry of tissue microarray (TMA) by using 263 cases of CCRCC, 139 of pRCC, 18 of CHRCC, and human kidney tissue as controls [28]. The gene discussed is ACE2; the disease is renal cell carcinoma.