Among these 13 genes, we focused on CDKN1A whose gene product acts as a cell cycle regulator being involved in genomic stability [28] for the following reasons: (i) according to the Human Protein Atlas database for several proteins (PAOX, FBXL15, RAB37, C21orf2) antibodies suitable for immunohistochemical staining are not available or unspecific; (ii) all proteins but CDKN1A are either not or only weakly expressed in renal cell carcinoma, which significantly hampers reliable TMA expression analysis. This evidence concerns the gene CDKN1A and hereditary clear cell renal cell carcinoma.