B2M and nonpapillary renal cell carcinoma: The different levels of TP53 expression for ACTB, GAPDH, and B2M in relation to number of analyzed cases should exclude those genes from RG panel for ccRCC, since the expression results of TP53 cannot change by the increased number of analyzed samples (i.e., under expression of TP53 when 12 T/C were selected versus overexpression of TP53 when 70 T/C was analyzed).