TP53 and renal cell carcinoma: Previously, Kang and Ku et al. found that, in RCC cell lines, transglutaminase 2 (TGase 2), an enzyme regulating covalent crosslinking between protein glutamine and lysine residues, cross-linked p53 into the autophagosome, thereby down-regulating p53 (J. H. Kang et al., 2016; Ku et al., 2013).