TP53 and neoplasm: In addition, immunohistochemistry of formalin-fixed paraffin-embedded (FFPE) sections from cell-derived xenografts showed that tumor-bearing ILK KO cells consistently exhibited increased SA-β-Gal staining, nuclear expression of p21, p16, p53, and pγH2AX, which facilitates specific DNA repair complexes during DNA damage (Fig. 1G, H).