Fig. 5

HAT p300, histone residues H3AcK14, and H3AcK18 mark renal clear cell carcinoma tumor grade progression. a Histograms show the level of histone H3AcK18 and H3AcK14 normalized to unmodified UMH3 found in normal (white) and tumor tissues (black) in ccRCC patients at different grade. b Histograms show the percentage of positive nuclei, evaluated in parallel by immunohistochemistry with anti-p300, anti-H3AcK18, and anti-H3AcK14 antibodies in cancer and paired normal tissue sections from 70 ccRCC specimen (Table 2). When grouped by differentiation grade (G1, G2, and G3), p300 and anti-H3AcK18 show a symmetrical and significant lower percentage of positive nuclei at G1 with respect to G2-G3 ccRCC and to their paired normal tissues. On the contrary, H3AcK14 displays significant increase of positive ccRCC cells at G1 decreasing through G2 and G3 versus the percentage found in the paired normal tissue. c Immunostaining of two representative G2 ccRCC cases (nos. 39 and 37) showing opposing behavior of p300 and H3AcK18 vs H3AcK14 expression. High nuclear expression of p300 is accompanied by a cytoplasm positivity in case no. 37. Avidin Biotin Immuno-peroxidase staining; enlargement 400×