The oncoprotein, gankyrin, is up-regulated in middle ear cholesteatoma

Gankyrin seems to be a better biomarker for cholesteatoma compared with Ki-67.

Gankyrin is an oncoprotein, and occurs in cancers but not in benign diseases. The goal of this study was to compare expression of gankyrin, p53, and a proliferation marker (Ki-67) in cholesteatoma and retroauricular skin (RAS), and to evaluate their significance as clinical parameters.

The levels of expression of gankyrin, Ki-67, and p53 in 10 cholesteatoma and 10 paired samples of normal RAS were evaluated by immunohistochemical staining and Western blot. The results were compared with clinical profiles to investigate a correlation.

The expression of gankyrin, Ki-67, and p53 proteins was observed in both basal and suprabasal layers of cholesteatoma. The intensity of gankyrin expression was 'positive' in two cases (20%) and 'strongly positive' in eight cases (80%); p53 expression in the suprabasal layer was 'positive' in 70% of cases; and the Ki-67 staining was 'focal' in 80% of cases. In RAS, these proteins were expressed dominantly in the basal layer. Western blot analysis showed that the gankyrin band was more intense in cholesteatoma than in RAS for three of four cases (p < 0.05). However, there was no significant difference in the expression of gankyrin, Ki-67, and p53 according to clinical variables.