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

Abstract

CONCLUSION: Gankyrin seems to be a better biomarker for cholesteatoma compared

with Ki-67. OBJECTIVE: 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. METHODS: 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. RESULTS: 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.