Are p53 and MIB-1 overexpressed in cholesteatoma?

INTRODUCTION: There is controversy regarding the expression of p53 and MIB-1 in cholesteatoma.1 This study was instituted to study this. p53 is an intracellular protein which plays a critical role in control of the cell cycle at the G1 check point. MIB-1 is recognized as a marker of cellular proliferation. Using deep meatal skin controls, the question addressed was, 'are p52 and MIB-1 overexpressed in cholesteatoma'? METHOD: Immunocytochemistry using the avidin-biotin technique on frozen tissue sections with primary antibody to p53 (n = 17, controls = 17) and MIB (n = 17, controls = 7) was performed on cholesteatoma and deep meatal skin control specimens. Appropriate positive and negative controls were employed for each antibody. Slides were analysed in a blind fashion by two independent observers. Statistical analysis was performed using the Mann-Whitney test. RESULTS: Expression of p53 was minimal or absent in both cholesteatoma and controls. No significant difference in p53 expression was found between the two groups (P = 0.02). MIB-1 expression was higher in cholesteatoma than in controls, although this was not statistically significant (P = 0.09). CONCLUSION: This study did not demonstrate an increased expression of p53 cholesteatoma, indicating no evidence of a dysfunctional cell cycle. MIB-1 results showed a possible trend towards significance, which requires a more powerful study to evaluate this further. The probability that there is an increased rate of cellular proliferation in cholesteatoma, when compared to deep meatal skin controls, cannot be excluded.