Immunohistochemical expression of p16INK4A protein as a helpful marker of a subset of potentially malignant oral epithelial lesions: study on a series with long-term follow-up

Montebugnoli L, Cervellati F, Cocchi R, Farnedi A, Pennesi M G, Flamminio F & Foschini M P (2010) Histopathology57, 528–534 Immunohistochemical expression of p16INK4A protein as a helpful marker of a subset of potentially malignant oral epithelial lesions: study on a series with long-term follow-up Aim: To examine a group of lesions that progressed to oral squamous cell carcinoma (OSCC) to determine whether p16INK4A expression is an early finding during malignant transformation, and whether immunohistochemical evaluation of p16INK4A is an appropriate prognostic marker. Methods and results: Twenty cases of OSCC were investigated. All cases had had a biopsy on the same site as OSCC performed at least 1 year before OSCC (range 1–11 years; mean 3.15 ± 3.1 years). Twenty specimens from normal oral mucosa served as controls. p16INK4A expression was evaluated by immunohistochemical analysis and cases showing >5% of stained cells were defined as ‘positive’. All 20 control cases were negative for p16INK4A. Oral lesions were p16INK4A-positive in nine cases and negative in 11. No significant relationship was found between p16INK4A positivity and the presence/absence of dysplasia. Among OSCC, nine tumours showed p16INK4A positivity and 11 showed negativity. A significant relationship (χ2 = 7.1; P