P53 Protein Expression in a Population-Based Series of Primary Vulval Squamous Cell Carcinoma and Immediate Adjacent Field Change

Abstract

Objectives.Our aim was to study correlations between survival, disease recurrence, and p53 protein expression in a well defined population-based series of vulval squamous cell carcinoma and immediate adjacent epithelial skin changes. Methods.One hundred fifteen vulval squamous cell carcinoma were studied. Epithelial skin changes immediately adjacent to tumor were classified into nonneoplastic epithelial disorders (NNED) or vulval intraepithelial neoplasia (VIN). Archival specimens containing primary tumor and immediate adjacent skin were immunostained with a mouse monoclonal antibody to p53 protein. Results.p53 overexpression, defined as greater than 10% nuclear epithelial staining, was observed in 68% of tumors. Tumor immunostaining did not correlate with actuarial survival or disease-free interval. p53 overexpression was associated with a nonsignificant trend toward shorter disease-free interval in those tumors with nodal metastatic disease at diagnosis ( P= 0.07). The only clinicopathological variable found to correlate with p53 expression was tumor grade ( P= 0.002). Immediate adjacent abnormal skin changes were associated with p53 overexpression in 32% of cases. Adjacent normal skin did not immunostain for p53. p53 overexpression was most likely to occur in adjacent epithelial changes incorporating both NNED and high grade VIN ( P= 0.005). Patterns of epithelial p53 overexpression in adjacent abnormal skin were either basal or full thickness. Full thickness epithelial p53 overexpression was most likely to occur in those disorders containing VIN ( P< 0.0001). Positive immunostaining of adjacent skin abnormalities did not predict local tumor recurrence. Conclusions.This study demonstrates that although vulval squamous tumor p53 expression is not of prognostic significance, distinct immunostaining patterns can be observed in immediate adjacent skin. Vulval epithelial skin disorders displaying histological features of both NNED and VIN III may contain a profile of underlying molecular change which is of significance in subsequent tumor development.