CYTOKERATIN SUBTYPES AND INVOLUCRIN IN SQUAMOUS-CELL CARCINOMA OF THEVULVA - AN IMMUNOHISTOCHEMICAL STUDY OF 41 CASES

Background. Histologic grade seems to be of limited prognostic signifi cance in patients with vulvar carcinoma. However, the study of cytoker atin expression is of potential interest because it allows a more prec ise evaluation of the degree of squamous differentiation. This study w as was conducted to investigate whether differences in cytokeratin exp ression exist between normal vulvar epithelium and vulvar carcinoma an d whether these differences are prognostically significant. Methods. T he expression of several differentiation markers, i.e., cytokeratin (C K) 10, CK 13, and involucrin, was studied in samples of 41 vulvar carc inomas. The expression of CK 8, 10, 13, and 14 was compared with CK ex pression in normal vulvar epithelium and was correlated with tumor gra de and tumor growth pattern. Tumor growth pattern was considered type A if infiltrating tumor cell nests showed a layer of small, basaloid c ells bordering the surrounding mesenchymal tissue and was considered t ype B if this was not the case. Prognosis was based on whether disease recurred or not. Results. Sixteen patients had disease recurrence. No prognostic significance of tumor grade was found. Tumor growth patter n was prognostically significant: in patients with a type A tumor, rec urrence was observed less often than in patients with a type B tumor ( P = 0.03). Cytokeratin 14, typical for basal cells of normal vulvar ep ithelium, was expressed in all tumors, whereas CK 8 was not expressed in any tumor. A relationship between tumor growth pattern and the conc ordant expression of differentiation markers was observed: in 55% of t ype A tumors and in no of type B tumors, concordant expression of CK 1 0, CK 13, and involucrin was found. Conclusion. The expression of diff erentiation markers in vulvar carcinoma is related strongly to the tum or growth pattern, and this pattern is prognostically significant.