Quantitation of proliferation-associated markers Ag-NOR and Ki-67 does not contribute to the prediction of lymph node metastases in squamous cell carcinoma of the vulva

Abstract A key prognostic parameter for vulvar carcinoma is the presence of lymph node metastases. Determination of proliferation markers has been suggested as a method to predict lymph node metastases in several tumor types. If this were true in vulvar carcinomas, reduced surgical therapy for patients with low-risk vulvar carcinoma could be considered. The authors analyzed whether the proliferation-associated markers silver nucleolar organizer region (Ag-NOR) and Ki-67 are predictors for inguinofemoral lymph node metastases in women with vulvar carcinoma. The authors also analyzed whether these proliferation markers are interrelated. Data were obtained from samples of 145 patients with T1/T2 squamous cell carcinoma of the vulva who were treated with vulvectomy and bilateral lymphadenectomy. None of these patients received preoperative therapy, and the invasion depth of the tumors was more than 1 mm. The median age was 71 years. The group consisted of 67 patients with differentiation grade 1, 64 with grade 2, and 18 with grade 3; 22% (15 of 67) of the patients with grade 1, 45% (29 of 64) with grade 2, and 43% (six of 14) with grade 3 had lymph node metastases. Formalin-fixed, paraffin-embedded sections were stained for proliferation markers Ag-NOR and MIB-1 (an equivalent of Ki-67 for fixed material). Both parameters were scored at the tumor stroma interface. Ag-NOR number and area were quantified by interactive image analysis and Ki-67 index was scored microscopically with a grid. No relation was found between Ki-67 or Ag-NOR and lymph node metastases. A relation was found between Ki-67 and mitotic index (MI), but not between Ag-NOR and MI or Ki-67 index. Therefore, it is questionable whether Ag-NOR is, indeed, a marker for proliferation. The authors conclude that quantitation of Ki-67 and Ag-NOR does not contribute to the prediction of inguinofemoral lymph node metastases in squamous cell carcinoma of the vulva.