KI-67 EXPRESSION IN VULVAR CARCINOMA

The proliferative activity of invasive squamous cell carcinoma of the vulva was examined using a Ki-67 equivalent monoclonal antibody (MIB1) , which gives a strong immunoreaction in paraffin-embedded tissue. Qua ntitation of Ki-67 immunostaining was accomplished by image analysis. Ki-67 immunostaining revealed two general patterns of reactivity in vu lvar tumors: (a) a diffuse distribution of Ki-67 positive nuclei withi n the tumor mass and (b) a localized distribution of Ki-67 positive nu clei staining predominantly basilar components of tumor aggregates. Th e distribution of localized and diffuse patterns did not differ signif icantly between various clinicopathologic categories (age, histologic type and grade, FIGO stage, and lymph node status). However, the survi val times for patients with a diffuse Ki-67 labelling pattern tended t o be shorter than those for patients with a localized pattern. Surviva l curves based on the median positive nuclear area (PNA) calculated by image analysis did not differ significantly. Thus, the pattern of Ki- 67 immunostaining, rather than the percentage of PNA, may have prognos tic significance in vulvar squamous cell carcinoma.