Expression of topoisomerase IIalpha, Ki-67, proliferating cell nuclear antigen, p53, and argyrophilic nucleolar organizer regions in vulvar squamous lesions

It was the aim of this study to investigate the expression of topoisomerase IIalpha (topo IIalpha), Ki-67, proliferating cell nuclear antigen (PCNA), p53, and argyrophilic nucleolar organizer region (AgNOR) staining in normal vulvar epithelia (NE, N = 10), vulvar condylomas (VC, N = 24), vulvar intraepithelial neoplasia (VIN, N = 26), as well as squamous cell carcinomas (SCC, N = 22) of the vulva. Formalin-fixed, paraffin-embedded archival tissue sections were immunostained with monoclonal antibodies against topo IIalpha, p53, and PCNA, as well as an affinity-isolated prediluted ready-to-use Ki-67 antibody using a standard immunohistochemical method, and stained with a colloid silver solution for AgNORs. Immunostaining was quantitated by determining the percentage of positively staining nuclei in each sample to express the labeling indices (LIs) by counting the immunoreactive nuclei in 1000 epithelial cells per case for each antibody. In each specimen 200 nuclei were examined using a x100 oil emersion lens, and the mean number of AgNORs per nucleus (AC) was calculated. The LIs for topo IIalpha, Ki-67, and PCNA as well as ACs increased stepwise from NE to VCs, VIN lesions, and SCCs. In contrast to PCNA LIs and ACs, a consistent correlation in all four groups was found for Ki-67 and topo IIalpha, suggesting that the latter is a proliferation-associated marker in these tissues. p53 expression was seen 8.3% of VCs, 30.8% of VIN lesions, and 54.45% of SCCs. p53 LIs were not correlated with LIs for topo IIalpha or Ki-67 in SCCs. The LIs for topo IIalpha, Ki-67, PCNA, p53, and ACs were not related to tumor progression, FIGO stage, or tumor grade in SCCs. This study presents topo IIalpha and Ki-67 as useful proliferation-associated markers of vulvar epithelia.