In squamous cell carcinoma of the vulva, overexpression of p53 is a late event and neither p53 nor mdm2 expression is a useful marker to predict lymph node metastases

To offer more tailored treatment to individual patients with squamous cell carcinoma of the vulva, more accurate prediction of lymph node metastases is required. As p53 and mdm2 are genes known to be involved in the development of other tumours, we studied expression of p53 and mdm2 in carcinogenesis of squamous cell carcinoma of the vulva and their clinical relevance. Archival material of 141 T1 and T2 vulvar tumours were used. Of the 141 primary tumours, the corresponding 39 lymph node metastases (LNM) were studied, and in 90 cases the pre-existent epithelia adjacent to the tumour (EAT) and in 14 cases vulvar intraepithelial neoplasia adjacent to the tumour (VIN) was also investigated. Detection of p53 and mdm2 protein was immunohistochemically performed. Scoring categories were: negative (1); weakly positive (2); moderately to markedly positive (3); and markedly positive (4). Overexpression of p53 was seen in 56% of the LNM, 39% of the primary tumours, 21% of the VIN lesions and 0% in the group of EAT. No relation was found between overexpression of p53 in the primary tumour and LNM. Expression of mdm2 was seen in 14% of the primary tumours, of which four cases were marked positive. In the group of LNM no mdm2-positive staining was observed. In the group of EAT, 25% was mdm2-positive, of which six cases were marked positive. In the group of VIN, 36% showed moderate (score 3) mdm2 expression. No relation was found between expression of mdm2 and LNM. In squamous cell carcinoma, overexpression of p53 is a late event in carcinogenesis. Marked expression of mdm2 is rarely seen in vulvar carcinomas, indicating that aberrant p53 cannot induce mdm2 expression. LNM cannot be predicted by detection of these proteins. © 1999 Cancer Research Campaign