Aminopeptidase A expression in cervical neoplasia and its relationship to neoplastic transformation and progression

Aminopeptidase A (AP-A) is a cell surface metallopeptidase which specifical ly cleaves the amino-terminal acidic residue from peptide substrates such a s angiotensin II. AP-A is identical to the differentiation-related antigen, murine BP-1 or human kidney gp160, and is involved in regulating cell diff erentiation and/or neoplastic transformation of certain normal and transfor med cells. We examined expression of AP-A in premalignant and malignant les ions of the uterine cervix, and investigated whether its expression was rel ated to disease progression and neoplastic transformation. Formalin-fixed, paraffin-embedded tissue sections including 14 cervical intraepithelial neo plasms (CIN) and 23 invasive squamous cell carcinomas (SCC) were immunohist ochemically evaluated. AP-A was localized in the basal cell layer in normal squamous epithelium. In GIN, AP-A expression was found on dysplastic cells , and increased with the severity of the precancerous lesions. In invasive cancer, 18 of 19 non-keratinizing-type SCCs and none of 4 kera- tinizing-ty pe SCCs expressed AP-A. In addition, AP-A immunoreactivity was significantl y correlated with proliferating cell nuclear antigen expression in both CIN and SCC cases. Furthermore, angiotensin II type 1 receptor was present in all AP-A-positive SCCs. These results indicate that AP-A is upregulated as the lesion progresses toward carcinoma in the cervical epithelium, and sugg est that AP-A may play a regulatory role in neoplastic transformation and d isease progression in cervical neoplasms and may serve as a potential tumor marker during cervical neoplasia development. Copyright(C)2000S.KargerAG,B asel.