Early acquisition of gelatinolytic activity in carcinogenesis of the uterine cervix.

Film in situ zymography is a newly developed technique for detecting in situ gelatinolytic activity. Using the film in situ zymography method to stamp preparations, we evaluated the gelatinolytic activity in early stage cervical neoplasia and invasive squamous cell carcinoma. To determine the sensitivity of film in situ zymography for detecting gelatinase expression, slides made from stamps of 50 specimens resected from the uterine cervix, including early invasive carcinoma (FIGO Ia1 and Ib1) and cervical intraepithelial neoplasia (CIN) were examined by film in situ zymography. The specimens were also examined immunohistochemically with regard to mitotic activity and gelatinase expression. Gelatinolytic activity was subdivided into two patterns, the homogeneous pattern and the heterogeneous pattern. The homogeneous pattern consisted of circumscribed areas around atypical cell clusters; these areas were composed of homogenously digested full-thickness collagen, whereas the heterogeneous pattern consisted of spottily digested areas of superficial collagen around atypical cell clusters. All invasive carcinomas (8/8 cases) and carcinoma in situ (14/14 cases) were positive for gelatinolytic activity, and 33.3%(5/15 cases) of the specimens of CIN-1, CIN-2, and severe dysplasia were also positive. All invasive carcinomas and 6 of 14 carcinoma in situ (43%) showed homogenous pattern, and the other positive specimens showed heterogenous pattern. The MIB-1 index was 33.8% in invasive carcinoma, increasing stepwise from dysplasia to carcinoma. Matrix metalloproteinase-2 immunostaining was positive in 4 of 8 cases of invasive carcinoma and generally stained the stromal area around the tumor nest. These results indicated that matrix metalloproteinases are functionally activated even in carcinoma in situ and in cervical intraepithelial neoplasia of the uterine cervix not showing invasive growth histologically. Film in situ zymography can detect with sensitivity the invasive potential of carcinoma in situ and cervical intraepithelial neoplasia. An analysis combining cytological examination and film in situ zymography is a potentially useful tool for estimating invasive activity.