A quantitative evaluation of active gelatinolytic sites in uterine endometrioid adenocarcinoma using film in situ zymography: association of stronger gelatinolysis with myometrial invasion.

Collagen matrix degradation by malignant tumor cells plays an essential role in the process of tumor invasion and metastasis. The purpose of this study was to detect in situ gelatinase activity in endometrioid adenocarcinomas of the uterine corpus. In order to carry out quantitative evaluation, autoexposure time (AET) on gelatin-coated film (film in situ zymography: FIZ) was measured. The gelatinase activity was located primarily within cancers and was prominently suppressed by the addition of a chelating agent to the film. This suggests that matrix metalloproteinases (MMPs) play an important role in the gelatinase activity. The gelatinase activity in the normal endometrium is almost negligible, despite positive immunoreactivity for MMP-2 and -9. Tumor tissues that had invaded more than half of the myometrium showed significantly higher activity than those that had invaded less than half. There was no significant difference in gelatinase activity among tumor stages, grades, vessel invasion or immunoreactivity for MMPs, with the exception that stage 2b cancers showed higher activity than stage 1a. The study suggested that the level of MMP-mediated gelatinolysis is an important factor for myometrial invasion in uterine endometrioid adenocarcinoma. Thus, a quantitative assessment of active gelatinolysis using FIZ and AET should be a useful tool in evaluating in situ matriolytic activity in local myometrial invasion by uterine endometrioid adenocarcinoma.