Localization of matrix metalloproteinase-2 in uterine endometrium and ectopic implants

We performed an immunohistochemical study on paraffin-embedded tissues to evaluate the invasion pattern of endometriotic implants by determination of matrix metalloproteinase (gelatinase A) expression. Endometriotic tissues (n=32) and uterine endometria (n=18) of patients with endometriosis and uterine endometria of normal-menstruating women without endometriosis (n=11) were examined. Endometriotic tissues showed statistically significantly stronger staining compared with uterine endometria. However, we did not find differences in staining between uterine endometrium of women with endometriosis and normal controls. Compared to uterine endometrium, ectopic endometrium has a significantly higher capacity to produce the latent forms (72 kD) of gelatinase A. This leads to the conclusion that endometriotic implants express the protease enabling the invasion of surrounding tissue.