MMP9 and endometriosis: Although the progression time of these lesions did not interfere in a statistically significant way in the MMP-9 (p = 0.214) and in the TIMP-2 staining (p = 0.66), our results suggest that the evaluation of MMP-9 and TIMP-2 could be used as a prognostic indicator of endometrial invasion; therefore, increasing the proteolytic activity would be one of the many factors that contribute to the invasive properties of the endometrium, resulting in the development of endometriosis.