The immunoreactivity with MMP-9 increased gradually from secretory to hyperplastic endometrium and serous carcinoma while its expression in all types of cancers except grade 1 endometrioid and clear cell compared to proliferative endometrium was significantly higher and increased from proliferative to grade 2, 3 endometrioid, serous, and undifferentiated endometrial carcinoma. This evidence concerns the gene MMP9 and endometrial undifferentiated carcinoma.