Roles of Matrix Metalloproteinases 2 and 9 in Uterine Leiomyosarcoma

Uterine leiomyosarcoma (uLMS) is a rare, highly malignant, and invasive cancer, with early metastasis. Mismatch repair (MMR) proteins and matrix metalloproteinases (MMPs) are associated with the occurrence, proliferation, and invasion of most malignant cancers; however, their abnormal expression in uLMS remains poorly clarified.

Immunohistochemistry was performed to assess MMR protein and MMP2/9 expression as well as Ki67 marker proliferation in benign and malignant uterine smooth muscle tumors. Data from 28 cases of uterine leiomyoma and 31 cases of uLMS were analyzed.

Tumor tissues from patients with uLMS had higher expression levels of MMP2 (p<0.001), MMP9 (p<0.05), and Ki67 (p<0.001) than those from patients with uterine leiomyoma; MMR protein expression showed the opposite trend (p<0.05). uLMS proliferation and metastasis correlated positively with MMP2 (p=0.012 and 0.015, respectively) but negatively with MMP9 (p=0.021 and 0.04, respectively). MMR protein expression did not correlate with uLMS proliferation or metastasis (p>0.05).

Expression levels of MMP2 and MMP9 were upregulated in malignant uLMS tumors when compared with those in benign uterine leiomyoma tumors. Increased MMP2 expression might promote uLMS invasion and migration. MMP9 overexpression might be related to uLMS occurrence; however, it protects against uLMS invasion and metastasis. MMP2 and MMP9 may be potential predictors of uLMS cell proliferation, metastasis, and prognosis. These findings could be helpful in developing new strategies for diagnosing and treating uLMS.