Matrix metalloproteinases and their inhibitors and inducer in gestational trophoblastic diseases and normal placenta

This study aimed to investigate the expression of recently identified matrix metalloproteinases (MMPs), their inhibitors (TIMPs), and inducer (CD147) in a wide range of gestational trophoblastic diseases (GTD) thereby expanding our understanding of the potential role of MMPs in GTD.

Paraffin sections of 10 normal first-trimester placentas (NP), 10 partial moles (PM), 10 complete moles (CM), 5 choriocarcinomas (CCA) and 5 placental site trophoblastic tumors (PSTT) were studied immunohistochemically for expression of MMP-7, MMP-14, MMP-21, MMP-28, TIMP-3, TIMP-4 and CD147. Immunolocalization of MMP-1, MMP-2, MMP-3, MMP-9, MMP-13 and TIMP-1 was performed on 5 CCA and 5 PSTTs.

CCA showed stronger intensity for MMP-14 and MMP-28 than PSTT (p<0.05, p<0.05). CCA and PSTT had stronger expression of MMP-21 than NP, PM and CM (p<0.05, p<0.05, p<0.01). PSTT (p<0.05, p<0.05), NP (p<0.01, p<0.01) and CM (p<0.01, p<0.05) showed stronger staining for TIMP-3 and TIMP-4 than CCA.

Choriocarcinoma's high expression of MMPs and low expression of MMP inhibitors may contribute to its invasiveness and metastatic potential. Similarly, PSTT's lower expression of MMPs and high expression of MMP inhibitors may partly explain its lower invasiveness. Agents that inhibit MMP may prove useful in treating GTD.