Beneficial influence of microsatellite instability on gelatinase-tissue inhibitors of metalloproteinase balance in colorectal cancer.

ABSTRACT

BACKGROUND: Colorectal cancers (CRC) with high level of microsatellite instability (MSI-H) are characterized by lower metastasis propensity and better prognosis than their stable microsatellite (MSS) counterpart. It was hypothesized that the difference in cancer progression might be related to distinct gelatinase-tissue inhibitors of metalloproteinase (TIMPs) balance in MSI-H and MSS sporadic CRC. PATIENTS AND METHODS: Levels of gelatinase-A (MMP-2) and -B (MMP-9), TIMP-1 and -2 and membrane-type matrix metallo-proteinase-1 (MT1-MMP) were compared in tumors and normal mucosa from patients with MSI-H and MSS CRC. RESULTS: Active levels of MMP-2 and -9, normalized to normal mucosa, were lower in MSI-H than MSS CRC. There was a trend for higher levels of TIMP-1 and TIMP-2 within MSI-H tumors compared with MSS tumors (p=0.08 and p=0.15, respectively), while TIMP-2 amounts were significantly higher in adjacent normal tissue (p<0.001) in patients with MSI-H vs. MSS cancers. There was also a trend for lower MT1-MMP activity in MSI-H than in MSS CRC. CONCLUSION: Our data suggest that the distinct invasive and metastatic behaviors of MSI-H and MSS CRC may be related to different patterns of gelatinase secretion and regulation.