Overexpression of MMP-9 correlates with growth of small hepatocellular carcinoma

Matrix metalloproteinases (MMP) play an important role in tumor cell invasion and metastasis. We examined the expression of MMPs in hepatocellular carcinoma (HCC) to determine whether they may help indicate the progression of HCC and patient outcome. The expression of MMP-1, -2, -7, -9, and MT1-MMP were determined in 37 pails of HCC and adjacent non-tumor tissue specimens by semiquantitative reverse transcription polymerase chain reaction (RT-PCR). The tumor to non-tumor (T/N) ratios for mRNA expression of each MMP were compared with the clinicopathological findings and two-year disease-free survival rates. Immunohistochemical analysis for MMP-1 and -9 was performed in 30 specimens. MMP-1 and -9 expression was significantly higher in tumor tissue than in non-tumor tissue (p=0.001 and 0.0078, respectively). By contrast, the expression of MMP-2 and -7 was significantly lower in tumor tissue than in non-tumor tissue (p=0.003 and 0.03, respectively). A higher MMP-9 TIN ratio was significantly associated with small HCCs (less than or equal to 2 cm) and higher serum AFP values (greater than or equal to 20 ng/ml) (p=0.013 and 0.028, respectively). Immunohistochemical analysis suggested that well differentiated HCC showed stronger immunoreactivity for MMP-9 than moderately differentiated HCC. MMP T/N ratio was not significantly associated with the disease-free survival rates. Overexpression of MMP-9 mRNA (T/N ratio greater than or equal to 2) may be associated with the progression of small HCC (less than or equal to 2 cm).