Inverse correlation between mRNA expression of plasminogen activator inhibitor-2 and lymph node metastasis in human breast cancer.

We examined mRNA expressions of urokinase-type plasminogen activator (u-PA), its specific receptor (u-PR), and plasminogen activator inhibitors (PAI-1 and PAI-2) in 50 human breast cancers by the reverse transcriptase-polymerase chain reaction method. The expressions of the genes are discussed in relation to the clinicopathological findings. In the overall population in breast cancers, a low level of PAI-2 expression was significantly associated with lymph node involvement (P < 0.0001). The u-PA, u-PR, and PAM expressions tended to be at high levels in such metastatic cancers. Also, positive expression of u-PA, u-PR, and PAI-1 was significantly correlated with negative expression of PAI-2. These results indicate that PAI-2 may play a critical role in the regulation of extracellular matrix degradation during tumor cell invasion and metastasis, and the expression of PAI-2 may be useful as a marker to evaluate the prognosis of breast cancers.