Simultaneous measurement of MMP9 and TIMP1 mRNA in human non small cell lung cancers by multiplex real time RT-PCR.

Extracellular matrix (ECM) homeostasis is strictly maintained by a coordinated balance between the expression of matrix metalloproteinases (MMPs) and their specific inhibitors (TIMPs). Our study was focused on the simultaneous measurement of the expression profile of MMP9 mRNA and its principal inhibitor, TIMP-1, in 100 non small cell lung cancers (NSCLC) and in corresponding adjacent non malignant tissues. The measurement was performed with a multiplex quantitative RT-PCR assay based on TaqMan assay, using two probes labelled with different fluorocromes. We found that both MMP9 and TIMP-1 mRNAs were significantly higher in NSCLC (P < 0.0001) in comparison to corresponding controls as well as the MMP9/TIMP-1 ratio (P = 0.014). MMP9 and TIMP-1 mRNA expression was highly correlated in cancer samples (r = 0.73, P < 0.0001). The analysis in the two main histotypes revealed a significant increase of MMP9 mRNA in adenocarcinomas in comparison to normal tissues (P = 0.006) but not in squamous cell carcinomas, while TIMP-1 mRNA showed a significative increase both in adenocarcinomas and in squamous cell carcinoma samples (P = 0.02 and 0.01, respectively). Both MMP9 and TIMP-1 mRNAs were significantly correlated to lymphnode invasion and cancer stage. Survival analysis revealed that high levels of expression of MMP9 mRNA, but not of TIMP-1, were significantly associated to an unfavourable outcome in NSCLC patients in toto (P = 0.017). In addition our results showed that high levels of MMP9 expression are of independent prognostic impact in operable NSCLC. Our data seem to demonstrate a simultaneous and coordinated up-regulation of MMP9 and TIMP-1 expression at the mRNA level in NSCLC, even if this phenomenon seems variable according to the histotype. In addition, the increase of MMP9/TIMP-1 ratio may reflect an unbalance of their production in affected tissues. The increased expression of the two mRNAs, even not necessarily equate their enzymatic activities, seems to parallel a major cancer aggressiveness.