The gene expression level of VEGFA, PGF, and their receptors FLT1 and KDR as well as MMP-2 and the inhibitors TIMP-1 and TIMP-2 was significantly higher in lung cancer specimens compared to pneumothorax samples and biopsies from lung transplant patients (P < 0.001; Figure 1). This evidence concerns the gene TIMP1 and pneumothorax.