In K-Ras G12V-driven lung cancer, epithelial cells secreted higher levels of activated MMP-9 [396], and in pancreatic cancer mouse models, increased expression of MMP3 cooperates with K-Ras activation to shape the stromal microenvironment, not only by stimulating immune cell influx but also as a primary proteolytic activator of MMP-9 [397]. This evidence concerns the gene MMP9 and lung cancer.