In this study, we examined the potential signalling between PI3K and MMP9 or RhoA in A549 cells exposed to fibronectin and found that MMP9 and RhoA expression decreased upon LY294002 treatment, suggesting that FAK further promotes A549 lung cancer cell invasion and migration through PI3K/MMP9 and PI3K/RhoA signalling mechanisms. The gene discussed is RHOA; the disease is lung cancer.