PDGFB and lung adenocarcinoma: In addition, our data revealed that the mRNA level of PDGFB was up-regulated in both A549 and SPCA1 cells (two lung adenocarcinoma cell lines) in comparison with the normal lung epithelial cell (BEAS-2B), while the mRNA expression of PDGFA, C and D was not always highly expressed in A549 and SPCA1 cells (Fig. 1C).