COL1A1 and lung cancer: The markers of COL1A1 (Fig. 3A), COL1A2 (Fig. 3B), and FAP (Fig. 3C) are significantly highly expressed in lung cancer, compared to normal tissues, while PDGFRA, PDGFRB, and ACTA2 either failed to be differentially expressed in cancer tissues, or were expressed in relative lower levels (Fig. S7A-C).