FLT1 and idiopathic pulmonary fibrosis: Comparison of microarray transcript levels of VEGF isoforms and receptors between these groups revealed significant underexpression of VEGFA in IPF lung tissue (U = 1,242, Z = 10.020, P < 0.0001, Figure 1A), as well as reduced expression of VEGFC (U = 1,847, Z = 8.42, P < 0.0001, Supplemental Figure 1), VEGFR1 (U = 2,094, Z = 8.69, P < 0.0001, Supplemental Figure 1), and VEGFR2 (U = 2006, Z = 8.378, P < 0.0001, Supplemental Figure 1).