SOX9 and idiopathic pulmonary arterial hypertension: We were able to identify 62 potential TFs in the downregulated genes of iPAH patients, such as Krüppel-like factor 4 (KLF4), signal transducer and activator of transcription 1 and 2 (STAT1 and STAT3), SRY-box transcription factor 9 (SOX9), and EGR1 (Figure 4A, Supplemental File S3).