Transcriptome profiling of CTEPH thrombus fibroblasts. (A) Immunofluorescence staining of fibroblasts isolated from CTEPH thrombus for FAP (red), matrix protein fibronectin (white), and α-SMA (green), with DAPI as the nuclear stain. Left: lower magnification (scale bar, 100 µm); right: higher magnification (scale bars, 20 µm) of the boxed area with single-channel images. (B) Volcano plot illustrating fold differences in gene expression (genes with fold change ≥2 are highlighted in red, black dots represent genes with nonsignificant expression differences, and gray dots show genes with a fold change of <2) of thrombus fibroblasts and corresponding adventitial fibroblasts from CTEPH patients (n = 4). (C) qPCR validation of 3 upregulated genes and (D) TGF-β pathway–associated genes in a larger cohort (n = 11-14). Data are shown as mean ± SEM. Adv Fib, adventitial fibroblasts; Thr Fib, thrombus fibroblasts; CLDN14, Claudin 14; PLA2G5, phospholipase A2 Group V. *P < .05 (unpaired Student t test).