FN1 and focal segmental glomerulosclerosis: Liang et al. found that JAK2/STAT3 pathways stimulated by cytokines such as TGFβ1, connective tissue growth factor (CTGF), and fibronectin (FN) might be responsible for abnormal accumulation of extracellular matrix (ECM) and myofibroblast transdifferentiation in FSGS [55].