IPF fibroblasts from patients who exhibited slow progression or stable disease (i.e. stable IPF fibroblasts) expressed the highest transcript expression of MAP3K19 compared with normal fibroblasts or IPF fibroblasts derived from IPF patients who exhibited rapid progression of disease (rapid IPF fibroblasts) (Fig. 1B). Here, MAP3K19 is linked to idiopathic pulmonary fibrosis.