IGFBP3 and idiopathic pulmonary fibrosis: IGFBP-3, IGFBP-4, and IGFBP-5 expression is increased in lungs of patients with IPF, and cultured IPF fibroblasts secrete and deposit IGFBP-3 and IGFBP-5 into the extracellular matrix (83, 84).