SOCS1 and idiopathic pulmonary fibrosis: Hyper-methylation of the SOCS1 promoter has been associated with reduced SOCS1 levels in hematopoetic malignances, gastric cancer [36], and hepatocellular carcinoma [13], and therefore the possibility that reduced SOCS1 levels in IPF lungs was due to increased methylation of the SOCS1 promoter was investigated.