PTPN11 and idiopathic pulmonary fibrosis: Our study group has previously shown that SHP2, a ubiquitously expressed non-receptor tyrosine phosphatase, was downregulated in IPF lungs, and when overexpressed, it attenuated fibrosis through negative regulation of pro-fibrotic kinase-related signal transduction pathways leading to impairment of fibroblast homeostasis [12].