PTEN and idiopathic pulmonary fibrosis: Emerging evidence indicates that the abnormal behaviors of fibroblasts in IPF are associated with a variety of genetic alterations and the aberrant reactivation of developmental signaling pathways, such as hyaluronan synthase2 [13], focal adhesion kinase-related non-kinase [14], and phosphatase and tensin homologue deleted on chromosome 10 (PTEN) [15–17].