SIX1 and idiopathic pulmonary fibrosis: Importantly in the context of IPF, increased SIX1 levels have been reported in lung tissue from patients with IPF (18, 19), as well as in an AT2-specific single-cell RNA-Seq (scRNA-Seq) data set that shows increased AT2 (CD326+HTII-280+) cell-specific expression of SIX1 in patients with IPF (20).