FNDC5 and cancer: The glycolytic enzyme enolase 1 (ENO1), also known as 2‐phospho‐D‐glycerate hydrolase, is encoded by the ENO1 gene that localizes to chromosome 1p36.23.[14] ENO1 plays a significant role in various cancers and autoimmune diseases, exerting effects of promoting proliferation and suppressing apoptosis.[15, 16, 17] Hyper‐proliferation and resistance to apoptosis of PASMCs have been widely recognized to endow PAH a cancer‐like phenotype.[18] However, whether the malignant phenotype associated with ENO1 is involved in the regulation of irisin levels in PAH remains unknown.