PIK3CA and cancer: Activated Type‐II or Type‐III EMT might be responsible for the process of smoking‐associated epithelial injury/repair, small airway fibrosis and obstruction, and carcinogenesis, as more than 90% of human cancer arises in epithelia with potential involvement of EMT, probably through the regulation of Wnt/β‐catenin pathway,34 p53 up‐acetylation,35 PI3K‐dominated signals,36 or OPN‐STAT3 pathway.37