PIK3CG and small cell lung carcinoma: In recent years, IPF can be viewed as a proliferative lung disease with similar genetic alterations, pathogenic mechanisms, and pathological features between IPF and lung cancer, particularly nonsmall cell carcinoma, and even in treatment strategies.[30,31] Epidermal growth factor receptors, such as EGFR, regulate tumor cell proliferation, apoptosis, angiogenesis, and lymphangiogenesis in small cell carcinoma of the lung mainly through the PI3K-AKT pathway and the Ras/Raf/Mek pathway.