PIK3R2 and squamous cell carcinoma: Of note, VEGF signaling (through the VEGFA, FLT4, and PIK3R2 genes) was one of the most frequently altered pathways in the PLC-LUAD cohort (11.8%, 5% in the Chinese-LUAD cohort, P = 0.22), and the patients with squamous cell carcinoma also harbored mutations in VEGFA. VEGF signaling is best known for its involvement in the development and maintenance of the blood and lymphatic vascular systems (25).