PIK3CG and cancer: Although EGFR is involved in the growth and development of cells and tissues under normal circumstances, its overexpression stimulates the growth and progression of tumour cells and promotes angiogenesis, invasion, and metastasis through major cascades such as Ras/Raf/MAPK, PIK-3/AKT, PLC-PKC, and STAT, which are related to the poor prognosis of malignant tumours (26, 27).