PIK3CA and lung cancer: As a crucial signaling node stimulating multiple pathways and transcriptional factors (such as PI3K-Akt, RAS-RAF-MEK-ERK, PLC-γ, Src, and JAK-STAT), EGFR (epidermal growth factor receptor) was prevalently mutated in lung cancer, while its genetic amplification and overexpression were also major causative events for gastrointestinal cancers (Du and Lovly 2018; Yarden and Sliwkowski 2001).