PIK3CA and neoplasm: Arachidonic acid is released from phospholipid or triglyceride by phospholipase and gives rise to eicosanoids that promote tumor growth and inflammation [31]; a pathway enhanced in tumors possessing activation-of-function mutations in PIK3CA and dependent on a PI3K signaling cascade correlated with REIMS-detectable arachidonic acid (Fig. 4A) [15].