In this context, we recently showed that phosphatidylcholine (PC)-specific phospholipase C (PC-PLC), enzyme responsible for PC hydrolysis into 1,2-diacylglycerol (DAG) and phosphocholine (PCho) and involved in signal transduction and cell proliferation [18, 20], exerts a pivotal role in regulating HER2 overexpression in human breast cancer cells [21]. The gene discussed is ERBB2; the disease is breast carcinoma.