There is growing evidence that phosphatidylinositol 3,4-bisphosphate [PI(3,4)P2] is a critical second messenger in cancer, regulating vesicular trafficking, clathrin-mediated endocytosis, cytoskeletal rearrangements (lamellipodia and invadopodia), and cell metabolism [micropinocytosis and mammalian target of rapamycin (mTOR) signaling] (4). This evidence concerns the gene MTOR and cancer.