PTEN and neoplasm: ThePI species identified in this study have clear biological relevance,with PI (38:4) known to be the most abundant mammalian phosphatidylinositol. Phosphatidyl inositide speciesare critical cell signaling secondary messenger molecules whose relativeabundance is both influenced by oncogene or tumor suppressor mutations(such as PIK3CA or KRAS mutations or PTEN loss), and are criticalfor characteristic tumor cell phenotypes including unrestrained growthand survival signaling.