Key genetic members of the Ras/Raf/MEK/ERK pathway [e.g.,RAS, RAF), MEK (rarely) [81-84], the downstream transcription factor (ETS) the Ras/PI3K/PTEN/Akt/mTOR (e.g.,PIK3CA, AKT, PTEN) pathway and upstream receptors (e.g.,ERBB1(EGF-R), ERBB2 (HER2), PDGFR, KIT, FLT3, FMS) were shown to fulfill this hypothesis as they were sometimes mutated/amplified/deleted in specific human cancers. The gene discussed is PTEN; the disease is cancer.