Frequency plots of genetic alterations at the output stream of sequencing efforts in cancer reveal a mountain of a few but frequent aberrations (e.g. EGFR, CDKN2A, TP53 and PTEN in glioblastoma, TP53, PI3K and HER2 in breast cancer, BRAF and NRAS in melanoma) and a long tail of many low frequency aberrations (http://www.cancergenome.nih.gov). The gene discussed is PTEN; the disease is glioblastoma.