Several works and recent cancer genomic projects described high rates of mutations in genes involved in the mTOR pathway, including PI3K, PTEN, AKT, and S6K1, 4EBP1, and EIF4E. Based in this data, mTOR inhibitors (rapamycin and its analogs) have become attractive therapeutic agents tested in several clinical trials, as single agents or in combination with other types of systemic treatment (9). The gene discussed is PTEN; the disease is cancer.