In order to investigate this target, they developed 5 leiomyosarcoma PDX models and uncovered that PI3K/mTOR inhibitors (BEZ235, also known as dactolisib) therapy inhibited cancer growth of 4/5 leiomyosarcoma PDX models, and the 4 responding models presented basal p-S6 expression but nonresponding model showed negative score, suggesting that dual PI3K/mTOR inhibition is a promising therapeutic strategy in uterine leiomyosarcoma, and p-S6 expression can be used for predicting its response 74. The gene discussed is MTOR; the disease is leiomyosarcoma.