This invention provides methods of identifying and treating cancer patients having activating alterations in the PEST domain of Notch1, Notch2 or Notch3, who will benefit from treatment with a Notch signaling pathway inhibitor, such as the [gamma]-secretase inhibitor PF-03084014, or a pharmaceutically acceptable salt thereof.本發明提供識別及治療在刻痕1、刻痕2或刻痕3之PEST結構域中具有活化改變之癌症病患之方法,該病患將獲益於刻痕傳訊途徑抑制劑(諸如γ分泌酶抑制劑PF-03084014或其醫藥上可接受之鹽)之治療。