Some embodiments are based on the discovery that proliferative diseases (e.g., neoplastic diseases, for example, tumors or cancers) having an FBW7 mutation or other FBW7 deficiency are sensitive to Mcl1 inhibiting agents, but resistant to pro-apoptotic drugs that do not inhibit Mcl1. Some embodiments provide methods of treating a proliferative disease based on an assessment of FBW7 expression level or mutation status. Some embodiments provide methods of classifying a hyperproliferative cell or cell population, for example, a malignant cell or cell population based on an assessment of FBW7 expression level or mutation status. Some embodiments provide methods of selecting a treatment regimen for treating a proliferative disease, for example, a malignant disorder, based on an assessment of FBW7 expression level or mutation status.