BCL2 and neoplasm: Concisely, upregulation of antiapoptotic proteins, such as Bcl-2, c-FLIP, Mcl-1, and survivin, and also overactivation of survival or proliferation-involved signaling axis (e.g., NF-κB, PI3K/AKT, and ERK) play a critical role in tumor cell resistance to TRAIL (103, 108).