CFLAR and breast cancer: C-FLIPL is a key substance that affects the sensitivity of BC to TRAIL, which can competitively bind FAS-associated protein with the death domain (FADD) to inhibit the self-shearing of procaspase-8, thus inhibiting apoptosis.[74] Metformin can inhibit the phosphorylation of mTOR/S6K1, thereby inhibiting c-FLIPL translation, downregulating its expression, and counteracting its inhibitory effect on death-inducing signaling complex (DISC)-induced apoptosis.[75]