MCL1 and osteosarcoma: For instance, in osteosarcoma, circ_0004674 can sponge miR-142-5p, upregulate the anti-apoptotic protein MCL1 of the Bcl-2 family, leading to osteosarcoma progression and doxorubicin resistance.590 In laryngeal squamous cell carcinoma (LSCC), circPARD3 sponges miR-145-5p to activate the PRKCI-Akt-mTOR pathway and inhibit autophagy, promoting tumor cell proliferation, migration, invasion, and cisplatin resistance.591 Moreover, circRNAs regulate the sensitivity to chemotherapy drugs by directly interacting with proteins.