IGHG3 and cancer: TfR1 monoclonal antibodies, including 42/6, A24, JST-TFR09, and ch128.1Av (anti-hTfR1 IgG3-Av), facilitate the accumulation of nonselective therapeutic agents in cancer cells, elevate the intracellular drug concentration, improve anticancer activity, and enhance therapeutic efficacy [14, 15].