PDCD1 and cancer: For example, chemotherapy agents such as cisplatin are known to induce muscle atrophy during cancer treatment.311 Studies in Pd-1 (programmed cell death protein 1) knockout mice have shown that after cisplatin treatment, the expression levels of ACSL4, HO-1, SAT1, and SLC39A14 are significantly increased in the gastrocnemius muscle,312 indicating that ferroptosis plays a role in chemotherapy-induced skeletal muscle atrophy.