ACVR2B and neoplasm: Among these ligands, activins are the most potent negative regulators of muscle mass.474 Treatment with sActRIIB, an ActRIIB decoy receptor, not only reversed the decrease in skeletal muscle mass and cancer-induced cardiac atrophy but also prolonged the survival of C26 tumor-bearing mice.434 Unfortunately, clinical trials involving decoy ActRIIB led to treatment-related bleeding problems in volunteers, causing their discontinuation as a potential treatment for cachexia (NCT01099761).