Arsenic trioxide (As2O3) targets the TRiC/CCT complex (Pan et al., 2010) and has been used to treat acute promyelocytic leukemia in patients who did not respond well to other types of chemotherapy (Shen et al., 1997; Soignet et al., 1998, 2001). The gene discussed is MARVELD2; the disease is acute promyelocytic leukemia.