In myeloid disorders, monosomy 7 or del(7q) are among the most common recurrent chromosome abnormalities. These aberrations occur in 8% of de novo acute myeloid leukemia (AML), in 5-10% of de novo patients with myelodysplastic syndrome (MDS), and in approximately 50% of therapy-related myeloid neoplasms. Myeloid malignancies with monosomy 7 or del(7q) respond poorly to chemotherapy and are associated with an unfavorable prognosis. Several commonly deleted regions (CDRs)located on 7q have been identified in MDS and AML, including CDRs at 7q22, 7q32-33, and 7q35-36. Loss of one or more yet unidentified tumor suppressor gene(s) is thought to contribute to leukemic growth in myeloid malignancies with -7/del(7q). CUX1 is a transcription factor encoded in the CDR at 7q22 that exerts tumor suppressor activity by regulating proliferative genes. Loss of CUX1 may thus contribute to disease pathogenesis. The CDR at 7q35-36 encodes nine genes including CUL1 and EZH2 which are the most promising candidates due to known function in and association with cancer.