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.