Presence of isochromosomes in hematologic diseases

Several different structural chromosome aberrations have been observed in human neoplasias. In this report we describe the isochromosomes found in nine patients with hematologic malignancies: five with leukemia, one with sideroblastic anemia, and three with malignant lymphomas. The isochromosomes i(7q), i(11q), i(17q), and i(21q) were detected in these patients. We suggest that the presence of isochromosomes permits us to speak of a gene-dosage effect and that this mechanism may play a role in malignant transformation.