A case is reported of an adult male patient with acute leukemia characterized by the presence of the novel cytogenetic abnormality, t(2;9)(p12;p23), in addition to a t(4;11)(q21;q23). The immunophenotype of the blast cell population was consistent with immature early pre-B cell acute lymphoblastic leukemia (ALL) (TdT+,HLA-DR+,CD19+,CD24±,CD10-) expressing myelo-monocytic antigens (CDw65,CD15). The genotype showed a clonal rearrangement of the immunoglobulin heavy chain locus. Because the immunoglobulin kappa (κ) light chain gene is located on chromosome 2 at band p12 and interferon alpha (α) and beta (β) map to chromosome 9p21-p22, rearrangements of these loci as a result of the t(2;9) were studied. There was no evidence for rearrangement of the region covering about 40 kilobases around the κ locus when hybridized to C(κ), the 3′ κ enhancer or the κ deleting element. Only germline size restriction fragments were also found for the interferon α and β genes. The patient's clinical features were typical for ALL associated with the t(4;11), including a high white blood cell count at presentation, hepatosplenomegaly, and a poor outcome. The potential significance of 2p and 9p abnormalities in addition to t(4;11) is discussed.
Bibliographical noteFunding Information:
This study was supported by NCI, DHHS grants CA21115 (Eastern Cooperative Oncology Group, Douglass C. Tormey), CA14958 (Einstein Cancer Center), CA20365 (Univ. Minnesota), CAl1083 (Univ. Rochester), CA15488 (Univ. Pennsylvania), and P30CA13330 (Einstein Cancer Center), by PHS grant CA42557 (J. D. Rowley for Univ. Chicago), and by the Chemotherapy Foundation (Einstein Cancer Center). The authors are grateful to Dr. Donald Sweet and his staff from Hinsdale Hospital, Hinsdale, Illinois, for providing clinical information on the patient reported in this study. We would like to thank Drs. S. Korsmeyer, P. Leder, M. Atchison, and P. SehgaI for providing the various human clones.