title: L-myc and N-myc in hematopoietic malignancies.
abstract: The myc proto-oncogenes encode nuclear DNA-binding phosphoproteins which regulate cell proliferation and differentiation. The c-myc gene is implicated in hematopoietic malignancies on the basis of its frequent deregulation in naturally occurring leukemias and lymphomas. Recent evidence suggests that also the N-myc and L-myc genes may have a role in normal and malignant hematopoiesis. N-myc and to a certain degree L-myc can substitute for c-myc in transformation assays in vitro, and their overexpression can block the differentiation of leukemia cell lines. Immunoglobulin heavy chain enhancer (IgH) -driven overexpression of N-myc or L-myc genes cause lymphatic and myeloid tumors, respectively, in transgenic mice. Furthermore, the L-myc and N-myc genes are expressed in several human leukemias and leukemia cell lines, L-myc predominantly in myeloid and N-myc both in myeloid and in some lymphoid leukemias. All N/L-myc positive leukemias and leukemia cell lines coexpress the c-myc gene, thus exemplifying a lack of negative cross-regulation between the different myc genes in leukemia cells. Taken together, these data suggest that L-myc and N-myc may participate in the growth regulation of hematopoietic cells.
authors.affiliation: Department of Medical Biochemistry, University of Turku, Finland.
authors.forename: H
authors.initials: H
authors.lastname: Hirvonen
authors.forename: V
authors.initials: V
authors.lastname: Hukkanen
authors.forename: T T
authors.initials: TT
authors.lastname: Salmi
authors.forename: T T
authors.initials: TT
authors.lastname: Pelliniemi
authors.forename: R
authors.initials: R
authors.lastname: Alitalo
mesh_terms: D000818:Animals; D015972:Gene Expression Regulation, Neoplastic; D016259:Genes, myc; D006801:Humans; D007938:Leukemia / Q000235:genetics*; D008223:Lymphoma / Q000235:genetics*; D016271:Proto-Oncogene Proteins c-myc / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger