Burkitt-like mutations in the c-myc gene locus in prolymphocytic leukemia.
The c-myc oncogene recently shown to act as a transcription factor, is involved in cellular proliferation. Deregulation of this gene can be one step in malignant transformation. In Burkitt's lymphoma (BL) the c-myc gene is consistently involved in chromosomal translocations and the first exon of the gene has been found to be a frequent target of somatic mutations. These mutations are believed to interfere with normal transcriptional regulation of the gene. We demonstrate a case of the rare prolymphocytic leukemia (PLL), a variant of chronic lymphocytic leukemia (CLL), that shows multiple Burkitt-like mutations in the first exon of c-myc and one nonconservative point mutation in the coding exon 2. Cytogenetic analysis revealed involvement of both chromosomes 8 in chromosomal translocations. Both chromosomes 8 are broken at (q23), the c-myc gene locus. Since the patient's leukemia cells exhibited high expression levels of the mutated allele of the c-myc mRNA, the point mutations alone may have accounted for transcriptional deregulation.
Brennscheidt
U
U
Abteilung für Hmatologie und Onkologie, Universität Freiburg, Germany.
Eick
D
D
Kunzmann
R
R
Martens
U
U
Kiehntopf
M
M
Mertelsmann
R
R
Herrmann
F
F
D000595:Amino Acid Sequence; D001483:Base Sequence; D002051:Burkitt Lymphoma / Q000235:genetics*; D002873:Chromosome Fragility; D002898:Chromosomes, Human, Pair 8; D002908:Chronic Disease; D005091:Exons; D016259:Genes, myc / Q000235:genetics*; D006801:Humans; D007621:Karyotyping; D015463:Leukemia, Prolymphocytic / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D017354:Point Mutation; D016133:Polymerase Chain Reaction