Detection of the t(2;5)-associated NPM/ALK fusion cDNA in peripheral blood cells of healthy individuals.
The translocation t(2;5), which leads to the fusion of the nucleophosmin gene (NPM) on chromosome 5q35 to the receptor kinase ALK on chromosome 2p23, is found in CD30+ anaplastic large cell lymphomas and some cases of B-cell lymphoma. Hodgkin's disease (HD) is a malignant lymphoma characterized by large multinucleated tumour cells, Hodgkin and Reed-Sternberg (H&RS) cells, surrounded by a dense lymphohistiocytic infiltrate. Our group recently demonstrated NPM/ALK fusion cDNAs by single-cell RT-PCR in < 3% of CD30+ tumour cells in 2/9 cases of HD. To further delineate the relevance of this finding for HD, we studied the occurrence of NPM/ALK fusion genes in peripheral blood cells of healthy donors by RT-PCR. NPM/ALK fusion cDNAs were found by RT-PCR in 14/29 healthy individuals and confirmed by hybridization with a breakpoint-specific oligonucleotide. Due to the low rate of NPM/ALK-positive cells in the peripheral blood of positive individuals, an assignment to a defined cellular subpopulation was not possible. We conclude that NPM/ALK fusion genes are present in peripheral blood cells of healthy donors. After t(14;18) and t(9;22), t(2;5) represents the third example of tumour-associated translocation products in blood cells of apparently healthy donors. The implications of this finding are discussed.
Trümper
L
L
Department of Internal Medicine I, University of Saarland, Homburg/Saar, Germany.
Pfreundschuh
M
M
Bonin
F V
FV
Daus
H
H
D015139:Blotting, Southern; D002889:Chromosomes, Human, Pair 2 / Q000235:genetics*; D002895:Chromosomes, Human, Pair 5 / Q000235:genetics*; D018076:DNA, Complementary / Q000235:genetics*; D006801:Humans; D016131:Lymphocyte Subsets / Q000737:chemistry; D008214:Lymphocytes / Q000737:chemistry*; D011505:Protein-Tyrosine Kinases / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014178:Translocation, Genetic / Q000235:genetics*
D018076:DNA, Complementary; D012333:RNA, Messenger; C107023:p80(NPM-ALK) protein; D011505:Protein-Tyrosine Kinases