Mitochondrial DNA sequence variation in single cells from leukemia patients.
A high frequency of mtDNA somatic mutation has been observed in many tumors as well as in aging tissues. In this study, we analyzed the mtDNA control region sequence variation in 3534 single normal cells and individual blasts from 18 patients with leukemia and 10 healthy donors, to address the mutation process in leukemic cells. We found significant differences in mtDNA sequence, as represented by the number of haplotypes and the mean number of cells with each nonaggregate haplotype in a population of cells, in patients compared to controls. Patients with similar clinical leukemia types, particularly acute myeloid leukemia (AML), did not show a uniform pattern of sequence variation in single blasts. Some patients at relapse presented a complex shift of major haplotypes in single cells. Four patients showed high frequencies of cells containing mutations 189, 260, 16150, and 16488, respectively, as a result of clonal expansion and could be considered as potential markers for their respective disease progression. To our knowledge, this is the first large-scale study of mtDNA variation in single malignant cells. Our results suggest that the somatic mutation process in leukemia is complex, leading to diverse levels of genetic alterations due to either intrinsic aspects of leukemia pathophysiology or chemotherapy effects.
Yao
Yong-Gang
YG
Hematology Branch and Flow Cytometry Core Facility, National Heart, Lung, and Blood Institute, NIH Bldg 10 CRC, Rm 3E-5216, 10 Center Dr Bethesda, MD 20892, USA. yaoy3@nhlbi.nih.gov
Ogasawara
Yoji
Y
Kajigaya
Sachiko
S
Molldrem
Jeffrey J
JJ
Falcão
Roberto P
RP
Pintão
Maria-Carolina
MC
McCoy
J Philip
JP
Rizzatti
Edgar Gil
EG
Young
Neal S
NS
D000293:Adolescent; D000328:Adult; D000368:Aged; D002467:Cell Nucleus / Q000235:genetics*; D002648:Child; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D014644:Genetic Variation; D006801:Humans; D007938:Leukemia / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D017354:Point Mutation; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA / Q000379:methods; D017384:Sequence Deletion
D004272:DNA, Mitochondrial