Somatic mitochondrial DNA mutations in oral cancer of betel quid chewers.
Somatic mitochondrial DNA alteration is a general phenomenon that occurs in cancerous cells. Although numerous mtDNA mutations have been identified in various tumors, the pathogenic significance of these mutations remains unclear. In order to better understand the role of mtDNA mutations in the neoplastic process of oral cancer, the occurrence of mtDNA mutations in oral squamous cell carcinomas was screened by temporal temperature gradient gel electrophoresis (TTGE). The entire mitochondrial genome was amplified with 32 pairs of overlapping primers. The DNA fragments showing different banding patterns between normal and tumor mtDNA were sequenced for the identification of the mutations. Fourteen of 18 (77.8%) tumors had somatic mtDNA mutations with a total of 26 mutations. Among them, 6 were in mRNA coding region. Three were missense mutations (C14F, H186R, T173P) in NADH dehydrogenase subunit 2 (ND2). One frameshift mutation, 9485delC, was in cytochrome c oxidase subunit III. Eight (44%) tumors had insertion or deletion mutations in the np303-309 poly C region of the D-loop. Our results demonstrate that somatic mtDNA mutations occur in oral cancer. The missense and frameshift mutations in the evolutionary conserved regions of the mitochondrial genome may have functional significance in the pathogenesis of oral cancer.
Tan
Duan-Jun
DJ
Institute for Molecular and Human Genetics, Georgetown University Medical Center, Washington, DC 20007, USA.
Chang
Julia
J
Chen
Woan-Ling
WL
Agress
Lesley J
LJ
Yeh
Kun-Tu
KT
Wang
Baotyan
B
Wong
Lee-Jun C
LJ
D000595:Amino Acid Sequence; D000818:Animals; D001114:Areca / Q000009:adverse effects*; D003528:Carcinoma, Adenoid Cystic / Q000139:chemically induced / Q000235:genetics; D002294:Carcinoma, Squamous Cell / Q000139:chemically induced / Q000235:genetics*; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000032:analysis*; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009062:Mouth Neoplasms / Q000139:chemically induced / Q000235:genetics*; D009154:Mutation; D016415:Sequence Alignment; D013624:Taiwan
D004272:DNA, Mitochondrial