Mutations in mitochondrial control region DNA in gastric tumours of Japanese patients

The non-coding control region of mitochondrial DNA (mtDNA), containing the hypervariable regions HV1 and HV2 and the D-loop region, was screened for m utations in 45 gastric tumours (15 tumours each of adenoma, differentiated adenocarcinoma and undifferentiated carcinoma). We found mutations in two o f the 45 tumours (4%); a 1 bp A deletion at nucleotide position 248 in a di fferentiated adenocarcinoma and a G to A transition at nucleotide position 16129 in an adenoma. We also observed 10 polymorphisms, four of which were not previously recorded. Both mtDNA mutations were present in replication e rror negative (RER-) tumours. Short mono- or dinucleotide repeats in the co ntrol region, such as (C)7, (A)5 or (CA)5, were not altered regardless of n uclear genetic instability. In summary, mtDNA is mutated in a subset of ben ign and malignant gastric tumours, but, disruption of the mtDNA repair syst em appears not to be significantly involved in gastric tumours of Japanese patients. (C) 1999 Elsevier Science Ltd. All rights reserved.