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.