Gastric carcinomas with microsatellite instability: clinical features and mutations to the TGF-beta type II receptor, IGFII receptor, and BAX genes.
The replication error phenotype (RER+) represents an important new form of genetic alteration characterized by widespread instability in repetitive nucleotide sequences. The aim of this study was to compare the features of RER+ gastric tumours with those of RER+ colonic tumours. RER status was determined by analysis of size alterations in the BAT-26 mononucleotide repeat microsatellite. Twelve of 121 (10 per cent) gastric carcinomas from a low-incidence region were found to be RER+. BAT-26 instability was associated with tumours showing an absence of nodal invasion ( p=0.009) and with a trend for improved prognosis. These tumours were more frequent in older, female patients. Frameshift mutations in mononucleotide repeat sequences within the transforming growth factor-beta receptor II (RII), insulin-like growth factor II receptor (IGFIIR), and BAX genes were observed in 83, 33, and 25 per cent, respectively, of RER+ tumours. Only 1/12 (8 per cent) RER+ tumours contained a p53 gene mutation compared with 29/109 (27 per cent) RER- tumours. RER+ gastric carcinomas therefore share several important features with RER+ colonic tumours, including less frequent nodal invasion, improved prognosis, a similar frequency of mutation in growth control genes containing repetitive nucleotide sequences, and a low frequency of mutation of the p53 tumour suppressor gene.
Department of Surgery, University of Western Australia, Nedlands 6907, Australia. bjiac@cyllene.uwa.edu.au
B J
BJ
Iacopetta
R
R
Soong
A K
AK
House
R
R
Hamelin
D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats; D009154:Mutation; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2; D017527:Receptor, IGF Type 2 / Q000235:genetics; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics; D013274:Stomach Neoplasms / Q000235:genetics* / Q000473:pathology; D051028:bcl-2-Associated X Protein
C494826:BAX protein, human; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D017527:Receptor, IGF Type 2; D018125:Receptors, Transforming Growth Factor beta; D051028:bcl-2-Associated X Protein