Chromosome 2p, 3p, 5q and 18q status in sporadic gastric cancer.
OBJECTIVE
The genetic make-up of gastric cancers in low-risk population groups from South Africa is largely unknown. The purpose of this study was to ascertain the incidence of microsatellite instability and loss of heterozygosity in this population.


METHODS
Thirty-seven gastrectomy specimens for sporadic gastric cancer were analysed for the following clinicopathological parameters: age, gender, race, histopathological type, size of tumour, lymph node status and the presence/absence of Helicobacter pylori. DNA was then extracted from paraffin-embedded tissue and seven microsatellite markers in 2p, 3p, 5q and 18q loci were examined using automated DNA fluorescent technology.


RESULTS
Only eight cases showed microsatellite instability (MSI) for one marker and were thus categorised as MSI-low. In the 3p region, loss of heterozygosity (LOH) was detected in 21.7-38.3% of informative cases, whilst in the 18q region CLOH ranged from 25 to 38.4%. LOH was not seen in the 2p locus and only one case showed LOH in the 5q region. When the molecular changes were compared with clinicopathological parameters, a statistically significant relationship did not emerge with any single parameter.


CONCLUSIONS
This study shows that sporadic gastric cancer from a low-risk population in South Africa is MSI-low or MSI-stable, and that LOH in the 3p and 18q regions is similar to that seen in other low-risk populations from different geographical regions.
Chetty
Runjan
R
Department of Pathology and Molecular Biology Research Facility, Nelson R. Mandela School of Medicine, Faculty of Health Sciences, University of Natal, Durban, South Africa. chettyr@nu.ac.za
Naidoo
Richard
R
Tarin
Michelle
M
Sitti
Christopher
C
D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044383:Black People / Q000235:genetics; D002352:Carrier Proteins; D002900:Chromosomes, Human, 1-3; D002887:Chromosomes, Human, Pair 18; D002895:Chromosomes, Human, Pair 5; D004273:DNA, Neoplasm / Q000032:analysis; D004268:DNA-Binding Proteins; D005260:Female; D017491:Genes, APC; D016163:Genes, DCC; D006801:Humans; D007194:India / Q000208:ethnology; D019656:Loss of Heterozygosity; D008297:Male; D018895:Microsatellite Repeats; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein; D009363:Neoplasm Proteins / Q000235:genetics; D009687:Nuclear Proteins; D016133:Polymerase Chain Reaction; D011518:Proto-Oncogene Proteins / Q000235:genetics; D013019:South Africa; D013274:Stomach Neoplasms / Q000208:ethnology / Q000235:genetics* / Q000601:surgery; D044465:White People / Q000235:genetics
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; C501486:MLH1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein