Helicobacter pylori-related and -non-related gastric cancers do not differwith respect to chromosomal aberrations

Gastric carcinogenesis is strongly associated with Helicobacter pylori infe ction, but the underlying genetic mechanisms are largely unknown. The aim o f this study was to correlate chromosomal aberrations in gastric cancer to H. pylori status and its different strains, as well as to histological type and other clinico-pathological variables. DNA from 46 gastric cancers (mal e/female 35/11, age 27-85 years) was extracted from formaldehyde-fixed, par affin-embedded material and tested for chromosomal gains and losses by comp arative genomic hybridization (CGH). Chromosomal aberrations with frequenci es of 20% or higher were considered to be non-random changes associated wit h gastric cancer. The mean number of chromosomal events per tumour was 9.7 (range 0-27), with a mean of 3.2 gains (range 0-16) and 6.5 losses (range 0 -15). Gains were most frequently found at chromosomes; 8q and 13q (24% and 26%, respectively). Losses were predominantly found on chromosome arms 2q, 9p, 12q, 14q, 15q, 16p, 16q, 17p, 17q, 19p, 19q, and 22q (22%, 30%, 43%, 22 %, 33%, 50%, 28%, 50%, 39%, 33%, 39%, and 37%, respectively). Common region s of overlap narrowed down to 2q11-14, 8q23, 9p21, 12q24, 13q21-22, 14q24 a nd 15q11-15. The mean number of gains was higher in tumours with metastases than in localized tumours (4.1 vs. 1.9, p = 0.04). Tumours with a loss at 17p showed a higher number of losses than tumours without a 17p loss (9.5 v s. 4.7 on average, p<0.001). Neither H. pylori status (+, n = 25; -, n = 21 ) nor H. pylori strain was correlated to the total number of events or to a ny specific chromosomal aberration, nor were there differences between inte stinal (n = 30) and diffuse (n = 15) cancers or any other clinico-pathologi cal variable tested. In conclusion, a complex of chromosomal aberrations is involved in gastric cancer, but their pattern does not depend on H. pylori status or strain, nor on the histological type of the tumour. The exact bi ological meaning of these aberrations in carcinogenesis needs further clari fication. Copyright (C) 2000 John Wiley & Sons, Ltd.