Genomic alterations in diffuse-type gastric cancer as shown by high-resolution comparative genomic hybridization.

Gastric adenocarcinoma is a serious public health concern, especially in northern Brazil. Gastric cancer can be subdivided into diffuse and intestinal types. Genetic imbalances in diffuse-type gastric cancer remain largely unknown. In the present study, we analyzed 24 advanced diffuse-type gastric cancer samples from northern Brazil subjects using high-resolution comparative genomic hybridization. We found chromosomal alterations in 75% of samples. In cancers with aneusomies, the mean genomic copy number alteration was 6.4. Losses of chromosome regions exceeded gains. The most frequent losses were located at chromosome regions 11q and 18q (five samples for each region), 1pq, 3q, 4q, 5q, 13q, and 14q (four samples), followed by 2pq, 7p, 9pq, 11p, and 16p (three samples). Our results confirm that gastric cancer has a complex pattern of chromosomal alterations that can be due to general chromosomal instability related to the advanced stage of gastric carcinogenesis. Loss of 11q and 18q were the most frequent chromosomal changes in diffuse-type gastric adenocarcinoma in individuals from northern Brazil. Frequent loss of 11q chromosome region in this gastric cancer may be peculiar among this population.