Numerical chromosomal abnormality in gastric MALT lymphoma and diffuse large B-cell lymphoma

Background: We investigated numerical chromosomal abnormalities, using the fluorescence in situ hybridization (FISH) method, in gastric mucosa-associated lymphoid tissue (MALT) lymphoma and diffuse large B-cell lymphoma (DLBL). We also compared the histopathological findings, including the presence or absence of Helicobacter pylori infection, with the analytical results. Methods: Sixteen patients who underwent operation for malignant gastric lymphoma in our department were divided into three groups: patients with low-grade gastric MALT lymphoma (l-MALT; n = 5), those with high-grade gastric MALT lymphoma (h-MALT; n = 8), and those with DLBL (n = 3). Numerical abnormalities of chromosomes 8, 9, 12, and 17 were investigated by the FISH method, and the presence or absence of H. pylori infection was microscopically examined. Results: Numerical abnormality was observed in chromosome 12 in 11 patients (68.8%), in chromosome 8 in 10 (62.5%), and in chromosome 17 in 5 (31.3%), showing a high frequency. H. pylori infection was detected in 80% and 50% of patients with l-MALT and h-MALT, respectively, but no H. pylori infection was observed in patients with DLBL. Conclusions: A new biological characteristic of gastric MALT lymphoma was obtained, i.e., a high frequency of numerical abnormalities of chromosomes 12, 8, and 17. There was no correlation between the numerical chromosomal abnormalities and the clinicopathological findings. Received: September 5, 2001 / Accepted: February 22, 2002 Acknowledgments. We sincerely appreciate the instruction and cooperation provided by Mr. A. Furuhata, Mr. S. Nakamura, and the staff, Department of Collaborative Pathology, Juntendo University, Tokyo, Japan. Reprint requests to: I. Watanobe