OBJECTIVETo determine the frequency of trisomy 3 in the intestinal B-cell lymphoma of mucosa associated lymphoid tissue (MALT) type and to explore the relationship between these two.

METHODSParaffin embedded tissue sections of intestinal B-cell lymphomas of MALT type, according to WHO classification, were successfully studied. Seven cases were classical MALT lymphoma, being clinically low-grade, and one MALT lymphoma with large cell transform, clinically high-grade. By using biotin labelled DNA probes specific for chromosome 3 centromeric, chromosome in situ hybridization (CISH) were performed. Probe for C16 was used as the positive reference of the method, and chronic intestinal inflammation as the experiment control for detection of C3 copies in tumor cells.

RESULTSOf the 7 low-grade classical MALT lymphoma, 5 showed trisomy 3 and 2 normal C3. The only case of MALT transformed was trisomy 3. The frequency of trisomy 3 in the intestinal low-grade lymphoma was 71.4%.

CONCLUSIONThe frequency of trisomy 3 in the intestinal low-grade lymphoma is high, indicating that it may be involved in the pathogenesis of this disease and may be of value for the diagnosis.