TRISOMY-3 IN LOW-GRADE B-CELL LYMPHOMAS OF MUCOSA-ASSOCIATED LYMPHOID-TISSUE

Characteristic chromosomal aberrations have been associated with subty pes of non-Hodgkin's lymphoma with distinct clinicopathologic features . Low-grade B-cell lymphomas of mucosa-associated lymphoid tissue (MAL T) form such a group and might be expected to be characterized by a sp ecific cytogenetic abnormality. Metaphase analyses of MALT lymphoma ar e rare due to problems with fresh tissue collection and poor in vitro proliferation. However, the small number of published series suggests that chromosome trisomies, particularly trisomy 3, might be characteri stic of these tumors. The application of interphase cytogenetic techni ques to routinely processed material allows the examination of a large series of archival cases and is particularly useful for the demonstra tion of chromosome trisomies, We have used this technique to analyze 7 0 cases of low-grade MALT lymphoma from various sites and found trisom y 3 in 60%. This finding compares with 16% in low-grade nodal B-cell l ymphoma and 27% in primary splenic lymphoma of marginal zone type (spl enic lymphoma with villous lymphocytes). These results provide further evidence that low-grade MALT lymphomas from all sites form a single p athologic entity distinct from nodal B-cell lymphomas. Although MALT l ymphoma and primary splenic lymphoma may arise from marginal zone B ce lls, they are genetically distinct. (C) 1995 by The American Society o f Hematology.