CHARACTERISTIC PATTERN OF CHROMOSOMAL GAINS AND LOSSES IN PRIMARY LARGE B-CELL LYMPHOMAS OF THE GASTROINTESTINAL-TRACT

In contrast to low-grade B-cell lymphomas originating in the gastroint estinal (GI) tract, only few cytogenetic data are available for the la rge cell, highly malignant variants. We studied 31 large B-cell lympho mas of the GI tract by comparative genomic hybridization (CGH) and flu orescence in situ hybridization using specific DNA probes (FISH). The most frequent aberrations were gains of all or of parts of chromosomes 11 (11 cases), 12 (9 cases), 1q (4 cases), and 3q (4 cases). Losses o f parts of chromosome 6q and of parts of the short arm of chromosome 1 7 (6 cases each) were found most frequently. In four cases a total of seven high-level DNA amplifications was detected. In two of these case s, involvement of specific protooncogenes (REL and MYC) was shown. Som e genetic aberrations seemed to be associated with an inferior clinica l course: patients with greater than or equal to 2 aberrations had a s ignificantly shorter median survival. Furthermore, all patients with g ains of all or parts of chromosome arm 1q and with high-level DNA ampl ifications as well as seven of nine patients with gains of all or part s of chromosome 12 died of lymphoma. In conclusion, the pattern of chr omosomal gains and losses in large B-cell lymphomas was different from data reported for low-grade (MALT) lymphomas of the stomach and bowel , especially with respect to the high incidence of partial gains of ch romosome arm 11q and of all or parts of chromosome 12 and the low freq uency of polysomy 3. In addition, our data suggest that chromosomal ga ins and losses detected by CGH and FISH may predict for the outcome of patients with this tumor entity. (C) 1998 by The American Society of Hematology.