Splenic marginal zone B-cell lymphomas: two cytogenetic subtypes, one withgain of 3q and the other with loss of 7q

Background and Objectives. Splenic marginal zone B-cell lymphoma (SMZBCL) h as clinical, immunophenotypic and histologic features distinct from other B -cell malignancies, but few chromosome studies have been previously reporte d. In the present study we performed conventional cytogenetics and in situ hybridization studies in 47 patients with SMZBCL. Design and Methods. We studied 47 cases of splenic marginal zone B-cell lym phoma combining conventional cytogenetics and in situ hybridization (ISH) t echniques using centromeric probes (chromosomes 3 and 12), locus specific p robes (7q31 and 17p13) and cross-species color banding fluorescent ISH prob es (RxFISH). The diagnosis of SMZBCL was ascertained in all cases after stu dying, morphologically and immunologically, peripheral blood and splenectom y specimens. Results. A clonal chromosome abnormality detected by conventional cytogenet ics and/or FlSH was found in 33/47 patients (70%) being identified in 18 (1 8/33, 55%) as a complex abnormality. The most frequently recurrent abnormal ities were: gain of 3q (10 cases), del(7q) (12 cases), and involvement of c hromosomes 1, 8 and 14, No patient showed translocation t(11;14) (q13;q32) or t(14;18) (q21;q32). Trisomy 3 was detected in eight cases (8/47, 17%), T wo novel cytogenetic abnormalities involving 14q32, t(6;14)(p12;q32) and t( 10;14) (q24;q32) were reported. Deletion of 17p13 (P53) was observed by FIS H in one case, Only one patient showed a gain of 3q or trisomy 3 and deleti on 7q in the same karyotype. Interpretation and Conclusions. Our findings support the interpretation tha t two forms of SMZBCL could be considered, one with gain of 30 and the othe r with deletions at 7q. (C) 2001, Ferrata Storti Foundation.