Molecular cytogenetic characterization of marginal zone B-cell lymphoma: correlation with clinicopathologic findings in 14 cases

Background and Objectives. To improve the definition of the incidence and s ignificance of chromosome lesions occurring in marginal zone B-cell lymphom a (MZBCL). Design and methods. Fourteen cases of MZBCL diagnosed according to the REAL classification were studied by conventional chromosome analysis (CCA) and by inter-phase fluorescence in site hybridization (FISH) using the followin g probes: 3q27/BCL6, 6q21, 7q31, 9p21/p16, 11q22/ATM, 13q14, 17p13, centrom eres of #3, #7, #12. Pertinent clinical data were collected. Results. Primary disease presentation consisted of histologically documente d splenic MZBCL in 9 cases, nodal MZBCL in 3 cases and extra-nodal MZBCL in 2 cases. Four cases showed evolution into a high-grade lymphoma, due to th e presence of a predominant large cell or blast cell component. Clonal kary otype anomalies were detected by CCA in 12 cases, 6 of which had a complex karyotype, including all 4 cases with high-grade histology. Interphase FISH confirmed cytogenetic data and revealed several cryptic chromosomal lesion s. Overall, total/partial +12 was found in five cases; 13q14 and 17p13 dele tion were found in four cases each; +3, 7q31 deletion and a BCL6 split sign al were found in three cases; deletions at 6q21 and 11q22.3 in two cases ea ch; +7 and a 9p21 deletion were found in one case each. Interpretation and Conclusions. i) Besides +3 and 7q-, 13q14 deletion, tota l/partial +12, BCL6 rearrangement, and deletions at 6q21, 11q22-23, and 17p 13.3 are relatively frequent events in MZBCL; ii) unlike in mantle cell lym phoma, 9p21 deletion occurred unfrequently in MZBCL; iii) a switch into hig h grade histology is usually associated with complex chromosome defects, in cluding 6q-, 11q-, +12, and 17p. (C) 2001, Fenata Storti Foundation.