Cytogenetic analysis of 363 consecutively ascertained diffuse large B-celllymphomas

Cytogenetic analysis was performed on 363 biopsy specimens with histologica lly confirmed diffuse large B-cell lymphoma (DLBCL), consecutively ascertai ned at the Memorial Sloan-Kettering Cancer Center, New York, between 1984 a nd 1994. Among 248 samples successfully karyotyped, clonal chromosomal abno rmalities were noted in 215 (87%). The salient cytogenetic features of DLBC L from this analysis comprised the following. Breakpoints clustered, in dec reasing frequency, at I 0 recurring sites: 14q32, 18q21, 1q21, 3q27, 1p36, 8q24, 3p21, 6q21 I, 1p22, and 22q11. Of these, deletion breaks affecting ba nds 3p21 and 1p22 and translocation breaks affecting bands 14q32, 3q27, and 1q21 were frequent and distinctive for this subset of lymphomas. Transloca tions affecting band 14q32 were noted in IIO cases (51%) of which 42 (20%) had t(14; 18)(q32;q21), 21 (10%) had t(8; 14)(q24;q32) or t(8;22)(q24;q11), 14 (6.5%) had t(3;14)(q27;q32) or t(3;22)(q27;q11), and 33 (15%) had other rearrangements of 14q32. Among 144 new translocations detected in the enti re group, the breakpoints in 19 were recurrent and clustered at three sites : 1q21, 3q27, and 14q32. Regions of common cytogenetic deletions were ident ified at I I sites, 1p36, 1p33-34, 1p31, 1q32, 3p25-26, 3p21, 3q21, 6q15, 6 q21, 6q23-24, and 7q32, suggesting possible loss of candidate tumor suppres sor genes associated with DLBCL development. Of these, only those at 6q21, 6q23, and 7q32 have previously been described in lymphoid neoplasms. The gr oup of DLBCL with translocations affecting band 14q32 showed a significantl y different pattern of additional cytogenetic changes compared to the group lacking such translocation. This new comprehensive cytogenetic characteriz ation provides the basis for investigations aimed at identifying molecular mechanisms as well as the clinical impact of cytogenetic changes in DLBCL. (C) 1999 Wiley-Liss, Inc.