Comparative genomic hybridization analysis of primary cutaneous B‐cell lymphomas: Identification of common genomic alterations in disease pathogenesis

To investigate genetic alterations in primary cutaneous B-cell lymphomas (PCBCLs), we have analyzed 29 cases of PCBCL. Comparative genomic hybridization showed chromosome imbalances (CIs) in 12 cases (41%). The mean number of CIs per sample was 2.05 +/- 2.97, with gains (1.48 +/- 2.38) more frequent than losses (0.56 +/- 1.40). The common regions of gains were 18/18q (50%), 7/7p (42%), 3/3q (33%), 20 (33%), 1p (25%), 12/12q (25%), and 13/13q (25%), whereas loss of 6q was frequent (42%). Among the different subsets of PCBCLs, CI was seen in 50% of diffuse large-cell lymphomas (DLCLs), 33% of marginal zone lymphomas, and 8% of follicle center cell lymphomas and unclassified lymphomas. A similar pattern of CI was observed in these lymphomas, but loss of 6q and gains of 3/3q were present only in DLCLs. Microarray-based genomic analysis of four DLCL cases identified oncogene gains of SAS/CDK4 (12q13.3) in three cases and MYCL1 (1p34.3), MYC (8q24), FGFR2 (10q26), BCL2 (18q21.3), CSE1L (20q13), and PDGFB (22q12-13) in two cases, whereas losses of AKT1 (14q32.3), IGFR1 (15q25-26), and JUNB (19p13.2) were identified in three cases, and losses of FGR (1p36), ESR (6q25.1), ABL1 (9q34.1), TOP2A (17q21-22), ERBB2 (17q21.2), CCNE1 (19q13.1), and BCR (22q11) were each identified in two cases. In addition, real-time-polymerase chain reaction detected amplification of BCL2 in 5 of 29 cases. These findings suggest that there are complex but consistent genetic alterations associated with the pathogenesis of PCBCLs.