Mechanism for BCL2 amplification in a diffuse large B-cell lymphoma. (A) Chromosome 18q–derived sequences were translocated to chromosome 1q32, which was further translocated to chromosomes 16 and 19 (case no. 6; Table 1). CGH profiles of chromosomes 1 and 18 are also shown. The karyotype is 48,X,–X,der(1),+3,del(6)(q12q22),+7,−16,+der(16),−19,+der(19),+r(?)×2, but only the chromosomes taking part in the translocations are described in the figure. The interpretation of the marker chromosomes was confirmed by painting, using probes specific for chromosomes 16, 18, and 19. (B) Fluorescence in situ hybridization using a chromosome 18-specific probe shows three labels (large arrows) in addition to normal chromosomes (small arrows). This shows that 18-derived material was translocated to three chromosomes. (C) DAPI (4,6-diamidino-2-phenylindole) and propidium iodide staining of the metaphase in (B).