Molecular cytogenetic analysis of patients with CEBP/IGH translocations. (A) Representative partial karyotypes of the 4 IGH translocation from left to right: G-banded, t(14;19)(q32;q13), t(14;20)(q32;q13), t(8;14)(q11;q32); and R-banded, t(14;14)(q11;q32). In the G-banded images the normal chromosomes are shown on the left and the abnormal (der) chromosomes are shown on the right (breakpoints arrowed). There are no normal chromosomes 14 in the R-banded image as both are involved in the translocation. (B) Equivalent FISH images of DAPI-stained metaphases hybridized with specific probes (from left to right) for CEBPA, CEBPB, CEBPD, and CEBPE (probe details are provided in Table 1). A normal red/green fusion signal is seen on the normal chromosomes at 19q13, 20q13, and 8q11. In t(14;14) the normal fusion is seen at 14q11 on the larger der(14) chromosome. A splitting of 1 fusion signal between the derivative chromosomes is shown, with the centromeric signal remaining on the derivative partner chromosome, while the telomeric signal has translocated to the IGH locus in 14q32 on the der(14) (arrows). (C) Idiograms to show the location of breakpoints cloned by LDI-PCR from the IGHJ6 segment. Representative breakpoint sequences with identity to IGHJ and the corresponding CEBP locus are shown.