Three-color FISH analyses of IgH, Igλ, and cyclin D3 in MM tumor samples.

(A) MM2 tumor: (Ai) CH (green), cyclin D3 cosmid (red), and chromosome 14 painting (purple) probes were hybridized to metaphase chromosomes (blue DAPI counterstain). Two copies of CH and cyclin D3 probes colocalize on der(14) t(6;14)(p21;q32) (only one der[14] shown). One copy of cyclin D3 is on normal chromosome 6. (Aii) The same metaphase chromosomes as in (Ai) were stripped and rehybridized with CH (green), VH (green), cyclin D3 BAC (red), and chromosome 6 painting (purple) probes. Two copies of CH and cyclin D3 colocalize on der(14), one copy of cyclin D3 is on normal chromosome 6, and one copy of VH and cyclin D3 colocalize on der(6). (Aiii) Interphase nucleus from (Ai) shows colocalization (arrowheads) of CH and cyclin D3 probes. (B) A25 tumor: (Bi) Cλ (green) and chromosome 22 painting (purple) probes were hybridized to metaphase chromosomes (blue DAPI counterstain). One copy of Cλ is on der(6) and no der(22) was seen. (Bii) The same metaphase chromosomes as in (Bi) were stripped and rehybridized with Cλ (green), cyclin D3 cosmid (red), and chromosome 6 painting (purple). One copy of Cλ and cyclin D3 colocalize on der(6) t(6;22)(p21;q11). (Biii) Interphase nucleus from (Bi) shows colocalizing Cλ and cyclin D3 probes (arrowhead). (C) CH (red), cyclin D3 BAC (green), and anti-IgL antibody (blue) were reacted with interphase nuclei from MM tumor P12. One copy of CH and cyclin D3 BAC colocalize (arrowhead) in the nucleus of the MM cell (arrow) that is identified by the anti-IgL antibody blue staining of its cytoplasm.