Fluorescence in situ hybridization for trisomy 12.

Depicted are the nuclei of NLC (large ovals) and CLL cells (small circles) examined for trisomy 12 by FISH. The 2 large NLC nuclei have only 2 bright fluorescence signal spots, whereas the 4 CLL cell nuclei each have 3 bright signal spots, reflecting the presence of trisomy 12.