Detection of t(14q32) by double-color FISH and Ig-light-chain staining in interphase plasma cells.

Cytospin slides from BM samples were fixed in 10% acetic acid solution in ethanol, followed by dehydration, denaturation (70% formamide), and dehydration. After hybridization of the probes overnight at 37°C, immunoglobulins were stained using FITC-conjugated goat anti-human light-chain antibodies to positively identify plasma cells. The IgH2 and C-α probes were detected following standard avidine-FITC and CY3 staining. The slides were mounted with antifade medium containing DAPI. Fusion signals of the probes indicate nontranslocated IgH loci, whereas split signals reflect a translocation of the IgH locus.