Combined analysis using interphase fluorescence in situ hybridization (FISH) and bromodeoxyuridine (BrdU) incorporation to assess proliferative activity of cytogenetically defined cell populations.

Incorporated BrdU was detected with a fluorescein isothiocyanate-labeled monoclonal antibody that produced the green fluorescent pattern of the nucleus. A Spectrum Orange-tagged probe specific for the retinoblastoma gene-1 (rb-1) was used for FISH analysis. Thus, of the 2 rb-1–deleted myeloma cells, 1 cell incorporated BrdU, indicating DNA synthesis and proliferation.