Simultaneous fluorescence immunophenotyping and interphase cytogenetics (fiction) in multiple myeloma

Multiple myeloma (MM) is a disease characterized by a
proliferation of malignant plasma cells (PC) in the bone marrow;
survival rate varies greatly but it is generally poor and
related to abnormalities of specific chromosomes, as translocations
involving the Ig heavy chain gene at 14q32 or partial/
total deletion of chromosome 13. Conventional cytogenetics of
MM is difficult owing to the low proliferation rate of malignant
PC; it has to be considered poorly informative if not associated
to separation or immunophenotyping techniques. We
present the results of FICTION analysis of patients at the
beginning of the disease.This technique combines immunofluorescence
and FISH analysis on interphase cells.
Immunophenotyping was performed by a primary antibody
against CD138 (also called syndecan 1), a heparan sulfate
rich membrane glycoprotein expressed on normal and malignant
plasma cells only, followed by a secondary antibody
AMCA-labeled. Interphase FISH experiments were performed
on the same slide using a probe (Texas red-labeled) specific
for the RB (13q14.2) locus, associated with Tel (13q) DNA
probe (fluoresceine-labeled).Results: PC were detected by the
intense signal of AMCA, while chromosome 13 probes were
analyzed with Texas Red- and FITC-filters. The results
obtained with FICTION procedure were compared with those obtained with the FISH analysis on interphase cells and chromosome samples using the same probes.