Quantitation of multiple myeloma oncogene 1/interferon-regulatory factor 4gene expression in malignant B-cell proliferations and normal leukocytes

Background: We studied multiple myeloma oncogene 1/interferon-regulatory fa ctor 4 (MUM1/IRF4) mRNA expression in various malignant human hematopoietic cell lines and normal leukocyte fractions. Materials and Methods: A quanti tative reverse transcription-polymerase chain reaction was used to assess e xpression and chromosomes were examined for anomalies by fluorescent in sit u hybridization. Results: Among 12 cell lines examined, mRNA transcripts we re expressed only in B-lymphoblastic and myeloma cell lines. Myeloma cells and malignant cell lines derived from mature B cells expressed more transcr ipt than cell lines derived from immature B cells. Transcript levels, howev er, showed no association with chromosomal translocations. Expression in B- cell fractions from healthy donors was much less than in the malignant cell s. In addition, MUM1/IRF4 mRNA expressed in samples from patients with acut e lymphoblastic leukemia derived from B cells but not T cells. Conclusion: Our results suggested that MUM1/IFR4 gene expression is related to stage of differentiation of malignant B cells and they indicated the possibility th at the quantitative analysis of MUM1/IRF4 gene is a useful tool for detecti on of malignant B-cell proliferations in clinical laboratory tests.