A new multiple myeloma cell line, MEF-1, possesses cyclin d1 overexpression and the p53 mutation

BACKGROUND. The t(11;14)(q13;q32) translocation with cyclin D1 overexpressi on commonly is found in mulitiple myeloma (MM) and in mantle cell lymphoma (MCL). Several reports have shown that p53 mutations in MCL lead to blastoi d transformation and a worse prognosis; however, the role of p53 mutations in MM with t(11;14) is unclear. METHODS. In this study the authors describe a patient with MM with t(11;14) adn a p53 mutation at presentation and characterized a cell line, MEF-1, e stablished from this patient. Immunohistochemical analysis of p53 and cycli n D1 proteins was performed. The p53 gene was analyzed by polymerase chain reaction-single strand conformation polymorphism and direct sequencing. The expression of cyclin D1 mRNA was examined by Northern blot analysis. RESULTS. MEF-1 had t(11;14) with overexpression of cyclin D1 mRNA and produ ced immunoglobulin kappa-light chain. MEF-1 had a mutation in exon 7 (codon 255-257) of the p53 gene, which was noted in the patient's myeloma cells. CONCLUSIONS. p53 mutations may be important genetic events in disease progr ession of MM with t(11;14). The MEF-1 cell line may be a useful tool to stu dy mechanisms of progression in MM based on abnormalities of the cyclin D1 gene. (C) 1999 American Cancer Society.