Longitudinal analysis of IgH-MMSET hybrid transcripts and FGFR3.

PB and BM samples collected over the course of disease from 2 t(4;14)⁺ FGFR3-expressing MM patients are shown. The monoclonal protein values (g/L) at each visit are marked above each PB sample, and BM samples are denoted by an asterisk. Clinical diagnosis and relapse along with therapy are noted. Auto-PBSCT indicates autologous peripheral blood stem cell transplantation following high-dose therapy; Mob PB, apheresis product from mobilized peripheral blood. Representative panels for each reaction are shown. J_H, J_H-ms6r hybrid transcript assay; Iμ1, Iμ1-ms6r hybrid transcript assay; FGFR3, FGFR3 expression; CDR2/3, CDR2-CDR3 patient-specific transcript assay; B2-M, positive control for integrity of RNA. (A) The patient whose results are shown has the MB4-3 breakpoint type; however, the breakpoint occurs between exon 4 and exon 4a, creating a doublet band. The upper band of the doublet results from alternative splicing to exon 4a, as in Figure 1A. (B) The patient whose results are shown has the MB4-1 breakpoint type.