The t(11;14)(q13;q32) and its molecular counterpart, BCL1 rearrangement, are consistent features of mantle cell lymphoma (MCL). Rearrangement is thought to deregulate the nearby CCND1 (BCL1/PRAD1) proto-oncogene, a member of the cyclin G1 gene family, and thereby to contribute to tumorigenesis. We and others have previously shown that the BCL1 locus is rearranged in 55% to 60% of MCL patients and that, on chromosome 11, more than 80% of the breakpoints are localized within a 1-kbp DNA segment known as the major translocation cluster (MTC). We have determined the nucleotide sequence for a portion of the MTC region, and constructed chromosome 11-specific oligonucleotides that were in conjunction with a consensus immunoglobulin (Ig) heavy chain joining region (JH) primer used to perform the polymerase chain reaction (PCR) to amplify t(11;14) chromosomal junctional sequences in DNA from 16 MCL patients with breakpoints in the MTC region. 15 of the 16 breakpoints that occurred at the MTC region were amenable to PCR detection. The sizes of the amplified bands, the existence or not of a Sac I site in the PCR products, and nucleotide sequencing of the amplified DNA from four patients showed that the breakpoints share a remarkable tendency to tightly cluster within 300 bp on chromosome 11, some of them occurring at the same nucleotide. On chromosome 14, the breakpoints were localized within the Ig JH. Our findings indicate that a BCL1 rearrangement can be detected using this approach in roughly one half of the MCL patients. This has implications for both the diagnosis and the clinical management of MCL.
A high remission rate is achieved with high-dose melphalan (HDM) in multiple myeloma (MM), and autologous transplantation of hematopoietic stem cells allows a prompt hematologic recovery after high-dose therapy. We treated 97 patients with high-risk MM (group 1:44 advanced MM including 14 primary resistances and 30 relapses; group 2: 53 newly diagnosed MM) with a first course of HDM. For responding patients a second course of high-dose therapy with hematopoietic stem cell support was proposed. After the first HDM, the overall response and complete remission rates were 71% and 25% with no significant difference between the two groups. The median durations of neutropenia and thrombocytopenia were significantly longer in group 1 (29.5 days and 32 days, respectively) than in group 2 (23 days and 17 days, respectively). This severe myelosuppression led to eight toxic deaths and the fact that only 38 of the 69 responders could proceed to the second course (three allogenic and 35 autologous transplantations). Among the 35 patients undergoing autologous transplantation (10 in group 1, 25 in group 2), 31 received their marrow unpurged collected after the first HDM, and four received peripheral blood stem cells. The median durations of neutropenia and thrombocytopenia after autologous transplantation were 24 days and 49 days, respectively. Two toxic deaths and nine prolonged thrombocytopenias were observed. The median survival for the 97 patients was 24 months (17 months in group 1, 37 months in group 2) and the median duration of response was 20 months. The only parameters that have a significant impact on the survival are the age (+/- 50 years) and the response to HDM. The median survival of the 35 patients undergoing autologous transplantation is 41 months, but the median duration of remission is 28 months with no plateau of the remission duration curve. Patients responding to HDM may have prolonged survival, but even a second course of high-dose therapy probably cannot eradicate the malignant clone.
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