Prognostic factors for hyperdiploid-myeloma: effects of chromosome 13 deletions and IgH translocations

Chromosomal hyperdiploidy is the defining genetic signature in 40-50% of myeloma (MM) patients. We characterize hyperdiploid-MM (H-MM) in terms of its clinical and prognostic features in a cohort of 220 H-MM patients entered into clinical trials. Hyperdiploid-myeloma is associated with male sex, kappa immunoglobulin subtype, symptomatic bone disease and better survival compared to nonhyperdiploid-MM (median overall survival 48 vs 35 months, log-rank P = 0.023), despite similar response to treatment. Among 108 H-MM cases with FISH studies for common genetic abnormalities, survival is negatively affected by the existence of immunoglobulin heavy chain (IgH) translocations, especially those involving unknown partners, while the presence of chromosome 13 deletion by FISH did not significantly affect survival (median overall survival 50 vs 47 months, log-rank P = 0.47). Hyperdiploid-myeloma is therefore a unique genetic subtype of MM associated with improved outcome with distinct clinical features. The existence of IgH translocations but not chromosome 13 deletion by FISH negatively impacts survival and may allow further risk stratification of this population of MM patients.

Clinical and biological implication of defective p53 pathway in multiple myeloma (MM)

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Background: The p53 tumor suppressor is commonly inactivated by mutations. Even in tumors without mutations, there are defects in the response to p53 activation. In MM, the prognostic significance of p53 mutation is unknown, while there has been no systematic study of p53 function. We seek to address these issues in this study. Methods: p53 mutation was studied by conformation sensitive gel electrophoresis with primers encompassing exons 1 to 10 followed by sequencing of DNA fragments with altered electrophoretic pattern in newly diagnosed MM patients entered into ECOG E9486 trial where patients were randomized to receive variations of melphalan-based conventional chemotherapy (VBMCP). Fisher’s exact tests were used to compare variables between patients. Kaplan-Meier survival curves were compared using the log-rank test. To investigate p53 function, we analyzed the expression of p53, and 3 of its transcriptional targets, APAF1, p21 and MDM2, in a separate cohort of 15 normal plasma cells (PC), 14 MGUS, 13 smoldering myeloma (SMM) and 101 MM (73 new and 28 relapsed) from the Mayo Clinic who had gene expression profiling performed on the Affymetrix U133A chip (Santa Clara, Ca). Results: Two hundred and sixty-eight patients had enough materials for study and were included in the analysis. The prevalence of p53 mutation was 3% (n = 9). Five of the 9 patients (56%, p = 0.001) with mutations also had p53 deletion (studied by fluorescent in-situ hybridization) resulting in bi-allelic loss of p53. Soft tissue plasmacytomas (37% v 7%, p = 0.018), and among the common translocations, t(4;14) and t(14;16) (50% v 18%) were more common in patients with p53 mutations. Despite similar response to treatment, those with p53 mutation had very short OS (16.7 v 41.4 months, p < 0.001). There was induction of p53 expression in MGUS and SMM with concurrent induction of APAF1, p21 and MDM2 whereas loss of this pattern was frequent in MM (45% in new MM and 60% in relapse MM compared to 15% in MGUS/SMM (p = 0.03)). Conclusions: p53 mutations are relatively rare in newly diagnosed MM patients but portend a short survival. However, functional abnormalities of p53 are prevalent and may be important in progression from MGUS/SMM to MM.

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Correlation of bone marrow angiogenesis and response to thalidomide dexamethasone in multiple myeloma

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Background: Thalidomide (Thal) in combination with dexamethasone (Dex) is an effective therapy for myeloma (MM). Though initially evaluated in MM because of its anti-angiogenic properties, it is not clear how much this contribute to its anti-MM effects. We examined whether the degree of angiogenesis influences response to Thal + Dex, as well as effect of therapy on marrow angiogenesis. We also examined whether expression of angiogenic cytokines by MM cells affect response to therapy. Methods: A total of 207 pts with newly diagnosed MM were randomized on the ECOG phase III trial (E1A00) to either Thal-Dex or Dex alone. Bone marrow microvessel density (MVD) was determined on 88 pts at diagnosis and at 4 mos after therapy in 25 pts. Expression of fibroblast growth factor (FGF) and vascular endothelial growth factor (VEGF) by MM cells was determined by RTPCR on 60 pts at diagnosis and on 22 pts at 4 mos. In addition, the percentage of marrow PCs in apoptosis was determined at diagnosis and 4 mos in 43 pts. A decrease in the serum M protein by 50% or in its absence, a decrease in urine M protein by 50% was considered a response. Results: The median BM MVD at diagnosis was 33 (3–118), and was similar in the pts responding to therapy (36.4) and in the non responders (45.4). We also separately looked at those receiving the combination vs. Dex alone, and did not find any correlation. The expression of FGF and VEGF in the PCs did not predict response to therapy with either the combination or Dex. Among the 17 responding pts, MVD decreased by a mean of 12 compared to an increase in the mean MVD of 3 among the non responders (P = NS). There was no significant correlation between the level of FGF or VEGF expression and the marrow MVD. There was no correlation between the percentage of myeloma cells in apoptosis at baseline and response to therapy. Conclusion: While the anti-angiogenic activity of Thal may play a role in its anti-myeloma effect, baseline MVD or tumor cell expression of angiogenic cytokines do not predict resistance or response to Thal-Dex or Dex alone. The findings here confirm previous observations that marrow angiogenesis is not related to the degree of secretion of angiogenic cytokines by individual cells, but rather the cumulative effect of the tumor mass.

No significant financial relationships to disclose.

Ploidy status rarely changes in myeloma patients at disease progression

Hyperdiploid and non-hyperdiploid multiple myeloma represents distinct biological entities characterized by different patterns of genetic changes. We sought to determine whether ploidy category (non-hyperdiploid versus hyperdiploid) remains stable over time from diagnosis to progression. Of the 43 patients studied (39 by flow cytometry DNA index and 4 by a FISH-based index), only five (12%) altered their ploidy status at progression. In three of these patients, the change may possibly be attributable to technical artifacts because of the low absolute change in DNA index. For those who retain their ploidy subtypes, the DNA index change minimally (3.75+/-4.87%). It would appear that the initiating genetic events underlying hyperdiploid and non-hyperdiploid MM that marks them out as distinct entities continue to dominate and persist during disease evolution and progression.

A multicenter phase 2 trial of stem cell transplantation for immunoglobulin light-chain amyloidosis (E4A97): an Eastern Cooperative Oncology Group Study

Stem cell transplantation was introduced as a new therapeutic modality for amyloidosis. The purpose of the current study was to determine the feasibility and toxicity of stem cell transplantation for amyloidosis in a cooperative group setting in which most participating institutions would have limited experience in managing the disorder. A total of 30 patients with biopsy-proven amyloidosis shown to be immunoglobulin light-chain type were enrolled on this trial. The protocol required mobilization of a minimum of 6 x 10(8) mononuclear cells/kg or 5 x 10(6) CD34(+) cells/kg ideal body weight. These targets had to be achieved within seven collections. Patients with advanced hepatic, renal, or cardiac failure were excluded. End points included objective response rate and overall survival. The secondary end point of the protocol was nonhematologic toxicity. Accrual to the study was faster than expected. The overall response rate (hematologic and organ) was 64%, with three treatment-related deaths. Another patient died before day 30 of sudden cardiac death not treatment related. The median follow-up of surviving patients is 30.3 months. Median survival has not been reached. Stem cell transplantation for selected patients with amyloidosis is feasible in a cooperative group setting. A multicenter phase 3 trial of high-dose therapy is indicated.