Light-chain only multiple myeloma is due to the absence of functional (productive) rearrangement of the IgH gene at the DNA level.

Although most multiple myeloma (MM) cases are characterized by the detection of a monoclonal immunoglobulin in the serum, about 15% of the patients present only immunoglobulin light chains, detected either in the urine or serum or both. These patients are designated as having light-chain (LC) MM. Using fiber-fluorescent in situ hybridization, and in contrast to patients and myeloma cell lines secreting heavy chains (who presented a legitimate functional IgH rearrangement in every case), LC MM never displayed a functional IgH recombination.

PCR detection of residual Bcl-2/IgH-positive cells after high-dose therapy with autologous stem cell transplantation is a prognostic factor for event-free survival in patients with low-grade follicular non-Hodgkin's lymphoma.

This study was designed to evaluate the results of high-dose therapy followed by purged autologous stem cell transplantation (ASCT) for patients with low-grade follicular non Hodgkin's lymphoma (LGFL), and the prognostic significance of PCR detection of residual Bcl-2/IgH-positive cells after ASCT. Between 1992 and 1998, 49 patients with LGFL received total body irradiation and high-dose cyclophosphamide followed by purged ASCT. PCR amplification of the Bcl-2/IgH rearrangement was performed at diagnosis, on stem cell collections before and after purging and on bone marrow and blood samples after ASCT.

Cyclin D1 expression in patients with multiple myeloma.

Introduction: Chromosomal abnormalities are detected in 50 to 70% of patients with multiple myeloma (MM). By conventional cytogenetic analysis, a t(11;14)(q13;q32) is observed at a frequency of 3 to 14%.

Materials And Methods: To demonstrate a cyclin D1 expression in MM patients or MM cell lines, 14 patients with multiple myeloma (MM) and nine human multiple myeloma cell lines (HMCL) were screened by a competitive RT-PCR and/or Northern blot analysis for cyclin D1 expression.

High incidence of N and K-Ras activating mutations in multiple myeloma and primary plasma cell leukemia at diagnosis.

Using allele-specific amplification method (ARMS), a highly sensitive one-stage allele-specific PCR, we have evaluated the incidence of NRAS and KRAS2 activating mutations (codons 12, 13, and 61) in 62 patients with either monoclonal gammopathy of undetermined significance (MGUS) or multiple myeloma (MM), primary plasma-cell leukemia (P-PCL), and also in human myeloma cell lines (HMCL). NRAS and/or KRAS2 mutations were found in 54.5% of MM at diagnosis (but in 81% at the time of relapse), in 50% of P-PCL, and in 50% of 16 HMCL.

IL-6 upregulates its own receptor on some human myeloma cell lines.

Interleukin 6 (IL-6) is the major survival factor of myeloma cells. In this study, we demonstrate that IL-6, oncostatin M (OSM) and leukemia inhibitory factor (LIF) upregulate membrane IL-6 receptor alpha (IL-6Ralpha) on OPM-2 myeloma cell line at transcriptional level. In OPM-2 cells, IL-6, OSM and LIF induce both signal transducers and activators of transcription (STAT), mitogen activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI 3-K) activation.

The cancer germ-line genes MAGE-1, MAGE-3 and PRAME are commonly expressed by human myeloma cells.

In this study, we have investigated the mRNA expression of the cancer germ-line genes MAGE, BAGE, GAGE, RAGE and the tumor-overexpressed gene PRAME by human myeloma cell lines and malignant plasma cells from patients with multiple myeloma (MM). By reverse transcription-PCR, we show that all myeloma cell lines (n = 16) express at least one of these genes, except RAGE-1 that was never expressed. We show that malignant plasma cells from the majority of MM patients (n = 21) expressed MAGE-1, MAGE-3 and PRAME.

Amplification of the 11q23 region in acute myeloid leukemia.

Cytogenetic abnormalities involving the 11q23 region are found in both acute lymphoblastic leukemia (ALL) and myeloid leukemia (AML). Molecular consequences of 11q23 translocations are the formation of chimeric genes, all of them involving the MLL (mixed-lineage leukemia) gene. To evaluate the usefulness of fluorescence in situ hybridization (FISH) in detecting MLL rearrangements in AML, we analyzed 181 patients with an MLL-specific probe.

Detection of t(11;14) using interphase molecular cytogenetics in mantle cell lymphoma and atypical chronic lymphocytic leukemia.

The chromosomal translocation t(11;14)(q13;q32) fuses the IGH and CCND1 genes and leads to cyclin D1 overexpression. This genetic abnormality is the hallmark of mantle cell lymphoma (MCL), but is also found in some cases of atypical chronic lymphocytic leukemia (CLL), characterized by a poor outcome. For an unequivocal assessment of this specific chromosomal rearrangement on interphase cells, we developed a set of probes for fluorescence in situ hybridization (FISH).

CD28, a marker associated with tumoral expansion in multiple myeloma.

CD28 expression was thoroughly investigated on plasma cells of monoclonal gammopathy of undetermined significance, multiple myeloma (MM), and human myeloma cell lines. CD28+ plasma cells were detected in 19% of 31 monoclonal gammopathy of undetermined significance, 41% of 116 MM, and 100% of 13 human myeloma cell lines. CD28+ myeloma cells were detected in 21 of 79 (26%) MM cases at diagnosis, 13 of 22 (59%) at medullary relapse (P < 0.

Metalloproteinases in multiple myeloma: production of matrix metalloproteinase-9 (MMP-9), activation of proMMP-2, and induction of MMP-1 by myeloma cells.

Multiple myeloma is a very devastating cancer with a high capacity to destroy bone matrix. Matrix metalloproteinases (MMPs) play a critical role in bone remodeling and tumor invasion. In this study, we have investigated the involvement of interstitial collagenase (MMP-1) and gelatinases (MMP-2 and MMP-9) in the biology of multiple myeloma.

Molecular cytogenetic abnormalities in multiple myeloma and plasma cell leukemia measured using comparative genomic hybridization.

Comparative genomic hybridization (CGH) was used to identify recurrent regions of DNA sequence loss and gain in 21 multiple myeloma (MM) and plasma cell leukemia (PCL) primary tumor specimens and cell lines. Multiple regions of non-random sequence loss and gain were observed in 8/8 primary advanced stage tumors and 13/13 cell lines. Identification of sequence copy number changes was facilitated by statistical analyses that reduce subjectivity associated with identification of copy number changes and by requiring that sequence changes are visible using both red- and green-labeled tumor DNA.

Chromosome mapping and expression of the human interleukin-13 receptor.

Interleukin-13 (IL-13) is a cytokine secreted by activated T cells and shares most but not all biological activities with interleukin-4 (IL-4). Both cytokines play an important role as a switch factor directing synthesis of IgE; they act on monocytes and endothelial cells, but unlike IL-4, IL-13 does not act on T cells. These cytokines have both common and distinct components in their respective receptors.

Comparative genomic hybridization detects genomic abnormalities in 80% of follicular lymphomas.

Comparative genomic hybridization (CGH) was used to analyse 34 follicular lymphoma (FL) samples. 27 samples showed DNA sequence copy number changes of at least one genomic region (26 samples with at least one gain and nine with at least one loss). Some chromosomes or chromosomal regions were preferentially involved.

Myeloma cell growth arrest, apoptosis, and interleukin-6 receptor modulation induced by EB1089, a vitamin D3 derivative, alone or in association with dexamethasone.

We have previously shown that malignant plasma cells expressed the specific receptor for 1,25-dihydroxyvitamin D3 and that this derivative could significantly inhibit the proliferation of such malignant cells. More recently, new vitamin D3 derivatives have been generated with extraordinarily potent inhibitory effects on leukemic cell growth in vitro. These new data prompted us to (re)investigate the capacity of such new vitamin D3 derivatives to inhibit myeloma cell growth in comparison with that of dexamethasone, a potent antitumoral agent in multiple myeloma.

High incidence of deletions but infrequent inactivation of the retinoblastoma gene in human myeloma cells.

We have studied the retinoblastoma (RB-1) susceptibility gene status and pRB expression in 22 human myeloma cell lines (HMCL) and in 10 patients with advanced multiple myeloma (MM). Deletions of the RB-1 gene were observed in 81% (17/21) of the informative HMCL, regardless of their paracrine or autocrine interleukin-6 (IL-6) status. Among the deleted HMCL, only one (U266) had a biallelic deletion and lacked pRB expression.

Deletion cartography around the D13S25 locus in B cell chronic lymphocytic leukemia and accurate mapping of the involved tumor suppressor gene.

The presence of an unidentified tumor suppressor gene on the long arm of chromosome 13 which could be involved in the development of B cell chronic lymphocytic leukemia has been suspected because of frequent deletions of the locus D13S25 which lies 1.6 cM telomeric to the retinoblastoma gene. In order to accurately map this gene, cells from 25 B cell chronic lymphocytic leukemia tumors have been analyzed for allelic loss using a panel of microsatellite markers located in this region.