Constitutional mismatch repair deficiency syndrome: clinical description in a French cohort.

BACKGROUND: Constitutional mismatch repair deficiency (CMMRD) syndrome is a childhood cancer predisposition syndrome involving biallelic germline mutations of MMR genes, poorly recognised by clinicians so far. METHODS: Retrospective review of all 31 patients with CMMRD diagnosed in French genetics laboratories in order to describe the characteristics, treatment and outcome of the malignancies and biological diagnostic data. RESULTS: 67 tumours were diagnosed in 31 patients, 25 (37%) Lynch syndrome-associated malignancies, 22 (33%) brain tumours, 17 (25%) haematological malignancies and 3 (5%) sarcomas. The median age of onset of the first tumour was 6.9 years (1.2-33.5). Overall, 22 patients died, 9 (41%) due to the primary tumour. Median survival after the diagnosis of the primary tumour was 27 months (0.26-213.2). Failure rate seemed to be higher than expected especially for T-cell non-Hodgkin's lymphoma (progression/relapse in 6/12 patients). A familial history of Lynch syndrome was identified in 6/23 families, and consanguinity in 9/23 families. PMS2 mutations (n=18) were more frequent than other mutations (MSH6 (n=6), MLH1 (n=4) and MSH2 (n=3)). CONCLUSIONS: In conclusion, this unselected series of patients confirms the extreme severity of this syndrome with a high mortality rate mostly related to multiple childhood cancers, and highlights the need for its early detection in order to adapt treatment and surveillance.

Efficient characterization of the TCR repertoire in lymph nodes by flow cytometry.

Analysis of the T-cell receptor (TCR) repertoire by flow cytometry proved to be relevant for investigating T-cell diversity and detecting reactive cells in blood samples. We used this approach to characterize non-malignant T-lymphocytes in lymph nodes and give insights into their origin. The TCR repertoire of CD4+ and CD8+ T-cells from 81 lymph nodes was analyzed with a four-color flow cytometer using a wide panel of 25 anti-Vbeta monoclonal antibodies. Flow cytometry proved to be a useful and informative technique. We demonstrated a diversified TCR-Vbeta repertoire, and only low level expansions, in 53% of the samples. They involved nearly all Vbeta families, were more frequent in the CD8+ subset of older patients, but were not related to pathology. No evidence could be demonstrated in favor of stimulation by common antigens. Interestingly, the TCR-Vbeta repertoire proved to be very similar in lymph nodes and blood samples. Our results argue that in the cases studied, lymph node enlargement is mainly due to an increased homing of circulating T-cells. They also provide reference values for expression of 25 TCR-Vbeta in lymph nodes, which could serve as a basis for further applications in diagnosis of T-cell lymphoproliferative disorders.

Clinical, cytogenetic and molecular characteristics of 14 T-ALL patients carrying the TCRbeta-HOXA rearrangement: a study of the Groupe Francophone de Cytogénétique Hématologique.

Recently, we and others described a new chromosomal rearrangement, that is, inv(7)(p15q34) and t(7;7)(p15;q34) involving the T-cell receptor beta (TCRbeta) (7q34) and the HOXA gene locus (7p15) in 5% of T-cell acute lymphoblastic leukemia (T-ALL) patients leading to transcriptional activation of especially HOXA10. To further address the clinical, immunophenotypical and molecular genetic findings of this chromosomal aberration, we studied 330 additional T-ALLs. This revealed TCRbeta-HOXA rearrangements in five additional patients, which brings the total to 14 cases in 424 patients (3.3%). Real-time quantitative PCR analysis for HOXA10 gene expression was performed in 170 T-ALL patients and detected HOXA10 overexpression in 25.2% of cases including all the cases with a TCRbeta-HOXA rearrangement (8.2%). In contrast, expression of the short HOXA10 transcript, HOXA10b, was almost exclusively found in the TCRbeta-HOXA rearranged cases, suggesting a specific role for the HOXA10b short transcript in TCRbeta-HOXA-mediated oncogenesis. Other molecular and/or cytogenetic aberrations frequently found in subtypes of T-ALL (SIL-TAL1, CALM-AF10, HOX11, HOX11L2) were not detected in the TCRbeta-HOXA rearranged cases except for deletion 9p21 and NOTCH1 activating mutations, which were present in 64 and 67%, respectively. In conclusion, this study defines TCRbeta-HOXA rearranged T-ALLs as a distinct cytogenetic subgroup by clinical, immunophenotypical and molecular genetic characteristics.

Multi-time scale analysis of the spatial representativeness of in situ soil moisture data within satellite footprints.

We conduct a novel comprehensive investigation that seeks to prove the connection between spatial and time scales in surface soil moisture (SM) within the satellite footprint (~50 km). Modeled and measured point series at Yanco and Little Washita in situ networks are first decomposed into anomalies at time scales ranging from 0.5 to 128 days, using wavelet transforms. Then, their degree of spatial representativeness is evaluated on a per time-scale basis by comparison to large-spatial scale datasets (the in situ spatial average, SMOS, AMSR2 and ECMWF). Four methods are used for this: temporal stability analysis (TStab), triple collocation (TC), the percentage of correlated areas (CArea) and a new proposed approach that uses wavelet-based correlations (WCor). We found that the mean of the spatial representativeness values tends to increase with the time scale but so does their dispersion. Locations exhibit poor spatial representativeness at scales below 4 days, while either very good or poor representativeness at seasonal scales. Regarding the methods, TStab cannot be applied to the anomaly series due to their multiple zero-crossings and TC is suitable for week and month scales but not for other scales where datasets cross-correlations are found low. In contrast, WCor and CArea give consistent results at all time-scales. WCor is less sensitive to the spatial sampling density, so it is a robust method that can be applied to sparse networks (1 station per footprint). These results are promising to improve the validation and downscaling of satellite SM series and the optimization of SM networks.

Genetics and epigenetics of 1q rearrangements in hematological malignancies.

Recently, we and others have described a novel class of chromosome aberrations that involves constitutive heterochromatin on human chromosome 1 (cytogenetic band 1q12). These anomalies are particularly frequent in B cell non-Hodgkins lymphoma (NHL) and multiple myeloma (MM) and, remarkably, almost invariably involve partial or total gain of chromosome 1q (including 1q12 heterochromatin) and the formation of novel heterochromatin/euchromatin junctions. This review discusses the pathological significance of these anomalies in light of i) recent integrated gene expression and array comparative genomic hybridisation (aCGH) profiling in MM and ii) increasing evidence of a key role for heterochromatin in the control of normal and pathological gene silencing.

[CDKN2A gene mutation and loss of p16 protein activity in a patient on levodopa presenting sporadic multiple primary melanoma]. / Mutation du gène CDKN2A et perte d'activité de la protéine p16 chez un malade traité par L-Dopa et atteint de mélanomes sporadiques multiples.

BACKGROUND: Cutaneous melanoma is a complex disease involving genetic and environmental factors. Levodopa has been incriminated in the development and/or progression of melanoma. OBSERVATION: We report the case of a man treated with levodopa and a dopadecarboxylase inhibitor for Parkinson's disease and presenting 22 cutaneous melanomas over a 4-year period. The patient is of phototype II and presents multiple nevi. Genetic analysis of predisposing genes demonstrated a CDKN2A mutation with loss of p16 activity. DISCUSSION: Multiple melanomas may be associated with genetic predisposition, and screening for the latter should be performed. The exceptionally high number of melanomas developed by our patient raised suspicions about levodopa, a precursor in melanin synthesis, as a potential inducer. Increased dermatologic controls and screening for predisposing genetic factors appear to us to be warranted in the event of melanoma development in patients on levodopa.

A variant translocation t(2;18) in follicular lymphoma involves the 5' end of bcl-2 and Ig kappa light chain gene.

We have examined three cases of human lymphoma bearing a t(2;18)(p11;q21) chromosome translocation. The bcl-2 gene appeared to be rearranged in all three cases and breakpoints were clustered in the 5' flanking region of the gene. In all three cases, bcl-2 was juxtaposed to J segments of the Ig kappa gene. This juxtaposition of the bcl-2 and Ig kappa genes is very similar to the variant chromosome translocations of Burkitt lymphoma that juxtapose the c-myc locus to IgL genes.

t(6;8), t(8;9) and t(8;13) translocations associated with stem cell myeloproliferative disorders have close or identical breakpoints in chromosome region 8p11-12.

A stem-cell myeloproliferative disorder involving T- and B-cell, and myeloid lineages, is associated with three different translocations with a breakpoint in region p11-12 of chromosome 8: t(6;8)(q27;p11), t(8;9)(p11;q33), and t(8;13)(p12;q12), respectively. Using fluorescence in situ hybridization (FISH), we have analysed blood cells from a series of five patients carrying these different translocations. We have identified cosmids from chromosome region 8p11-12 that span the breakpoint in all the cases. They are specific for the FCFR1 gene that encodes a receptor for members of the FGF family. The breakpoint was further detected by Southern and pulsed-field gel electrophoresis analyses with probes from the FGFR1 locus.

Prognostic significance of karyotype in de novo adult acute myeloid leukemia. The BGMT group.

A group of 201 adult patients, 127 younger and 74 older than 55 years, with de novo acute myeloid leukemia were investigated to determine the prognostic significance of karyotype on early death (toxic or aplastic death occurring before hematopoietic recovery), drug resistance, continuous complete remission (CCR) and survival probabilities at 5 years. A good prognostic impact was found for t(8;21), t(15;17) and inv(16). The best factor proved to be t(8;21) (5-year survival probability: 50%), followed by t(15;17) (5-year survival probability: 39%) and by inv(16) (5-year survival probability: 43%). An intermediate outcome was found in patients with trisomy 8 (27% alive at 5 years) and in patients with numerical abnormalities other than -7 and +8 (33% in CCR and 62% alive at 5 years). Normal karyotypes had a different prognostic impact according to age: intermediate in young and good in older patients. A poor outcome was observed among patients with del(5q)/-5 (median survival: 1 month), with 11q23 rearrangements (median survival: 1.5 months) and with del(7q)/-7 (median survival: 10 months). The 'other structural change' group was also found to be a poor risk population (5-year survival probability: 5%) whereas complex karyotypes were predictive of short survivals only in older patients. Conversely, del(7q)/-7 and +8 as secondary changes, had no prognostic impact.

Translocation t(3;22)(q23;q11) in three patients with diffuse large B cell lymphoma.

In our series of 134 patients with a diagnosis of non-Hodgkin's lymphoma (NHL) and clonal chromosomal abnormalities, three were found to show an identical t(3;22)(q28;q11) translocation. All were old patients with isolated lymphadenomegaly and diffuse large noncleaved cell lymphoma. All expressed a B cell immunophenotype, and all entered a complete remission when treated with aggressive chemotherapy. This translocation could, therefore, delineate a particular subtype of diffuse large cell NHL.

Establishment and characterization of a granulocytic subclone (UM 384) from the monoblastic cell line U 937.

The human cell line U 937 spontaneously expresses monocytic maturation and can be induced into macrophage-like cells when treated with retinoic acid, sodium butyrate, or 2,3-O-tetra decanoylphorbol-13-acetate. We have selected a subclone, designated UM 384, that expresses granulocytic characteristics and can be induced to mature to granulocytes after exposure to retinoic acid, actinomycin D, and dimethylsulfoxide, and to monocyte-like cells when treated with sodium butyrate and phytohemagglutinin-stimulated leukocyte-conditioned medium. These cells retain the same constitutive markers as the parent line including histocompatibility leukocyte antigens and karyotype but share numerous chromosomal abnormalities, mainly t(X;8) (p21;q12).

Human chronic myeloid leukemic cell line with positive Philadelphia chromosome exhibits megakaryocytic and erythroid characteristics.

A cell line (LAMA-84) has been established from the blood of a patient with chronic myeloid leukemia in acute phase. LAMA-84 cells retained the patient's chromosome abnormalities, i.e., triplication of all chromosomes except chromosome 18, the presence of Philadelphia (Ph) chromosome in 4-5 copies, and the presence of chromosome markers. LAMA-84 cells have morphological features of undifferentiated blast cells, but analyses have indicated that they belong to the megakaryocytic lineage; platelet peroxidase (PPO) was found in 8.5% of cells; LAMA-84 cells reacted spontaneously with poly- and monoclonal antibodies against the platelet glycoproteins (GP) IIb, IIIa, and the GPIIb/IIIa complex, whose presence was confirmed by crossed immunoelectrophoresis. LAMA-84 cells lack the membrane characteristics of lymphoid and mature granulocytic cells but do, however, react with certain antibodies to immature myeloid cells. Furthermore, they are positive with an antiglycophorin antibody, and contain alpha- and gamma-globin mRNA, thus demonstrating erythroid marker expression. Thus LAMA-84 is a tripotent, megakaryocytic, erythroid, and granulocytic cell line. The megakaryocytic and erythroid markers were enhanced by the addition of DMSO, butyrate, TPA, and hemin. The LAMA-84 cell line represents an interesting tool for the study of megakaryocytic and erythroid differentiation and the mechanisms of neoplastic growth.

Viability of 3h grown bacterial micro-colonies after direct Raman identification.

Clinical diagnostics in routine microbiology still mostly relies on bacterial growth, a time-consuming process that prevents test results to be used directly as key decision-making elements for therapeutic decisions. There is some evidence that Raman micro-spectroscopy provides clinically relevant information from a limited amount of bacterial cells, thus holding the promise of reduced growth times and accelerated result delivery. Indeed, bacterial identification at the species level directly from micro-colonies at an early time of growth (6h) directly on their growth medium has been demonstrated. However, such analysis is suspected to be partly destructive and could prevent the further growth of the colony needed for other tests, e.g. antibiotic susceptibility testing (AST). In the present study, we evaluated the effect of the powerful laser excitation used for Raman identification on micro-colonies probed after very short growth times. We show here, using envelope integrity markers (Syto 9 and Propidium Iodide) directly on ultra-small micro-colonies of a few tens of Escherichia coli and Staphylococcus epidermidis cells (3h growth time), that only the cells that are directly impacted by the laser lose their membrane integrity. Growth kinetics experiments show that the non-probed surrounding cells are sometimes also affected but that the micro-colonies keep their ability to grow, resulting in normal aspect and size of colonies after 15h of growth. Thus, Raman spectroscopy could be used for very early (<3h) identification of grown micro-organisms without impairing further antibiotics susceptibility characterization steps.

Effects of retinoic acid on a new human erythromegakaryocytic cell line AP-217.

We have characterized a new human cell line AP-217, derived from the peripheral blood of a patient with chronic myeloid leukemia in blastic crisis. The analysis of cell surface antigens and ploidy showed that AP-217 was an erythro-megakaryocytic cell line. The effects of inducers of differentiation were studied and focused on retinoic acid (RA). Uninduced AP-217 cells produced a low level of hemoglobin (Hb) that showed a moderate but significant dose-dependent increase after 13 cis-RA induction (four times above the control at 10(-5) M). To outline this effect, AP-217 cells were cloned at limiting dilution. A subclone (clone 2) was isolated which expressed glycophorin A on 12% of cells, and showed a marked sensitivity to RA. After a 4 day induction with increasing concentrations of RA (1-10 x 10(-6) M) Hb production by clone 2 cells was enhanced 12 times over the control at the highest concentration (10(-5) M). No effect of RA on the Hb production of K-562 and HEL was observed. This increased Hb production occurred simultaneously with a growth inhibition in clonogenic cultures (20% reduction) associated with a drastic reduction of the colony size. Moreover, we demonstrated the expression of mRNA for the beta globin gene in clone 2 and AP-217-cells. This is the first report of a positive effect of RA on the erythroid differentiation of a human leukemic cell line.

Interphase FISH: a rapid method for detecting malignant plasma cells in multiple myeloma patients submitted to autologous transplantation.

Fluorescence in situ hybridization (FISH) on interphase nuclei has been shown to be an efficient method for detecting aneuploidy in multiple myeloma (MM). The aim of this study was to test the feasibility of FISH techniques for detecting malignant cells in the harvests of MM patients submitted to autologous transplantation. As trisomy 9 (T9) is a frequent event in MM, we used it as a genetic marker of malignant plasma cells. T9 was detected in 45 out of 55 MM bone marrow samples (81.8%) using a chromosome 9 centromeric (C9C) probe. Twenty-four of the 55 MM patients were subjected to high-dose therapy followed by autologous unselected progenitor cell transplantation. Trisomy 9 was detected in 20 patients and was used as a marker of malignant cells. Upon karyotypic analysis, three of the four remaining patients without T9 showed an unbalanced translocation leading to a complete trisomy of the long arm of chromosome 1 (T1q). We thus used a 1q juxtacentromeric probe, pUC1.77, as another genetic marker of malignant plasma cells in these three further patients. FISH with C9C or pUC1.77 probes was performed on the harvests of these 23 patients and detected clonal cells in 11 transplants. The disease-free survival from graft was significantly longer for the patients who had no malignant cells in their transplant (P=0.009). The median disease-free survival was 23 months in these patients, as compared to 12 months in the patients whose transplant was contaminated. As almost all MM are cytogenetically abnormal, FISH with adequate probes represents a simple, quantitative tool for rapid detection of malignant cells in the harvests. Our results also suggest that the presence of MM cells in the transplant may be predictive of poor outcome.

Bloom's syndrome: in vitro correction of the sister chromatid exchange rate by normal cells.

A significant decrease of sister chromatid exchange (SCE) frequencies was observed in Bloom's syndrome(BS) fibroblasts by cocultivation with normal fibroblasts at 5:1, 1:1, 1:5 ratios, and by culture in medium previously used to support normal fibroblasts. On the other hand, the SCE rate of normal fibroblasts was not modified. These results are compared with those from other studies and discussed.

Translocation (4;11) in a case of malignant lymphoma.

The translocation t(4;11)(q21;q23) is considered a chromosomal marker of acute lymphoid leukemia. We report here a case of a well-differentiated B-cell type non-Hodgkin's lymphoma presenting the same (4;11) translocation.

Translocation t(13;17)(q12-14;p12-13) in two patients with lymphocytic lymphoma.

Cytogenetic studies were performed at the time of diagnosis on two patients with diffuse small cell lymphocytic lymphoma. Both patients had a similar simple karyotype with a t(13;17)(q12-14;p12-13). These observations confirm the nonrandom involvement of band 13q13 in chronic lymphoproliferative diseases.

Deletion 7q in B-cell low-grade lymphoid malignancies: a cytogenetic/fluorescence in situ hybridization and immunopathologic study.

Ten cases presenting a simple karyotype and del(7q) as a primary event were selected out of 353 patients referred as B-cell low-grade malignant lymphoproliferative disorders. Chromosome 7-specific painting probes confirmed the deletion that was tentatively assigned to bands q31q35. Chromosome 7 was involved in an interstitial deletion in seven cases, in an unbalanced translocation in two cases, and in a ring chromosome in one case. Common clinical/hematological features included advanced age, marked splenomegaly, and peripheral blood monoclonal IgM(D) lymphocytosis. Regardless of morphologic entity, most cases shared lymphoplasmacytoid features. Deletion 7q may delineate a variety of low-grade B-cell lymphoid disorders characterized by a common clinical history and immunopathologic similarities. The cytogenetic pattern and the ongoing work on molecular mapping of this deletion suggest that the loss of a putative tumor-supressor gene at 7q31q32 may constitute an early event in their pathogenesis.

Human herpesvirus 8 and Epstein Barr-virus in a cutaneous B-cell lymphoma and a malignant cell line established from the blood of an AIDS patient.

Human Herpesvirus 8 (HHV-8) has been consistently associated with Primary Effusion Lymphoma (PEL or body-cavity-based lymphoma) but not with other lymphomas. This paper reports on an AIDS patient without obvious malignant effusion in body cavities but with a cutaneous lymphoma where HHV-8 and Epstein-Barr virus (EBV) were detected by PCR and electron microscopy. Both viruses were also detected in all the cells of a malignant cell line (BBG1) established from the patient's peripheral blood mononuclear cells. As in PEL and PEL-derived cell lines, both the tumor and the lines lacked B-antigen expression in immunological studies but were of the same B origin as shown by clonal immunoglobulin gene rearrangements. In contrast to other co-infected cell lines, BBG1 and subclones spontaneously expressed the HHV-8 lytic antigens p40, p27, p60 and the EBV transforming latent antigen EBNA2. These data suggest that the clinical and biological features of HHV-8-and EBV-associated lymphomas could be wider than has been described to date in PEL particularly with the in vivo presence of circulating malignant dually-infected cells engaged in a spontaneous HHV-8 lytic infection.