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Molybdenum dithiocarbamates (MoDTCs) are lubricant additives very efficient in reducing the friction of steel, and they are used in a number of industrial applications. The functionality of these additives is ruled by the chemical interactions occurring at the buried sliding interface, which are of key importance for the improvement of the lubrication performance. Yet, these tribochemical processes are very difficult to monitor in real time. Ab initio molecular dynamics simulations are the ideal tool to shed light on such a complicated reactivity. In this work, we perform ab initio simulations, both in static and tribological conditions, to understand the effect of surface oxidation on the tribochemical reactivity of MoDTC, and we find that when the surfaces are covered by oxygen, the first dissociative steps of the additives are significantly hindered. Our preliminary tribological tests on oxidized steel discs support these results. Bare metallic surfaces are necessary for a stable adsorption of the additives, their quick decomposition, and the formation of a durable MoS2 tribolayer. This work demonstrates the importance of the catalytic role of the substrate and confirms the full capability of the computational protocol in the pursuit of materials and compounds more efficient in reducing friction.

International audience; Amide molybdate has been recently introduced as a friction modifier for tribological applications. Combined with zinc dithiophosphate (ZDDP) and fatty amines, it provides an ultralow friction coefficient. The ultimate product of Mo compound transformations in tribological contact, due to frictional heating and shearing, as well as chemical interactions with oil additives, is molybdenum sulfide (MoS2). Understanding the decomposition of amide molybdate leading to MoS2 is of primary importance to the optimization of the design of lubricant formulations. This study focuses on the investigation by Raman spectroscopy of amide molybdate decomposition intermediates. Raman spectra of tribofilms, obtained after friction tests under different temperatures and pressures, revealed the formation of an amorphous MoS3 intermediate coexisting with MoS2. However, under severe conditions, the tribofilms are mostly composed of MoS2.

Amide molybdate has been recently introduced as a friction modifier for tribological applications. Combined with zinc dithiophosphate (ZDDP) and fatty amines, it provides an ultralow friction coefficient. The ultimate product of Mo compound transformations in tribological contact, due to frictional heating and shearing, as well as chemical interactions with oil additives, is molybdenum sulfide (MoS

Outcome of adult acute lymphoblastic leukemia (ALL) with central nervous system (CNS) involvement is not clearly defined. We studied 104 patients presenting with CNS involvement at diagnosis among 1493 patients (7%) included into the LALA trials, and 109 patients presenting CNS disease at the time of first relapse among the 709 relapsing patients (15%). Eighty-seven patients (84%) with CNS leukemia at diagnosis achieved complete remission (CR). Fifty-three patients underwent stem cell transplantation (SCT): 25 allogeneic SCT, 28 autologous SCT, while 34 continued with chemotherapy alone. Seven-year overall survival (OS) and disease-free survival (DFS) were 34% and 35%, respectively. There were no significant differences in terms of CR, OS and DFS among patients with CNS involvement at diagnosis and those without CNS disease. There were also no differences among the two groups regarding T lineage ALL, B lineage ALL, and among those who underwent SCT. After a first relapse, 38 patients with CNS recurrence (35%) achieved a second CR. The median OS was 6.3 months. Outcome was similar to that of relapsing patients without CNS disease. CNS leukemia in adult ALL is uncommon at diagnosis as well as at the time of first relapse. With intensification therapy, patients with CNS leukemia at diagnosis have a similar outcome than those who did not present with CNS involvement. CNS leukemia at first relapse remains of similar poor prognosis than all other adult ALL in first relapse.

International audience; 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.

To evaluate the results of autologous stem cell transplantation (ASCT) in a large population of adults with acute lymphoblastic leukemia (ALL) in first complete remission (CR), we performed an individual data-based overview of the last three trials from the LALA group. Overall, 349 patients with ALL prospectively randomized in the consecutive LALA-85, -87, and -94 trials to receive either ASCT or chemotherapy as post-CR treatment were analyzed. Eligibility criteria were 15-50-year-old patients without sibling donors in both LALA-85/87 trials and 15-55-year-old patients with high-risk ALL and no sibling donors in the LALA-94 trial. Intent-to-treat analysis, which compared 175 patients from the ASCT arm to 174 patients from the chemotherapy arm, showed that ASCT was associated with a lower cumulative incidence of relapse (66 vs 78% at 10 years; P=0.05), without significant gain in disease-free or overall survival. Despite a possible lack of statistical power, a nested case-control analysis performed in 85 patient pairs adjusted for time to transplant and prognostic covariates confirmed these intent-to-treat results in patients actually transplanted. Of interest, the reduced relapse risk after ASCT translated in better disease-free survival in the 300 rapid responders who reached CR after the first induction course.

Purpose We analyzed the benefits of a risk-adapted postremission strategy in adult lymphoblastic leukemia (ALL), and re-evaluated stem-cell transplantation (SCT) for high-risk ALL. Patients and Methods A total of 922 adult patients entered onto the trial according to risk groups: standard-risk ALL (group 1), high-risk ALL (group 2), Philadelphia chromosome-positive ALL (group 3), and CNS-positive ALL (group 4). All received a standard four-drug/4-week induction course. Patients from group 1 who achieved a complete remission (CR) after one course of induction therapy were randomly assigned between intensive and less intensive postremission chemotherapy, whereas those who achieved CR after salvage therapy were then included in group 2. Patients in groups 2, 3, and 4 with an HLA-identical sibling were assigned to allogeneic SCT. In groups 3 and 4, autologous SCT was offered to all other patients, whereas in group 2 they were randomly assigned between chemotherapy and autologous SCT. Results Overall, 771 patients achieved CR (84%). Median disease-free survival (DFS) was 17.5 months, with 3-year DFS at 37%. In group 1, the 3-year DFS rate was 41%, with no difference between arms of postremission randomization. In groups 2 and 4, the 3-year DFS rates were 38% and 44%, respectively. In group 2, autologous SCT and chemotherapy resulted in comparable median DFS. Patients with an HLA-matched sibling (groups 2 and 4) had improved DFS. Three-year DFS was 24% in group 3. Conclusion Allogeneic SCT improved DFS in high-risk ALL in the first CR. Autologous SCT did not confer a significant benefit over chemotherapy for high-risk ALL.

To accurately estimate the incidence of HOX11L2 expression, and determine the associated cytogenetic features, in T-cell acute lymphoblastic leukemia (T-ALL), the Groupe Francais de Cytogenetique Hematologique (GFCH) carried out a retrospective study of both childhood and adult patients. In total, 364 patients were included ( 211 children less than or equal to15 years and 153 adults), and 67 ( 18.5%) [ 47 children ( 22.4%) and 20 adults (13.1%)] were shown to either harbor the t(5; 14) q35; q32) translocation or express the HOX11L2 gene or both. Most of the common hematological parameters did not show significant differences within positive and negative populations, whereas the incidence of CD1a+/CD10+ and cytoplasmic CD3+ patients was significantly higher in positive than in negative children. Out of the 63 positive patients investigated by conventional cytogenetics, 32 exhibited normal karyotype, whereas the others 31 showed clonal chromosome abnormalities, which did not include classical T-ALL specific translocations. Involvement of the RANBP17/HOX11L2 locus was ascertained by fluorescence in situ hybridization in six variant or alternative (three-way translocation or cytogenetic partner other than 14q32) translocations out of the 223 patients. Our results also show that HOX11L2 expression essentially occurs as a result of a 5q35 rearrangement, but is not associated with another identified T-ALL specific recurrent genetic abnormality, such as SIL-TAL fusion or HOX11 expression.

Resume Les leucemies aigues lymphoblastiques (LAL) sont des proliferations clonales malignes des cellules souches engagees dans la differenciation lymphoide B (LAL-B) ou T (LAL-T). Des anomalies chromosomiques clonales sont retrouvees dans la majorite des cas : 80 % chez l’enfant et 70 % chez l’adulte. Elles ont une valeur pronostique independante qui rend le caryotype indispensable avant la mise en route du traitement car il conditionne la therapeutique. D’autres techniques comme la FISH et la RT-PCR sont des complements indispensables du caryotype car celui-ci peut etre d’interpretation difficile dans cette pathologie et de plus, il existe des anomalies chromosomiques cryptiques qui echappent au caryotype conventionnel. On distingue des anomalies de nombre et des anomalies de structure bien que ces deux types d’anomalies soient parfois associes : le pronostic est alors celui qui est lie a l’anomalie de plus mauvais pronostic. Dans cette revue, sont presentes les principales anomalies cytogenetiques, leur frequence, leur valeur diagnostique et pronostique ainsi que les genes impliques dans les anomalies de structure.

The t(10;11)(p13-14;q14-21) associated with CALM-AF10 is considered to be rare and associated with a variety of acute lymphoid and myeloid leukemias. Twelve (9%) of 131 unselected T-cell acute lymphoid leukemias (T-ALLs) expressed CALM-AF10 by reverse transcription-polymerase chain reaction or fluorescence in situ hybridization (or both), including 8% of children and 10% of adults, of whom only half demonstrated a t(10;11) by classical cytogenetics. CALM-AF10 was not found in T-cell-receptor alphabeta (TCRalphabeta) lineage T-ALLs, as defined by expression of TCRalphabeta, cytoplasmic TCRbeta, or TCRbetaVDJ rearrangement in immature cytoplasmic TCRbeta- cases, compared with 19% of TCRgammadelta T-ALLs and 33% of immature delta/gamma T-ALLs. The latter differed from their CALM-AF10- immature counterparts by a CD5+/CD2-phenotype, as found in TCRgammadelta but not TCRalphabeta T-ALLs and in their TCRgamma and TCRdelta configurations, altogether suggesting that CALM-AF10+ immature delta/gammaT-ALLs are TCRgammadelta precursors and that, within T-ALL, CALM-AF10 is specific for this lineage. Nine of 12 immature CALM-AF10 T-ALLs demonstrated 3' fusion transcripts, whereas 6 of 7 TCRgammadelta T-ALLs demonstrated 5' fusion transcripts. The latter retain the AF10 extended LAP/PHD domain necessary for homo-oligomerization. All 8 patients with CALM-AF10+TCRgammadelta T-ALLs are alive, compared with only 3 of 12 with immature CALM-AF10+ T-ALLs. Six CALM-AF10+ non-T acute leukemias all expressed CD7 and demonstrated T-restricted TCRdelta rearrangements, suggesting that they may also be related to the TCRgammadelta lineage. CALM-AF10 is therefore the most common fusion protein in T-ALL. It requires molecular and immunophenotypic characterization for appropriate prognostic evaluation and should be included in diagnostic screening panels of T-ALL and immature acute leukemias. Analysis of immature CALM-AF10+ leukemias will also facilitate analysis of the early stages of development of the TCRgammadelta lineage.

It is known that cigarette smoking is associated with an approximately 50% increase in leukemia risk. In order to detect a possible influence of cigarette smoking on initial characteristics at the time of presentation and on the course of the disease, we conducted a retrospective study in 643 patients with newly diagnosed acute myeloid leukemia.The study comprised 339 males and 304 females (median age 59 years, range 18-84 years). Two hundred and ninety-six patients (46%), smoking at least one cigarette per day for 6 months, were considered as smokers, while 347 patients (54%) were non-smokers.Cigarette smoking was significantly related to male gender (P0.0001), professional occupancy (P = 0.002), presence of organomegaly (P = 0.01), and lower peripheral blood and bone marrow leukemic cell involvement (P = 0.007 and P = 0.0001, respectively). Leukemia of French-American-British (FAB) M1 subtype was more frequent in non-smokers (P = 0.005). Although not statistically significant, smokers tended to have lower leukocyte counts than non-smokers. No difference was noted in terms of complete remission rates between smokers and non-smokers (67% compared to 64%). However, a higher rate of severe pulmonary infection was observed in smokers during induction chemotherapy (P = 0.02). Cigarette smoking (or=20 pack-years or smoking durationor=30 years) was significantly associated with shorter disease-free survival (P = 0.03) and overall survival (OS; P = 0.02 and P = 0.004, respectively). Other characteristics associated with poor prognosis included mainly older age, unfavorable karyotype, secondary acute myeloid leukemia (AML) and elevated World Health Organization (WHO) performance status. Cigarette smoking was associated with shorter OS in younger adults, but did not significantly influence survival in patients60 years old. Cigarette smoking worsened the poor OS in patients with unfavorable karyotype, but did not significantly influence the prognosis of other karyotypic risk groups. In a multivariate analysis, only karyotypic grouping and age remained of prognostic value for the occurrence of disease-free and overall survival.Cigarette smoking has a deleterious effect on survival in AML by shortening complete remission duration and subsequent survival. It was associated with severe infections during aplasia. Leukemogenic compounds favoring complex karyotypic abnormalities could also be involved.

Resume L'analyse cytogenetique des leucemies aigues revele des anomalies chromosomiques acquises non aleatoires dans 50 a 90 % des caryotypes. Elles peuvent etre correlees avec des parametres morphologiques [t(15;17)(q22;q12) et LAM3] et/ou immunologiques [t(1;19)(q23;p13) et LAL PreB / early pre-B]. Elles constituent un facteur pronostique independant des autres facteurs de risque, favorable dans une LAL avec hyperdiploidie > 50 chromosomes, une LAM avec inv(16)(p13q22), defavorable dans une LAL avec chromosome Philadelphie ou t(4;11)(q21 ;q23), une LAM avec deletion du bras long d'un chromosome 5 ou un caryotype complexe. Le caryotype est necessaire pour le suivi des patients en cas de rechute et pour l'evaluation de la maladie residuelle. La detection de points de cassure recurrents est a l'origine de l'identification de genes impliques dans la pathogenese des leucemies par les biologistes moleculaires.

Summary Background Since 1976, erythroleukemia has been included within the FAB classification system of acute myeloid leukemia (AML) which designates it as M6 AML This report describes the data of 54 patients with newly diagnosed M6 AML, consecutively seen in our hospital between May 1976 and May 1999 Patients and methods There were 40 males and 14 females Median age was 59 years Pancytopenia was the most common feature at diagnosis Twenty-six percent of cases presented with secondary AML Karyotype was successfully performed in 35 cases Eleven patients presented with normal karyotype, nine with simple karyotypic abnormalities, and fifteen with major karyotypic abnormalities Fifty of the fifty-four patients received one or two courses of induction chemotherapy combining anthracyclines with cytarabine according to different successive protocols One elderly patient only received low-dose cytarabine, and three patients died before any chemotherapy could be given Results Complete remission (CR) was achieved in 29 cases (54%, 95% confidence interval (CI) 40%-67%) As postremission therapy, four patients could be allografted, and two underwent autologous transplantation All other treated patients received continuation chemotherapy Twenty-one patients have relapsed (72%) Median time to relapse was six months. Among those patients, only eight achieved a second CR (38%) The median disease-free survival (DFS) was eight months (95% CI 4-10 months) with a five-year survival rale of 17% Median overall survival (OS) was nine months (95% CI 5-12 months) with a five-year survival rate of 13% In univanate analysis, poor prognostic factors for DFS were secondary AML (P = 0 05) and initial platelet count 60 years (P - 0.005), secondary AML(P = 0 05), initial 'blastic' fever (P - 0 0004), and initial haemoglobin level < 90 g/1 (P = 0.03). All factors, but haemoglobin level, remained significant in the multivanate analysis Although it was not statistically significant, there was a trent for a better prognosis of M6 patients presenting with normal karyotype as compared to those displaying chromosomal abnormality. Conclusions This retrospective analysis points to a somewhat heterogenous group of AML in terms of clinical and biological features, and outcome Distinctive subgroups can be identified according to prognostic factors related to survival A larger multicenter study with well-defined diagnostic criteria is warranted to further clarify treatment effects

The EU Concerted Action Workshop on 11q23 Abnormalities in Hematological Malignancies collected 550 patients with abnormalities involving 11q23. Of these, 53 patients had a translocation involving chromosome 11, breakpoint q23, and chromosome 19, breakpoint p13. Karyogram review enabled each patient to be further defined as t(11;19)(q23;p13.1) (21 patients) or t(11;19)(q23;p13.3) (32 patients). There was a marked difference between the type of banding and the translocation identified: t(11;19)(q23;p13.1) was detected predominantly by R-banding, whereas t(11;19)(q23;p13.3) was detected almost solely by G-banding. Additional change was extremely rare in patients with t(11;19)(q23;p13.1) but occurred in nearly half of the patients with t(11;19)(q23;p13.3). Patients with t(11;19)(q23;p13.1) all had leukemia of a myeloid lineage, mostly acute myeloid leukemia (AML), and were predominantly adult. In contrast patients with t(11;19)(q23;p13.3) had malignancies of both myeloid and lymphoid lineage and were mainly infants less than 1 year old. The survival of both groups of patients was generally poor, over 50% of t(11;19)(q23;p13.1) patients died within 2 years of diagnosis and the median survival of acute lymphoblastic leukemia (ALL) patients with t(11;19)(q23;p13.3) was 17.6 months.

B cell chronic lymphocytic leukemias (B-CLL) like other blood cell malignancies are characterized by chromosomal anomalies directly involved in tumor pathogenesis. We report here the molecular characterization of a t(7;14)(q21;q32) chromosomal translocation observed during the course of a B-CLL. We show that this translocation led to the juxtaposition of the immunoglobulin heavy chain locus on chromosome 14 to an endogenous retroviral sequence belonging to the THE family (transposable-like human element) on chromosome 7q21. RT-PCR analysis demonstrated that this sequence is transcribed in most of the tumoral and normal tissue analyzed and in the B-CLL described here. These data raise the question of the role of transposable elements in the pathogeny of some leukemias or at least, in the occurrence of chromosomal rearrangements. Structural rearrangements of the 7q21-22 region are frequently encountered in myeloid disorders, and the work presented here could help in their characterization.

Resume L'analyse cytogenetique revele des anomalies chromosomiques dans 40 a 60 % des SMD de novo et 80 % des SMD induits chez l'adulte comme chez l'enfant. A l'exception de la trisomie 8, les anomalies les plus frequentes sont des pertes de materiel chromosomique: la deletion 5q et la monosomie 7 totale ou partielle, moins souvent les deletions 20q, 11q, 12p et la perte de l'Y. Les translocations reciproques sont rares: plusieurs translocations sont recurrentes comme les t(3;3)(q26;q21), t(3;21)(q26;q22) et la t(5;12)(q31;p12) mais les translocations specifiques des leucemies aigues myeloides (LAM) ne sont jamais rencontrees. Ces differentes anomalies peuvent etre associees sur un meme caryotype (caryotypes complexes), et la plupart sont communes avec les LAM et les syndromes myeloproliferatifs. Leur repartition varie en fonction de l'âge (monosomie 7 chez l'enfant, deletion 5q chez l'adulte), en fonction des differents groupes de la classification FAB et selon la nature de novo ou secondaire du SMD. Certains types d'anomalies peuvent etre rattaches a des tableaux hematologiques particuliers: syndrome 5q- chez la femme âgee, point de cassure 3q26 et thrombocytose, 11q21 et anemie refractaire avec sideroblastes en couronne (ASAI), del(12p) et leucemie myelomonocytaire chronique (LMMC). Un rearrangement de la bande 11q23 suggere la possibilite d'une myelodysplasie secondaire a un traitement par un inhibiteur de la topoisomerase II. La valeur pronostique du caryotype est reconnue dans les SMD: on oppose le role favorable d'un 5q- isole, d'un caryotype normal au role pejoratif d'une monosomie 7 ou d'un caryotype complexe. L'etude cytogenetique a permis de focaliser le travail des biologistes moleculaires sur des points precis du genome pour identifier les genes impliques dans les SMD et les LAM.

SummaryHuntingtin is the protein mutated in Huntington's disease, a devastating neurodegenerative disorder. We demonstrate here that huntingtin is essential to control mitosis. Huntingtin is localized at spindle poles during mitosis. RNAi-mediated silencing of huntingtin in cells disrupts spindle orientation by mislocalizing the p150Glued subunit of dynactin, dynein, and the large nuclear mitotic apparatus NuMA protein. This leads to increased apoptosis following mitosis of adherent cells in vitro. In vivo inactivation of huntingtin by RNAi or by ablation of the Hdh gene affects spindle orientation and cell fate of cortical progenitors of the ventricular zone in mouse embryos. This function is conserved in Drosophila, the specific disruption of Drosophila huntingtin in neuroblast precursors leading to spindle misorientation. Moreover, Drosophila huntingtin restores spindle misorientation in mammalian cells. These findings reveal an unexpected role for huntingtin in dividing cells, with potential important implications in health and disease.

PAX5 is the main target of somatic mutations in acute B lymphoblastic leukemia (B-ALL). We analyzed 153 adult and child B-ALL harboring karyotypic abnormalities at chromosome 9p, to determine the frequency and the nature of PAX5 alterations. We found PAX5 internal rearrangements in 21% of the cases. To isolate fusion partners, we used classic and innovative techniques (rolling circle amplification-rapid amplification of cDNA ends) and single nucleotide polymorphism-comparative genomic hybridization arrays. Recurrent and novel fusion partners were identified, including NCoR1, DACH2, GOLGA6, and TAOK1 genes showing the high variability of the partners. We noted that half the fusion genes can give rise to truncated PAX5 proteins. Furthermore, malignant cells carrying PAX5 fusion genes displayed a simple karyotype. These data strongly suggest that PAX5 fusion genes are early players in leukemogenesis. In addition, PAX5 deletion was observed in 60% of B-ALL with 9p alterations. Contrary to cases with PAX5 fusions, deletions were associated with complex karyotypes and common recurrent translocations. This supports the hypothesis of the secondary nature of the deletion. Our data shed more light on the high variability of PAX5 alterations in B-ALL. Therefore, it is probable that gene fusions occur early, whereas deletions should be regarded as a late/secondary event.

Fifty-four percent of adults with acute lymphoblastic leukemia (ALL) who entered the LALA-94 trial experienced a first relapse. We examined the outcome of these 421 adult patients. One hundred and eighty-seven patients (44%) achieved a second complete remission (CR). The median disease-free survival (DFS) was 5.2 months with a 5-year DFS at 12%. Factors predicting a better outcome after relapse were any transplant performed in second CR (P0.0001), a first CR duration1 year (P=0.04) and platelet level100 x 10(9)/l at relapse (P=0.04). Risk groups defined at diagnosis and treatment received in first CR did not influence the outcome after relapse. The best results were obtained in a subset of patients who were eligible for allogeneic stem cell transplantation (SCT). Geno-identical allogeneic SCT was performed in 55 patients, and 3 patients received donor lymphocyte infusions. Forty-four transplantations were performed from an unrelated donor (of which four were cord blood). We conclude that most adult patients with recurring ALL could not be rescued using current available therapies, although allogeneic SCT remains the best therapeutic option.

A defect in microtubule (MT)-based transport contributes to the neuronal toxicity observed in Huntington's disease (HD). Histone deacetylase (HDAC) inhibitors show neuroprotective effects in this devastating neurodegenerative disorder. We report here that HDAC inhibitors, including trichostatin A (TSA), increase vesicular transport of brain-derived neurotrophic factor (BDNF) by inhibiting HDAC6, thereby increasing acetylation at lysine 40 of α-tubulin. MT acetylationin vitroand in cells causes the recruitment of the molecular motors dynein and kinesin-1 to MTs. In neurons, acetylation at lysine 40 of α-tubulin increases the flux of vesicles and the subsequent release of BDNF. We show that tubulin acetylation is reduced in HD brains and that TSA compensates for the transport- and release-defect phenotypes that are observed in disease. Our findings reveal that HDAC6 inhibition and acetylation at lysine 40 of α-tubulin may be therapeutic targets of interest in disorders such as HD in which intracellular transport is altered.

Prospective multicentric molecular study for poor prognosis fusion transcripts at diagnosis in adult B-lineage ALL patients: the LALA 94 experience

The NUP98 gene is fused with 19 different partner genes in various human hematopoietic malignancies. In order to gain additional clinico-hematological data and to identify new partners of NUP98, the Groupe Francophone de Cytogenetique Hematologique (GFCH) collected cases of hematological malignancies where a 11p15 rearrangement was detected. Fluorescence in situ hybridization (FISH) analysis showed that 35% of these patients (23/66) carried a rearrangement of the NUP98 locus. Genes of the HOXA cluster and the nuclear-receptor set domain (NSD) genes were frequently fused to NUP98, mainly in de novo myeloid malignancies whereas the DDX10 and TOP1 genes were equally rearranged in de novo and in therapy-related myeloid proliferations. Involvement of ADD3 and C6ORF80 genes were detected, respectively, in myeloid disorders and in T-cell acute lymphoblastic leukemia (T-ALL), whereas the RAP1GDS1 gene was fused to NUP98 in T-ALL. Three new chromosomal breakpoints: 3q22.1, 7p15 (in a localization distinct from the HOXA locus) and Xq28 were detected in rearrangements with the NUP98 gene locus. The present study as well as a review of the 73 cases previously reported in the literature allowed us to delineate some chromosomal, clinical and molecular features of patients carrying a NUP98 gene rearrangements.

Imatinib mesylate (Gleevec), an inhibitor of the BCR-ABL tyrosine kinase, was introduced recently into the therapy of chronic myeloid leukemia (CML). Several cases of emergence of clonal chromosomal abnormalities after therapy with imatinib have been reported, but their incidence, etiology and prognosis remain to be clarified. We report here a large series of 34 CML patients treated with imatinib who developed Philadelphia (Ph)-negative clones. Among 1001 patients with Ph-positive CML treated with imatinib, 34 (3.4%) developed clonal chromosomal abnormalities in Ph-negative cells. Three patients were treated with imatinib up-front. The most common cytogenetic abnormalities were trisomy 8 and monosomy 7 in twelve and seven patients, respectively. In 15 patients, fluorescent in situ hybridization with specific probes was performed in materials archived before the initiation of imatinib. The Ph-negative clone was related to previous therapy in three patients, and represented a minor pre-existing clone that expanded after the eradication of Ph-positive cells with imatinib in two others. However, in 11 patients, the new clonal chromosomal abnormalities were not detected and imatinib may have had a direct effect. No myelodysplasia was found in our cohort. With a median follow-up of 24 months, one patient showed CML acceleration and two relapsed.

To reveal the relationship between hypodiploidy with 30 to 39 chromosomes and near-triploidy in acute lymphoblastic leukemia (ALL), we studied 24 patients presenting with one of these aneuploidies among 623 adults with ALL registered in the Leucemie Algue Lymphoblastique de l'Adulte (LALA) protocols. The 2 ploidy groups presented a striking similarity of their cytogenetic profiles: chromosomes 2, 3, 4, 7, 13, 15, 16, and 17, significantly monosomic in hypodiploidy 30 to 39, were also frequently disomic in near-triploidy, whereas those retained in pairs in hypo diploidy 30 to 39 were frequently tetrasomic in near-triploidy. DNA content data revealed the simultaneous presence of 2 aneuploid peaks in most tested cases (DNA indexes: 0.72-0.87/1.39-1.89) and a multiple correspondence analysis applied on cytogenetic profiles ascertained their strong relationship. We thus assumed that near-triploidy derives from the duplication of hypodiploidy with 30 to 39 chromosomes and that both aneuploid groups are 2 expressions of the same disease. These 24 patients presented with B-cell phenotype, low leukocytoses (median white blood cell count, 4.2 x 10(9)/L), and poor prognosis (complete remission, 57%; median disease-free-survival, 8 months; median survival, 10.4 months) comparable to that of Ph+ patients treated according to the same protocol. We suggest that hypodiploidy with 30 to 39 chromosomes or near-triploidy should be regarded as a new high-risk factor in the risk stratification of adult ALL protocols. (C) 2004 by The American Society of Hematology.

Polyglutamine expansion (polyQ) in the protein huntingtin is pathogenic and responsible for the neuronal toxicity associated with Huntington's disease (HD). Although wild-type huntingtin possesses antiapoptotic properties, the relationship between the neuroprotective functions of huntingtin and pathogenesis of HD remains unclear. Here, we show that huntingtin specifically enhances vesicular transport of brain-derived neurotrophic factor (BDNF) along microtubules. Huntingtin-mediated transport involves huntingtin-associated protein-1 (HAP1) and the p150Glued subunit of dynactin, an essential component of molecular motors. BDNF transport is attenuated both in the disease context and by reducing the levels of wild-type huntingtin. The alteration of the huntingtin/HAP1/p150Glued complex correlates with reduced association of motor proteins with microtubules. Finally, we find that the polyQ-huntingtin-induced transport deficit results in the loss of neurotrophic support and neuronal toxicity. Our findings indicate that a key role of huntingtin is to promote BDNF transport and suggest that loss of this function might contribute to pathogenesis.

Acute lymphoblastic leukemias (ALL) represent malignant clonal proliferations of stem cells committed in lymphoid differentiation, B or T-cell ALL. Clonal chromosomal abnormalities are found in 80% children and 70% adult cases. They are associated with an independent prognostic value which modifies the therapeutic approach and therefore karyotyping at diagnosis is mandatory. Molecular techniques such as FISH and RT-PCR are very helpful too as cryptic chromosomal abnormalities have been described. In this review, numerical and structural abnormalities are described: frequency, diagnosis and prognosis value as well as genes involved in structural abnormalities.

Data on all patients with acute lymphoblastic leukemia (ALL) aged 60 or older, referred to our institution over a 18-year period, were studied to determine the incidence and range of clinical and biological subtypes, and the outcome of different therapeutic approaches. Sixty-nine ALL cases (median age: 68 years) were diagnosed between 1980 and 1998 (18% of all adult ALL seen during this period). Ten of them (14%) had a past history of previous malignancy. Karyotypic analysis was performed successfully in 42 cases. Ten patients were diagnosed as Philadelphia chromosome positive (Ph(+)) ALL. Immunophenotyping was performed in 63 cases. Fifty-six patients had B-cell lineage ALL. T lymphoid markers were observed only in 5 cases. Co-expression of myeloid markers was observed in 19% of tested cases. Five patients died before any chemotherapy could be given. All other patients received "curative" treatment according to different protocols used during the period of study. Overall complete remission (CR) rate of these patients was 62% (95% confidence interval (CI): 50-74%). Thirty-nine patients achieved CR after one course of chemotherapy and 4 patients after salvage therapy. Median disease-free survival (DFS) of the entire cohort was 8.3 months (95% CI: 5-12.8 months) and median overall survival was 7 months (95% CI: 6-10 months). In multivariate analysis, the presence of hemorrhage (P = 0.02) was a poor prognostic for CR achievement. Higher WHO performance status (P = 0.003) and the presence of hemorrhage (P = 0.01) at diagnosis were poor prognostics for overall survival. When patients were stratified into three groups according to the time of admission, survival appeared significantly longer for patients admitted between July 1992 and December 1998 (median overall survival at 10 months) than for patients admitted before July 1992 (P = 0.04). "Age-adapted" therapy appeared superior to "young adult-like" therapy in terms of CR rate (96% versus 60%; P = 0.007). However, "age-adapted" therapy did not show any advantage in terms of DFS or overall survival, making the difference in CR rates questionable. We conclude that the pejorative overall outcome in elderly ALL points to the need for new therapeutic trials taking into account the specific characteristics of ALL in this age group.

In chronic myelogenous leukemia (CML), autologous stem cell transplantation could be a promising new approach for patients with no cytogenetic response after interferon alpha (IFN-alpha) therapy. We report data on 28 CML patients autotransplanted in chronic phase with peripheral blood progenitor cells mobilized with G-CSF (5 microg/kg/day x 5 days) given subcutaneously while continuing IFN-alpha therapy. At mobilization, 23 patients (82%) were in complete hematological remission (CHR), 16 (57%) achieved a minor cytogenetic response (mcr). We obtained, after stimulation, a median of 37.4 x 10(9)/l (6.9-108) white blood cells, 7.2 x 10(8)/kg (2.2-16.6) mononuclear cells, 39 x 10(4)/kg (4.8-403.5) CFU-GM and 4.2 x 10(6)/kg (0-58.6) CD34+ cells. Six patients received GM-CSF after transplantation. All patients engrafted, with no significant influence stemming from the Sokal index score and pretransplantation IFN-alpha therapy duration. The first cytogenetic evaluation after transplantation showed 11 (39%) major cytogenetic response (Mcr), and nine (32%) mcr with no significant correlation between these responses, the Sokal index score, and pretransplantation IFN-alpha therapy duration, although there was a significant impact from GM-CSF administration (P=0.01). After transplantation, 26 patients received IFN-alpha alone or associated with hydroxyurea. The median follow-up was 12 months after transplantation and 57 months after diagnosis. At the time of follow-up, nine patients were in CHR, six remained stable in chronic phase, three presented an mcr and one remained in Mcr. At the last follow-up, 22 patients were alive. We conclude that the results of this strategy are encouraging in poor IFN-alpha responders but that other prospective studies that try to maintain the cytogenetic responses obtained immediately after transplantation are needed.

Fifty-five adult patients with newly diagnosed T-lineage acute lymphoblastic leukemia (ALL) were analysed for CD10 expression on leukemic cells. CD10 was expressed on 18/55 (33%) cases. There were no differences between CD10+ and CD10- cases in clinical features or karyotypic patterns, except for white blood cell (WBC) counts that were higher in CD10+ patients. CD10 positivity was significantly associated with the expression of CD1 (p = 0.0001), and tend to be associated with that of CD4 and CD8. CD10 negativity tend to be associated with CD34 expression. After intensive induction chemotherapy according to LALA protocols, 50 of the 55 patients (91%, 95% confidence interval [CI]: 80-97%) achieved a complete remission (CR). The median disease-free survival (DFS) and the median overall survival were 26 and 36 months respectively with 2-year survival rates of 40% and 47%. Relapse was observed in 21 cases (42% of patients achieving CR). Despite better results in CD10+ cases, no statistical differences were seen between CD10+ and CD10- patients in terms of CR rates, DFS and overall survival. We conclude that this lack of statistical difference could be related to the use of adapted therapy involving cytarabine and cyclophosphamide. However, a trend for a better outcome in CD10+ patients warrants a more intensive form of therapy in patients with CD10- expression.

Treatment of adult acute lymphoblastic leukemia (ALL) remains unsatisfactory [1-4]. Different strategies such as allogenic, autologous transplantation or more intensive chemotherapy may improve the outcome. Their exact place is still controversial according to the stage (first or second remission) or to the aggressiveness of the disease (high or standard risk).

Philadelphia chromosome positive (Ph+) acute lymphoblastic leukemia (ALL) is an aggressive form of acute leukemia that represents about one third of all adult ALL. Between 1984 and 1996, forty-three cases of Ph+ ALL (22 males and 21 females) were diagnosed in our institution by successful cytogenetic studies and/or molecular biology. Median age was 42 years (range, 20-71 years) with 28 patients aged below 50 years. Median leukocyte count was 39.7 x 10(9)/l on admission. Tumoral syndrome was seen only in 21 patients (49%) of which 4 cases presented with central nervous system (CNS) involvement. Among the 38 patients classified according to the French-American-British (FAB) criteria, 26 showed L1 and 9 L2 morphology. Three patients showed undifferentiated leukemia. Immunological study at diagnosis only showed B-cell lineage ALL with 95% of patients expressing CD10 and 50% expressing CD20. The Ph+ as sole anomaly was seen in 13 patients (31%), while additional chromosome changes were observed in 28 cases. Two patients were diagnosed only on molecular biology showing a Bcr/Abl rearrangement. Thirty-nine patients treated according to LALA protocols were eligible for the analysis of treatment outcome. Complete remission (CR) was achieved in 25 cases (64%, 95% CI: 47-79%). The median disease-free survival (DFS) and the median overall survival were 6 and 9 months respectively. Relapse was observed in 16 cases (64% of patients achieving CR). Initial parameters associated with a statistically significant worse prognosis were "blastic" fever, hyperuricemia, the presence of an extra Ph chromosome and patients whose marrow does not contain any normal mitosis (AA cases). As post-induction therapy, 13 cases followed a chemotherapy program (group 1) while 11 received early bone marrow (BM) or peripheral stem cell (PSC) transplantation (group 2) (5 allogeneic BM transplantation and 6 autologous BM or PSC transplantation). One patient did not receive any post-induction therapy. In group 1, the median DFS and overall survival were of 5 and 11 months respectively, while they were of 9 months and not reached respectively in group 2 with a 2-year survival rate of 51% (95% CI: 21-83%) confirming the requirement for intensified therapy in Ph+ ALL.

The EU Concerted Action Workshop on 11q23 Abnormalities in Hematological Malignancies collected 550 patients with abnormalities involving 11q23. Of these, 53 patients had a translocation involving chromosome 11, breakpoint q23, and chromosome 19, breakpoint p13. Karyogram review enabled each patient to be further defined as t(11;19)(q23;p13.1) (21 patients) or t(11;19)(q23;p13.3) (32 patients). There was a marked difference between the type of banding and the translocation identified: t(11;19)(q23;p13.1) was detected predominantly by R-banding, whereas t(11;19)(q23;p13.3) was detected almost solely by G-banding. Additional change was extremely rare in patients with t(11;19)(q23;p13.1) but occurred in nearly half of the patients with t(11;19)(q23;p13.3). Patients with t(11;19)(q23;p13.1) all had leukemia of a myeloid lineage, mostly acute myeloid leukemia (AML), and were predominantly adult. In contrast patients with t(11;19)(q23;p13.3) had malignancies of both myeloid and lymphoid lineage and were mainly infants less than 1 year old. The survival of both groups of patients was generally poor, over 50% of t(11;19)(q23;p13.1) patients died within 2 years of diagnosis and the median survival of acute lymphoblastic leukemia (ALL) patients with t(11;19)(q23;p13.3) was 17.6 months.

Although the presence of a chromosome 11q23 breakpoint is of recognized poor prognosis in acute lymphoblastic leukemia, its prognostic significance in acute myeloid leukemia (AML) has been the object of conflicting reports, perhaps reflecting the possibility of different entities. It has been found that only typical and generally balanced 11q23 chromosomal anomalies involve the MLL gene while atypical and generally unbalanced do not. To determine whether these two categories of AML patients had different initial characteristics and evolution, supporting different pathogenetic mechanisms, we analyzed clinical and biologic characteristics of newly diagnosed AML patients with balanced 11q23 breakpoint and/or MLL rearrangement seen over a 10-year period in our institution and compared them to cases with unbalanced 11q23 anomaly seen over the same period. These two categories of patients were compared with newly diagnosed patients with normal karyotype and no MLL rearrangement when tested, seen over the same period of time and treated similarly. Over this period, 442 newly diagnosed adult (> 15 years) AML seen in our institution had a successful karyotype performed before any therapy. Thirty-six cases (8%) had a chromosome 11q23 breakpoint including 19 cases with a balanced translocation or inversion and 17 cases with an unbalanced anomaly. Eighty-seven recently diagnosed cases of AML, for whom frozen cellular material was available, were analyzed by Southern blot for the presence of MLL gene rearrangement. Fourteen cases (16% of the tested cases) had a rearrangement of the MLL gene, including seven cases with an apparently successful karyotype not showing any 11q23 breakpoint and two cases with no available karyotype. The only case with unbalanced 11q23 chromosomal anomaly which was tested had no MLL rearrangement. There was a clear-cut clinical difference between the 28 patients having a balanced 11q23 anomaly/MLL rearrangement and the 17 patients having an unbalanced chromosomal anomaly: AML with unbalanced 11q23 anomalies occurred in older patients (P = 0.07) tended to be less frequently associated with previous exposure to topoisomerase II-active drugs and with M4/M5 FAB cytological subtypes, were always associated with other chromosomal anomalies (P < 0.0001), expressed more frequently the CD34 antigen (P = 0.05) and were of considerably poorer prognosis for achievement of CR (P = 0.005) and survival (P = 0.0005). When compared to the control population, patients with balanced anomalies had more frequent history of toxic exposure (P = 0.0003) particularly to topoisomerase II-active drugs, tended to be more frequently of M4/M5 FAB subtypes (P = 0.07), expressed more frequently HLA-DR antigen (P = 0.02) and had shorter DFS (P = 0.02). Patients with unbalanced anomalies had more frequent splenomegaly (P = 0.009), lower WBC count (P = 0.04), and much poorer prognosis for CR achievement (P = 0.0001), survival (P < 0.0001) and DFS (P = 0.01). This study confirms the high frequency of 11q23 chromosomal breakpoint/MLL rearrangement in adult AML and the probable existence of two different entities with different clinical features according to the presence of a balanced or unbalanced cytogenetic abnormality, the latter being not associated with MLL rearrangement.

In order to potentially mobilize and harvest the Ph cells observed in most patients with chronic myeloid leukaemia (CML) during interferon-alpha (IF-alpha) therapy, G-CSF (filgrastim), 5 microg/kg/d, was administered subcutaneously together with IF-alpha to 30 CML patients in haematological remission but with various degrees of cytogenetic remission, after IF-alpha therapy. Peripheral blood stem cells (PBSC) were harvested using standard aphereses from day 5 of G-CSF Patients underwent one to four (median three) aphereses. Median total yields/kg were 7.6 (range 3.8-25) x 10(8) MNC, 3.4 (0-140) x 10(6) CD34+ cells, and 17 (1.1-107) x 10(4) CFU-GM. No patient had a significant increase in the percentage of Ph+ cells in the bone marrow under G-CSF therapy. The percentage of Ph+ cells in apheresis products tended to decrease between the first and the last apheresis (P = 0.05). 14 patients who were not responsive to IF-alpha were transplanted after conditioning with busulphan 16 mg/kg and melphalan 140 mg/m2. Median time to neutrophils > 0.5 x 10(9)/l was 20 d (16-114 d) and to platelets > 50 x 10(9)/l 18 d (12-149 d). Nine patients had a major cytogenetic response post graft, which correlated with the amount of Ph+ cells reinfused with the graft (P = 0.02). We conclude that this procedure is feasible, allowing the harvest of enough PBSC, some of them Ph- in patients who responded to IF-alpha, to allow autologous transplantation.

Recurrent anomalies of the short arm of chromosome 9, including interstitial deletions and translocations, have often been described. Recently two cyclin-dependent kinase inhibitors, known as P16 (INK4A/MTS1) and P15 (INK4B/MTS2), which map to 9p21, have been found deleted in a wide range of tumors and particularly in leukemic cells. We report here Southern blot analyses of cyclin-dependent kinase inhibitors (P16, P15, P21, and P27) status in primary tumoral cells of 121 patients with acute lymphoblastic leukemias, 85 patients with acute myeloid leukemias and 42 patients with B-chronic lymphocytic leukemias. P16 inactivation was found in 25 of 38 T-ALLs and in 28 of 83 B-lineage ALLs. In eight cases (three T-ALLs and five B-lineage ALLs), one or both alleles of P16 locus were rearranged. In these cases, breakpoints occurred within the two major breakpoints cluster regions previously described in T-ALLs. Homozygous P16 deletions were observed in two of 85 AMLs but in none of the 42 B-CLL cases tested. Our results suggest that P16 inactivation are the most frequent event observed in ALL (44%), are quite rare in AML (

Cytogenetic study reveals non random chromosomal abnormalities in 50-80% of patients with acute leukemia. These changes are correlated with morphological [t(15;17) closely connected with FAB M3] and (or) immunological findings [t(1;19) with pre-B/early pre-B ALL]. Karyotype in ALL is an independent prognostic factor. Patients with ALL and hyperdiploidy50 chromosomes fared the best as well as patients with AML and inv(16). Conversely the Philadelphia chromosome or t(4;11) in ALL, del5q or trisomy 8 in AML have shown an adverse predictive value. Cytogenetic study is a useful tool to detect relapse and residual disease. Cytogenetic abnormalities have also provided focus for molecular studies of leukemogenesis.

Seventy-five adult patients with newly diagnosed acute lymphoblastic leukemia (ALL) were analyzed for CD34 expression on leukemic cells. CD34 was significantly associated with B-cell lineage ALL (p = 0.0002). In B-lineage ALL, CD34 positivity was significantly associated with expressions of CD9 (p = 0.001), CD19 (p = 0.00001) and CD22 (p = 0.002). CD34 was more expressed in B-ALLs with higher WBC cell count (p = 0.04), and higher percentage of peripheral blood leukemic cells (p = 0.005), total or partial monosomy of chromosome 7 (p = 0.0001) or Ph+ chromosome (p = 0.01); and less expressed in cases with hyperdiploidy (or = 50 chromosomes) (p = 0.03). CD34 was more expressed in poor risk B-ALLs patients, defined according to Hoelzer criteria (p = 0.01). In T-lineage ALL, CD34 positivity was inversely correlated with the expression of CD10 (p = 0.05). After intensive induction therapy, 58 of 73 evaluable patients (79%) achieved a complete remission (CR). CD34 positivity was correlated with the persistence of blast cells in day 15 bone marrow aspirates (p = 0.001) and after one course of induction chemotherapy (p = 0.01). With a median follow-up of 11 months, no statistical differences were seen in leukemia-free survival and overall survival between CD34 positive and negative cases, even when stratifying by immunophenotype. We conclude that CD34 expression is associated with features of poor prognosis in adult ALL. Its study might therefore become useful in the design of future prognostic models.

Fourteen cases of dic(9;12)(p11-13;p11-12) in early B-lineage acute lymphoblastic leukemia (ALL) and other hematological malignancies are reported with a review of the literature. Altogether 36 cases were collected for analysis: ALL at diagnosis (31 cases) or in relapse (one case), chronic myeloid leukemia in lymphoid blast crisis (two cases), T-cell lymphoblastic lymphoma (one case) and T-cell non-Hodgkin's lymphoma (one case). We report the first cases of dic(9;12) with a T-cell phenotype. Dic(9;12) occurs predominantly in B-progenitor ALL of childhood and young adults (age range, 1-47 years, median 12 years) but not of infancy. One or more adverse clinical features, age10 years, WBC100 x 10(9)/l, pre-B immunophenotype, platelets100 x 10(9)/l, were found in over 90% of cases. Additional structural chromosomal changes or trisomy 8 were frequently present. Nevertheless with a median follow-up of 5 years, 29/31 cases (94%) remain in first remission conferring an excellent prognosis to this leukemia. Additional cases are being sought to confirm the prognostic value of this cytogenetic aberration in various hematological malignancies.

In 1988 and 1989, 79 children have been treated for induction of acute leukemia. 68 presented an acute lymphoblastic leukemia (ALL) and 11 an acute non-lymphoblastic leukemia (ANLL). The complete remission rate was 92% (96% in ALL, 73% in ANLL). Fever occurred in 50% of the children, with positive blood cultures in 11 of them. One child died from streptococcal sepsis. No metabolic disorder was noted. Four patients were transferred into the intensive care unit. After 8 days, the treatment of ALL was continued in the outpatient clinic in more than 50% of the cases. The treatment of ANLL is frequently complicated by hemorrhages and sepsis and needs adapted supportive care in a specialized unit.

X deletions result generally in one or many features characteristic of Turner syndrome but each feature cannot be attribute to a well defined deletion. We present 3 cases of Xq partial deletion: 2 in girls with primary amenorrhea and normal stature, 1 in a patient with secondary amenorrhea and short stature. X inactivation is a complex phenomenon, the mechanism is not yet clear. Inactivation center(s) and active genes on inactive chromosome could explain the manifestation or the absence of clinical symptoms in X deletions.

A 46,XX,r(17) karyotype was observed in a 9-year-old infant with short stature, moderate mental retardation but without other physical abnormality. Eight cases with an r(17) have since been reported: 4 can be compared with our patient, one was detected by amniocentesis, and 3 have Miller-Dieker syndrome. Submicroscopic deletions in the subband p13.3 are probably the cause of Miller-Dieker syndrome. They are present in some cases of r(17) but, in others, this short arm region is entirely preserved.

We describe a patient in whom the concomitant diagnosis of refractory anemia with excess of blasts (16% on initial marrow examination) and chronic lymphocytic leukemia was made more than 9 years ago. The myeloid clone showed a complex karyotypic abnormality. Evolution has so far been remarkably stable, without transformation into acute leukemia. Clonogenic assays showed that patient's serum inhibited the patient's own granulocyte-macrophage colony-forming units (CFU-GM). This inhibition was also present for a control subject's CFU-GM and acute myeloid leukemia clonogenic cells. This raises the problem of a down-regulation of the myeloid clone by the malignant lymphoid clone in this patient, and the possible mechanisms for this are discussed.

Fetal chromosome analysis in a 39-year-old mother revealed a chromosome 11 aberration interj ireted as a duplication of the centromere. This was also found in the mother's karyotype, raising the possibility that the abnormality was a new variant of no clinical consequence.

A 46-year-old man with mental retardation, growth failure and some dysmorphic features is found to have a 46,XX,r(3)(p26q29) karyotype in 93% of his peripheral lymphocytes. This observation is compared with previously cases of ring 3. The existence of a "ring syndrome" is considered.

The expression of myeloid surface markers was investigated in 41 cases of untreated adult acute lymphoblastic leukemia (ALL). Nineteen cases (46%) reacted with at least one myeloid monoclonal antibody (CD15 in 16 cases, CD13 in 10 cases, CD14 in five cases, and CD33 in four cases). Double-staining confirmed the coexpression of myeloid and lymphoid markers. In addition, 35 samples were tested for CD34 expression. Fourteen of the 17 myeloid-positive cases tested were positive for CD34 vs. eight of 18 negative cases (p less than 0.05). A t(9;22) translocation was found in eight cases, and a t(4;11) translocation in two cases, all expressing CD34 and myeloid antigens. These findings confirm the high frequency of myeloid markers on the surface of adult ALL blasts, and suggest that these leukemias may originate in a poorly differentiated precursor cell with mixed differentiation capacities.

In some cases of acute lymphoblastic leukaemia (ALL) the percentage of cells in G2 + M is higher than anticipated when compared with the percentage in S phase. This increase in G2 + M, as detected by flow cytometry measurement of DNA content, may be due to an accumulation of cells, either in G2 or during the end of S phase; it may also be related to the existence of small tetraploid clones generally ignored by cytogeneticists. In order to identify possible subpopulations of cells with a DNA index greater than or equal to 2.0, we have compared the results of a cytogenetic analysis to the G2 + M values. We have also studied the distribution of S phase cells in 24 cases of ALL by incorporating 5-bromodeoxyuridine, labelling the cells by indirect immunofluorescence, and analysing them by flow cytometry after propidium iodide staining. The distribution of cells during S phase was quantified: no accumulation of cells was ever observed at the end of S phase. The question of the existence of small tetraploid clones, G2 arrested cells or cells with a G2 elongation remains open. However, we feel that it is more probable that, in this pathology, an elongation of the duration of G2 occurs.