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Nucleophosmin (NPM, also known as B23, numatrin or NO38) is a ubiquitously expressed phosphoprotein belonging to the nucleoplasmin family of chaperones. NPM is mainly localized in the nucleolus where it exerts many of its functions, but a proportion of the protein continuously shuttles between the nucleus and the cytoplasm. A growing number of cellular proteins have been described as physical interactors of NPM, and consequently, NPM is thought to have a relevant role in diverse cellular functions, including ribosome biogenesis, centrosome duplication, DNA repair and response to stress. NPM has been implicated in the pathogenesis of several human malignancies and intriguingly, it has been described both as an activating oncogene and a tumor suppressor, depending on cell type and protein levels. In fact, increased NPM expression is associated with different types of solid tumors whereas an impairment of NPM function is characteristic of a subgroup of hematolologic malignancies. A large body of experimental evidence links the deregulation of specific NPM functions to cellular transformation, yet the molecular mechanisms through which NPM contributes to tumorigenesis remain elusive. In this review, we have summarized current knowledge concerning NPM functions, and attempted to interpret its multifaceted and sometimes apparently contradictory activities in the context of both normal cellular homeostasis and neoplastic transformation. [ABSTRACT FROM AUTHOR]

Alterations of the retinoic acid receptor (RAR)alpha locus are found in 100% of acute promyelocytic leukemia patients, where chromosomal translocations generate the promyelocytic leukemia (PML)-RARalpha chimeric protein. Here, we have investigated the biological properties of the other RAR isoforms (RARbeta and RARgamma), through the generation and characterization of artificial PML-RAR'x' fusion proteins. Surprisingly, we found that all of the RAR isoforms share an identical oncogenic potential in vitro, thus implying that the selection of the RARalpha locus in leukemia patients must occur--rather than through functional differences among the various RAR isoforms-as the consequence of the nuclear architecture of the different RAR loci. [ABSTRACT FROM AUTHOR]

Recent studies suggest that components of the prosurvival signal transduction pathways involving the Ras-mitogen-activated protein kinase (MAPK) can confer an aggressive, apoptosis-resistant phenotype to leukemia cells. In this study, we report that acute promyelocytic leukemia (APL) cells exploit the Ras-MAPK activation pathway to phosphorylate at Ser112 and to inactivate the proapoptotic protein Bad, delaying arsenic trioxide (ATO)-induced apoptosis. Both in APL cell line NB4 and in APL primary blasts, the inhibition of extracellular signal-regulated kinases 1/2 (ERK1/2) and Bad phosphorylation by MEK1 inhibitors enhanced apoptosis in ATO-treated cells. We isolated an arsenic-resistant NB4 subline (NB4-As(R)), which showed stronger ERK1/2 activity (2.7-fold increase) and Bad phosphorylation (2.4-fold increase) compared to parental NB4 cells in response to ATO treatment. Upon ATO exposure, both NB4 and NB4-As(R) cell lines doubled protein levels of the death antagonist Bcl-xL, but the amount of free Bcl-xL that did not heterodimerize with Bad was 1.8-fold greater in NB4-As(R) than in the parental line. MEK1 inhibitors dephosphorylated Bad and inhibited the ATO-induced increase of Bcl-xL, overcoming ATO resistance in NB4-As(R). These results may provide a rationale to develop combined or sequential MEK1 inhibitors plus ATO therapy in this clinical setting. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented about the role of retinoic acid receptor isoforms in leukemogenesis which also shows a significant function of genome topology as well as in the selection of mutagenic events in cancer.

The p66ShcA protein controls cellular responses to oxidative stress, senescence, and apoptosis. Here, we test the hypothesis that aging phenotype(s) commonly associated with the broad category of chronic kidney disease are accelerated in diabetic kidneys and linked to the p66ShcA locus. At the organ level, tissue stem cells antagonize senescent phenotypes by replacing old dysfunctional cells. Using established methods, we isolated a highly purified population of stem cell antigen-1-positive mesenchymal stem cells (Sca-1+ MSCs) from kidneys of wild-type (WT) and p66 knockout (p66 KO) mice. Cells were plated in culture medium containing normal glucose (NG) or high glucose (HG). Reactive oxygen species (ROS) metabolism was substantially increased in WT MSCs in HG medium in association with increased cell death by apoptosis and acquisition of the senescent phenotype. DNA microarray analysis detected striking differences in the expression profiles of WT and p66 KO-MSCs in HG medium. Unexpectedly, the analysis for p66 KO-MSCs revealed upregulation of Wnt genes implicated in self-renewal and differentiation. To test the in vivo consequences of constitutive p66 expression in diabetic kidneys, we crossed the Akita diabetic mouse with the p66KO mouse. Homozygous mutation at the p66 locus delays or prevents aging phenotype(s) in the kidney that may be precursors to diabetic nephropathy [ABSTRACT FROM AUTHOR]

The Melanoma Independent Board (MIB) held its first conference from 21 to 22 October, 2013, in Rome, Italy. Like the MIB itself, the conference brought together specialists from all aspects of cancer care: doctors, patient associations, journalists, and representatives from local government, hospitals, and pharma to encourage an interdisciplinary discussion on the future of melanoma. It was hoped that the conference would be an opportunity for all participants to see and understand each other's points of view. In memoriam of melanoma pioneer Natalie Cascinelli, the conference focussed on innovation and sustainability as well as the latest drug developments. [ABSTRACT FROM AUTHOR]

Background: Classification of lung carcinoids into typical and atypical is a diagnostic challenge since no immunohistochemical tools are available to support pathologists in distinguishing between the two subtypes. A differential diagnosis is essential for clinicians to correctly discuss therapy, prognosis and follow-up with patients. Indeed, the distinction between the two typical and atypical subtypes on biopsies/cytological specimens is still unfeasible and sometimes limited also after radical surgeries. By comparing the gene expression profile of typical (TC) and atypical carcinoids (AC), we intended to find genes specifically expressed in one of the two subtypes that could be used as diagnostic markers.Methods: Expression profiling, with Affymetrix arrays, was performed on six typical and seven atypical samples. Data were validated on an independent cohort of 29 tumours, by means of quantitative PCR and immunohistochemistry (IHC).Results: High-throughput gene expression profiling was successfully used to identify a gene signature specific for atypical lung carcinoids. Among the 273 upregulated genes in the atypical vs typical subtype, GC (vitamin D-binding protein) and CEACAM1 (carcinoembryonic antigen family member) emerged as potent diagnostic markers. Quantitative PCR and IHC on a validation set of 17 ACs and 12 TCs confirmed their reproducibility and feasibility.Conclusions: GC and CEACAM1 can distinguish between TC and AC, defining an IHC assay potentially useful for routine cytological and histochemical diagnostic procedures. The high sensitivity and reproducibility of this new diagnostic algorithm strongly support a further validation on a wider sample size. [ABSTRACT FROM AUTHOR]

Background:Classification of lung carcinoids into typical and atypical is a diagnostic challenge since no immunohistochemical tools are available to support pathologists in distinguishing between the two subtypes. A differential diagnosis is essential for clinicians to correctly discuss therapy, prognosis and follow-up with patients. Indeed, the distinction between the two typical and atypical subtypes on biopsies/cytological specimens is still unfeasible and sometimes limited also after radical surgeries. By comparing the gene expression profile of typical (TC) and atypical carcinoids (AC), we intended to find genes specifically expressed in one of the two subtypes that could be used as diagnostic markers.Methods:Expression profiling, with Affymetrix arrays, was performed on six typical and seven atypical samples. Data were validated on an independent cohort of 29 tumours, by means of quantitative PCR and immunohistochemistry (IHC).Results:High-throughput gene expression profiling was successfully used to identify a gene signature specific for atypical lung carcinoids. Among the 273 upregulated genes in the atypical vs typical subtype, GC (vitamin D-binding protein) and CEACAM1 (carcinoembryonic antigen family member) emerged as potent diagnostic markers. Quantitative PCR and IHC on a validation set of 17 ACs and 12 TCs confirmed their reproducibility and feasibility.Conclusions:GC and CEACAM1 can distinguish between TC and AC, defining an IHC assay potentially useful for routine cytological and histochemical diagnostic procedures. The high sensitivity and reproducibility of this new diagnostic algorithm strongly support a further validation on a wider sample size. [ABSTRACT FROM AUTHOR]

The article discusses the results of the study that evaluates the effect of the combined nucleophosmin (NPMc +) and Fms-related Tyrosine Kinase 3 (FLT3-ITD) mutations on leukemia development in mouse model. It demonstrates that NPMc + and FLT3-ITD mutations cooperate efficiently in inducing acute myeloid leukemia (AML) in mice. It suggests that the combined mutations are enough to initiate and promote leukemogenesis.

Nucleophosmin (NPM), a ubiquitously and abundantly expressed protein, occurs in the nucleolus, shuttling between the nucleoplasm and cytoplasm. The NPM gene is mutated in almost 30% of human acute myeloid leukemia cells. NPM interacts with p53 and p19Arf, directs localization of p19Arf in the nucleolus and protects the latter from degradation. Hepatocyte odd protein shuttling (HOPS) is also a ubiquitously expressed protein that moves between the nucleus and cytoplasm. Within the nucleus of resting cells, HOPS overexpression causes cell cycle arrest in G0/G1. HOPS knockdown causes centrosome hyperamplification leading to multinucleated cells and the formation of micronuclei. We demonstrate a direct interaction of HOPS with NPM and p19Arf, resulting in a functionally active trimeric complex. NPM appeared to regulate HOPS half-life, which, in turn, stabilized p19Arf and controlled its localization in the nucleolus. These findings suggest that HOPS acts as a functional bridge in the interaction between NPM and p19Arf, providing new mechanistic insight into how NPM and p19Arf will oppose tumor cell proliferation. [ABSTRACT FROM AUTHOR]

A letter to the editor on the use of N- and C-terminal antibodies anti-nucleophosmin 1 in immunofluorescence experiments in acute myeloid leukaemia patients, is presented.

In acute promyelocytic leukemia (APL) the retinoic acid receptor alpha (RARα) becomes an oncogene through the fusion with several partners, mostly with promyelocytic leukemia protein (PML), all of which have in common the presence of a self-association domain. The new fusion proteins, therefore, differently from the wild-type RARα, which forms only heterodimers with retinoic X receptor alpha, are also able to homo-oligomerize. The presence of such a domain has been suggested to be crucial for the leukemogenic potential of the chimeric proteins found in APL blasts. Whether or not any self-association domain is sufficient to bestow a leukemogenic activity on RARα is still under investigation. In this work, we address this question using two different X-RARα chimeras, where X represents the coiled-coil domain of PML (CC-RARα) or the oligomerization portion of the yeast transcription factor GCN4 (GCN4-RARα). We demonstrate that in vitro both proteins have transforming potential, and recapitulate the main PML-RARα biological properties, but CC-RARα is uniquely able to disrupt PML nuclear bodies. Indeed, in vivo only the CC-RARα chimera induces efficiently APL in a murine transplantation model. Thus, the PML CC domain represents the minimal structural determinant indispensable to transform RARα into an oncogenic protein. [ABSTRACT FROM AUTHOR]

The ability to reprogram adult cells into stem cells has raised hopes for novel therapies for many human diseases. Typical stem cell reprogramming protocols involve expression of a small number of genes in differentiated somatic cells with the c-Myc and Klf4 proto-oncogenes typically included in this mix. We have previously shown that expression of oncogenes leads to DNA replication stress and genomic instability, explaining the high frequency of p53 mutations in human cancers. Consequently, we wondered whether stem cell reprogramming also leads to genomic instability. To test this hypothesis, we examined stem cells induced by a variety of protocols. The first protocol, developed specifically for this study, reprogrammed primary mouse mammary cells into mammary stem cells by expressing c-Myc. Two other previously established protocols reprogrammed mouse embryo fibroblasts into induced pluripotent stem cells by expressing either three genes, Oct4, Sox2 and Klf4, or four genes, OSK plus c-Myc. Comparative genomic hybridization analysis of stem cells derived by these protocols revealed the presence of genomic deletions and amplifications, whose signature was suggestive of oncogene-induced DNA replication stress. The genomic aberrations were to a significant degree dependent on c-Myc expression and their presence could explain why p53 inactivation facilitates stem cell reprogramming. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented that focuses on a study on the identification of a rare chromosomal rearrangement in an acute myeloid leukemia patient that results in a MYB-GATA1 fusion product.

Computed tomography (CT) screening of lung cancer allows the detection of early tumors. The objective of our study was to verify whether initial asymptomatic lung cancers, identified by high-resolution low-dose CT (LD-CT) on a high-risk population, show genetic abnormalities that could be indicative of the early events of lung carcinogenesis. We analyzed 78 tumor samples: 21 (pilot population) from heavy smokers with asymptomatic non-screening detected early-stage lung cancers and 57 from 5203 asymptomatic heavy smoker volunteers, who underwent a LD-CT screening study. During surgical resection of the detected tumors, tissue samples were collected and short-term cultures were started for karyotype evaluation. Samples were classified according to the normal (NK) or aneuploid (AK) karyotype. The NK samples were further analyzed by the Affymetrix single-nucleotide polymorphisms (SNPs) technology. Metaphase spreads were obtained in 73.0% of the selected samples: 80.7% showed an AK. A statistically significant correlation was found between presence of vascular invasion and abnormal karyotype. A total of 10 NK samples were suitable for SNPs analysis. Subtle genomic alterations were found in eight tumors, the remaining two showing no evidence to date of chromosomal aberrations anywhere in the genome. Two common regions of amplification were identified at 5p and 8p11. Mutation analysis by direct sequencing was conducted for the K-RAS, TP53 and EGFR genes, confirming data already described for heavy smokers. We show that: (i) the majority of screening-detected tumors are aneuploid; (ii) early-stage tumors tend to harbor a less abnormal karyotype; (iii) whole genome analysis of NK tumors allows for the detection of common regions of copy number variation (such as amplifications at 5p and 8p11), highlighting genes that might be considered candidate markers of early events in lung carcinogenesis. [ABSTRACT FROM AUTHOR]

Objective:To analyze the effect of the juice obtained from two varieties of sweet orange (Citrus sinensis L. Osbeck), Moro (a blood orange) and Navelina (a blond orange), on fat accumulation in mice fed a standard or a high-fat diet (HFD).Methods:Obesity was induced in male C57/Bl6 mice by feeding a HFD. Moro and Navelina juices were provided instead of water. The effect of an anthocyanin-enriched extract from Moro oranges or purified cyanidin-3-glucoside (C3G) was also analyzed. Body weight and food intake were measured regularly over a 12-week period. The adipose pads were weighted and analyzed histologically; total RNA was also isolated for microarray analysis.Results:Dietary supplementation of Moro juice, but not Navelina juice significantly reduced body weight gain and fat accumulation regardless of the increased energy intake because of sugar content. Furthermore, mice drinking Moro juice were resistant to HFD-induced obesity with no alterations in food intake. Only the anthocyanin extract, but not the purified C3G, slightly affected fat accumulation. High-throughput gene expression analysis of fat tissues confirmed that Moro juice could entirely rescue the high fat-induced transcriptional reprogramming.Conclusion:Moro juice anti-obesity effect on fat accumulation cannot be explained only by its anthocyanin content. Our findings suggest that multiple components present in the Moro orange juice might act synergistically to inhibit fat accumulation. [ABSTRACT FROM AUTHOR]

We explored in a phase I/II clinical trial the combination of valproic acid (VPA), a clinically available histone deacetylase inhibitor, with standard chemoimmunotherapy in patients with advanced melanoma, to evaluate its clinical activity, to correlate the clinical response with the biological activity of VPA and to assess toxicity. Patients were treated initially with VPA alone for 6 weeks. The inhibition of the target in non-tumour peripheral blood cells (taken as a potential surrogate marker) was measured periodically, and valproate dosing adjusted with the attempt to reach a measurable inhibition. After the treatment with valproate alone, dacarbazine plus interferon-alpha was started in combination with valproate. Twenty-nine eligible patients started taking valproate and 18 received chemoimmunotherapy and are assessable for response. We observed one complete response, two partial remissions and three disease stabilisations lasting longer than 24 weeks. With the higher valproate dosages needed to reach a measurable inhibition of the target, we observed an increase of side effects in those patients who received chemoimmunotherapy. The combination of VPA and chemoimmunotherapy did not produce results overtly superior to standard therapy in patients with advanced melanoma and toxicity was not negligible, casting some doubts on the clinical use of VPA in this setting (at least in the administration schedule adopted). [ABSTRACT FROM AUTHOR]

Cancer is generally characterized by loss of CG dinucleotides methylation resulting in a global hypomethylation and the consequent genomic instability. The major contribution to the general decreased methylation levels seems to be due to demethylation of heterochromatin repetitive DNA sequences. In human immunodeficiency, centromeric instability and facial anomalies syndrome, demethylation of pericentromeric satellite 2 DNA sequences has been correlated to functional mutations of the de novo DNA methyltransferase 3b (DNMT3b), but the mechanism responsible for the hypomethylated status in tumors is poorly known. Here, we report that human glioblastoma is affected by strong hypomethylation of satellite 2 pericentromeric sequences that involves the stem cell compartment. Concomitantly with the integrity of the DNMTs coding sequences, we report aberrations in DNA methyltrasferases expression showing upregulation of the DNA methyltransferase 1 (DNMT1) and downregulation of the de novo DNA methyltransferase 3a (DNMT3a). Moreover, we show that DNMT3a is the major de novo methyltransferase expressed in normal neural progenitor cells (NPCs) and its forced re-expression is sufficient to partially recover the methylation levels of satellite 2 repeats in glioblastoma cell lines. Thus, we speculate that DNMT3a decreased expression may be involved in the early post-natal inheritance of an epigenetically altered NPC population that could be responsible for glioblastoma development later in adult life.Oncogene (2008) 27, 358–365; doi:10.1038/sj.onc.1210642; published online 23 July 2007 [ABSTRACT FROM AUTHOR]

p66Shc, a redox enzyme that enhances reactive oxygen species (ROS) production by mitochondria, promotes T cell apoptosis. We have addressed the mechanisms regulating p66Shc-dependent apoptosis in T cells exposed to supraphysiological increases in [Ca2+]c. p66Shc expression resulted in profound mitochondrial dysfunction in response to the Ca2+ ionophore A23187, as revealed by dissipation of mitochondrial transmembrane potential, cytochrome c release and decreased ATP levels. p66Shc expression also caused a dramatic alteration in the cells’ Ca2+-handling ability, which resulted in Ca2+ overload after A23187 treatment. The impairment in Ca2+ homeostasis was ROS dependent and caused by defective Ca2+ extrusion due at least in part to decreased plasma membrane ATPase (PMCA) expression. Both effects of p66Shc required Ca2+-dependent serine-36 phosphorylation. The mitochondrial effects of p66Shc were potentiated by but not strictly dependent on the rise in [Ca2+]c. Thus, Ca2+-dependent p66Shc phosphorylation causes both mitochondrial dysfunction and impaired Ca2+ homeostasis, which synergize in promoting T cell apoptosis.Cell Death and Differentiation (2007) 14, 338–347. doi:10.1038/sj.cdd.4401997; published online 23 June 2006 [ABSTRACT FROM AUTHOR]

Nucleophosmin (NPM) is a nucleus–cytoplasmic shuttling protein that is implicated in centrosome duplication, cell cycle progression and stress response. At the steady state, NPM localizes mainly in the nucleolus, where it forms a complex with different cellular proteins. One-third of acute myeloid leukemias (AML) are characterized by aberrant cytoplasmic localization of NPM, due to mutations within its last coding exon (exon 12) that cause a frameshift and the formation of novel C-termini. We report here our investigations on the molecular basis for the aberrant localization of mutated NPM. Alignment of the C-terminus of the various NPM mutants revealed the obligatory presence of four amino-acid residues that match a CRM1-dependent nuclear export signal (NES). Single alanine-substitutions at these sites provoked nuclear re-localization, while fusion of the mutated C-terminus to a heterologous nuclear protein induced CRM1-dependent cytoplasmic localization. Molecular characterization of one exceptional AML carrying cytoplasmic NPM and germ line exon 12 revealed a somatic mutation in the splicing donor site of exon 9 that caused the formation of a functional NES. It appears, therefore, that AMLs are frequently characterized by gain-of-function mutations of NPM that create functional NES, suggesting that alterations of nuclear export might represent a general mechanism of leukemogenesis and a novel target for therapeutic intervention.Oncogene (2006) 25, 4376–4380. doi:10.1038/sj.onc.1209453; published online 27 February 2006 [ABSTRACT FROM AUTHOR]

p66(Shc) regulates both steady-state and environmental stress-dependent reactive oxygen species (ROS) generation. Its deletion was shown to confer resistance to oxidative stress and protect mice from aging-associated vascular disease. This study was aimed at verifying the hypothesis that p66(Shc) deletion also protects from diabetic glomerulopathy by reducing oxidative stress. Streptozotocin-induced diabetic p66(Shc) knockout (KO) mice showed less marked changes in renal function and structure, as indicated by the significantly lower levels of proteinuria, albuminuria, glomerular sclerosis index, and glomerular and mesangial areas. Glomerular content of fibronectin and collagen IV was also lower in diabetic KO versus wild-type mice, whereas apoptosis was detected only in diabetic wild-type mice. Serum and renal tissue advanced glycation end products and plasma isoprostane 8-epi-prostaglandin F2alpha levels and activation of nuclear factor kappaB (NF-kappaB) were also lower in diabetic KO than in wild-type mice. Mesangial cells from KO mice grown under high-glucose conditions showed lower cell death rate, matrix production, ROS levels, and activation of NF-kappaB than those from wild-type mice. These data support a role for oxidative stress in the pathogenesis of diabetic glomerulopathy and indicate that p66(Shc) is involved in the molecular mechanism(s) underlying diabetes-induced oxidative stress and oxidant-dependent renal injury. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Aberrant Subcellular Expression of Nucleophosmin and NPM-MLF1 Fusion Protein in Acute Myeloid Leukaemia Carrying t(3;5): A Comparison With NPMc+ AML," published in the December 8, 2005 issue.

Six patients with de novo acute myeloid leukemia (AML) and a t(2;3)(p15–21;q26–27) were identified among approximately 1000 cases enrolled in the GIMEMA trial. The t(2;3) was the sole anomaly in three patients, whereas in three cases monosomy 7, trisomy 15 and 22, and trisomy 14 represented additional aberrations. No cryptic chromosome deletions at 5q, 7q, 12p, and 20q were observed. One patient carried a FLT3 D835 mutation; FLT3 internal tandem duplication (ITD) was not detected in three patients tested. Characterization of the translocation breakpoints using a 3q26 BAC contig specific for the PRDM3 locus showed that the breakpoints were located 5′ to EVI1 as follows: within myelodysplatic syndrome (MDS) intron 1 (# 3), between MDS1 exons 2 and 3 in three patients (# 1, 2, 4) with a 170 bp cryptic deletion distal to the breakpoint in one (# 2), and in a more centromeric position spanning from intron 2 to the 5′ region of EVI1 (# 6, 5). A set of 2p16–21 BAC probes showed that the breakpoints on chromosome 2p were located within BCL11A in two separate regions (# 1, 4 and # 2–5), within the thyroid adenoma-associated (THADA) gene (# 6) or distal to the ZFP36L2 locus (# 3). Regulatory elements were present in proximity of these breakpoints. RACE PCR studies revealed a chimeric transcript in 1/6 patient analyzed, but no fusion protein. Quantitative PCR showed a 21–58-fold overexpression of the EVI1 gene in all cases analyzed. The patients showed dysplasia of at least two myeloid cell lineages in all cases; they had a low-to-normal platelet count and displayed an immature CD34+ CD117+ immunophenotype. Despite intensive chemotherapy and a median age of 43 years (range 36–59), only two patients attained a short-lived response; one patient is alive with active disease at 12 months, five died at 4–14 months. We arrived at the following conclusions: (a) the t(2;3) is a recurrent translocation having an approximate 0.5% incidence in adult AML; (b) breakpoints involve the 5′ region of EVI1 at 3q26, and the BCL11A, the THADA gene or other regions at 2p16.1–21; (c) cryptic deletions distal to the 3q26 breakpoint may occur in some cases; (d) the juxtaposition of the 5′ region of EVI1 with regulatory elements normally located on chromosome 2 brings about EVI1 overexpression; (e) clinical outcome in these cases is severe.Leukemia (2006) 20, 48–54. doi:10.1038/sj.leu.2404020; published online 24 November 2005 [ABSTRACT FROM AUTHOR]

Summary Eosinophilic crystals have been described in the upper and lower respiratory tract, gall bladder, intrahepatic bile ducts and glandular stomach of different laboratory mice strains. They have been recently identified as chitinase–like (Ym1/Ym2) proteins. Here we describe the occurrence of eosinophilic crystals in the renal tubules of mice with experimentally induced acute myelogenous leukaemia. Fourteen FVB/N and 29 129Sv mice of both sexes, 8–10 weeks of age, were employed to establish a model of human acute myelogenous leukaemia. Nine mice that developed a widespread acute myelogenous leukaemia revealed the presence of eosinophilic crystals in renal tubules. The presence of eosinophilic crystals in the kidneys was constantly associated with a hyaline droplet nephropathy. Immunohistochemistry showed that the crystals and the hyaline droplets were composed of chitinase-like (Ym1/Ym2) proteins. Furthermore, immunoreactivity for Ym1/Ym2 proteins was also detected in the crystalline material stored in the cytoplasm of large macrophage-like cells or in extracellular localization within the leukaemic infiltrates. On the basis of our results we hypothesize that the detection of the Ym1/Ym2 proteins in the urine of mice might represent a feasible indicator of the burden and progression of the leukaemic condition in our murine model. [ABSTRACT FROM AUTHOR]

We analyzed the relationship between the reinfusion of large or very large amounts of peripheral blood progenitor cells (PBPC) and hematologic toxicity in twenty-one advanced breast cancer patients subjected to a myeloablative dose of melphalan at the end of a high-dose sequential chemotherapy (HDSC) program. We also evaluated the influence of the white blood cell (WBC) count to predict an optimal PBPC harvest after high-dose chemotherapy and growth factor priming. Twenty-one patients with high-risk or metastatic breast cancer sequentially received: high-dose cyclophosphamide (HD-Cy) and G-CSF followed by PBPC harvest, HD-methotrexate plus vincristine, HD-doxorubicin, cisplatin and finally HD-melphalan 200 mg/m2 (HD-L-PAM) followed by PBPC reinfusion. No growth factor was administered after HD-L-PAM. CD34+ cytofluorimetric analysis, WBC count and clonogenic assays were employed to monitor circulating cells and to analyze the PBPC harvest. Correlation between different PBPC doses and hematologic toxicity as well as leukocyte and platelet recovery time was attempted. Patients received a median number of 16 (4–25.1) × 106/kg CD34+ cells, 81.3 (30.8–228) × 104/kg CFU-GM and 4.2 (1.3–7.3) × 108/kg nucleated cells (NC) after HD-L-PAM. The number of days with fewer than 1 × 109/l leukocytes and 20 × 109/l platelets were 6 (range 4–9) and 0 (range 0–3), respectively. The CD34+ cell dose significantly correlated with both platelet count nadir (r = 0.73) and time to 50 × 109/l platelets (r = 0.7), but did not correlate with time to reach more than 1 × 109/l WBC count (r = 0.2). In particular, we found that in 12 patients given very large amounts of CD34+ cells, ranging between 15.8 and 25.1 × 106/kg (V-LA-CD34+), the platelet nadir count never... [ABSTRACT FROM AUTHOR]

Typical acute promyelocytic leukemia (APL) is associated with the t(15;17) translocation, expression of a PML/RARA fusion transcript, and responsiveness to all-trans retinoic acid (ATRA). Rare APL cases implicating the RARA but not the PML gene have been reported. Cases with t(11;17)(q23;q21) which fuses the PLZF and RARA genes do not respond to ATRA. In contrast, cases with t(11;17)(q13;q21) and t(5;17)(q35;q21) which fuse RARA with NuMA and NPM, respectively, were reported to be sensitive to ATRA. We described previously an APL case with an unbalanced t(5;17) implicating RARA but neither PML nor PLZF. Here, we show that in this case: (1) the NPM gene is not involved, as demonstrated by RT-PCR and Southern blot; (2) response to ATRA in vitro is atypical, as demonstrated by morphological and functional maturation assays; and (3) PML nuclear bodies are not disrupted, as evidenced by immunofluorescence staining. [ABSTRACT FROM AUTHOR]

We have analyzed the differentiation program of growth factor-dependent TF-1 erythroleukemia cells as well as clones with inducible expression of the APL-specific PML/RARalpha protein. We have shown that TF-1 cells may be induced to megakaryocytic differentiation by phorbol ester (phorbol dibutyrate, PDB) addition, particularly when combined with thrombopoietin (Tpo). RT-PCR studies showed that Tpo induces Tpo receptor (TpoR or c-mpl), whose expression was further potentiated by PDB addition. When the cells are induced with both PDB and Tpo erythropoietin receptor (EpoR) expression was inhibited. In the absence of Zn2+-induced PML/RARalpha expression, PDB and Tpo induced megakaryocytic differentiation of TF-1 MTPR clones as observed in 'wild-type' TF-1 cells. Conversely, when PML/RARalpha expression was induced by Zn2+, PDB and Tpo treatment of these clones caused only a reduced level of megakaryocytic differentiation. These observations indicate that: (1) TF-1 cells as well as other erythroleukemic cells, possess the capacity to differentiate to megakaryocytic cells when grown in the presence of protein kinase (PKC) activators and more efficiently when combined with Tpo; (2) the PML/RARalpha gene has a wide capacity to interfere with the program of hematopoietic differentiation, including megakaryocytic differentiation. Finally, we also observed that PML/RARalpha expression in TF-1 cells induces an up-modulation of interleukin-3 receptor, c-kit and c-mpl, a phenomenon which may offer these cells a growth advantage. [ABSTRACT FROM AUTHOR]

Since in vitro observations indicated that all-trans retinoic acid (ATRA), especially in combination with IFNalpha, can exert significant suppressive effects on Ph+ cells, we investigated the effects and the pharmacokinetic profile of ATRA in a selected cohort of patients with Ph+ chronic myeloid leukemia (CML) in chronic phase. Eighteen patients were treated with ATRA at a dose of 80 mg/m2/day (p.o.), divided into two equal doses after meals, for 7 consecutive days every other week for a maximum of 12 courses (1 course = 1 week on and 1 week off). Pharmacokinetic profiles of ATRA were evaluated during intermittent therapy on days 1 and 7 of course 1; on day 1 of course 2; on day 1 of course 6. Out of the 18 patients treated with ATRA, 11 (61%) went off study before the sixth course of treatment because of progressive hyperleukocytosis (seven cases), or thrombocytosis (one case), or refusal (three cases). Seven (39%) patients completed the first six courses (12 weeks) of treatment with ATRA and two of them (11%) maintained a white blood cell (WBC) <10 x 10[9]/l which was induced by the pretreatment with hydroxyurea. One patient completed the 12th course of ATRA maintaining WBC <10 x 10(9)/l, platelets <500 x 10(9)/l and spleen not palpable. The treatment with ATRA was well tolerated and only one patient discontinued the therapy because of non-hematological side-effects. The area under the concentration-time curve (AUC) decreased significantly (P< 0.001) during the first week of therapy. By adopting an intermittent dosing regimen, 1 week on/ 1 week off (1 course), at the start of courses 2 and 6, we obtained the ATRA AUCs equivalent to the ones achieved on day 1 of course 1. In conclusion, our results showed that ATRA alone appeared to be unable to control the WBC expansion in the CML patients in chronic phase. Moreover, it did not induce any remarkable cytoreductive effects on the platelet count and on the hemoglobin level. The major interest of ATRA would be in combination with other therapies. If ATRA was given in combination with IFNalpha or other agents, dose reduction of these would not be planned. On the basis of the pharmacokinetic profile, ATRA should be administered intermittently rather than continuously. [ABSTRACT FROM AUTHOR]

The article offers information on chromosome rearrangements in acute myeloid leukemia (AML).

A letter to the editor is presented about PDGFRB-positive acute myeloid malignancy that is published within the issue.

The article offers information about the importance of spectral karyotyping (SKY) in studying human chromosomes.

A correction to the article "In vivo expression of an aberrant MYB-GATA1 fusion induces leukemia in the presence of GATA1 reduced levels," by E. Belloni and colleagues that was published in 2011 issue is presented.

A correction to the article "Aberrant subcellular expression of nucleophosmin and NPM-MLF1 fusion protein in acute myeloid leukemia carrying t(3;5): A comparison with NPMc+AML" that appeared in the march 9, 2006 issue of the journal "Leukemia" is presented.

A correction to the article "Characterization of a Recurrent Translocation t(2;3)(p15–22;q26) Occurring in Acute Myeloid Leukemia," that was published in the previous issues of the journal is presented.

Presents a corrected reprint of the article "Inhibitors of histone deacetylases induce tumor-selective apoptosis through activation of the death receptor pathway," by A. Insinga, S. Monestiroli, S. Ronzoni et al., published in the Number 11, 2005 issue of the "Nature Medicine" journal.

Presents a correction to the name of the author of the article "Arsenic Trioxide and MEK1 Inhibition Synergize to Induce Apoptosis in Acute Promyelocytic Leukemia Cells" that appeared in the 2005 issue of the journal "Leukemia."