Frequency and clinical impact of CDKN2A/ARF/CDKN2B gene deletions as assessed by in-depth genetic analyses in adult T cell acute lymphoblastic leukemia

Recurrent deletions of the CDKN2A/ARF/CDKN2B genes encoded at chromosome 9p21 have been described in both pediatric and adult acute lymphoblastic leukemia (ALL), but their prognostic value remains controversial, with limited data on adult T-ALL. Here, we investigated the presence of homozygous and heterozygous deletions of the CDKN2A/ARF and CDKN2B genes in 64 adult T-ALL patients enrolled in two consecutive trials from the Spanish PETHEMA group. Alterations in CDKN2A/ARF/CDKN2B were detected in 35/64 patients (55%). Most of them consisted of 9p21 losses involving homozygous deletions of the CDKNA/ARF gene (26/64), as confirmed by single nucleotide polymorphism (SNP) arrays and interphase fluorescence in situ hybridization (iFISH). Deletions involving the CDKN2A/ARF/CDKN2B locus correlated with a higher frequency of cortical T cell phenotype and a better clearance of minimal residual disease (MRD) after induction therapy. Moreover, the combination of an altered copy-number-value (CNV) involving the CDKN2A/ARF/CDKN2B gene locus and undetectable MRD (≤ 0.01%) values allowed the identification of a subset of T-ALL with better overall survival in the absence of hematopoietic stem cell transplantation.

Impact of NADPH oxidase functional polymorphisms in acute myeloid leukemia induction chemotherapy

Efficacy and toxicity of anthracycline treatment in acute myeloid leukemia (AML) is mediated by reactive oxygen species (ROS). NADPH oxidase is the major endogenous source of ROS and a key mediator of oxidative cardiac damage. The impact of NADPH oxidase polymorphisms (CYBA:rs4673, NCF4:rs1883112, RAC2:rs13058338) was evaluated in 225 adult de novo AML patients. Variant alleles of NCF4 and RAC2 were related to higher complete remission (P=0.035, P=0.016), and CYBA homozygous variant showed lower overall survival with recessive model (P=0.045). Anthracycline-induced cardiotoxicity was associated to NCF4 homozygous variant (P=0.012) and CYBA heterozygous genotype (P=0.027). Novel associations were found between variant allele of CYBA and lower lung and gastrointestinal toxicities, and a protective effect in nephrotoxicity and RAC2 homozygous variant. Moreover, RAC2 homozygous variant was related to delayed thrombocytopenia recovery. This study supports the interest of NADPH oxidase polymorphisms regarding efficacy and toxicity of AML induction therapy, in a coherent integrated manner.

Energy transduction and signal averaging of fluctuating electric fields by a single protein ion channel

A biological ion channel is used to charge a conventional capacitor from an external fluctuating electrical noise.

Voltage-controlled current loops with nanofluidic diodes electrically coupled to solid state capacitors

Nanofluidic diodes electrically coupled to solid state capacitors show electrical properties reminiscent of a resistor with memory.

The relationship of TP53 R72P polymorphism to disease outcome and TP53 mutation in myelodysplastic syndromes

Nonsynonymous TP53 exon 4 single-nucleotide polymorphism (SNP), R72P, is linked to cancer and mutagen susceptibility. R72P associations with specific cancer risk, particularly hematological malignancies, have been conflicting. Myelodysplastic syndrome (MDS) with chromosome 5q deletion is characterized by erythroid hypoplasia arising from lineage-specific p53 accumulation resulting from ribosomal insufficiency. We hypothesized that apoptotically diminished R72P C-allele may influence predisposition to del(5q) MDS. Bone marrow and blood DNA was sequenced from 705 MDS cases (333 del(5q), 372 non-del(5q)) and 157 controls. Genotype distribution did not significantly differ between del(5q) cases (12.6% CC, 38.1% CG, 49.2% GG), non-del(5q) cases (9.7% CC, 44.6% CG, 45.7% GG) and controls (7.6% CC, 37.6% CG, 54.8% GG) (P=0.13). Allele frequency did not differ between non-del(5q) and del(5q) cases (P=0.91) but trended towards increased C-allele frequency comparing non-del(5q) (P=0.08) and del(5q) (P=0.10) cases with controls. Median lenalidomide response duration increased proportionate to C-allele dosage in del(5q) patients (2.2 (CC), 1.3 (CG) and 0.89 years (GG)). Furthermore, C-allele homozygosity in del(5q) was associated with prolonged overall and progression-free survival and non-terminal interstitial deletions that excluded 5q34, whereas G-allele homozygozity was associated with inferior outcome and terminal deletions involving 5q34 (P=0.05). These findings comprise the largest MDS R72P SNP analysis.

Monosomal karyotype in MDS: explaining the poor prognosis?

Monosomal karyotype (MK) is associated with an adverse prognosis in patients in acute myeloid leukemia (AML). This study analyzes the prognostic impact of MK in a cohort of primary, untreated patients with myelodysplastic syndromes (MDS). A total of 431 patients were extracted from an international database. To analyze whether MK is an independent prognostic marker in MDS, cytogenetic and clinical data were explored in uni- and multivariate models regarding overall survival (OS) as well as AML-free survival. In all, 204/431 (47.3%) patients with MK were identified. Regarding OS, MK was prognostically significant in patients with ≤ 4 abnormalities only. In highly complex karyotypes (≥ 5 abnormalities), MK did not separate prognostic subgroups (median OS 4.9 months in MK+ vs 5.6 months in patients without MK, P=0.832). Based on the number of abnormalities, MK-positive karyotypes (MK+) split into different prognostic subgroups (MK+ and 2 abnormalities: OS 13.4 months, MK+ and 3 abnormalities: 8.0 months, MK+ and 4 abnormalities: 7.9 months and MK+ and ≥ 5 abnormalities: 4.9 months; P<0.01). In multivariate analyses, MK was not an independent prognostic factor. Our data support the hypothesis that a high number of complex abnormalities, associated with an instable clone, define the subgroup with the worst prognosis in MDS, independent of MK.

Wnt signaling pathway is epigenetically regulated by methylation of Wnt antagonists in acute myeloid leukemia

Activation of the Wnt signaling pathway has been implicated recently in the pathogenesis of leukemia. We studied the function of epigenetic regulation of the Wnt pathway and its prognostic relevance in acute myelogenous leukemia (AML). We used a methylation-specific polymerase chain reaction approach to analyze the promoter methylation status of a panel of Wnt antagonists including sFRP1, sFRP2, sFRP4, sFRP5, DKK1 and DKK3. Aberrant methylation of Wnt antagonists was detected in four AML cell lines and in up to 64% of AML marrow samples. Treatment of the cell lines with 5-aza-2'-deoxycytidine induced reexpression of methylated Wnt antagonists and inactivation of the Wnt pathway by downregulating the Wnt pathway genes cyclin D1, TCF1 and LEF1 and reducing nuclear localization of beta-catenin. In a subgroup of patients 60 years and younger with newly diagnosed AML and intermediate-risk cytogenetics, abnormal methylation of Wnt antagonists was associated with decreased 4-year relapse-free survival (28 vs 61%, respectively, P=0.03). Our results indicate a function of the epigenetic regulation of the Wnt pathway in predicting relapse in a subgroup of AML patients.

Biweekly docetaxel and gemcitabine as first line chemotherapy in advanced non-small cell lung cancer (NSCLC)

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Background: The activity and tolerability of third-generation agents led many investigators to evaluate doublet combinations in the hope that platinum analogues could be eliminated from the treatment of advanced NSCLC. To improve the therapeutic index of this combination, we performed a study with biweekly gemcitabine and docetaxel. Primary objective was determination of objective response rate (ORR). Secondary objectives were time to progression, tolerability and overall survival. Methods: Patients histologically confirmed of non-small cell lung cancer, aged ≥ 18, ECOG PS 0–2, measurable lesion according RECIST criteria, adequate bone marrow, renal and hepatic function were included. Prior chemotherapy was not allowed. Patients received treatment with a combination of Docetaxel 50 mg/m2 and gemcitabine 20,00 mg/m2 each 15 days for a maximum of 8 cycles. Results: Fifty patients were included between July 2005 and October 2006.Now we present the results of the first 32 patients: 88% were male, median age was 62.7 years old, 69% had ECOG 0–1 and 81% of patients had stage IV. Histology was squamous cell carcinoma (53%) adenocarcinoma (31%) and large cell carcinoma (16%). A total 221 cycles were administrated . Over 30 patients evaluable for response, none achieved CR, 11 PR (36%), 7 SD (23%) and 12 PD, with an overall response rate of 36%. Median follow up of patients is 16 months, with a median overall survival of 9 months. Grade 3–4 toxicity per patient was: neutropenia (6%).Grade 1–2 toxicity per patient asthenia (75%), and nauseas (30%). Conclusions: These results suggest that biweekly schedule of gemcitabine / docetaxel is a safe and active regimen in first line advanced NSCLC patients.Updated results will be presented.

No significant financial relationships to disclose.

An assessment of cancer-related fatigue in patients (pts) with chemotherapy-induced anaemia (CIA) treated with darbepoetin alfa (DA): Comparison of two quality of life (QoL) questionnaires

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Background: CIA is often associated with debilitating fatigue and reduced QoL. DA can effectively treat CIA when administered once every 3 weeks (Q3W).This study aims to compare the psychometrics of the Functional Assessment of Cancer Therapy Fatigue Subscale (FACT-F) and The Fatigue Symptom Inventory (FSI) in CIA pts treated with DA Q3W. Methods: Longitudinal single- centre prospective study in adult pts with solid tumours undergoing chemotherapy (CT) and with mild to moderate cancer-related fatigue (CRF) (Visual Analogue Scale (VAS) =30 mm). Pts with haemoglobin (HB) levels <11 g/dL were treated with DA 500 mcg Q3W. Key clinical parameters, FACT-F, and FSI measurements were collected at the beginning and end of the CT treatment period. Psychometric indicators for reliability and validity were calculated. Results: A preliminary analysis was conducted in 58 pts: mean age, 61.3 years (SD 12.3), 51.7% women, 25.9% with breast cancer, 91.4% ECOG 0–1, 69.0% IV stage, 63% had no prior CT. At baseline, the mean CRF score by VAS was 58.8 mm (SD 19.4) and the mean Hb was 10.2 g/dL (SD 0.7). Median CT duration was 15.1 weeks (range, 3.3 - 25.7) and all pts received DA treatment during CT (median duration of CT, 6.6 wks [range, 0 - 19]). The median number of DA doses administered was 3 (range, 1–7). The rate of hematopoietic response (Hb ≥ 12 g/dL or Hb rise from baseline ≥ 2 g/dL) was 69.0%. FACT-F and FIS scores improved by 5.6 and 13.0 points respectively during CT. Consistency (Cronbach alpha coefficient - CA) was high and similar for both questionnaires (FACT-F=0.98; FSI=0.97). Conclusions: Both the FACT-F and FIS QoL questionnaires measured a change in fatigue during the study with high and similar consistency. DA administered at a fixed dose of 500 mcg Q3W seems to be effective in clinical practice.

No significant financial relationships to disclose.

[Complications and sequelae after nasal trauma]

Septal haematoma after nasal trauma is a complication that can lead to septal abscess if unrecognized or early intervention is not performed. It can cause compression and thereby necrosis that evolve to a septal abscess in which cultures reveal saprophyte bacteria. Cartilage necrosis and destruction can produce impaired breathing and aesthetic deformities with collapse of the dorsum and the tip of the nose. We present a 10 year old masculine infant, that suffered a nasal fracture with a septal haematoma that remained undiagnosed. The patient developed a septal abscess that required drainage and resulted in nasal sequelae with collapse of dorsum and cranial displacement of tip and columella. Functional and aesthetic reconstruction was performed using rib cartilage grafts. No complications occurred. Functional and aesthetic improvement was observed. Result after 2 months of follow-up is considered favourable.

MRS as endogenous molecular imaging for brain and prostate tumors: FP6 project "eTUMOR"

Molecular imaging has become during the last years in an important tool for supporting cancer diagnosis and prognosis. PET and SPECT are the most common molecular imaging techniques, although very promising and specific biological molecular agent contrast for CT and MRI are being recently developed. However, the above imaging techniques require exogenous contrast agents and usually a sole molecular image can be obtained at once. On the contrary, in vivo magnetic resonance spectroscopy (MRS), in particular 1H MRS can simultaneously provide several molecular images using endogenous metabolites. In addition to biochemical spatial information from molecular imaging spectroscopy, MRS can also provide average metabolite profile of the selected affected tissue region. Initially MRS, especially 1H MRS, was extensively applied to complete and improve the diagnosis and prognosis of central nervous system (CNS) pathologies, in particular brain tumors. However, during the last years the MRS applications have been extent to the diagnosis of different very common cancer types such as breast, prostate, colon carcinoma, and ovarian, among others. Likewise, MRS has been also used for lymph node assessment. In this contribution, the added value of MRS for the diagnosis, prognosis, and treatment selection of two different, important types of cancer: (1) brain tumors and (2) prostate, will be presented and discussed. Brain tumors are the leading cause of death in children under 15, and although in adults, brain cancers are proportionately less common than other cancers, it is a devastating disease with high mortality. There is a great need to increase our understanding of brain tumor biology to improve diagnosis and to develop new treatments. 1H MRS is currently the only noninvasive method that can be used to investigate molecular profile of brain tumors and also provide molecular images, more than six in one acquisition, of the distribution of chemicals in a tumor, which are also generally heterogeneous. A summary of the applications of 1H MRS to the in vivo diagnosis and prognosis of brain tumors will be presented. In addition, examples of metabolite limits, infiltration and high cellularity location for neurosurgery applications by MRS molecular images will be shown. Likewise, new ex vivo methods of studying the detailed biochemistry of tumor biopsies as metabolomic (high resolution magic angle spinning [HR-MAS]) and transcriptomic (DNA microarrays) will be discussed as complementary to in vivo MRS (FP6 European project eTUMOR). A preliminary comparison between molecular images from PET and 1H MRS will be also presented. Finally, the application of 1H MRS to the improvement of prostate diagnosis and prognosis, the second leading cause of cancer death, will also discussed, with particular attention to the location cancer contribution from MRS molecular images.

Theoretical Description of the Ion Transport Across Nanopores With Titratable Fixed Charges: Analogies Between Ion Channels and Synthetic Pores

Recently developed nanometer-sized synthetic pores display several properties so far believed to be distinctive features of a large variety of biological wide ion channels. Thus conductance in the pS-nS range, pH-dependent ion selectivity, fluctuations of current between open and closed states, flux inhibition caused by protons or divalent cations, current rectification, and the ability to perform selective macromolecule sizing and counting are found in synthetic and biological channels alike. Despite other differences such as pore size and geometry, the similarities open a new field for exploring specific technological applications via the chemical modification of synthetic pores with biological molecules. This article reviews some of the basic concepts and theories relevant to ion transport in nanopores with titratable charges stressing the analogies between synthetic pores and biological ion channels. The ultimate goal is to show that continuum theories may account for the essential features of these systems. A simple electrodiffusion model and its comparison with experimental results are chosen as a case study.

Genetic abnormalities associated with the t(12;21) and their impact in the outcome of 56 patients with B-precursor acute lymphoblastic leukemia

The ETV6/RUNX1 rearrangement is found in 20-30% of children with B-cell precursor acute lymphoblastic leukemia and is associated with a good outcome. To determine the cytogenetic and molecular abnormalities associated with the ETV6/RUNX1 rearrangement and the influence of this rearrangement in patients' evolution, we analyzed the molecular cytogenetic profiles of 56 children with this rearrangement and B-cell precursor acute lymphoblastic leukemia. Secondary changes detected with conventional cytogenetics and with fluorescence in situ hybridization were found in 71.4% of cases, the most frequent being the loss of the normal ETV6 allele, 12p aberrations, duplication of the fusion gene, and trisomy 21, as in replicating the results of previous studies. In this preliminary series, with a mean follow-up of 69.3 months, secondary abnormalities did not influence patients' outcome. It seems therefore that the prognostic value of the t(12;21) does not vary and that ETV6/RUNX1 rearrangement is an independent indicator of good prognosis.

Implante coclear en malformaciones congénitas

OBJECTIVE

The main objective is to evaluate the complications and problems encountered in a population with inner ear congenital malformation undergoing cochlear implantation.

MATERIALS AND METHODS

The present study includes 33 patients with congenital inner ear malformation, from a total population of 346 cochlear implant patients, implanted from February 1993 to March 2004. Radiological evaluation and neurological exams were performed to all these patients in order to evaluate all the preoperative conditions.

RESULTS

The most common cochlear anomalies we found were: cochlear hypoplasia, Incomplete partition and Common cavity (n=15). In 4 cases an enlarge aqueduct was also associated to the cochlear anomaly. We also found 6 cases with labyrinthine anomalies. The surgical procedure was performed in 23 cases, and in 18 of them we obtained an electrical stimulation of the neural elements.

CONCLUSIONS

There are no differences between patients with Incomplete Partition of the cochlea and mild Cochlea hypoplasia, if compared with those with normal cochlea. Severe malformations as Common Cavity or severe hypoplasia may have a higher rate of surgical complications and the outcome cannot be predicted.

Calculation of the wetting parameter from a cluster model in the framework of nanothermodynamics

The critical wetting parameter omega(c) determines the strength of interfacial fluctuations in critical wetting transitions. In this Brief Report, we calculate omega(c) from considerations on critical liquid clusters inside a vapor phase. The starting point is a cluster model developed by Hill and Chamberlin in the framework of nanothermodynamics [Proc. Natl. Acad. Sci. USA 95, 12779 (1998)]. Our calculations yield results for omega(c) between 0.52 and 1.00, depending on the degrees of freedom considered. The findings are in agreement with previous experimental results and give an idea of the universal dynamical behavior of the clusters when approaching criticality. We suggest that this behavior is a combination of translation and vortex rotational motion (omega(c)=0.84).

Standardized, unrelated donor cord blood transplantation in adults with hematologic malignancies

The potential role of unrelated donor cord blood transplantation (UD-CBT) in adults remains unclear. This study reports the results of UD-CBT in 22 adults with hematologic malignancies following conditioning with thiotepa, busulfan, cyclophosphamide, and antithymocyte globulin in 21, with thiotepa, fludarabine, and antithymocyte globulin in 1, and graft-versus-host disease (GVHD) prophylaxis with cyclosporine and prednisone. Median age was 29 years (range, 18-46 years), and median weight was 69.5 kg (range, 41-85 kg). HLA match was 6 of 6 in 1 case, 5 of 6 in 13 cases, and 4 of 6 in 8 cases. Median number of nucleated cells infused was 1.71 x 10(7)/kg (range, 1.01 x 10(7)/kg to 4.96 x 10(7)/kg). All 20 patients surviving more than 30 days had myeloid engraftment, and only 1, who received the lowest cell dose, developed secondary graft failure. Median time to reach an absolute neutrophil count of at least 0.5 x 10(9)/L was 22 days (range, 13-52 days). Median time to platelets numbered at least 20 x 10(9)/L was 69 days (range, 49-153 days). Seven patients (32%) developed acute GVHD above grade II, and 9 of 10 patients at risk developed chronic GVHD, which became extensive in 4 patients. Twelve patients remained alive and disease-free 3 to 45 months after transplantation. Disease-free survival (DFS) at 1 year was 53%. Age strongly influenced DFS (P =.01). For patients aged 30 years or younger, the DFS at 1 year was 73%. These preliminary results suggest that UD-CBT should be considered a reasonable alternative in young adults with hematologic malignancy and no appropriate bone marrow donor.

Additional cytogenetic changes do not influence the outcome of patients with newly diagnosed acute promyelocytic leukemia treated with an ATRA plus anthracyclin based protocol. A report of the Spanish group PETHEMA

BACKGROUND AND OBJECTIVES

To analyze in patients with de novo acute promyelocytic leukemia (APL) treated with an ATRA plus anthracyclin-based protocol if the presence of additional cytogenetic aberrations to the t(15;17) influences: 1. clinical and biological presenting features; 2. disease outcome.

DESIGN AND METHODS

One hundred and thirteen patients with newly diagnosed APL enrolled in the APL-96 protocol of the Spanish PETHEMA group were studied by conventional karyotyping, FISH and RT-PCR for the PML-RARa fusion. Treatment was homogeneous in all cases and consisted of anthracyclines and ATRA.

RESULTS

Additional chromosome aberrations were observed in 30% of cases. The most frequent secondary changes were +8 (14 cases), and abnormalities of chromosomes 9 or 3 (4 patients each), and of chromosomes 1 and 8 (3 cases each). No clinical, biological, morphological, immunophenotypic or molecular differences were observed between the group of APLs with t(15;17) alone and the group of patients with additional changes. Patients with additional changes had a higher rates of complete remission (CR) and 4-year disease-free survival (DFS) (97%, and 97%, respectively) than patients with t(15;17) alone (CR, 70% and DFS, 84%) but these differences were not statistically significant.

INTERPRETATION AND CONCLUSIONS

Patients with APL and additional cytogenetic abnormalities do not show different clinical, biological, morphological or molecular features as compared to patients with t(15;17) alone. The prognosis of patients with APL and t(15;17) alone and those with additional changes is similar in both groups. This study indicates that there is no rationale for administering more intensive treatment in APL patients with additional cytogenetic abnormalities receiving ATRA plus anthracycline-based chemotherapy.

Recent improvements in outcome for elderly patients with de novo acute myeloblastic leukemia

A retrospective analysis was performed on 263 consecutive patients aged over 60 with de novo acute myeloid leukemia (AML) diagnosed in a single institution between 1979 and 1998. Eighty-nine patients (33%) received only palliative treatment, while 174 patients (67%) were treated with different intensive chemotherapy regimens. The 5- and 10-year overall survival (OS) for the whole series was 7.7+/-1.2 and 4.3+/-1.6%, respectively. For patients receiving chemotherapy, OS was 10.5+/-2.5 and 7+/-2.6%, while for those patients receiving supportive treatment it was 1.1+/-1.1 and 0%, respectively (P=0.002). Within the group of patients receiving chemotherapy, the complete remission (CR) rate was 46%; treatment failure rate was 54% (36% due to treatment-related mortality and 18% due to resistant disease). Variables influencing CR rate were FAB subtype, CD7 positivity, chemotherapy regimen, creatinine level, hepatomegaly, and period of diagnosis. Median disease-free survival (DFS) duration was 8.4 months with a probability of being disease-free at 10 years of 10+/-5%. There were no significant differences in DFS according to age. According to the period of diagnosis (1979-1986 vs. 1987-1998), improvements in the CR rate (27 vs. 56%, P=0.0002), and OS (10.9 vs. 15.7 months, P=0.0007) were observed. This large single-center study of unselected de novo AML elderly patients substantiates the progressive improvement achieved in the management of elderly patients with AML, probably due to an improvement in supportive care and the administration of conventional induction chemotherapy.

Unrelated donor cord blood transplantation in adults with chronic myelogenous leukemia: results in nine patients from a single institution

The potential role of unrelated donor cord blood transplantation (UD-CBT) in adults is not well established. We report the results of UD-CBT in nine adult patients with chronic myeloid leukemia (CML). The median age was 27 years (range, 19-41 years), and the median weight was 62 kg (range, 45-78 kg). At transplant, six patients were in chronic phase (five in first, and one in second), two in blast crisis, and one in accelerated phase. Eight had received intensive chemotherapy, and three had undergone autologous peripheral blood hematopoietic stem cell transplantation. Four had received interferon with no cytogenetic response, and only three underwent UD-CBT within 1 year of diagnosis. After serological typing for class I antigens, and high-resolution DNA typing for DRB1, the degree of HLA match between patients and cord blood (CB) units was 4/6 in six cases and 5/6 in three cases. The median number of nucleated cells infused was 1.7 x 10(7)/kg (range, 1.2 to 4.9 x 10(7)/kg), and was above 2 x 10(7)/kg in only two cases. All patients received thiotepa, busulfan, cyclophosphamide and anti-thymocyte globulin as conditioning; cyclosporine and prednisone for graft-versus-host disease (GVHD) prophylaxis; and G-CSF from day +7 until engraftment. All seven evaluable cases engrafted. The median time to reach an absolute neutrophil count > or =0.5 x 10(9)/l and > or =1 x 10(9)/l was 22 days (range, 19-52 days) and 28 days (range, 23-64 days), respectively. In the four patients evaluable for platelet recovery time to levels of > or =20 x 10(9) platelets/l, > or =50 x 10(9) platelets/l, and > or =100 x 10(9) platelets/l, these ranged from 50 to 128 days, 60 to 139 days, and 105 to 167 days, respectively. Three patients developed acute GVHD above grade II, and three of the five patients at risk developed extensive chronic GVHD. Four patients, all transplanted in chronic phase, remain alive in molecular remission more than 18, 19, 24 and 42 months after transplantation. These preliminary results suggest that UD-CBT may be considered a reasonable alternative in adults with CML who lack an appropriate bone marrow donor.

Heterogeneous lack of expression of the tumour suppressor PTEN protein in human neoplastic tissues

PTEN, a tumour suppressor gene located at chromosome 10q23 and commonly mutated or deleted in a variety of tumours, encodes a dual-specific/phosphatidylinositol-3,4,5-triphosphate (PIP3) phosphatase. We report the generation of an anti-PTEN monoclonal antibody (MAb) that recognises an epitope at the C-terminus of PTEN, and describe the heterogeneous lack of expression of the PTEN protein in human tumour tissues, as demonstrated by immunohistochemical methods. Our anti-PTEN MAb provides a useful tool for the study of PTEN protein expression in tumour samples, in the search for tumour prognostic molecular markers.

Rapid quantitative detection of BCR-ABL transcripts in chronic myeloid leukemia patients by real-time reverse transcriptase polymerase-chain reaction using fluorescently labeled probes

BACKGROUND AND OBJECTIVES

The limited value of qualitative reverse transcription polymerase chain-reaction (RT-PCR) for monitoring chronic myeloid leukemia (CML) patients has prompted the development of quantitative assays. We have developed a quantitative real-time PCR (QC-PCR) method in the LightCycler, based on the use of fluorescently labeled probes (HybProbes), to estimate BCR-ABL fusion gene transcripts in samples from CML patients.

DESIGN AND METHODS

Fifty-two samples (45 peripheral blood, five bone marrow, and two apheresis product samples) from nine patients with CML were analyzed. Seven patients were studied at diagnosis and during follow-up after hematopoietic stem cell transplantation (HSCT), whereas two were evaluated only after HSCT. The PCR reaction was carried out in capillary tubes in a final volume of 10 microL, using 2 microL cDNA, the Mensik et al. primers, and two HybProbes. The results for BCR-ABL were normalized with reference to ABL. The PCR program is completed in only 45 min.

RESULTS

The sensitivity attained allowed the detection of rearrangements at dilutions of between 5-10(-4) and 10(-5) K562 cDNA. The within-assay coefficient of variation was 11% for BCR-ABL, and 9% for ABL. A greater than 2 log reduction in the BCR-ABL/ABL ratio was evident shortly after transplantation in all allografted patients.

INTERPRETATION AND CONCLUSIONS

We may conclude that the TaqMan probe technology can be easily adapted to HybProbes with equivalent results. Besides, the results of BCR-ABL quantification in the follow-up of patients clearly confirm that real-time PCR with HybProbes is a reliable and sensitive method for monitoring minimal residual leukemia after HSCT in CML patients.

Carbamate kinase can replace in vivo carbamoyl phosphate synthetase. Implications for the evolution of carbamoyl phosphate biosynthesis

The exclusive involvement of carbamate kinase (CK) in fermentative ATP production and of carbamoyl phosphate synthetase (CPS) in the production of carbamoyl phosphate (CP) for pyrimidines and arginine biosynthesis was challenged by the finding of CK as the only activity synthesising CP in the archaea Pyrococcus furiosus and Pyrococcus abyssi. We now show that CK can replace CPS in vivo: transformation of Escherichia coli devoid of the CPS gene with plasmids encoding the CK from P. furiosus or from Enterococcus faecalis (which uses CK for making ATP) restores the ability of CPS-deficient E. coli to grow in the absence of arginine and uracil if ammonia and bicarbonate are present.