Long-term follow-up of essential thrombocythemia patients treated with anagrelide: subgroup analysis according to JAK2/CALR/MPL mutational status.

BACKGROUND: Anagrelide represents a treatment option for essential thrombocythemia, although its place in therapy remains controversial. AIM: To assess the impact of mutational status in response rates and development of adverse events during long-term use of anagrelide. METHODS: We retrospectively evaluated 67 patients with essential thrombocythemia treated with anagrelide during 68 (4-176) months. RESULTS: Mutational frequencies were 46.3%, 28.3%, and 1.5% for JAK2V617F, CALR and MPL mutations. Anagrelide yielded a high rate of hematologic responses, which were complete in 49.25% and partial in 46.25%, without differences among molecular subsets. The rate of thrombosis during treatment was one per 100 patient-years, without excess bleeding. Anemia was the major adverse event, 30.3% at 5-yr follow-up, being more frequent in CALR(+) (P < 0.05). Myelofibrotic transformation developed in 14.9% (12.9%, 21%, and 12.5% in JAK2V617F(+), CALR(+), and triple-negative patients, respectively, P = NS) and those treated >60 months were at higher risk, OR (95% CI) 9.32 (1.1-78.5), P < 0.01, indicating the need for bone marrow monitoring during prolonged treatment. CONCLUSION: Although CALR(+) patients were at higher risk of developing anemia, anagrelide proved effective among all molecular subsets, indicating that mutational status does not seem to represent a major determinant of choice of cytoreductive treatment among essential thrombocythemia therapies.

Evaluación del Sistema Cobas Ampliprep/Cobas Amplicor HIV-1 Monitor tm test 1.5 en plasma seminal / Evaluation of the Cobas Ampliprep/Cobas Amplicor HIV-1 Monitor tm test 1.5 system in sperm samples

La determinación de la carga viral de HIV y la detección del ADN proviral en semen se utilizan en protocolos de fertilización para parejas discordantes (hombre HIV positivo - mujer AMPLICOR HIV-1 MONITOR tm Test versión 1.5 (Roche) en plasma seminal para estimar la carga viral. Se procesaron 31 muestras de plasma seminal, diluidas y sin diluir para evaluar la amplificación del control interno y descartar posibles inhibiciones. Luego se contaminaron 22 muestras con plasma de pacientes HIV positivos para verificar la cuantificación del ARN viral. Finalmente, se procesaron 12 muestras en paralelo por Nuclisens HIV-1 QT (Biomerieux) para descartar potenciales falsos negativos. Concluimos que el sistema evaluado es un método adecuado para cuantificar ARN viral en plasma seminal. No se observó inhibición, ni falsos negativos y los valores de carga viral y el límite de detección no se vieron modificados por la matriz diferente.

Analyses of the HIV load and presence of proviral DNA in sperm samples are used in assisted fertilization protocols for discordant couples (infected man-healthy woman). We evaluated the use of the COBAS Ampliprep/COBAS AMPLICOR HIV-1 MONITOR tm Test versión 1.5 (Roche) for viral load quantification in seminal plasma samples. We first tested 31 sperm samples for amplification of the internal control to discard potential inhibition. Seminal plasmas were analyzed directly and diluted. We then spiked 21 sperm samples with human plasma from HIV-positive patients to confirm that HIV RNA could be amplified. We also compared the results of 12 samples with NASBA (Nuclisens HIV-1 QT, Biomerieux), and confirmed lack of false negative results. We conclude that the new assay is an adequate methodology to analyze HIV load in sperm samples. We did not observed inhibition, neither false negative results and quantification demonstrated equivalent HIV loads.

The CT-element of the c-myc gene does not predispose to chromosomal breakpoints in Burkitt's lymphoma.

BACKGROUND: Chromosomal translocations are causally related to the development of many tumors. In Burkitt's lymphoma, abnormalities involving the c-myc gene are essential. The CT-element of the c-myc promoter adopts non-B-conformation in vivo and in vitro, and therefore provides a potential fragile site. METHODS: We have developed a LM-PCR-based approach to test if chromosomal breakpoints indeed cluster in this region. RESULTS: Amplifying both, wild-type as well as the translocated c-myc gene by LM-PCR, it was shown that chromosomal breakpoints did not cluster within the CT-element. CONCLUSIONS: Therefore, the CT-element is not especially susceptible to the formation of breakpoints leading to chromosomal translocations in Burkitt's lymphoma.

High level expression of N-acetylgluosamine-6-O-sulfotransferase is characteristic of a subgroup of paediatric precursor-B acute lymphoblastic leukaemia.

Microarray analysis is a powerful technology, but its impact on routine diagnosis for the near future maybe in revealing individual genes, which are useful diagnostic markers. Recently microarray analysis has identified a novel subgroup of childhood precursor-B acute lymphoblastic leukaemia (ALL) from a unique gene expression profile of over 30 genes. We have evaluated the four most highly expressed genes from this profile, by quantitative real time RT-PCR, to determine whether any of these genes by itself could be useful as a diagnostic indicator. The levels of expression of N-acetylglucosamine-6-O-sulfotransferase (GN6ST), protein tyrosine phosphatase receptor M (PTPRmu), G protein-coupled receptor 49 (HG38) and KIAA1099 protein were determined in childhood precursor-B ALL samples from a cohort of 116 Indian patients. In nine cases, three or four of these genes exhibited very high expression levels, but only GN6ST was consistently over-expressed. We suggest that very high level expression of GN6ST is a useful diagnostic marker for a subgroup of previously unclassified ALL.

Childhood and adult ALL: differences in epigenetic lesions associated with cell cycle genes.

The impact of silencing tumor suppressor genes involved in cell proliferation in adult and pediatric ALL is still unknown. We analyzed methylation of the master regulators (p73, p53, Rb), CDKIs (p27, p57), and the INK4 locus (p15) in childhood ALLs and describe a relatively low frequency. Comparisons with adult ALL showed that p57 clearly differed in children (7% methylation) and adults (50% methylation). While >20% of adult ALL Ph1 chromosome-negative undergo methylation of p73, p57, and p15, only 3% of childhood ALL carried such anomalies, which is very significant when a higher fraction of pediatric patients has non-Ph1 ALL than do the adult patients. We have studied a large p57 CpG island and expression by real-time RT-PCR. We observed that 53% of childhood leukemias lacked p57 transcripts, and the overall level was 8-fold lower than in normal lymphocytes (P < 0.0001). However, no correlation with methylation was found. Thus, loss of p57 expression in the absence of methylation may be frequent in childhood ALL, suggesting that methylation is not the sole mechanism of p57 downregulation. Methylation differences in ALL may be age-related or, alternatively, reflect different pathogenesis.

Curcumin suppresses growth and induces apoptosis in primary effusion lymphoma.

The mechanisms that regulate induction of the antiapoptotic state and mitogenic signals in primary effusion lymphoma (PEL) are not well known. In efforts to identify novel approaches to block the proliferation of PEL cells, we found that curcumin (diferuloylmethane), a natural compound isolated from the plant Curcuma Ionga, inhibits cell proliferation and induces apoptosis in a dose dependent manner in several PEL cell lines. Such effects of curcumin appear to result from suppression of the constitutively active STAT3 through inhibition of Janus kinase 1 (JAK1). Our data also demonstrate that curcumin induces loss of mitochondrial membrane potential with subsequent release of cytochrome c and activation of caspase-3, followed by polyadenosin-5'-diphosphate-ribose polymerase (PARP) cleavage. Altogether, our findings suggest a novel function for curcumin, acting as a suppressor of JAK-1 and STAT3 activation in PEL cells, leading to inhibition of proliferation and induction of caspase-dependent apoptosis. Therefore, curcumin may have a future therapeutic role in PEL and possibly other malignancies with constitutive activation of STAT3.

Inhibition of phosphatidylinositol 3'-kinase/AKT signaling promotes apoptosis of primary effusion lymphoma cells.

PURPOSE: Phosphatidylinositol 3'-kinase (PI3'-kinase) can be activated by the K1 protein of Kaposi sarcoma-associated herpes virus (KSHV). However, the role of PI3'-kinase in KSHV-associated primary effusion lymphoma (PEL) is not known. To assess this, we studied survival and apoptosis in PEL cell lines following inhibition of PI3'-kinase. EXPERIMENTAL DESIGN: Constitutive activation of several targets of PI3-kinase and apoptotic proteins were determined by Western blot analysis using specific antibodies. We used LY294002 to block PI3'-kinase/AKT activation and assess apoptosis by flow cytometric analysis. RESULTS: Blocking PI3'-kinase induced apoptosis in PEL cells, including BC1, BC3, BCBL1, and HBL6, whereas BCP1 was refractory to LY294002-induced apoptosis. LY294002-induced apoptosis did not seem to involve Fas/Fas-L but had an additive effect to CH11-mediated apoptosis. We also show that AKT/PKB is constitutively activated in all PELs and treatment with LY294002 causes complete dephosphorylation in all cell lines except BCP1 where a residual AKT phosphorylation remained after 24 hours of treatment. FKHR and GSK3 were also constitutively phosphorylated in PELs and treatment with LY294002 caused their dephosphorylation. Although inhibition of PI3'-kinase induced cleavage of BID in all cell lines, cytochrome c was released from the mitochondria and caspase-9 and caspase-3 were activated in LY294002-induced apoptotic BC1 but not in resistant BCP1. Similarly, XIAP, a target of AKT, was down-regulated after LY294002 treatment only in sensitive PEL cells. CONCLUSIONS: Our data show that the PI3'-kinase pathway plays a major role in survival of PEL cells and suggest that this cascade may be a promising target for therapeutic intervention in primary effusion lymphomas.

Single monochrome real-time RT-PCR assay for identification, quantification, and breakpoint cluster region determination of t(9;22) transcripts.

t(9;22) generates the BCR-ABL fusion gene, the hallmark of chronic myeloid leukemia (CML) but also found in acute lymphoblastic leukemia (ALL). Multiple chimeric transcripts translate to proteins of 190 or 210 kd and, rarely, 230 kd. CML typically carries p210 BCR-ABL while ALL is most often associated with p190. Detection and quantification of these fusion transcripts is useful in clinical management. We have exploited the unique melting profiles of these transcripts to design a new, simple, and cost-effective assay based on monochrome multiplex real-time RT-PCR for identification and quantification of each of these transcripts (b3-a2, b2-a2, and e1-a2) without further manipulation. The sensitivity of this assay was 10(-4) for e1-a2 and 10(-5) for b3-a2/b2-a2, which is appropriate for detection of minimal residual disease (MRD). Inter- and intra-assay variation was minimal. We applied this assay to assess the distribution of p190 and p210 in 260 childhood ALL samples from India. BCR-ABL was detected in 19 (7.3%), including one T-ALL. Eight patients (3.1%) demonstrated mBCR-ABL (p190) and 11 (4.2%) had MBCR-ABL (p210). Transcript levels varied markedly (up to 3000-fold) but e1-a2 were generally expressed at higher levels than b3/b2-a2 (P = 0.05). This simple real-time multiplex assay can thus be easily applied to monitor patients with ALL as well as CML.

Monochrome LightCycler PCR assay for detection and quantification of five common species of Candida and Aspergillus.

Invasive fungal pathogens, especially in immunocompromised hosts, can result in life-threatening infections. Current laboratory/radiological methods for fungal identification are time-consuming and lack sensitivity and specificity. A monochrome, multiplex, real-time PCR assay for the identification and quantification of Candida albicans, Candida krusei, Candida tropicalis, Aspergillus flavus and Aspergillus fumigatus is described here. Detection of each of these fungi was specific and demonstrated 100 % concordance with biochemical/culture identification in all 60 isolates tested. Samples from 16 febrile neutropenic patients with haematological malignancies were also analysed and the utility of the assay in clinical samples was reconfirmed without false-negative results. The sensitivity of this assay was 0.1 pg fungal genomic DNA, corresponding to three cells, for C. albicans, C. krusei, C. tropicalis and A. flavus, and 0.01 pg fungal genomic DNA, i.e. less than one cell, for A. fumigatus. The analysis allows a low-cost, simple, rapid and sensitive alternative for clinical identification and quantification of these five common fungal species.

Aberrant methylation of multiple tumor suppressor genes in acute myeloid leukemia.

Hypermethylator phenotype, a propensity of tumors to incur nonrandom concurrent methylation, has been described in several tumors, including acute myeloid leukemia (AML). More recent studies identified methylation of other tumor suppressor genes, DAP-kinase and SOCS1, singly in AML. We therefore assessed the methylation status of these genes concurrently with other known targets of methylation. We used methylation-specific PCR or COBRA to determine the extent of methylation of 10 genes in 28 AML samples from Turkey. In addition to DAP-kinase and SOCS1, we included ER, p15, and E-cadherin (reported to be frequently methylated) as well as p16, GSTP1, and HIC1 (reported as rarely methylated). We also included RARbeta and p73 for which only minimal data in AML is available. All samples were methylated at least in one locus and all except one demonstrated methylation of DAP-kinase, SOCS1, p15, and/or ER. DAP-kinase is the most frequently methylated gene in both pediatric (70%) and adult AML (55%). RARbeta is methylated in 18% and p73 in 10% of AMLs. Methylation of E-cadherin and RARbeta occurs preferentially in AMLs with high methylation index (MI), while epigenetic lesions in SOCS1, DAP-kinase, and p15 appear to be independent. MI may be age-dependent, with a peak in young adults. FAB M3 demonstrated a higher extent of methylation than M2/M4. This study provides an impetus for larger studies to define if the extent and pattern of methylation in subgroups of AML are clinically relevant.

Frequent silencing of fragile histidine triad gene (FHIT) in Burkitt's lymphoma is associated with aberrant hypermethylation.

The fragile histidine triad (FHIT) gene, a potential tumor-suppressor gene, is frequently inactivated in multiple human cancers. However, the FHIT gene remains largely unexplored in Burkitt's lymphoma (BL). Hence, we assessed whether loss of FHIT expression occurs in BL, and, if so, what is the mechanism of such loss. Lack of protein expression was observed in 50% of BL cell lines. Methylation-specific polymerase chain reaction (MSP) showed that 45% of BL cell lines carried aberrantly methylated FHIT alleles. Sequencing of bisulfite-treated DNA confirmed these data and indicated a very high density of methylation in all methylated alleles. Real-time, quantitative reverse-transcription PCR analysis indicated that attenuation of full-length FHIT transcription was correlated with methylation. Sequencing of transcripts illustrated that aberrant transcription resulting in loss of FHIT exons occurred more commonly in BL containing unmethylated FHIT genes. However, such transcripts often coexisted with full-length FHIT transcripts. Not surprisingly, therefore, loss of FHIT protein in BL correlated with CpG island methylation, rather than with aberrant transcription. FHIT methylation also was detected in 31% (16 of 51) of the primary BLs examined, including 2 samples whose derived cell lines also manifested FHIT hypermethylation. Aberrant methylation can thus occur in vivo. In summary, this report provides evidence that epigenetic modification frequently results in loss of FHIT expression in BL.

CpG island methylation in Schistosoma- and non-Schistosoma-associated bladder cancer.

Urothelial carcinomas (TCC) constitute the vast majority of bladder cancers in most of the world. On the other hand, squamous cell bladder carcinoma, a rare subtype in the Western world, is a common subtype in areas with endemic Schistosoma infection. Although schistosomal infection has been reported to influence DNA methylation, the pattern and extent of CpG island hypermethylation in squamous cell carcinomas remain unknown. In this study, we used methylation-specific PCR to characterize 12 cancer-related genes in 41 bladder cancer samples from Egypt (31 squamous cell carcinomas (SCC), 21 of them associated with Schistosoma and 10 TCC, five of which were Schistosoma-associated). The genes analyzed included E-cadherin, DAP-Kinase, O6MGMT, p14, p15, p16, FHIT, APC, RASSF1A, GSTP1, RARbeta and p73. Methylation of at least one gene was detected in all squamous cell tumors except two, and 45% of samples had at least three methylated genes. The average methylation index was 0.24, corresponding to three of the 12 analyzed genes. Schistosoma-associated tumors had more genes methylated than non-Schistosoma tumors (average MI: 0.29 vs 0.14) (P = 0.027). Although the extent of methylation in TCC (average MI: 0.16) was lower than in squamous cell carcinomas (SCC), the overall profile of methylation was similar, with Schistosoma-associated cases having a higher methylation index. Our results suggest that schistosomal involvement associates with a greater degree of epigenetic changes in the bladder epithelium.

Differences in the expression of apoptotic proteins in Burkitt's lymphoma cell lines: potential models for screening apoptosis-inducing agents.

Mammalian cells undergo programmed cell death by orchestrated interactions involving multiple independent pathways. At least one of them, the p53-dependent pathway is commonly compromised in Burkitt's lymphoma (BL) cell lines. Differences in the integrity of this pathway in various BL cell lines have made them useful experimental models in understanding response to standard or novel antitumor drugs vis-a-vis the p53 pathway. Non-p53-dependent loss of apoptotic regulation also contributes to the genesis and/or progression of lymphomas and it is possible that BL cell lines also represent these models. We have characterized the expression of multiple apoptotic proteins in a panel of BL cell lines and describe cell lines with loss of cIAP1, cIAP2, Bax, Bak, Bcl-Xs and p38 MAP-kinase. This data should make this panel of cell lines a useful screening system for testing novel apoptotic inducers.

Immature B cell malignancies synthesize VEGF, VEGFR-1 (Flt-1) and VEGFR-2 (KDR).

Expression of VEGF and VEGFR support a role for angiogenic pathways in the pathogenesis of some hematological malignances. Our goal was to determine if expression of these angiogenic molecules also extend to childhood precursor B cell acute lymphoblastic leukemia (pre-B ALL). We now show that transcripts of VEGF, and its receptors VEGFR-1 and VEGFR-2 are concomitantly expressed in both ALL cell lines and primary pre-B ALL. Western blot and ELISA consistently detected VEGF protein in the supernatants of the cell lines. Similarly, VEGFR-1 and VEGFR-2 proteins are also detectable by FACS analysis. Interestingly, the expression of the receptors in immature B cells is limited to the intra-cytoplasmic compartment and may suggest either internalization of the receptors or a block in trafficking of the receptor to the surface.

The tumor suppressor gene 14-3-3 sigma is commonly methylated in normal and malignant lymphoid cells.

14-3-3 sigma/Stratifin was first identified as an epithelial cell antigen (HME-1) exclusively expressed in epithelia. However, the functional role of sigma in cell proliferation and apoptosis would suggest that this protein could be relevant to the regulation of growth and differentiation of multiple cell types. Recent evidence demonstrates that sigma acts as a tumor suppressor gene that is inactivated by methylation of its 5' CpG islands in epithelial tumor cells. In normal epithelia, sigma is commonly unmethylated. The objective of this study was to determine the methylation status of sigma in lymphoid cells. We now demonstrate by methylation-specific PCR analysis that sigma is also methylated in normal and malignant lymphocytes. Such methylation, however, fails to completely silence its expression. Compared with the robust expression in epithelial cells, lymphocytes showed basal, but clearly evident, levels of sigma as determined by reverse transcription-PCR and Western blot. The finding of sigma 5' region methylation in lymphocytes has direct implications in the use of body fluids on methylation tests for noninvasive monitoring of occult epithelial tumor cells and suggests that sigma may not be an adequate biomarker for methylation-specific PCR analysis.

Discrete alterations in the BZLF1 promoter in tumor and non-tumor-associated Epstein-Barr virus.

BACKGROUND: Although the Epstein-Barr virus (EBV) is associated with malignant and nonmalignant diseases, its lytic replication is predominantly associated with nonmalignant diseases such as acute infectious mononucleosis (IM) or chronic active EBV infection. Lytic replication is also associated with type B EBV more than with type A EBV. Sustained lytic replication, however, is not compatible with tumor growth. We investigated whether control of an EBV lytic regulatory gene, BZLF1, differed in these diseases. METHODS: Polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and direct DNA sequence analyses were used to characterize the promoter sequence of BZLF1 (Zp) in 52 tumors (34 non-Hodgkin's lymphomas, 13 post-transplant lymphoproliferative disease samples, and five nasopharyngeal carcinomas), and in peripheral blood lymphocytes from seven patients with chronic active EBV, six with IM, and 40 healthy, EBV-seropositive individuals. All sequences were compared with the prototype EBV strain B95.8 sequence. All statistical tests were two-sided. RESULTS: Three polymorphic Zp sequences were detected. Among the malignant samples, sequence Zp-P, associated with 84% of type A EBV, was identical to that of EBV strain B95.8, whereas a second sequence (Zp-V3), associated exclusively with type B EBV (P<.001), contained three base substitutions. Among the nonmalignant samples, a distinct polymorphism, Zp-V4, containing the substitutions detected in Zp-V3 and an additional base change, was identified in all samples from chronic active EBV, IM, and healthy individuals, but in none of the malignant samples (P<.001). Zp-V4 was independent of the EBV type. CONCLUSIONS: Polymorphisms in the regulatory sequences of BZLF1 are differentially distributed among malignant and nonmalignant cells and may identify EBV subtypes with various lytic activities, including those not associated with malignancies.

Preclinical validation of a monochrome real-time multiplex assay for translocations in childhood acute lymphoblastic leukemia.

PURPOSE: The purpose is to develop a real-time multiplex reverse transcription-PCR assay for detection and quantification of leukemia-specific chimeric transcripts that identify the genetic subgroups of acute lymphoblastic leukemias (ALLs) proposed by the WHO classification. EXPERIMENTAL DESIGN: Real-time multiplex assay for t(12;21), t(4;11), and t(1;19) with hypoxanthine phosphoribosyltransferase as internal standard used in tandem with a new real time quantitative-RT-PCR assay for the t(9;22). This new strategy was designed to yield an amplicon from each translocation with a distinct melting peak allowing dependable identification using only Sybr green I, without any need for expensive hybridization probes. RESULTS: We validated this method with 92 primary ALLs and identified 4 E2A-PBX1, 4 mBCR-ABL and 10 TEL-AML1. When compared with conventional RT-PCRs and Southern blot analyses, 100% concordance was obtained. During the course of these studies, we found marked variations in the levels of the TEL-AML1 transcripts in individual patients. We, therefore, extended the study to accurately and reproducibly determine TEL-AML1 mRNA levels in 47 additional patients with t(12;21). The results indicated that the level of expression of TEL-AML1 varied among individual patients, and it was independent of the WBC count. CONCLUSIONS: Our new real-time multiplex assay can be used for rapid, simple, and reliable classification of pediatric ALL. Its reproducible quantification results should also facilitate studies on minimal residual disease. The observed variation in TEL-AML1 transcript levels is of interest because it could reflect biological and/or clinical heterogeneity in the behavior of these leukemias.

Estudios citogenéticos en tumores del sistema nervioso / Cytogenetic studies in tumors of the nervous system

Se presenta el estudio citogenético efectuado en 3 pacientes con tumores del sistema nervioso: 2 astrocitomas grado III y un neuroblastoma estadio I. Los dos primeros mostraron una distribución bimodal en tanto que el neuroblatoma presentó un número modal diploide. En los 3 casos se encontraron alteraciones cromosómicas clonales, observándose los marcadores i(lq), 9p+, 3p+, dicéntricos y un metacéntrico pequeño de origen desconocido en gliomas. En el neuroblastoma se observó el marcador 11p+. Los dos astrocitomas presentaron cromosomas dobles diminutos (DM), fenómeno indicador de amplificación génica que correlaciona con el estadio avanzado de la enfermedad. Las anormalías numéricas clonales fueron trisomías 16 y 18 en los gliomas y monosomía 15 en el neuroblastoma