A dual program for translation regulation in cellular proliferation and differentiation.

A dichotomous choice for metazoan cells is between proliferation and differentiation. Measuring tRNA pools in various cell types, we found two distinct subsets, one that is induced in proliferating cells, and repressed otherwise, and another with the opposite signature. Correspondingly, we found that genes serving cell-autonomous functions and genes involved in multicellularity obey distinct codon usage. Proliferation-induced and differentiation-induced tRNAs often carry anticodons that correspond to the codons enriched among the cell-autonomous and the multicellularity genes, respectively. Because mRNAs of cell-autonomous genes are induced in proliferation and cancer in particular, the concomitant induction of their codon-enriched tRNAs suggests coordination between transcription and translation. Histone modifications indeed change similarly in the vicinity of cell-autonomous genes and their corresponding tRNAs, and in multicellularity genes and their tRNAs, suggesting the existence of transcriptional programs coordinating tRNA supply and demand. Hence, we describe the existence of two distinct translation programs that operate during proliferation and differentiation.

Lenalidomide-bendamustine-rituximab in patients older than 65 years with untreated mantle cell lymphoma.

For elderly patients with mantle cell lymphoma (MCL), there is no defined standard therapy. In this multicenter, open-label phase 1/2 trial, we evaluated the addition of lenalidomide (LEN) to rituximab-bendamustine (R-B) as first-line treatment for elderly patients with MCL. Patients >65 years with untreated MCL, stages II-IV were eligible for inclusion. Primary end points were maximally tolerable dose (MTD) of LEN and progression-free survival (PFS). Patients received 6 cycles every four weeks of L-B-R (L D1-14, B 90 mg/m2 IV, days 1-2 and R 375 mg/m2 IV, day 1) followed by single LEN (days 1-21, every four weeks, cycles 7-13). Fifty-one patients (median age 71 years) were enrolled from 2009 to 2013. In phase 1, the MTD of LEN was defined as 10 mg in cycles 2 through 6, and omitted in cycle 1. After 6 cycles, the complete remission rate (CRR) was 64%, and 36% were MRD negative. At a median follow-up time of 31 months, median PFS was 42 months and 3-year overall survival was 73%. Infection was the most common nonhematologic grade 3 to 5 event and occurred in 21 (42%) patients. Opportunistic infections occurred in 3 patients: 2 Pneumocystis carinii pneumonia and 1 cytomegalovirus retinitis. Second primary malignancies (SPM) were observed in 8 patients (16%). LEN could safely be combined with R-B when added from the second cycle in patients with MCL, and was associated with a high rate of CR and molecular remission. However, we observed a high degree of severe infections and an unexpected high number of SPMs, which may limit its use. This trial is registered at www.Clinicaltrials.gov as #NCT00963534.

Frequent NFKBIE deletions are associated with poor outcome in primary mediastinal B-cell lymphoma.

We recently reported a truncating deletion in the NFKBIE gene, which encodes IκBε, a negative feedback regulator of NF-κB, in clinically aggressive chronic lymphocytic leukemia (CLL). Because preliminary data indicate enrichment of NFKBIE aberrations in other lymphoid malignancies, we screened a large patient cohort (n = 1460) diagnosed with different lymphoid neoplasms. While NFKBIE deletions were infrequent in follicular lymphoma, splenic marginal zone lymphoma, and T-cell acute lymphoblastic leukemia (<2%), slightly higher frequencies were seen in diffuse large B-cell lymphoma, mantle cell lymphoma, and primary central nervous system lymphoma (3% to 4%). In contrast, a remarkably high frequency of NFKBIE aberrations (46/203 cases [22.7%]) was observed in primary mediastinal B-cell lymphoma (PMBL) and Hodgkin lymphoma (3/11 cases [27.3%]). NFKBIE-deleted PMBL patients were more often therapy refractory (P = .022) and displayed inferior outcome compared with wild-type patients (5-year survival, 59% vs 78%; P = .034); however, they appeared to benefit from radiotherapy (P =022) and rituximab-containing regimens (P = .074). NFKBIE aberrations remained an independent factor in multivariate analysis (P = .003) and when restricting the analysis to immunochemotherapy-treated patients (P = .008). Whole-exome sequencing and gene expression profiling verified the importance of NF-κB deregulation in PMBL. In summary, we identify NFKBIE aberrations as a common genetic event across B-cell malignancies and highlight NFKBIE deletions as a novel poor-prognostic marker in PMBL.

Molecular Monitoring after Autologous Stem Cell Transplantation and Preemptive Rituximab Treatment of Molecular Relapse; Results from the Nordic Mantle Cell Lymphoma Studies (MCL2 and MCL3) with Median Follow-Up of 8.5 Years.

The main objectives of the present study were to monitor minimal residual disease (MRD) in the bone marrow of patients with mantle cell lymphoma (MCL) to predict clinical relapse and guide preemptive treatment with rituximab. Among the patients enrolled in 2 prospective trials by the Nordic Lymphoma Group, 183 who had completed autologous stem cell transplantation (ASCT) and in whom an MRD marker had been obtained were included in our analysis. Fresh samples of bone marrow were analyzed for MRD by a combined standard nested and quantitative real-time PCR assay for Bcl-1/immunoglobulin heavy chain gene (IgH) and clonal IgH rearrangements. Significantly shorter progression-free survival (PFS) and overall survival (OS) was demonstrated for patients who were MRD positive pre-ASCT (54 patients) or in the first analysis post-ASCT (23 patients). The median PFS was only 20 months in those who were MRD-positive in the first sample post-ASCT, compared with 142 months in the MRD-negative group (P < .0001). OS was 75% at 10 years and median not reached in the MRD-negative group, compared with only 35 months in the MRD-positive group (P < .0001). Of the 86 patients (47%) who remained in continuous molecular remission, 73% were still in clinical remission after 10 years. For all patients, the median time from ASCT to first molecular relapse was 55 months, with a continuous occurrence of late molecular relapses. Fifty-eight patients who experienced MRD relapse received rituximab as preemptive treatment on 1 or more occasions, and in this group, the median time from first molecular relapse to clinical relapse was 55 months. In most cases, rituximab converted patients to MRD negativity (87%), but many patients became MRD-positive again later during follow-up (69%). By multivariate analysis, high-risk Mantle Cell Lymphoma International Prognostic Index score and positive MRD status pre-ASCT predicted early molecular relapse. In conclusion, preemptive rituximab treatment converts patients to MRD negativity and likely postpones clinical relapse. Molecular monitoring offers an opportunity to select some patients for therapeutic intervention and to avoid unnecessary treatment in others. MRD-positive patients in the first analysis post-ASCT have a dismal prognosis and thus are in need of novel strategies.

Loss of PRDM11 promotes MYC-driven lymphomagenesis.

The PR-domain (PRDM) family of genes encodes transcriptional regulators, several of which are deregulated in cancer. By using a functional screening approach, we sought to identify novel tumor suppressors among the PRDMs. Here we demonstrate oncogenic collaboration between depletion of the previously uncharacterized PR-domain family member Prdm11 and overexpression of MYC. Overexpression of PRDM11 inhibits proliferation and induces apoptosis. Prdm11 knockout mice are viable, and loss of Prdm11 accelerates MYC-driven lymphomagenesis in the Eµ-Myc mouse model. Moreover, we show that patients with PRDM11-deficient diffuse large B-cell lymphomas (DLBCLs) have poorer overall survival and belong to the nongerminal center B-cell-like subtype. Mechanistically, genome-wide mapping of PRDM11 binding sites coupled with transcriptome sequencing in human DLBCL cells evidenced that PRDM11 associates with transcriptional start sites of target genes and regulates important oncogenes such as FOS and JUN. Hence, we characterize PRDM11 as a putative novel tumor suppressor that controls the expression of key oncogenes, and we add new mechanistic insight into B-cell lymphomagenesis.

Global hypomethylation is an independent prognostic factor in diffuse large B cell lymphoma.

Global hypomethylation has been linked to disease progression in several cancers, but has not been reported for Diffuse Large B Cell Lymphoma (DLBCL). This study aimed to assess global methylation in DLBCL and describe its prognostic value. Mean LINE1 methylation, a validated surrogate measure for global methylation, was measured in DNA from 67 tumor biopsies. Additionally, cell-free circulating DNA (cfDNA) in plasma samples from 74 patients was tested to assess the feasibility of global hypomethylation as a biomarker in liquid biopsies. LINE1 methylation was assessed using a commercially available kit, based on pyrosequencing of PCR amplified bisulfite-treated DNA. Global hypomethylation was detected in a subset of cases and was associated with poor overall survival in both tumor biopsies (P = .001) and cfDNA (P = .009). It was the strongest risk factor in multivariate analysis in both biopsies (HR: 10.65, CI: 2.03-55.81, P = .005) and cfDNA (HR: 11.87, CI: 2.80-50.20, P = .001), outperforming conventional clinical risk factors. Finally, hierarchical cluster analyses were performed for the cfDNA samples using previously published gene-specific methylation data. This analysis shows that global hypomethylation co-occurs with other epigenetic abnormalities, including DAPK1 promoter hypermethylation. In conclusion, we have shown that global hypomethylation is strongly associated with poor survival in DLBCL both when present in tumor biopsy DNA and when detected in plasma cfDNA, and has potential for clinical application as a prognostic biomarker.

15-year follow-up of the Second Nordic Mantle Cell Lymphoma trial (MCL2): prolonged remissions without survival plateau.

In recent decades, the prognosis of Mantle Cell Lymphoma (MCL) has been significantly improved by intensified first-line regimens containing cytarabine, rituximab and consolidation with high-dose-therapy and autologous stem cell transplantation. One such strategy is the Nordic MCL2 regimen, developed by the Nordic Lymphoma Group. We here present the 15-year updated results of the Nordic MCL2 study after a median follow-up of 11·4 years: For all patients on an intent-to-treat basis, the median overall and progression-free survival was 12·7 and 8·5 years, respectively. The MCL International Prognostic Index (MIPI), biological MIPI, including Ki67 expression (MIPI-B) and the MIPI-B including mIR-18b expression (MIPI-B-miR), in particular, significantly divided patients into distinct risk groups. Despite very long response durations of the low and intermediate risk groups, we observed a continuous pattern of relapse and the survival curves never reached a plateau. In conclusion, despite half of the patients being still alive and 40% in first remission after more than 12 years, we still see an excess disease-related mortality, even among patients experiencing long remissions. Even though we consider the Nordic regimen as a very good choice of regimen, we recommend inclusion in prospective studies to explore the benefit of novel agents in the frontline treatment of MCL.

Nordic MCL3 study: 90Y-ibritumomab-tiuxetan added to BEAM/C in non-CR patients before transplant in mantle cell lymphoma.

The main objective of the MCL3 study was to improve outcome for patients not in complete remission (CR) before transplant by adding (90)Y-ibritumomab-tiuxetan (Zevalin) to the high-dose regimen. One hundred sixty untreated, stage II-IV mantle cell lymphoma patients <66 years received rituximab (R)-maxi-CHOP (cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisone) alternating with R-high-dose cytarabine (6 cycles total), followed by high-dose BEAM/C (bis-chloroethylnitrosourea, etoposide, cytarabine, and melphalan or cyclophosphamide) and autologous stem cell transplantation from 2005 to 2009. Zevalin (0.4 mCi/kg) was given to responders not in CR before transplant. Overall response rate pretransplant was 97%. The outcome did not differ from that of the historic control: the MCL2 trial with similar treatment except for Zevalin. Overall survival (OS), event-free survival (EFS), and progression-free survival (PFS) at 4 years were 78%, 62%, and 71%, respectively. For responding non-CR patients who received Zevalin, duration of response was shorter than for the CR group. Inferior PFS, EFS, and OS were predicted by positron emission tomography (PET) positivity pretransplant and detectable minimal residual disease (MRD) after transplant. In conclusion, positive PET and MRD were strong predictors of outcome. Intensification with Zevalin may be too late to improve the outcome of patients not in CR before transplant. This trial was registered at www.clinicaltrials.gov as #NCT00514475.

Evaluation of clinical trial eligibility and prognostic indices in a population-based cohort of systemic peripheral T-cell lymphomas from the Danish Lymphoma Registry.

Clinical trials (CTs) are needed to improve the outcome for peripheral T-cell lymphomas (PTCL), and accrual into CTs is one of the main recommendations in international treatment guidelines. The use of risk-adapted strategies has been suggested as a way to optimize treatment outcome in PTCL. The aim of the present study was to evaluate CT eligibility and selected prognostic indices in a population-based PTCL cohort of 481 PTCL patients identified from the Danish Lymphoma Registry in the period 2000-2010. According to five predefined parameters (age, performance status, P-creatinine, P-ALAT and measurable tumour lesion), patients were subdivided into four groups: 'younger fit', 'elderly fit', 'frail' and 'not CT eligible'. International prognostic index (IPI), prognostic index for T-cell lymphoma (PIT) and anaplastic lymphoma kinase (ALK) protein expression were tested at subtype-specific level. Overall, 41% of the patients were considered eligible for interventional CTs implicating curatively intended multiagent chemotherapy, including, if considered appropriate, consolidating stem cell transplantation (SCT), as part of the upfront management strategy. Moreover, 28% was elderly fit and eligible for interventional CT, including those with SCT as part of the trial design. Approximately 7% were defined as 'too frail' for aggressive treatment schedules, whereas 24% were deemed not to be eligible for any CT. Both overall and progression-free survivals were effectively predicted by IPI and PIT (p < 0.001). ALK-positive anaplastic large cell lymphoma patients were significantly younger (median age 40 vs. 62, p < 0.001) and had a better outcome than their ALK-negative counterparts (p < 0.001). However, ALK expression lost its prognostic significance when adjusting for age. In a population-based cohort of adult Caucasian PTCL patients, approximately half were eligible for multiagent chemotherapy with or without consolidating SCT. Both IPI and PIT are useful prognostic indices in all 'primary nodal' PTCL entities. The prognostic value of ALK protein expression in anaplastic large cell lymphoma is significantly downsized when adjusting for age.

SOX11 and TP53 add prognostic information to MIPI in a homogenously treated cohort of mantle cell lymphoma--a Nordic Lymphoma Group study.

Mantle cell lymphoma (MCL) is an aggressive B cell lymphoma, where survival has been remarkably improved by use of protocols including high dose cytarabine, rituximab and autologous stem cell transplantation, such as the Nordic MCL2/3 protocols. In 2008, a MCL international prognostic index (MIPI) was created to enable stratification of the clinical diverse MCL patients into three risk groups. So far, use of the MIPI in clinical routine has been limited, as it has been shown that it inadequately separates low and intermediate risk group patients. To improve outcome and minimize treatment-related morbidity, additional parameters need to be evaluated to enable risk-adapted treatment selection. We have investigated the individual prognostic role of the MIPI and molecular markers including SOX11, TP53 (p53), MKI67 (Ki-67) and CCND1 (cyclin D1). Furthermore, we explored the possibility of creating an improved prognostic tool by combining the MIPI with information on molecular markers. SOX11 was shown to significantly add prognostic information to the MIPI, but in multivariate analysis TP53 was the only significant independent molecular marker. Based on these findings, we propose that TP53 and SOX11 should routinely be assessed and that a combined TP53/MIPI score may be used to guide treatment decisions.

Cryopreserved ovarian cortex from patients with leukemia in complete remission contains no apparent viable malignant cells.

Some women suffering from leukemia require bone marrow transplantation to be cured. Bone marrow transplantation is associated with a high risk of sterility, and some patients are offered fertility preservation by cryopreservation of the ovarian cortex. Transplantation of the ovarian cortex to women cured of leukemia who became menopausal is currently not performed because of the risk of introducing the disease. In this study, individual pieces of ovarian cortex intended for reimplantation from 25 patients with leukemia were transplanted to each of 25 nude mice for 20 weeks. The ovarian cortex was examined before and after transplantation by histology and immunohistochemistry, and RT-quantitative PCR (in the 7 patients with a known marker). Seventeen patients had the ovarian cortex retrieved when they were in complete remission. Before transplantation, 4 of 7 pieces (2 from patients in complete remission) of ovarian cortex had a positive RT-quantitative PCR. After transplantation, none of the mice revealed any sign of disease, neither in the pieces of ovarian cortex transplanted nor in any of the murine organs evaluated. Thus, the ovaries from patients in complete remission do not appear to contain viable malignant cells contrasting ovarian tissue retrieved before treatment.

Diagnostic microRNA profiling in cutaneous T-cell lymphoma (CTCL).

Cutaneous T-cell lymphomas (CTCLs) are the most frequent primary skin lymphomas. Nevertheless, diagnosis of early disease has proven difficult because of a clinical and histologic resemblance to benign inflammatory skin diseases. To address whether microRNA (miRNA) profiling can discriminate CTCL from benign inflammation, we studied miRNA expression levels in 198 patients with CTCL, peripheral T-cell lymphoma (PTL), and benign skin diseases (psoriasis and dermatitis). Using microarrays, we show that the most induced (miR-326, miR-663b, and miR-711) and repressed (miR-203 and miR-205) miRNAs distinguish CTCL from benign skin diseases with > 90% accuracy in a training set of 90 samples and a test set of 58 blinded samples. These miRNAs also distinguish malignant and benign lesions in an independent set of 50 patients with PTL and skin inflammation and in experimental human xenograft mouse models of psoriasis and CTCL. Quantitative (q)RT-PCR analysis of 103 patients with CTCL and benign skin disorders validates differential expression of 4 of the 5 miRNAs and confirms previous reports on miR-155 in CTCL. A qRT-PCR-based classifier consisting of miR-155, miR-203, and miR-205 distinguishes CTCL from benign disorders with high specificity and sensitivity, and with a classification accuracy of 95%, indicating that miRNAs have a high diagnostic potential in CTCL.

Genome-wide profiling identifies a DNA methylation signature that associates with TET2 mutations in diffuse large B-cell lymphoma.

The discovery that the Ten-Eleven Translocation (TET) hydroxylases cause DNA demethylation has fundamentally changed the notion of how DNA methylation is regulated. Clonal analysis of the hematopoetic stem cell compartment suggests that TET2 mutations can be early events in hematologic cancers and recent investigations have shown TET2 mutations in diffuse large B-cell lymphoma. However, the detection rates and the types of TET2 mutations vary, and the relation to global methylation patterns has not been investigated. Here, we show TET2 mutations in 12 of 100 diffuse large B-cell lymphomas with 7% carrying loss-of-function and 5% carrying missense mutations. Genome-wide methylation profiling using 450K Illumina arrays identified 315 differentially methylated genes between TET2 mutated and TET2 wild-type cases. TET2 mutations are primarily associated with hypermethylation within CpG islands (70%; P<0.0001), and at CpG-rich promoters (60%; P<0.0001) of genes involved in hematopoietic differentiation and cellular development. Hypermethylated loci in TET2 mutated samples overlap with the bivalent (H3K27me3/H3K4me3) silencing mark in human embryonic stem cells (P=1.5×10(-30)). Surprisingly, gene expression profiling showed that only 11% of the hypermethylated genes were down-regulated, among which there were several genes previously suggested to be tumor suppressors. A meta-analysis suggested that the 35 hypermethylated and down-regulated genes are associated with the activated B-cell-like type of diffuse large B-cell lymphoma in other studies. In conclusion, our data suggest that TET2 mutations may cause aberrant methylation mainly of genes involved in hematopoietic development, which are silenced but poised for activation in human embryonic stem cells.

World Health Organization-defined classification of myeloproliferative neoplasms: morphological reproducibility and clinical correlations--the Danish experience.

We examined inter- and intraobserver reproducibility and concordance between histological diagnosis and independently collected clinical findings in a large series of patients with the major subtypes of myeloproliferative neoplasms (MPNs) and controls. Seven hematopathologists reviewed 272 bone marrow biopsies including 43 controls. Diagnoses were determined according to the 2008 criteria of the World Health Organization (WHO). The participants were blinded to all clinical data except patient age. After initial evaluation all hematopathologists participated in a 3-day meeting with a leading clinician chaired by an expert hematopathologists. In cases with lack of consensus on fiber grading (n = 57), a new evaluation was performed. In cases with discordance on morphological diagnosis (n = 129), an additional nonblinded evaluation taking clinical data into consideration was carried out. For remaining cases with a lack of concordance between morphological diagnosis and clinical diagnosis (n = 33), a similar nonblinded evaluation was performed. Consensus on final histological diagnosis and concordance with clinical diagnosis were determined. Blinded histological evaluation resulted in a 53% consensus rate. After re-evaluation of fiber content, consensus was reached in 60% of cases. Adding clinical data increased the histological consensus to 83%. For cases with a histological consensus, we found a concordance of 71% with the clinician's diagnoses. This is the first study to present a larger cohort of MPN patients mimicking the diagnostic challenges that hematopathologists face in their daily practice. The results support the postulates of the WHO that both morphological and clinical findings are essential for a valid diagnosis

Nordic MCL2 trial update: six-year follow-up after intensive immunochemotherapy for untreated mantle cell lymphoma followed by BEAM or BEAC + autologous stem-cell support: still very long survival but late relapses do occur.

Mantle cell lymphoma (MCL) is a heterogenic non-Hodgkin lymphoma entity, with a median survival of about 5 years. In 2008 we reported the early - based on the median observation time of 4 years - results of the Nordic Lymphoma Group MCL2 study of frontline intensive induction immunochemotherapy and autologous stem cell transplantation (ASCT), with more than 60% event-free survival at 5 years, and no subsequent relapses reported. Here we present an update after a median observation time of 6·5 years. The overall results are still excellent, with median overall survival and response duration longer than 10 years, and a median event-free survival of 7·4 years. However, six patients have now progressed later than 5 years after end of treatment. The international MCL Prognostic Index (MIPI) and Ki-67-expression were the only independent prognostic factors. Subdivided by the MIPI-Biological Index (MIPI + Ki-67, MIPI-B), more than 70% of patients with low-intermediate MIPI-B were alive at 10 years, but only 23% of the patients with high MIPI-B. These results, although highly encouraging regarding the majority of the patients, underline the need of a risk-adapted treatment strategy for MCL. The study was registered at www.isrctn.org as ISRCTN 87866680.

Notch1 as a potential therapeutic target in cutaneous T-cell lymphoma.

Deregulation of Notch signaling has been linked to the development of T-cell leukemias and several solid malignancies. Yet, it is unknown whether Notch signaling is involved in the pathogenesis of mycosis fungoides and Sézary syndrome, the most common subtypes of cutaneous T-cell lymphoma. By immunohistochemistry of 40 biopsies taken from skin lesions of mycosis fungoides and Sézary syndrome, we demonstrated prominent expression of Notch1 on tumor cells, especially in the more advanced stages. The γ-secretase inhibitor I blocked Notch signaling and potently induced apoptosis in cell lines derived from mycosis fungoides (MyLa) and Sézary syndrome (SeAx, HuT-78) and in primary leukemic Sézary cells. Specific down-regulation of Notch1 (but not Notch2 and Notch3) by siRNA induced apoptosis in SeAx. The mechanism of apoptosis involved the inhibition of nuclear factor-κB, which is the most important prosurvival pathway in cutaneous T-cell lymphoma. Our data show that Notch is present in cutaneous T-cell lymphoma and that its inhibition may provide a new way to treat cutaneous T-cell lymphoma.

The Mantle Cell Lymphoma International Prognostic Index (MIPI) is superior to the International Prognostic Index (IPI) in predicting survival following intensive first-line immunochemotherapy and autologous stem cell transplantation (ASCT).

Mantle cell lymphoma (MCL) has a heterogeneous clinical course. The recently proposed Mantle Cell Lymphoma International Prognostic Index (MIPI) predicted the survival of MCL better than the International Prognostic Index in MCL patients treated with conventional chemotherapy, but its validity in MCL treated with more intensive immunochemotherapy has been questioned. Applied here to 158 patients of the Nordic MCL2 trial of first-line intensive immunochemotherapy followed by high-dose chemotherapy and autologous stem cell transplantation, the MIPI and the simplified MIPI (s-MIPI) predicted survival significantly better (P < .001) than the International Prognostic Index (P > .004). Both the MIPI and the s-MIPI mainly identified 2 risk groups, low and intermediate versus high risk, with the more easily applied s-MIPI being just as powerful as the MIPI. The MIPI(B) (biological), incorporating Ki-67 expression, identified almost half of the patients as high risk. We suggest that also a simplified MIPI(B) is feasible.

A novel immunohistochemical sequential multi-labelling and erasing technique enables epitope characterization of bone marrow pericytes in primary myelofibrosis.

AIM: In Philadelphia (Ph)-negative chronic myeloproliferative neoplasms, increased microvascular density, bizarre vessel architecture and increased number of pericytes are among the distinct histopathological features. The aim of this study was to characterize bone marrow pericytes in primary myelofibrosis (PMF) using a novel multi-labelling immunohistochemical technique. METHODS AND RESULTS: Bone marrow biopsies from a normal donor (n = 1) and patients with PMF (n = 3) were subjected to an immunohistochemical sequential multi-labelling and erasing technique (SE-technique). Antigens of interest in the first and/or second layer were detected with an immunoperoxidase system and visualized with aminoethylcarbazole. After imaging, erasing and blocking of immunoreagents, the slides were stained with a traditional double immunolabelling procedure. In addition, we applied a Photoshop® colour palette, creating a single composite image of the sequential staining procedures. We successfully applied four layers of antibodies on one slide using CD146, smooth muscle actin, CD34, CD271 and Ki67 in different combinations. The SE-technique significantly improves morphological and phenotypical studies in bone marrow specimens. CONCLUSIONS: To our knowledge, the SE-technique is the first to multi-label antigens, identifying vessel and pericyte architecture in bone marrow by light microscopy. This technique may unravel novel aspects of the composition of the microvessel structures in patients with PMF and related neoplasms.

Ectopic expression of B-lymphoid kinase in cutaneous T-cell lymphoma.

B-lymphoid kinase (Blk) is exclusively expressed in B cells and thymocytes. Interestingly, transgenic expression of a constitutively active form of Blk in the T-cell lineage of mice results in the development of T-lymphoid lymphomas. Here, we demonstrate nuclear factor-kappa B (NF-kappaB)-mediated ectopic expression of Blk in malignant T-cell lines established from patients with cutaneous T-cell lymphoma (CTCL). Importantly, Blk is also expressed in situ in lesional tissue specimens from 26 of 31 patients with CTCL. Already in early disease the majority of epidermotropic T cells express Blk, whereas Blk expression is not observed in patients with benign inflammatory skin disorders. In a longitudinal study of an additional 24 patients biopsied for suspected CTCL, Blk expression significantly correlated with a subsequently confirmed diagnosis of CTCL. Blk is constitutively tyrosine phosphorylated in malignant CTCL cell lines and spontaneously active in kinase assays. Furthermore, targeting Blk activity and expression by Src kinase inhibitors and small interfering RNA (siRNA) inhibit the proliferation of the malignant T cells. In conclusion, this is the first report of Blk expression in CTCL, thereby providing new clues to the pathogenesis of the disease.

Long-term progression-free survival of mantle cell lymphoma after intensive front-line immunochemotherapy with in vivo-purged stem cell rescue: a nonrandomized phase 2 multicenter study by the Nordic Lymphoma Group.

Mantle cell lymphoma (MCL) is considered incurable. Intensive immunochemotherapy with stem cell support has not been tested in large, prospective series. In the 2nd Nordic MCL trial, we treated 160 consecutive, untreated patients younger than 66 years in a phase 2 protocol with dose-intensified induction immunochemotherapy with rituximab (R) + cyclophosphamide, vincristine, doxorubicin, prednisone (maxi-CHOP), alternating with R + high-dose cytarabine. Responders received high-dose chemotherapy with BEAM or BEAC (carmustine, etoposide, cytarabine, and melphalan/cyclophosphamide) with R-in vivo purged autologous stem cell support. Overall and complete response was achieved in 96% and 54%, respectively. The 6-year overall, event-free, and progression-free survival were 70%, 56%, and 66%, respectively, with no relapses occurring after 5 years. Multivariate analysis showed Ki-67 to be the sole independent predictor of event-free survival. The nonrelapse mortality was 5%. The majority of stem cell products and patients assessed with polymerase chain reaction (PCR) after transplantation were negative. Compared with our historical control, the Nordic MCL-1 trial, the event-free, overall, and progression-free survival, the duration of molecular remission, and the proportion of PCR-negative stem cell products were significantly increased (P < .001). Intensive immunochemotherapy with in vivo purged stem cell support can lead to long-term progression-free survival of MCL and perhaps cure. Registered at www.isrctn.org as #ISRCTN 87866680.