Local Polarization and Isothermal Local Equilibrium in Relativistic Heavy Ion Collisions.

We show that the inclusion of a recently found additional term of the spin polarization vector at local equilibrium which is linear in the symmetrized gradients of the velocity field, and the assumption of hadron production at constant temperature restore the quantitative agreement between hydrodynamic model predictions and local polarization measurements in relativistic heavy ion collisions at sqrt[s_{NN}]=200 GeV. The longitudinal component of the spin polarization vector turns out to be very sensitive to the temperature value, with a good fit around 155 MeV. The implications of this finding are discussed.

Lenalidomide plus R-CHOP21 in newly diagnosed diffuse large B-cell lymphoma (DLBCL): long-term follow-up results from a combined analysis from two phase 2 trials.

Lenalidomide-RCHOP (R2-CHOP21) has been shown to be safe and effective in patients with untreated diffuse large B-cell lymphoma (DLBCL). The aim of this analysis is to report long-term outcome and toxicities in newly diagnosed DLBCL patients who received R2-CHOP21 in two independent phase 2 trials, conducted by Mayo Clinic (MC) and Fondazione Italiana Linfomi (FIL). All patients received R-CHOP21 plus lenalidomide. Long-term progression-free survival (PFS), time to progression (TTP), overall survival (OS) and late toxicities and second tumors were analyzed. Hundred and twelve patients (63 MC, 49 FIL) were included. Median age was 69 years, 88% were stage III-IV. At a median follow-up of 5.1 years, 5y-PFS was 63.5%, 5y-TTP 70.1% and 5y-OS 75.4%; according to cell of origin (COO): 5y-PFS 52.8% vs 64.5%, 5y-TTP 61.6% vs 69.6% and 5y-OS 68.6% vs 74.1% in germinal center (GCB) vs non-GCB respectively. Four patients experienced grade 4-5 late toxicities. Grade ≤ 3 toxicities were infections (N = 4), thrombosis (N = 1) and neuropathy (N = 3). Seven seconds tumors were observed. Long-term follow-up demonstrates that R2-CHOP21 efficacy was maintained with high rates of PFS, TTP, and OS. Lenalidomide appears to mitigate the negative prognosis of non-GCB phenotype. Incidence of therapy-related secondary malignancies and late toxicities were low.

Emerging therapies provide new opportunities to reshape the multifaceted interactions between the immune system and lymphoma cells.

The acquisition of a complete neoplastic phenotype requires cancer cells to develop escape mechanisms from the host immune system. This phenomenon, commonly referred to as 'immune evasion,' represents a hallmark of cancers and results from a Darwinian selection of the fittest tumor clones. First reported in solid tumors, cancer immunoescape characterizes several hematological malignancies. The biological bases of cancer immunoescape have recently been disclosed and include: (i) impaired human leukocyte antigen-mediated cancer cell recognition (B2M, CD58, CTIIA, CD80/CD86, CD28 and CTLA-4 mutations); (ii) deranged apoptotic mechanisms (reduced pro-apoptotic signals and/or increased expression of anti-apoptotic molecules); and (iii) changes in the tumor microenvironment involving regulatory T cells and tumor-associated macrophages. These immune-escape mechanisms characterize both Hodgkin and non-Hodgkin (B and T cell) lymphomas and represent a promising target for new anti-tumor therapies. In the present review, the principles of cancer immunoescape and their role in human lymphomagenesis are illustrated. Current therapies targeting these pathways and possible applications for lymphoma treatment are also addressed.

A novel patient-derived tumorgraft model with TRAF1-ALK anaplastic large-cell lymphoma translocation.

Although anaplastic large-cell lymphomas (ALCL) carrying anaplastic lymphoma kinase (ALK) have a relatively good prognosis, aggressive forms exist. We have identified a novel translocation, causing the fusion of the TRAF1 and ALK genes, in one patient who presented with a leukemic ALK+ ALCL (ALCL-11). To uncover the mechanisms leading to high-grade ALCL, we developed a human patient-derived tumorgraft (hPDT) line. Molecular characterization of primary and PDT cells demonstrated the activation of ALK and nuclear factor kB (NFkB) pathways. Genomic studies of ALCL-11 showed the TP53 loss and the in vivo subclonal expansion of lymphoma cells, lacking PRDM1/Blimp1 and carrying c-MYC gene amplification. The treatment with proteasome inhibitors of TRAF1-ALK cells led to the downregulation of p50/p52 and lymphoma growth inhibition. Moreover, a NFkB gene set classifier stratified ALCL in distinct subsets with different clinical outcome. Although a selective ALK inhibitor (CEP28122) resulted in a significant clinical response of hPDT mice, nevertheless the disease could not be eradicated. These data indicate that the activation of NFkB signaling contributes to the neoplastic phenotype of TRAF1-ALK ALCL. ALCL hPDTs are invaluable tools to validate the role of druggable molecules, predict therapeutic responses and implement patient specific therapies.

Pathogenetic and diagnostic significance of microRNA deregulation in peripheral T-cell lymphoma not otherwise specified.

Peripheral T-cell lymphomas not otherwise specified (PTCLs/NOS) are rare and aggressive tumours whose molecular pathogenesis and diagnosis are still challenging. The microRNA (miRNA) profile of 23 PTCLs/NOS was generated and compared with that of normal T-lymphocytes (CD4+, CD8+, naive, activated). The differentially expressed miRNA signature was compared with the gene expression profile (GEP) of the same neoplasms. The obtained gene patterns were tested in an independent cohort of PTCLs/NOS. The miRNA profile of PTCLs/NOS then was compared with that of 10 angioimmunoblastic T-cell lymphomas (AITLs), 6 anaplastic large-cell lymphomas (ALCLs)/ALK+ and 6 ALCLs/ALK-. Differentially expressed miRNAs were validated in an independent set of 20 PTCLs/NOS, 20 AITLs, 19 ALCLs/ALK- and 15 ALCLs/ALK+. Two hundred and thirty-six miRNAs were found to differentiate PTCLs/NOS from activated T-lymphocytes. To assess which miRNAs impacted on GEP, a multistep analysis was performed, which identified all miRNAs inversely correlated to different potential target genes. One of the most discriminant miRNAs was selected and its expression was found to affect the global GEP of the tumours. Moreover, two sets of miRNAs were identified distinguishing PTCL/NOS from AITL and ALCL/ALK-, respectively. The diagnostic accuracy of this tool was very high (83.54%) and its prognostic value validated.

Platelet-derived growth factor alpha mediates the proliferation of peripheral T-cell lymphoma cells via an autocrine regulatory pathway.

Peripheral T-cell lymphomas not otherwise specified (PTCL/NOS) are very aggressive tumors characterized by consistent aberrant expression of platelet-derived growth factor receptor alpha (PDGFRA). In this study, we aimed to identify the determinants of PDGFRA activity in PTCL/NOS and to elucidate the biological consequences of its activation. We observed overexpression of the PDGFRA gene by gene expression profiling in most of the tested PTCLs and confirmed the expression of PDGFRA and phospho-PDGFRA using immunohistochemistry. The integrity of the PDFGRA locus was demonstrated using several different approaches, including massive parallel sequencing and Sanger sequencing. PDGF-AA was found to be expressed and secreted by PTCL/NOS cells and to be necessary and sufficient for PDGFRA phosphorylation ex vivo by sustaining an autocrine stimulation. We documented consistently high PDGF-A expression in primary biopsies and patients' plasma and tracked PDGFRA signaling in primary tumors, achieving evidence of its activation. Indeed, we found that STAT1 and STAT5 are implicated in PDGFRA signaling transduction. Finally, we demonstrated that PDGFRA activation supported tumor cell proliferation and provided the first evidence of the anti-lymphoma activity of PDGRA inhibition in a PTCL/NOS patient. Altogether, our data demonstrated that PDGFRA activity fosters PTCL/NOS proliferation via an autocrine loop.

Functional impact of NOTCH1 mutations in chronic lymphocytic leukemia.

The purpose of this study was to compare the expression and function of NOTCH1 in chronic lymphocytic leukemia (CLL) patients harboring a wild-type (WT) or mutated NOTCH1 gene. NOTCH1 mRNA and surface protein expression levels were independent of the NOTCH1 gene mutational status, consistent with the requirement for NOTCH1 signaling in this leukemia. However, compared with NOTCH1-WT CLL, mutated cases displayed biochemical and transcriptional evidence of an intense activation of the NOTCH1 pathway. In vivo, expression and activation of NOTCH1 was highest in CLL cells from the lymph nodes as confirmed by immunohistochemistry. In vitro, the NOTCH1 pathway was rapidly downregulated, suggesting that signaling relies upon micro-environmental interactions even in NOTCH1-mutated cases. Accordingly, co-culture of Jagged1(+) (the NOTCH1 ligand) nurse-like cells with autologous CLL cells sustained NOTCH1 activity over time and mediated CLL survival and resistance against pro-apoptotic stimuli, both abrogated when NOTCH1 signaling was pharmacologically switched off. Together, these results show that NOTCH1 mutations have stabilizing effects on the NOTCH1 pathway in CLL. Furthermore, micro-environmental interactions appear critical in activating the NOTCH1 pathway both in WT and mutated patients. Finally, NOTCH1 signals may create conditions that favor drug resistance, thus making NOTCH1 a potential molecular target in CLL.

The EGFR family members sustain the neoplastic phenotype of ALK+ lung adenocarcinoma via EGR1.

In non-small cell lung cancer (NSCLC), receptor tyrosine kinases (RTKs) stand out among causal dominant oncogenes, and the ablation of RTK signaling has emerged as a novel tailored therapeutic strategy. Nonetheless, long-term RTK inhibition leads invariably to acquired resistance, tumor recurrence and metastatic dissemination. In ALK+ cell lines, inhibition of ALK signaling was associated with coactivation of several RTKs, whose pharmacological suppression reverted the partial resistance to ALK blockade. Remarkably, ERBB2 signaling synergized with ALK and contributed to the neoplastic phenotype. Moreover, the engagement of wild-type epidermal growth factor receptor or MET receptors could sustain cell viability through early growth response 1 (EGR1) and/or Erk1/2; Akt activation and EGR1 overexpression prevented cell death induced by combined ALK/RTK inhibition. Membrane expression of ERBB2 in a subset of primary naive ALK+ NSCLC could be relevant in the clinical arena. Our data demonstrate that the neoplastic phenotype of ALK-driven NSCLC relays 'ab initio' on the concomitant activation of multiple RTK signals via autocrine/paracrine regulatory loops. These findings suggest that molecular and functional signatures are required in de novo lung cancer patients for the design of efficacious and multi-targeted 'patient-specific' therapies.

Stem cells based therapy in high grade glioma: why the intraventricular route should be preferred?

AIM: Mesenchymal stem cells (MSCs) migrate in response to chemokines and possess extensive tropism for experimental glioma. Antitumor effects have been reported following intracranial and intravenous administration of gene-modified MSCs. Among the different routes for cell transplant, the intraventricular (IV) approach found very little employment in comparison with intraparenchymal, intratumoral and intravenous administration protocols. Nevertheless, IV transplantation offers advantages in terms of cells viability and distribution toward target sites, opening interesting opportunities for its clinical application. METHODS: Using a rat glioma model, we investigated migratory capacity, tumor tropism, distribution and differentiation of MSCs following IV administration. RESULTS: Transplanted MSCs create niches of viable cells in the subventricular zone and can be stimulated to migrate to sites of tumor infiltration. MSCs seemed not to be involved in tumor growth and angiogenesis. CONCLUSION: We speculate that the IV route can be used to achieve a kind of reservoir of self-renewal cells, potentially active against the spread of cancer cells. Further studies are needed to shed light on MSCs distribution close to the ventricular wall, in order to define their lifespan and their capacity to migrate towards new-enhancing foci time after implantation.

Clinical and molecular characterization of diffuse large B-cell lymphomas with 13q14.3 deletion.

BACKGROUND: Deletions at 13q14.3 are common in chronic lymphocytic leukemia and are also present in diffuse large B-cell lymphomas (DLBCL) but never in immunodeficiency-related DLBCL. To characterize DLBCL with 13q14.3 deletions, we combined genome-wide DNA profiling, gene expression and clinical data in a large DLBCL series treated with rituximab, cyclophosphamide, doxorubicine, vincristine and prednisone repeated every 21 days (R-CHOP21). PATIENTS AND METHODS: Affymetrix GeneChip Human Mapping 250K NspI and U133 plus 2.0 gene were used. MicroRNA (miRNA) expression was studied were by real-time PCR. Median follow-up of patients was 4.9 years. RESULTS: Deletions at 13q14.3, comprising DLEU2/MIR15A/MIR16, occurred in 22/166 (13%) cases. The deletion was wider, including also RB1, in 19/22 cases. Samples with del(13q14.3) had concomitant specific aberrations. No reduced MIR15A/MIR16 expression was observed, but 172 transcripts were significantly differential expressed. Among the deregulated genes, there were RB1 and FAS, both commonly deleted at genomic level. No differences in outcome were observed in patients treated with R-CHOP21. CONCLUSIONS: Cases with 13q14.3 deletions appear as group of DLBCL characterized by common genetic and biologic features. Deletions at 13q14.3 might contribute to DLBCL pathogenesis by two mechanisms: deregulating the cell cycle control mainly due RB1 loss and contributing to immune escape, due to FAS down-regulation.

Transient atypical monocytosis mimic acute myelomonocytic leukemia in post-chemotherapy patients receiving G-CSF: report of two cases.

Granulocyte colony-stimulating factor (G-CSF) is now widely used in patients with malignant disorders receiving intensive chemotherapy to increase leukocyte count and to upregulate phagocyte function during neutropenia. Monocytosis associated with G-CSF has been reported in anecdotal literature. We report two cases of pseudoleukemia secondary to G-CSF administration. Both patients initially presented with myelodysplastic syndrome with chromosome 7 abnormalities that evolved into acute myeloid leukemia. Case one had deletion 7q while case two initially had monosomy 7 and subsequently developed a balanced translocation between the short (p) arm of chromosome 1 and long (q) arm of chromosome 15. Following the induction chemotherapy and G-CSF administration, both of these patients developed pseudoleukemia. Patient 1 had white blood cell (WBC) count of 26 x 10(9)/l with 72% monocytes, while patient two had WBC of 14.1 x 10(9)/l with 30% monocytes. In both patients the monocytosis resolved after the discontinuation of G-CSF therapy. In summary, patients treated with G-CSF should be followed closely. In those cases with pseudoleukemia discontinuation of the drug with no supplemental chemotherapy is probably enough to control the atypical monocytosis.

Gene expression profiling of B cell chronic lymphocytic leukemia reveals a homogeneous phenotype related to memory B cells.

B cell-derived chronic lymphocytic leukemia (B-CLL) represents a common malignancy whose cell derivation and pathogenesis are unknown. Recent studies have shown that >50% of CLLs display hypermutated immunoglobulin variable region (IgV) sequences and a more favorable prognosis, suggesting that they may represent a distinct subset of CLLs which have transited through germinal centers (GCs), the physiologic site of IgV hypermutation. To further investigate the phenotype of CLLs, their cellular derivation and their relationship to normal B cells, we have analyzed their gene expression profiles using oligonucleotide-based DNA chip microarrays representative of approximately 12,000 genes. The results show that CLLs display a common and characteristic gene expression profile that is largely independent of their IgV genotype. Nevertheless, a restricted number of genes (<30) have been identified whose differential expression can distinguish IgV mutated versus unmutated cases and identify them in independent panels of cases. Comparison of CLL profiles with those of purified normal B cell subpopulations indicates that the common CLL profile is more related to memory B cells than to those derived from naive B cells, CD5(+) B cells, and GC centroblasts and centrocytes. Finally, this analysis has identified a subset of genes specifically expressed by CLL cells of potential pathogenetic and clinical relevance.

Nucleotide sequence, transcription map, and mutation analysis of the 13q14 chromosomal region deleted in B-cell chronic lymphocytic leukemia.

Deletions of the 13q14 chromosome region are associated with B-cell chronic lymphocytic leukemia (B-CLL) and several other types of cancer, suggesting the presence of a tumor suppressor gene. In previous studies the minimal region of deletion (MDR) was mapped to a less than 300-kilobase (kb) interval bordered by the markers 173a12-82 and 138G4/1.3R. For the identification of the putative tumor suppressor gene, the entire MDR (approximately 347 kb) has been sequenced, and transcribed regions have been identified by exon trapping, EST-based full-length complementary DNA cloning, database homology searches, and computer-assisted gene prediction analyses. The MDR contains 2 pseudogenes and 3 transcribed genes: CAR, encoding a putative RING-finger containing protein; 1B4/Leu2, generating noncoding transcripts; and EST70/Leu1, probably representing another noncoding gene (longest open reading frame of 78 codons). These genes have been sequenced in 20 B-CLL cases with 13q14 hemizygous deletion, and no mutations were found. Moreover, no somatic variants were found in the entire MDR analyzed for nucleotide substitutions by a combination of direct sequencing and fluorescence-assisted mismatch analysis in 5 B-CLL cases displaying 13q14-monoallelic deletion. The nondeleted allele of the CAR and EST70/Leu1 genes was expressed in B-CLL specimens, including those with monoallelic loss, whereas no expression of 1B4/Leu2 was detectable in B-CLL, regardless of the 13q14 status. These results indicate that allelic loss and mutation of a gene within the MDR is an unlikely pathogenetic mechanism for B-CLL. However, haplo-insufficiency of one of the identified genes may contribute to tumorigenesis. (Blood. 2001;97:2098-2104)

The cyclin dependent kinase inhibitor p27 and its prognostic role in breast cancer.

p27 is an inhibitor of cyclin dependent kinase involved in the regulation of the cell cycle. In this commentary we discuss the current knowledge on p27 in breast cancer and its significance in predicting the outcome. p27 protein levels are high in most cases of breast carcinomas, are correlated with the levels of cyclin D1 and estrogen receptor, and could be a useful predictor of survival, because they are low in aggressive carcinomas. Immunodetection of p27 in breast tumors could be useful in the assessment of prognosis, especially in those cases in which the commonly used parameters are insufficient, and might ultimately influence the therapy of this disease.

Role of the F-box protein Skp2 in lymphomagenesis.

The F-box protein Skp2 (S-phase kinase-associated protein 2) positively regulates the G(1)-S transition by controlling the stability of several G(1) regulators, such as the cell cycle inhibitor p27. We show here that Skp2 expression correlates directly with grade of malignancy and inversely with p27 levels in human lymphomas. To directly evaluate the potential of Skp2 to deregulate growth in vivo, we generated transgenic mice expressing Skp2 targeted to the T-lymphoid lineage as well as double transgenic mice coexpressing Skp2 and activated N-Ras. A strong cooperative effect between these two transgenes induced T cell lymphomas with shorter latency and higher penetrance, leading to significantly decreased survival when compared with control and single transgenic animals. Furthermore, lymphomas of Nras single transgenic animals often expressed higher levels of endogenous Skp2 than tumors of double transgenic mice. This study provides evidence of a role for an F-box protein in oncogenesis and establishes SKP2 as a protooncogene causally involved in the pathogenesis of lymphomas.