Case Report: Durable therapy response to Osimertinib in rare EGFR Exon 18 mutated NSCLC.

Up to 20% of all non-small cell lung cancer patients harbor tumor specific driver mutations that are effectively treated with tyrosine kinase inhibitors. However, for the rare EGFR deletion-insertion mutation of exon 18, there is very little evidence regarding the effectiveness of tyrosine kinase inhibitors. A particular challenge for clinicians in applying tyrosine kinase inhibitors is not only diagnosing a mutation but also interpreting rare mutations with unclear therapeutic significance. Thus, we present the case of a 65-year-old Caucasian male lung adenocarcinoma patient with an EGFR Exon 18 p.Glu709_Thr710delinsAsp mutation of uncertain therapeutic relevance. This patient initially received two cycles of standard platinum-based chemotherapy without any therapeutic response. After administration of Osimertinib as second line therapy, the patient showed a lasting partial remission for 12 months. Therapy related toxicities were limited to mild thrombocytopenia, which ceased after dose reduction of Osimertinib. To our knowledge, this is the first report of effective treatment of this particular mutation with Osimertinib. Hence, we would like to discuss Osimertinib as a viable treatment option in EGFR Exon 18 p.Glu709_Thr710delinsAsp mutated lung adenocarcinoma.

Case Report: A Well-Hidden Cause for Myelopathy.

Introduction: Sarcoidosis is a rare, systemic inflammatory disease and can involve multiple organs, especially the lungs and lymph nodes. The nervous system is affected in <10 percent of patients, which is called neurosarcoidosis. Neurosarcoidosis can cause a multitude of symptoms and can mimic various diseases. A rare manifestation is bone marrow involvement. We describe a case of spinal cord syndrome due to myelopathy that was caused by sarcoidosis of the bone marrow. Case Presentation: A male patient presented to our hospital with incomplete spinal cord syndrome. He suffered from numbness of the legs which had progressed to severe paraparesis. Magnetic resonance imaging revealed thoracic myelopathy without contrast enhancement. Thorough diagnostics found no explanation for the myelopathy, and the patient was treated symptomatically with high-dose steroids. When the patient developed non-resolving leukopenia, a bone marrow biopsy was performed. The bone marrow showed changes due to sarcoidosis. Further testing revealed myocardial involvement of the sarcoidosis. The patient was started on oral prednisolone and methotrexate. Over the course of time, his symptoms improved, but he still suffers from spastic leg paresis and needs aids to walk farther than 1 kilometre. Conclusion: In patients presenting with neurological deficits of unknown cause, neurosarcoidosis is a potential explanation. If it manifests primarily in the bone marrow, the diagnosis can be easily overlooked. Abnormalities in a full blood count should make the treating physician consider this diagnosis, and a bone marrow biopsy should be performed.

Mutation patterns in recurrent and/or metastatic oropharyngeal squamous cell carcinomas in relation to human papillomavirus status.

Patients with HPV-driven (HPV+) oropharyngeal squamous cell carcinoma (OPSCC) have a significantly improved overall survival compared to patients with HPV-negative (HPV-) OPSCC. Nevertheless, 13%-25% of patients with HPV+OPSCC develop local/distant recurrence (LDR) and have a course of disease similar to HPV-OPSCC. We hypothesize that HPV+OPSCCs of patients with LDR have a mutation frequency and pattern similar to HPV-OPSCCs, which is associated with severe outcome. We performed targeted next-generation sequencing using a customized gene panel and compared data from 56 matched HPV+and HPV-OPSCC of patients with/without LDR regarding protein-altering variants. Despite improved overall survival of patients with HPV+OPSCC, those who develop LDR show a strongly reduced survival rate that is similar or even worse compared to HPV-OPSCC patients. Overall, the number of mutations was similar in OPSCC of patients with and without LDR. In total and with respect to TP53, HPV-OPSCC had significantly more protein-altering mutations than HPV+OPSCC. The number of mutations was similar in HPV-OPSCC of patients with and without LDR with the exception of FAT1, which was mutated more frequently in patients without LDR. In HPV+OPSCC, HRAS, PIK3R1, STK11 and TP63 were more frequently mutated in patients with LDR compared to patients without. HPV+OPSCC of patients with LDR have a similar mutation pattern as HPV-OPSCC, except TP53, which was mutated to a significantly lower extent. In conclusion, HPV-and HPV+OPSCC with LDR have similar mutation counts in the analyzed genes. We suspect that the number of mutations is not causal for disease progression, rather specific mutations could be important.

Cyclophilin inhibitors restrict Middle East respiratory syndrome coronavirus via interferon-λ in vitro and in mice.

While severe coronavirus infections, including Middle East respiratory syndrome coronavirus (MERS-CoV), cause lung injury with high mortality rates, protective treatment strategies are not approved for clinical use.We elucidated the molecular mechanisms by which the cyclophilin inhibitors cyclosporin A (CsA) and alisporivir (ALV) restrict MERS-CoV to validate their suitability as readily available therapy in MERS-CoV infection.Calu-3 cells and primary human alveolar epithelial cells (hAECs) were infected with MERS-CoV and treated with CsA or ALV or inhibitors targeting cyclophilin inhibitor-regulated molecules including calcineurin, nuclear factor of activated T-cells (NFATs) or mitogen-activated protein kinases. Novel CsA-induced pathways were identified by RNA sequencing and manipulated by gene knockdown or neutralising antibodies. Viral replication was quantified by quantitative real-time PCR and 50% tissue culture infective dose. Data were validated in a murine MERS-CoV infection model.Both CsA and ALV reduced MERS-CoV titres and viral RNA replication in Calu-3 cells and hAECs, improving epithelial integrity. While neither calcineurin nor NFAT inhibition reduced MERS-CoV propagation, blockade of c-Jun N-terminal kinase diminished infectious viral particle release but not RNA accumulation. Importantly, CsA induced interferon regulatory factor 1 (IRF1), a pronounced type III interferon (IFNλ) response and expression of antiviral genes. Downregulation of IRF1 or IFNλ increased MERS-CoV propagation in the presence of CsA. Importantly, oral application of CsA reduced MERS-CoV replication in vivo, correlating with elevated lung IFNλ levels and improved outcome.We provide evidence that cyclophilin inhibitors efficiently decrease MERS-CoV replication in vitro and in vivo via upregulation of inflammatory antiviral cell responses, in particular IFNλ. CsA might therefore represent a promising candidate for treating MERS-CoV infection.

PTPIP51 crosslinks the NFκB signaling and the MAPK pathway in SKBR3 cells.

AIM: PTPIP51 interacts with NFκB signaling at the RelA and IκB level. NFκB signaling is linked to the initiation, progression and metastasis of breast cancer. Her2-amplified breast cancer cells frequently display activation of the NFκB signaling. We aimed to clarify the effects of NFκB inhibition on the NFκB- and MAPK-related interactome of PTPIP51 and cell viability in HaCat cells and SKBR3 cells. RESULTS: IKK-16 selectively reduced cell viability in SKBR3 cells. PDTC induced a formation of the Raf1/14-3-3/PTPIP51 complex in SKBR3 cells, indicating a shift of PTPIP51 into MAPK signaling. CONCLUSION: IKK-16 selectively inhibits cell viability of SKBR3 cells. In addition, PTPIP51 might serve as the mediator between NFκB signaling and the MAPK pathway in SKBR3.

Genetic alterations in human papillomavirus-associated oropharyngeal squamous cell carcinoma of patients with treatment failure.

OBJECTIVES: Despite improved survival rates of patients with HPV-associated OPSCC, a subset has distant metastasis or develops local recurrence during follow-up. To investigate potential underlying genetic alterations, we analyzed patients with HPV-driven OPSCC who suffered from recurrence in comparison to matching pairs with successful tumor control. MATERIALS AND METHODS: We performed chromosomal copy number analyses and targeted next generation sequencing using a custom panel comprising genes that are frequently mutated in HPV-associated OPSCC. RESULTS: Specific differences regarding chromosomal aberrations were not observed between both groups. In HPV-driven OPSCC from patients with recurrence we found higher mutation rates compared to patients with successful tumor control. Especially mutation rates of HRAS (p ≤ 0.05) PIK3R1, STK11 and TP63 (p ≤ 0.1 each) were statistically significant or trending towards significance. The respective genes can be linked to transcription factors and signaling pathways involved in cell cycle regulation, proliferation and survival. Additionally, combinations of alterations were observed on chromosomes 16 and 19, which might also influence outcome. CONCLUSION: Patients with HPV-driven OPSCC who develop recurrence or have metastasis may be defined by genetic alterations that might be responsible for poor outcome after standard therapy. This might be of importance for stratification in future de-escalation and targeted therapy.

Importance of Mechanoreceptors and Other Neural Structures Within the Anterior Intermeniscal Ligament in the Etiology of Anterior Knee Pain After Tibial Nailing.

BACKGROUND: Anterior knee pain is the most common complication after intramedullary tibial nailing. The cause is often multifactorial and varies among individuals. Violation of the anterior intermeniscal ligament (AIL) during intramedullary tibial nailing might be a possible source of postsurgical anterior knee pain. Although there is a certain ambiguity regarding the importance and function of the AIL, neural structures in the AIL tissue might play a significant role with respect to functional purposes and pain perception. METHODS: We subjected 6 AIL specimens to histologic examination to identify the neural structures that are a mandatory requirement as a source of anterior knee pain. Specifically, we performed three-dimensional immunohistochemical investigation of subtyping, orientation, and detailed characterization of neural structures within the AIL tissue. RESULTS: Histologic and three-dimensional immunohistochemical examinations confirmed the presence of neural structures in all 6 AIL specimens. We identified myelinated and unmyelinated nerve fibers, as well as all types of mechanoreceptors. CONCLUSIONS: Free nerve endings are a mandatory requirement for pain perception as a result of AIL violation during tibial nailing. Our verification of all different types of mechanoreceptors in the AIL tissue makes a role of the ligament in knee joint function and proprioception highly probable. Further investigations are necessary to clarify possible correlations between neural supply and function of the AIL. Violation of the ligament during operative procedures should be avoided, although the significance of the AIL is still debated.

Effectiveness of EGFR/HER2-targeted drugs is influenced by the downstream interaction shifts of PTPIP51 in HER2-amplified breast cancer cells.

Breast cancer is the most common female cancerous disease and the second most cause of cancer death in women. About 20-30% of these tumors exhibit an amplification of the HER2/ErbB2 receptor, which is coupled to a more aggressive and invasive growth of the cancer cells. Recently developed tyrosine kinase inhibitors and therapeutic antibodies targeting the HER2 receptor improved the overall survival time compared with sole radio- and chemotherapy. Upcoming resistances against the HER2-targeted therapy make a better understanding of the receptor associated downstream pathways an absolute need. In earlier studies, we showed the involvement of Protein Tyrosine Phosphatase Interacting Protein 51 (PTPIP51) in the mitogen-activated protein kinase (MAPK) pathway. The MAPK pathway is one of the most frequently overactivated pathways in HER2-amplified breast cancer cells. This study is aimed to elucidate the effects of four different TKIs on the interactome of PTPIP51, namely with the receptors EGFR and HER2, 14-3-3/Raf1 (MAPK pathway), its regulating enzymes, and the mitochondria-associated interaction partners in HER2 breast cancer cell lines (SK-BR3 and BT474) by using the Duolink proximity ligation assay, immunoblotting and knockdown of PTPIP51. Inhibition of both EGFR and HER2/ErbB2R shifted PTPIP51 into the MAPK pathway, but left the mitochondria-associated interactome of PTPIP51 unattended. Exclusively inhibiting HER2/ErbB2 by Mubritinib did not affect the interaction of PTPIP51 with the MAPK signaling. Selective inhibition of HER2 induced great alterations of mitochondria-associated interactions of PTPIP51, which ultimately led to the most-effective reduction of cell viability of SK-BR3 cells of all tested TKIs. The results clearly reveal the importance of knowing the exact mechanisms of the inhibitors affecting receptor tyrosine kinases in order to develop more efficient anti-HER2-targeted therapies.

Impairment of IGF2 gene expression in prostate cancer is triggered by epigenetic dysregulation of IGF2-DMR0 and its interaction with KLF4.

BACKGROUND: Human cancer cells often exhibit impaired IGF2 expression and the underlying mechanisms are multifaceted and complex. Besides the well-known imprinting control region IGF2/H19-ICR, the involvement of a differentially methylated region in the promoter P0 of IGF2 gene (IGF2-DMR0) has been suggested. Here, we evaluate several mechanisms potentially leading to up- and/or down-regulation of IGF2 expression in prostate cancer and present a novel role of Kruppel-like factor 4 (KLF4) as a transcriptional regulator of IGF2 binding in IGF2-DMR0. METHODS: Putative binding sites for transcription factors were identified in IGF2-DMR0 using JASPAR CORE database. Gene expressions were analyzed by RT-qPCR in prostate carcinoma and adjacent benign prostate hyperplasia samples obtained by radical prostatectomy (86 RP-PCa and 47 RP-BPH) and BPH obtained by transurethral prostate resection (13 TUR-BPH). Pyrosequencing and qMSP were used for DNA methylation studies in IGF2-DMR0, IGF2/H19-ICR and Glutathione-S-transferase-P1 (GSTP1) promoter. Loss of imprinting (LOI) was analyzed by RFLP. Copy number variation (CNV) test was performed using qBiomarker CNV PCR Assay. KLF4-binding and histone-modifications were analyzed by ChIP-qPCR in prostate cancer cell lines exhibiting differentially methylated IGF2-DMR0 (LNCaP hypomethylated and DU145 hypermethylated). KLF4 protein was analyzed by western blot. Statistical associations of gene expression to methylation, IGF2 LOI and CNV were calculated by Mann-Whitney-U-test. Correlations between gene expression and methylation levels were evaluated by Spearman's-Rank-Correlation-test. RESULTS: We found a significant reduction of IGF2 expression in the majority of RP-PCa and RP-BPH in comparison to TUR-BPH. Analyzing potential molecular reasons, we found in RP-PCa and RP-BPH in comparison to TUR-BPH a significant hypomethylation of IGF2-DMR0, which coincided with hypermethylation of GSTP1-promoter, a prominent marker of prostate tumors. In contrast, IGF2 LOI and CNV did not associate significantly with up- and/or down-regulation of IGF2 expression in prostate tumors. By analyzing IGF2-DMR0, we detected a consensus sequence for KLF4 with a z-score of 7.6. Interestingly, we found that KLF4 binds to hypomethylated (17%) IGF2-DMR0 enriched with H3K9me3 and H3K27me3 (LNCaP), but does not bind under hypermethylated (85%) and H3K4me3-enriched conditions (DU145). KLF4 expression was detected in TUR-BPH as well as in RP-BPH and RP-PCa and showed a highly significant correlation to IGF2 expression. CONCLUSIONS: Our study demonstrated that in human prostate cancer the impairment of IGF2 expression is accompanied by hypomethylation of IGF2-DMR0. We revealed that KLF4 is a putative transcriptional regulator of IGF2, which binds in IGF2-DMR0 in dependence of the prevailing epigenetic state in this region. Herewith we provide complementary new insights into IGF2 dysregulation mechanisms as a critical process in prostate tumorigenesis.

Influenza Virus Infects Epithelial Stem/Progenitor Cells of the Distal Lung: Impact on Fgfr2b-Driven Epithelial Repair.

Influenza Virus (IV) pneumonia is associated with severe damage of the lung epithelium and respiratory failure. Apart from efficient host defense, structural repair of the injured epithelium is crucial for survival of severe pneumonia. The molecular mechanisms underlying stem/progenitor cell mediated regenerative responses are not well characterized. In particular, the impact of IV infection on lung stem cells and their regenerative responses remains elusive. Our study demonstrates that a highly pathogenic IV infects various cell populations in the murine lung, but displays a strong tropism to an epithelial cell subset with high proliferative capacity, defined by the signature EpCamhighCD24lowintegrin(α6)high. This cell fraction expressed the stem cell antigen-1, highly enriched lung stem/progenitor cells previously characterized by the signature integrin(ß4)+CD200+, and upregulated the p63/krt5 regeneration program after IV-induced injury. Using 3-dimensional organoid cultures derived from these epithelial stem/progenitor cells (EpiSPC), and in vivo infection models including transgenic mice, we reveal that their expansion, barrier renewal and outcome after IV-induced injury critically depended on Fgfr2b signaling. Importantly, IV infected EpiSPC exhibited severely impaired renewal capacity due to IV-induced blockade of ß-catenin-dependent Fgfr2b signaling, evidenced by loss of alveolar tissue repair capacity after intrapulmonary EpiSPC transplantation in vivo. Intratracheal application of exogenous Fgf10, however, resulted in increased engagement of non-infected EpiSPC for tissue regeneration, demonstrated by improved proliferative potential, restoration of alveolar barrier function and increased survival following IV pneumonia. Together, these data suggest that tropism of IV to distal lung stem cell niches represents an important factor of pathogenicity and highlight impaired Fgfr2b signaling as underlying mechanism. Furthermore, increase of alveolar Fgf10 levels may represent a putative therapy to overcome regeneration failure after IV-induced lung injury.

Macrophage-epithelial paracrine crosstalk inhibits lung edema clearance during influenza infection.

Influenza A viruses (IAV) can cause lung injury and acute respiratory distress syndrome (ARDS), which is characterized by accumulation of excessive fluid (edema) in the alveolar airspaces and leads to hypoxemia and death if not corrected. Clearance of excess edema fluid is driven mostly by the alveolar epithelial Na,K-ATPase and is crucial for survival of patients with ARDS. We therefore investigated whether IAV infection alters Na,K-ATPase expression and function in alveolar epithelial cells (AECs) and the ability of the lung to clear edema. IAV infection reduced Na,K-ATPase in the plasma membrane of human and murine AECs and in distal lung epithelium of infected mice. Moreover, induced Na,K-ATPase improved alveolar fluid clearance (AFC) in IAV-infected mice. We identified a paracrine cell communication network between infected and noninfected AECs and alveolar macrophages that leads to decreased alveolar epithelial Na,K-ATPase function and plasma membrane abundance and inhibition of AFC. We determined that the IAV-induced reduction of Na,K-ATPase is mediated by a host signaling pathway that involves epithelial type I IFN and an IFN-dependent elevation of macrophage TNF-related apoptosis-inducing ligand (TRAIL). Our data reveal that interruption of this cellular crosstalk improves edema resolution, which is of biologic and clinical importance to patients with IAV-induced lung injury.

Expression and pro-survival function of phospholipase Cγ2 in diffuse large B-cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) can be cured in about 60% of cases with immuno-chemotherapy. However, a large subset of patients with DLBCL do not go into remission, or relapse after first-line therapy. Further therapy options are therefore needed. Phospholipase Cγ2 (PLCγ2) is one of the key regulators of the B cell receptor signaling pathway, which targets several pro-proliferative factors, such as nuclear factor κB (NFκB), Ras and Akt. Using immunohistochemistry, we found that PLCγ2 was strongly expressed in 63% of cases of DLBCL. The PLC inhibitor U73122 had an inhibitory effect on cell proliferation and induced apoptosis and G0/G1 cell cycle arrest. Co-treatment with enzastaurin or the Src inhibitor pp2 together with U73122 had an additive effect on cell proliferation compared to U73122 alone. Unexpectedly, strong PLCγ2 expression was associated with better overall survival. In conclusion, PLCγ2 is strongly expressed in a significant number of DLBCLs and has prognostic implications. Inhibition of PLCγ2 could be a new target for lymphoma treatment.

Extracardiac juvenile rhabdomyoma of the larynx: a rare pathological finding.

The extracardiac juvenile rhabdomyoma is extremely rare in the field of Otorhinolaryngology. The tumour usually arises from the soft tissue of the face or from mucosal sites, especially the oropharynx and the oral cavity but only sporadic endolaryngeal cases have been described in literature so far with predominance of young males. Here, we describe the very rare case of endolaryngeal extracardiac juvenile rhabdomyoma in a 42-year-old male. Clinical examination showed a mass of the right vocal cord, resembling a cystic lesion. Microlaryngoscopy revealed a non-encapsulated lesion and histopathology including immunohistochemistry which consecutively led to the correct diagnosis. This case suggests that the endolaryngeal extracardiac juvenile rhabdomyoma can be easily confused with a vocal cord cyst. Malignant transformations have not been reported but recurrences have been described. When total excision cannot be accomplished, reoperation or narrow follow-up is indicated to prevent advanced revision surgeries.

Alveolar epithelial cells orchestrate DC function in murine viral pneumonia.

Influenza viruses (IVs) cause pneumonia in humans with progression to lung failure. Pulmonary DCs are key players in the antiviral immune response, which is crucial to restore alveolar barrier function. The mechanisms of expansion and activation of pulmonary DC populations in lung infection remain widely elusive. Using mouse BM chimeric and cell-specific depletion approaches, we demonstrated that alveolar epithelial cell (AEC) GM-CSF mediates recovery from IV-induced injury by affecting lung DC function. Epithelial GM-CSF induced the recruitment of CD11b+ and monocyte-derived DCs. GM-CSF was also required for the presence of CD103+ DCs in the lung parenchyma at baseline and for their sufficient activation and migration to the draining mediastinal lymph nodes (MLNs) during IV infection. These activated CD103+ DCs were indispensable for sufficient clearance of IVs by CD8+ T cells and for recovery from IV-induced lung injury. Moreover, GM-CSF applied intratracheally activated CD103+ DCs, inducing increased migration to MLNs, enhanced viral clearance, and attenuated lung injury. Together, our data reveal that GM-CSF-dependent cross-talk between IV-infected AECs and CD103+ DCs is crucial for effective viral clearance and recovery from injury, which has potential implications for GM-CSF treatment in severe IV pneumonia.

Does insulin-like growth factor 1 receptor (IGF-1R) targeting provide new treatment options for chordomas? A retrospective clinical and immunohistochemical study.

AIMS: The overall prognosis of chordoma is poor, and current treatment options are limited. The insulin-like growth factor 1 receptor (IGF-1R) pathway is important for cell signalling, and attractive for selective inhibition. We investigated the expression of IGF-1R and its ligands, IGF-1 and IGF-2, in a series of 50 chordomas, in order to assess whether IGF-1R-signalling could be a potential target for specific inhibition in chordomas. METHODS AND RESULTS: Fifty chordomas (34 primary tumours, 16 recurrences) from 44 patients were evaluated immunohistochemically for the expression of IGF-1R, IGF-1 and IGF-2. Thirty-eight chordomas (76%) expressed IGF-1R, 46 (92%) expressed IGF-1 and 25 (50%) expressed IGF-2. Semi-quantitative analyses revealed a moderate to strong staining intensity in ≥ 50% of tumour cells for IGF-1R, IGF-1 and IGF-2 in 18 (36%), 32 (64%) and eight (16%) chordomas, respectively. Tumour volume correlated significantly with IGF-1R-staining intensity in primary chordomas (P = 0.042). CONCLUSIONS: IGF-1R and IGF-1 are expressed in the majority of chordomas. IGF-1 expression is much stronger than IGF-2 expression. Patients whose chordomas show a moderate to strong staining intensity in ≥ 50% of tumour cells for IGF-1R (36%) might benefit most from IGF-1R targeting, particularly if they suffer from large and surgically non-resectable chordomas.

Epigenetic down regulation of RASSF10 and its possible clinical implication in prostate carcinoma.

BACKGROUND: Ras association domain family (RASSF) comprises several tumor suppressor genes, which are often epigenetically inactivated in human tumors. Here, we aim to analyze the relevance of the recently identified member RASSF10 in prostate carcinogenesis. METHODS: RASSF10 promoter methylation and mRNA expression were investigated by bisulfite-pyrosequencing and qRT-PCR, respectively, in prostate carcinoma (PCa) cell lines (LNCaP, 22Rv1, DU-145) and in 83 primary PCa and 53 primary benign prostatic hyperplasia (BPH) tissues obtained after radical prostatectomy. Histological localization of RASSF10 was done by in situ hybridization. To prove the epigenetic nature of RASSF10 down regulation, PCa cell lines were treated with 5-aza-2-deoxycytidine and trichostatin A. Potential function of RASSF10 was analyzed in LNCaP by colony formation and apoptosis assays. RESULTS: RASSF10 mRNA was localized to cells of the basal layer of the prostatic gland. Absence (LNCaP) and decrease (22Rv1, DU-145) of RASSF10 expression was associated with promoter methylation and could be restored by demethylating agents. A link between RASSF10 mRNA reduction and promoter methylation was also detected in primary prostate tissues (P = 0.006), where PCa showed more frequently reduced RASSF10 levels when compared with BPH (33.7% vs. 13.2%, P = 0.009). RASSF10 methylation could be further associated with advanced tumor stage and advanced age (P-values < 0.05). Our preliminary functional assays revealed the ability of RASSF10 to inhibit colony formation (P = 0.018) and to increase apoptosis (P = 0.035). CONCLUSIONS: This is the first study, which demonstrates the frequent epigenetic inactivation of RASSF10 in PCa and its implication in clinical symptoms of PCa.

Regulatory T cells facilitate the nuclear accumulation of inducible cAMP early repressor (ICER) and suppress nuclear factor of activated T cell c1 (NFATc1).

Inducible cAMP early repressor (ICER) is a transcriptional repressor, which, because of alternate promoter use, is generated from the 3' region of the cAMP response modulator (Crem) gene. Its expression and nuclear occurrence are elevated by high cAMP levels in naturally occurring regulatory T cells (nTregs). Using two mouse models, we demonstrate that nTregs control the cellular localization of ICER/CREM, and thereby inhibit IL-2 synthesis in conventional CD4(+) T cells. Ablation of nTregs in depletion of regulatory T-cell (DEREG) mice resulted in cytosolic localization of ICER/CREM and increased IL-2 synthesis upon stimulation. Direct contacts between nTregs and conventional CD4(+) T cells led to nuclear accumulation of ICER/CREM and suppression of IL-2 synthesis on administration of CD28 superagonistic (CD28SA) Ab. In a similar way, nTregs communicated with B cells and induced the cAMP-driven nuclear localization of ICER/CREM. High levels of ICER suppressed the induction of nuclear factor of activated T cell c1 (Nfatc1) gene in T cells whose inducible Nfatc1 P1 promoter bears two highly conserved cAMP-responsive elements to which ICER/CREM can bind. These findings suggest that nTregs suppress T-cell responses by the cAMP-dependent nuclear accumulation of ICER/CREM and inhibition of NFATc1 and IL-2 induction.

Epstein-Barr virus infection is not a characteristic feature of multiple sclerosis brain.

Multiple sclerosis is an inflammatory demyelinating disease of the central nervous system (CNS) that is thought to be caused by a combination of genetic and environmental factors. To date, considerable evidence has associated Epstein-Barr virus (EBV) infection with disease development. However, it remains controversial whether EBV infects multiple sclerosis brain and contributes directly to CNS immunopathology. To assess whether EBV infection is a characteristic feature of multiple sclerosis brain, a large cohort of multiple sclerosis specimens containing white matter lesions (nine adult and three paediatric cases) with a heterogeneous B cell infiltrate and a second cohort of multiple sclerosis specimens (12 cases) that included B cell infiltration within the meninges and parenchymal B cell aggregates, were examined for EBV infection using multiple methodologies including in situ hybridization, immunohistochemistry and two independent real-time polymerase chain reaction (PCR) methodologies that detect genomic EBV or the abundant EBV encoded RNA (EBER) 1, respectively. We report that EBV could not be detected in any of the multiple sclerosis specimens containing white matter lesions by any of the methods employed, yet EBV was readily detectable in multiple Epstein-Barr virus-positive control tissues including several CNS lymphomas. Furthermore, EBV was not detected in our second cohort of multiple sclerosis specimens by in situ hybridization. However, our real-time PCR methodologies, which were capable of detecting very few EBV infected cells, detected EBV at low levels in only 2 of the 12 multiple sclerosis meningeal specimens examined. Our finding that CNS EBV infection was rare in multiple sclerosis brain indicates that EBV infection is unlikely to contribute directly to multiple sclerosis brain pathology in the vast majority of cases.

Quantitation of the JAK2V617F mutation in microdissected bone marrow trephines: equal mutational load in myeloid lineages and rare involvement of lymphoid cells.

The JAK2V617F mutation is an essential oncogenic event in Philadelphia negative chronic myeloproliferative disorders (Ph-cMPD). It is still unclear how a unique tyrosine kinase mutation can give rise to the broad clinical and morphologic spectrum of Ph-cMPD. One possible explanation could be differences in the JAK2V617F gene dosage, or different maturation stages on which myeloid lineages are affected by the mutation. The extent of lymphoid lineage involvement in JAK2V617F-positive cMPD is still controversial. We comparatively studied the zygosity status of microdissected megakaryocytes, nonmegakaryocytic hematopoietic cells, and reactive as well as neoplastic lymphoid nodules from bone marrow trephines of 61 patients with Ph-cMPD. The presence of the mutation and mutant gene dosage were determined by allele-specific polymerase chain reaction and TaqMan analysis, respectively. The mutation was detected in 22/32 (68%) cases of essential thrombocythemia, all cases of polycythemia vera, and 4/8 (50%) idiopathic myelofibrosis. Comparison of whole bone marrow sections and the different myeloid lineages showed similar percentages of the mutated allele. Restriction to a particular lineage or major differences in allele dosage were not observed, except for 2 cases in which megakaryocytes revealed a higher frequency of the mutated allele. A heterozygous JAK2V617F mutation was detected in 3/8 "reactive" lymphoid nodule in patients with Ph-cMPD, whereas all concomitant non-Hodgkin lymphoma of B-cell type were negative. These results demonstrate that different myeloid lineages usually show similar frequencies of the JAK2V617F allele. The occasional detection of JAK2V617F in benign lymphocytes points to involvement of the lympho-myeloid stem cell.