Better prognosis of gastric cancer patients with high levels of tumor infiltrating lymphocytes is counteracted by PD-1 expression.

The prognostic potential of anti-tumor immune responses is becoming increasingly important in adenocarcinoma of the gastroesophageal junction and stomach (AGE/S) especially regarding the use of immune checkpoint inhibitors. This study analyzes for the first time the prognostic impact of tumor-infiltrating lymphocytes (TILs) and checkpoint inhibitors in a large Caucasian cohort in patients with AGE/S. We screened tissue samples from 438 therapy-naïve patients with AGE/S undergoing surgery between 1992 and 2005, examined in a tissue microarray (TMA) and stained against human CD3, CD4, CD8, PD-1, and PD-L1. Out of 438 tissue samples, 210 were eligible for multivariate analysis. This revealed that high infiltration with CD3+, CD4+, or CD8+ TILs was associated with an increased overall survival in AGE/S patients, which could only be confirmed in multivariate analysis for CD3 (HR: 0.326; p = .023). Independent improved survival was limited to gastric cancer patients and to early tumor stages as long as TILs did not express PD-1 (HR: 1.522; p = .021). Subgroup analyses indicate that TIL-dependent anti-tumor immune response is only effective in gastric cancer patients in early stages of disease in PD-1 negative TILs. Combined analysis of PD-1 and CD3 could serve as a prognostic marker for the clinical outcome of gastric cancer patients and could also be of interest for immunotherapy.

Interference of tumour mutational burden with outcome of patients with head and neck cancer treated with definitive chemoradiation: a multicentre retrospective study of the German Cancer Consortium Radiation Oncology Group.

BACKGROUND: Tumour mutational burden (TMB) estimated from whole exome sequencing or comprehensive gene panels has previously been established as predictive factor of response to immune checkpoint inhibitors (ICIs). Its predictive value for the efficacy of concurrent chemoradiation (cCRTX), a potential combination partner of ICI, remains unknown. METHODS: The accuracy of TMB estimation by an in-house 327-gene panel was established in the Cancer Genome Atlas (TCGA) head and neck squamous cell carcinoma (HNSCC) data set. Interference of TMB with outcome after cCRTX was determined in a multicentre cohort of patients with locally advanced HNSCC uniformly treated with cCRTX. Targeted next-generation sequencing was successfully applied in 101 formalin-fixed, paraffin-embedded pretreatment tumour samples. In a subset of cases (n = 40), tumour RNA was used for immune-related gene expression profiling by the nanoString platform. TMB was correlated with TP53 genotype, human papilloma virus (HPV) status, immune expression signatures and survival parameters. Results were validated in the TCGA HNSCC cohort. RESULTS: A high accuracy of TMB estimation by the 327-gene panel was established. High TMB was significantly associated with an increased prevalence of TP53 mutations and immune gene expression patterns unrelated to T cell-inflamed gene expression profiles. Kaplan-Meier analysis revealed significantly reduced overall survival in the patient group with high TMB (hazard ratio for death: 1.79, 95% confidence interval: 1.02-3.14; P = 0.042) which remained significant after correcting for confounding factors in the multivariate model. The prognostic value of TMB was confirmed in the TCGA HNSCC cohort. CONCLUSION: High TMB identifies HNSCC patients with poor outcome after cCRTX who might preferentially benefit from CRTX-ICI combinations.

Clinical characteristics and immunohistochemical analysis of p53, Ki-67 and cyclin D1 in 80 odontogenic keratocysts.

OBJECTIVE: The aim of this study was to evaluate clinical parameters and expression patterns of Ki-67, cyclin D1 and p53 in odontogenic keratocysts. MATERIAL AND METHODS: In this study, fifty-three patients with 80 odontogenic keratocysts were included. The medical records of these patients were reviewed retrospectively. To elucidate the molecular pathogenesis of the disease, the expression of p53, Ki-67 and cyclin D1 was analyzed using immunohistochemistry. RESULTS: A total of 53 patients (mean age 38 years) with a median follow-up of 4.2 years (ranging from 4 days to 14.4 years) were evaluated. The rates of recurrence and post-operative complications varied depending on the surgical approach: cystectomy and peripheral ostectomy led to manageable low rates of complications and recurrence frequency. Immunohistochemical evaluation revealed that all lesions were positive for Ki-67 and cyclin D1 expression. The expression of Ki-67 was associated with the degree of inflammation. Cyclin D1 was expressed significantly higher in syndrome-associated keratocystic lesions. In contrast to non-syndromal lesions, all syndromal lesions expressed p53. CONCLUSION: This investigation demonstrates that the pathogenesis of syndromal keratocysts appears to differ from sporadic odontogenic keratocysts. Additionally, the primary and recurrent non-syndromal keratocysts have a similar etiology, as no differences in the expression patterns of Ki-67, p53 and cyclin D1 were observed.

Molecular alterations in bone marrow mesenchymal stromal cells derived from acute myeloid leukemia patients.

The contribution of molecular alterations in bone marrow mesenchymal stromal cells (BM-MSC) to the pathogenesis of acute myeloid leukemia (AML) is poorly understood. Thus we assessed genome-wide genetic, transcriptional and epigenetic alterations in BM-MSC derived from AML patients (AML BM-MSC). Whole-exome sequencing (WES) of AML BM-MSC samples from 21 patients revealed a non-specific pattern of genetic alterations in the stromal compartment. The only mutation present in AML BM-MSC at serial time points of diagnosis, complete remission and relapse was a mutation in the PLEC gene encoding for cytoskeleton key player Plectin in one AML patient. Healthy donor controls did not carry genetic alterations as determined by WES. Transcriptional profiling using RNA sequencing revealed deregulation of proteoglycans and adhesion molecules as well as cytokines in AML BM-MSC. Moreover, KEGG pathway enrichment analysis unravelled deregulated metabolic pathways and endocytosis in both transcriptional and DNA methylation signatures in AML BM-MSC. Taken together, we report molecular alterations in AML BM-MSC suggesting global changes in the AML BM microenvironment. Extended investigations of these altered niche components may contribute to the design of niche-directed therapies in AML.

[Predictive PD-L1 immunohistochemistry for non-small cell lung cancer : Current state of the art and experiences of the first German harmonization study]. / Prädiktive PD-L1-Immunhistochemie beim nichtkleinzelligen Bronchialkarzinom : Aktueller Stand und Erfahrungen der ersten deutschen Harmonisierungsstudie.

BACKGROUND: Antibodies against PD-1 and PD-L1 can cause strong and durable anti-tumor immune responses in non-small cell lung cancer (NSCLC). Immunohistochemistry for PD-L1 (PD-L1 IHC) was tested as a predictive biomarker. Several IHC assays and interpretation criteria were developed in parallel. AIM: The clinical significance of PD-L1 IHC in NSCLC and the optimum method for staining and interpretation of the results are the subject of ongoing studies. The diagnostic application of immunotherapy in NSCLC necessitates harmonization of PD-L1 IHC to obtain evidence for guidelines; therefore, a consensus opinion on a well-founded diagnostic mode of testing should be defined based on published studies and the results of the first German PD-L1 IHC harmonization study. METHODS: 1. Summary of the current data situation. 2. Evaluation of the first German PD-L1 IHC harmonization study (centralized, staining with PD-L1 IHC analogous to studies, 15 cases of NSCLC, 4 IHC study assays [28­8, 22C3, SP142 and SP263] and scoring by 9 pathologists). RESULTS: The use of PD-L1 IHC in NSCLC is suitable for identification of patients with an increased probability of a clinical benefit from immunotherapy. The various proportional cut-offs used to interpret the staining results can be summarized in a total score, which can be reproducibly assessed. The staining patterns of the four assays investigated were, however, not congruent in all situations. DISCUSSION: In principle, the use of PD-L1 IHC for assessment of the expression in tumor cells is a reliably determinable biomarker. Evaluation algorithms should be based on published clinical trials. For NSCLC approvals with obligatory PD-L1 IHC are to be expected but it remains to be seen to what extent PD-L1 IHC will be implemented in the clinical routine.

[Space-occupying lesion in the maxillary sinus]. / Eine Raumforderung im Sinus maxillaris.

During the preoperative diagnostics of an 80-year-old male patient prior to a planned endarterectomy, an unclear space-occupying lesion was detected in the right nasopharyngeal cavity. It proved to be a dense soft tissue space-occupying lesion of the right maxillary sinus. The histological investigations revealed a partially necrotically decomposed malignant tumor below normal respiratory mucosa free from dysplasia. This case demonstrates the difficulties in differential diagnostics, particularly involving (aberrant) expression of cytokeratin.

Targeted next-generation sequencing of locally advanced squamous cell carcinomas of the head and neck reveals druggable targets for improving adjuvant chemoradiation.

BACKGROUND: Despite clear differences in clinical presentation and outcome, squamous cell carcinomas of the head and neck (SCCHN) arising from human papilloma virus (HPV) infection or heavy tobacco/alcohol consumption are treated equally. Next-generation sequencing is expected to reveal novel targets for more individualised treatment. PATIENTS AND METHODS: Tumour specimens from 208 patients with locally advanced squamous cell carcinoma of the hypopharynx, oropharynx or oral cavity, all uniformly treated with adjuvant cisplatin-based chemoradiation, were included. A customised panel covering 211 exons from 45 genes frequently altered in SCCHN was used for detection of non-synonymous point and frameshift mutations. Mutations were correlated with HPV status and treatment outcome. RESULTS: Mutational profiles and HPV status were successfully established for 179 cases. HPV- tumours showed an increased frequency of alterations in tumour suppressor genes compared to HPV+ cases (TP53 67% versus 4%, CDKN2A 18% versus 0%). Conversely, HPV+ carcinomas were enriched for activating mutations in driver genes compared to HPV- cases (PIK3CA 30% versus 12%, KRAS 6% versus 1%, and NRAS 4% versus 0%). Hotspot TP53 missense mutations in HPV- carcinomas correlated with an increased risk of locoregional recurrence (hazard ratio [HR] 4.3, 95% confidence interval [CI] 1.5-12.1, P=0.006) and death (HR 2.2, 95% CI 1.1-4.4, P=0.021). In HPV+ SCCHN, driver gene mutations were associated per trend with a higher risk of death (HR 3.9, 95% CI 0.7-21.1, P=0.11). CONCLUSIONS: Distinct mutation profiles in HPV- and HPV+ SCCHN identify subgroups with poor outcome after adjuvant chemoradiation. Mutant p53 and the phosphoinositide 3-kinase pathway were identified as potential druggable targets for subgroup-specific treatment optimisation.

A 2015 update on predictive molecular pathology and its role in targeted cancer therapy: a review focussing on clinical relevance.

In April 2013 our group published a review on predictive molecular pathology in this journal. Although only 2 years have passed many new facts and stimulating developments have happened in diagnostic molecular pathology rendering it worthwhile to present an up-date on this topic. A major technical improvement is certainly given by the introduction of next-generation sequencing (NGS; amplicon, whole exome, whole genome) and its application to formalin-fixed paraffin-embedded (FFPE) tissue in routine diagnostics. Based on this 'revolution' the analyses of numerous genetic alterations in parallel has become a routine approach opening the chance to characterize patients' malignant tumors much more deeply without increasing turn-around time and costs. In the near future this will open new strategies to apply 'off-label' targeted therapies, e.g. for rare tumors, otherwise resistant tumors etc. The clinically relevant genetic aberrations described in this review include mutation analyses of RAS (KRAS and NRAS), BRAF and PI3K in colorectal cancer, KIT or PDGFR alpha as well as BRAF, NRAS and KIT in malignant melanoma. Moreover, we present several recent advances in the molecular characterization of malignant lymphoma. Beside the well-known mutations in NSCLC (EGFR, ALK) a number of chromosomal aberrations (KRAS, ROS1, MET) have become relevant. Only very recently has the clinical need for analysis of BRCA1/2 come up and proven as a true challenge for routine diagnostics because of the genes' special structure and hot-spot-free mutational distribution. The genetic alterations are discussed in connection with their increasingly important role in companion diagnostics to apply targeted drugs as efficient as possible. As another aspect of the increasing number of druggable mutations, we discuss the challenges personalized therapies pose for the design of clinical studies to prove optimal efficacy particularly with respect to combination therapies of multiple targeted drugs and conventional chemotherapy. Such combinations would lead to an extremely high complexity that would hardly be manageable by applying conventional study designs for approval, e.g. by the FDA or EMA. Up-coming challenges such as the application of methylation assays and proteomic analyses on FFPE tissue will also be discussed briefly to open the door towards the ultimate goal of reading a patients' tissue as 'deeply' as possible. Although it is yet to be shown, which levels of biological information are most informative for predictive pathology, an integrated molecular characterization of tumors will likely offer the most comprehensive view for individualized therapy approaches. To optimize cancer treatment we need to understand tumor biology in much more detail on morphological, genetic, proteomic as well as epigenetic grounds. Finally, the complex challenges on the level of drug design, molecular diagnostics, and clinical trials make necessary a close collaboration among academic institutions, regulatory authorities and pharmaceutical companies.

[Head and neck hamartomas: 10 years of experience at the Charité--University Medical Center Berlin]. / Hamartome im Kopf-Hals-Bereich: 10 Jahre Erfahrung an der Charité--Universitätsmedizin Berlin.

BACKGROUND: Head and neck tumors are rare entities in neonates. Hamartomas are benign congenital neoplasms. To date, there is a lack of sufficient epidemiological data concerning hamartomas in the field of otorhinolaryngology. MATERIALS AND METHODS: We retrospectively analyzed experiences at the Charité over the past 10 years in an ICD-10-based manner. Our otorhinolaryngology department maintains close cooperation with the level 1 perinatal center on our campus. RESULTS: The authors identified 3 patients suffering from fibrous hamartomas. This corresponds to an incidence of 2-3/30,000 newborns. The clinical aspects and courses are described in detail. Experiences with the management of hamartomas obstructing the upper aerodigestive tract are described. CONCLUSION: Head and neck hamartomas are very rare malformations. They possess the ability to cause otorhinolaryngological emergencies in newborns. Interdisciplinary management and histological assessment are mandatory. Anmerkung.

Contribution of human papilloma virus to the incidence of squamous cell carcinoma of the head and neck in a European population with high smoking prevalence.

BACKGROUND: Increases in incidence of oropharyngeal squamous cell carcinoma (OPSCC) in countries with falling tobacco use have been attributed to a growing role of human papilloma virus (HPV) in the carcinogenesis. Trends of HPV prevalence in populations with persistently high portions of smokers are poorly characterised. PATIENTS AND METHODS: Registry data from East Germany were used to determine incidence trends between 1998 and 2011. Data from patients treated at the Charité University Medicine Berlin between 2004 and 2013 (cohort 1, N=436) were used for estimation of trends in HPV prevalence, smoking and survival. HPV prevalence was prospectively confirmed in cohort 2 (N=213) comprising all primary HNSCC cases at the Charité in 2013. RESULTS: Between 1998 and 2011 incidence of both OPSCC and non-OPSCC increased. An increase in HPV prevalence (% of HPV+ cases in 2004-2006 versus 2012-2013: 27% versus 59%, P=0.0004) accompanied by a moderate decrease in the portion of current smokers was observed in OPSCC but not in non-OPSCC. The change in disease epidemiology in OPSCC was associated with significant improvement in overall survival. Increased HPV prevalence in OPSCC (48%) compared to non-OPSCC (11%) was confirmed in cohort 2. CONCLUSIONS: Despite clear differences to the United States in terms of tobacco use, the increase in OPSCC incidence in a European population was also mainly attributed to HPV, and the HPV status significantly affected prognosis. For clinical trial design it is important to consider the large group of smokers within HPV-induced OPSCC.

A comprehensive analysis of the cellular and EBV-specific microRNAome in primary CNS PTLD identifies different patterns among EBV-associated tumors.

Primary central nervous system (pCNS) posttransplant lymphoproliferative disorder (PTLD) is a complication of solid organ transplantation characterized by poor outcome. In contrast to systemic PTLD, Epstein-Barr virus (EBV)-association of pCNS PTLD is almost universal, yet viral and cellular data are limited. To identify differences in the pattern of EBV-association of pCNS and systemic PTLD, we analyzed the expression of latent and lytic EBV transcripts and the viral and cellular microRNAome in nine pCNS (eight EBV-associated) and in 16 systemic PTLD samples (eight EBV-associated). Notably although 15/16 EBV-associated samples exhibited a viral type III latency pattern, lytic transcripts were also strongly expressed. Members of the ebv-miR-BHRF1 and ebv-miR-BART clusters were expressed in virtually all EBV-associated PTLD samples. There were 28 cellular microRNAs differentially expressed between systemic and pCNS PTLD. pCNS PTLD expressed lower hsa-miR-199a-5p/3p and hsa-miR-143/145 (implicated in nuclear factor kappa beta and c-myc signaling) as compared to systemic PTLD. Unsupervised nonhierarchical clustering of the viral and cellular microRNAome distinguished non-EBV-associated from EBV-associated samples and identified a separate group of EBV-associated pCNS PTLD that displayed reduced levels of B cell lymphoma associated oncomiRs such as hsa-miR-155, -21, -221 and the hsa-miR-17-92 cluster. EBV has a major impact on viral and cellular microRNA expression in EBV-associated pCNS PTLD.

Detection of circulating tumor cells for prediction of recurrence after adjuvant chemoradiation in locally advanced squamous cell carcinoma of the head and neck.

BACKGROUND: The prognostic role of persistence of circulating tumor cells (CTC) after upfront tumor surgery for outcome of adjuvant (chemo)radiation in locally advanced squamous cell carcinoma of the head and neck (LASCCHN) was evaluated. PATIENTS AND METHODS: In this prospective study, peripheral blood samples from 144 patients with LASCCHN presenting after tumor resection for adjuvant treatment were analyzed for CTC. Their detection was correlated with tumor site, clinical risk factors, disease-free (DFS) and overall survival (OS). RESULTS: CTC were detected in 42 of 144 patients (29%). CTC detection was higher in cases with nodal involvement and in carcinomas located at the tonsil or base of tongue but was not influenced by age, smoking history, T stage, extracapsular lymph node extension, surgical margins or the human papillomavirus status. Overall, the presence of CTC was not predictive for OS or DFS. However, while in oropharyngeal carcinomas (OPC, n = 63), the detection of CTC was associated per trend with improved DFS [CTC+ versus CTC- (% of patients without evidence of disease at 2 years): 100% versus 79%; log rank: P = 0.059]; the reverse was observed for carcinomas from other sites (non-OPC, n = 81; CTC+ versus CTC-: 29% versus 75%; P = 0.001). In multivariate analysis, CTC remained an independent prognostic marker for DFS [hazard ratio (HR) 4.3, 95% confidence interval (CI) 1.7-10.9, P = 0.002] and OS (HR 2.7, 95% CI 1.2-6.3, P = 0.016) in non-OPC. CONCLUSIONS: Assessment of CTC in non-OPC should prove useful for identification of patients who benefit from treatment intensification. The basis for the good prognostic value of CTC in OPC has to be elucidated in future studies.

[Epstein-Barr virus-associated lymphoproliferations and lymphomas]. / Epstein-Barr-Virus-assoziierte Lymphoproliferationen und Lymphome.

Epstein-Barr virus (EBV) is a lymphotropic herpesvirus infecting > 95 % of the worldwide population. In case of an immunodeficiency of various causes, the virus may lead to the development of a wide spectrum of lymphoproliferations and lymphomas. This encompasses mononucleosis-like lymphoproliferations, hyperplasias of various B-cell subsets as well as aggressive non-Hodgkin lymphomas and classical Hodgkin lymphoma. These lesions occur frequently extranodal and present with a polymorphous histology with angioinvasion and necrosis. Clinical data combined with the immunohistological detection of CD30 expression in the activated infected cells and the demonstration of EBV-encoded proteins and RNA transcripts are helpful for achieving precise classification of these lesions.

Predictive molecular pathology and its role in targeted cancer therapy: a review focussing on clinical relevance.

The increasing importance of targeting drugs in the treatment of several tumor entities (breast, colon, lung, malignant melanoma (MM), lymphoma, and so on) and the necessity of a companion diagnostic (human epidermal growth factor receptor 2, Kirsten rat sarcoma viral oncogene, epidermal growth factor receptor (EGFR), v-raf murine sarcoma viral oncogene homolog B1 (BRAF), and so on) is leading to new challenges for surgical pathology. As all the biomarkers to be specifically detected are tissue based, a precise and reliable diagnostic is absolutely crucial. To meet this challenge, surgical pathology has adapted a number of molecular methods (semi-quantitative immunohistochemistry, fluorescence in situ hybridization), PCR and its multiple variants, (pyro/Sanger) sequencing, next-generation sequencing, DNA-arrays, methylation analyses, and so on) to be applicable for formalin-fixed paraffin-embedded (FFPE) tissue. To read a patients' tissue as 'deeply' as possible and to obtain information on morphological, genetic, proteomic as well as epigenetic background is the actual task of pathologists and molecular biologists in order to provide the clinicians with information relevant for individualized medicine. The intensified cooperation of clinicians and pathologists will provide the basis of improved clinical drug selection as well as guide development of new cancer gene therapies and molecularly targeted drugs by research units and the pharmaceutical industry. This review will give some information on (1) biomarker detection methods adapted to FFPE tissue, (2) the potency of predictive pathology in tumor detection and treatment and (3) the implications of pathology on the development of new drugs in molecularly targeted and gene therapies.

Diagnosis of chronic disseminated candidosis from liver biopsies by a novel PCR in patients with haematological malignancies.

Hepatic Candida infection (HCI; known as chronic disseminated candidosis or CDC) is a distinct form of disseminated Candida infection with predominant involvement of the liver. Diagnosis of HCI is usually made on clinical suspicion together with multiple lesions in liver on ultrasound (US), CT and/or MRI scan. Fungal elements may not always be visible in liver tissue and mycological culture is frequently negative, making the evidence for proven fungal disease difficult. We studied a novel commercially available low-cost and density-array (LCD) chip technique for a molecular diagnosis of HCI. This is a two-step procedure with PCR amplification after DNA extraction followed by hybridization on a small chip provided by the manufacturer (Fungi 2.1, Chipron GmbH). The analysis of DNA from 45 fungal control strains showed an excellent specificity and sensitivity. The DNA from 11 liver biopsies of patients with haematological malignancies suffering from CDC was analysed on the LCD chip and overall 11 fungal pathogens could be detected in eight liver biopsies, supporting the clinical diagnosis of HCI/CDC. Analysis of liver biopsies from controls was negative for fungal DNA in all samples studied. In conclusion, the novel LCD chip technique examined in our study was able to detect fungal pathogens in liver biopsies from patients with haematological malignancies and suspected HCI/CDC but was negative in control biopsies.

High-level expression of Mastermind-like 2 contributes to aberrant activation of the NOTCH signaling pathway in human lymphomas.

Inappropriate activation of the NOTCH signaling pathway, for example, by activating mutations, contributes to the pathogenesis of various human malignancies. Here, we demonstrate that aberrant expression of an essential NOTCH coactivator of the Mastermind-like (MAML) family provides an alternative mechanism to activate NOTCH signaling in human lymphoma cells. We detected high-level MAML2 expression in several B cell-derived lymphoma types, including classical Hodgkin lymphoma (cHL) cells, relative to normal B cells. Inhibition of MAML-protein activity by a dominant negative form of MAML or by small hairpin RNAs targeting MAML2 in cHL cells resulted in downregulation of the NOTCH target genes HES7 and HEY1, which we identified as overexpressed in cHL cells, and in reduced proliferation. Furthermore, a NOTCH gene-expression signature in cHL cells confirmed their cell-autonomous NOTCH activity. Finally, in line with the essential role of MAML proteins for assembly and activity of the NOTCH transcriptional complex (NTC), we show that MAML-derived small-peptide constructs block NOTCH activity and disrupt NTC formation in vitro. These data strongly suggest direct targeting of the NTC as treatment strategy for NOTCH-dependent malignancies.

Allogeneic gene-modified tumor cells (RCC-26/IL-7/CD80) as a vaccine in patients with metastatic renal cell cancer: a clinical phase-I study.

Despite novel targeted agents, prognosis of metastatic renal cell cancer (RCC) remains poor, and experimental therapeutic strategies are warranted. Transfection of tumor cells with co-stimulatory molecules and/or cytokines is able to increase immunogenicity. Therefore, in our clinical study, 10 human leukocyte antigen (HLA)-A(*)0201(+) patients with histologically-confirmed progressive metastatic clear cell RCC were immunized repetitively over 22 weeks with 2.5-40 × 10(6) interleukin (IL)-7/CD80 cotransfected allogeneic HLA-A(*)0201(+) tumor cells (RCC26/IL-7/CD80). Endpoints of the study were feasibility, safety, immunological and clinical responses. Vaccination was feasible and safe. In all, 50% of the patients showed stable disease throughout the study; the median time to progression was 18 weeks. However, vaccination with allogeneic RCC26/IL-7/CD80 tumor cells was not able to induce TH1-polarized immune responses. A TH2 cytokine profile with increasing amounts of antigen-specific IL-10 secretion was observed in most of the responding patients. Interferon-γ secretion by patient lymphocytes upon antigen-specific and non-specific stimulation was substantially impaired, both before and during vaccination, as compared with healthy controls. This is possibly due to profound tumor-induced immunosuppression, which may prevent induction of antitumor immune responses by the gene-modified vaccine. Vaccination in minimal residual disease with concurrent depletion of regulatory cells might be one strategy to overcome this limitation.

[Female patient with Muir-Torre syndrome]. / Patientin mit Muir-Torre-Syndrom.

Muir-Torre syndrome is a rare form of genodermatosis characterized by sebaceous tumours or keratocanthoma and early occurrence of intestinal malignancies. In addition to the patient history immunohistochemical and genetic analysis for microsatellite instability and reduced expression of the mismatch repair gene MSH2 and MLH1 can be used to confirm the diagnosis. Because of this important association, Muir-Torre syndrome should be excluded if a patient presents with a sebaceous tumour.

[Classification and pathogenesis of malignant lymphomas]. / Klassifikation und Pathogenese der malignen Lymphome.

The classification of malignant lymphomas according to the WHO scheme of 2001 is based on modern knowledge of B- and T-cell differentiation, the immunophenotype and genetic alterations of the neoplastic cells, as well as on clinical features. Conventional histology does not suffice for a reliable diagnosis of lymphoma diseases and the application of additional methods is required. Immunophenotyping by means of immunohistochemistry is indicated in practically all instances. In a number of cases, the analysis of clonality by PCR and cytogenetic alterations by FISH also need to be applied. A high risk cause of B-cell lymphomagenesis involves rearrangements at the immunoglobulin locus and events occurring during the germinal centre reaction (somatic mutations and immunoglobulin heavy chain class switch) which may result in molecular accidents in the form of chromosomal translocations and/or gain or loss of functional mutations. This may disrupt B-cell homeostasis resulting in increased proliferation, inhibition of apoptosis or both. Clinical behaviour may be influenced by the microenvironment, e.g. T-cells, cytokines and pathogenic microorganisms.

Different T-bet expression patterns characterize particular reactive lymphoid tissue lesions.

AIMS: To investigate T-bet expression profiles in various lymphoid tissue diseases caused by intracellular pathogens and to compare them in disorders without an infective aetiology. Murine and in vitro experiments have shown that the expression/induction of T-bet, the master regulator of Th1 differentiation, can be achieved by obligate intracellular pathogens and high interferon (IFN)-gamma levels. METHODS: Lymph node biopsies were analysed immunohistochemically employing single and double labelling for T-bet and CD20, CD4, CD8 and CD30 detection. RESULTS: In disorders associated with high IFN-gamma levels and intracellular pathogens (infectious mononucleosis, HIV-associated lymphadenopathy, cat-scratch disease, and toxoplasmic lymphadenitis), T-bet-expressing CD4 cells were accompanied by significant numbers of T-bet-positive CD8 and B cells. A similar profile was also found in histiocytic necrotizing (Kikuchi) lymphadenitis, a disease of unknown cause. In contrast, T-bet expression in disorders without an infective aetiology was observed in only a small portion of lymphocytes. CONCLUSIONS: Increased T-bet expression does not only identify intracellular infections in lymphoid tissue associated with high IFN-gamma levels, but also implies that, under these conditions, it becomes induced in B cells, which apparently support the Th1 response. T-bet expression in Kikuchi lymphadenitis underscores the hypothesis that it is caused by an intracellular microorganism.