[Neuroendocrine neoplasms of the breast]. / Neuroendokrine Neoplasien der Mamma.

Neuroendocrine neoplasms (NEN) of the breast are specific tumor entities. According to the literature up to 5% of breast neoplasms are malignant epithelial neoplasms of the breast. They are defined by a neuroendocrine (NE) architecture and cytology combined with an expression of the neuroendocrine vesicle markers chromogranin A and/or synaptophysin. The diagnosis is supplemented by the receptor status and the proliferative activity. According to the World Health Organization (WHO) classification of 2012 the following groups of NEN are distinguished: (1) invasive breast carcinoma with NE differentiation, (2) well-differentiated neuroendocrine tumor (NET) and (3) poorly differentiated small cell carcinoma (NEC). This review article focuses on (1) the definition and basic principles of diagnostics, (2) the history, nomenclature and WHO classification from 2003 and 2012, (3) the frequency of breast NEN, (4) the hereditary background and functional activity, (5) the expression of receptors and (6) the possible clinical implications. In addition, the first results of a retrospective single center study (n = 465 patients with breast cancer over a time period of 4 years) on the frequency of NEN of the breast at the Breast Center of the University Hospital Düsseldorf are presented. In this study a frequency of 4.5% of NEN was found based on a diagnostic cut-off of > 50% Chromogranin A and/or synaptophysin positive tumor cells.

[Neuroendocrine neoplasms of the distal jejunum and ileum]. / Neuroendokrine Neoplasien des distalen Jejunums und Ileums.

Neuroendocrine neoplasms (NEN) of the distal jejunum and ileum derive from serotonin-producing enterochromaffin (EC) cells. Due to their low proliferation rate and their infiltrative growth, they are often discovered at an advanced disease stage when metastasis has already occurred. The biology of these tumours is different from other NEN of the digestive tract. In order to standardise and improve diagnosis and therapy, the guidelines for the diagnosis and clinical management of jejuno-ileal NEN as well as for the management of patients with liver and other distant metastases from NEN were revised by the European Neuroendocrine Tumour Society (ENETS) in 2012. This review focuses on aspects relevant for surgical pathology.

[Neuroendocrine tumours of the GI tract--data from the German NET Registry]. / Neuroendokrine Tumoren des Verdauungstrakts - Daten des deutschen NET-Registers.

BACKGROUND: Neuroendocrine tumours (NET) are rare and heterogeneous neoplasia. To obtain valid data on epidemiology, diagnostics, therapy, prognosis and risk factors is the aim of the German NET registry. PATIENTS AND METHODS: Data from 2009 histologically proven NET were collected from 35 NET centres between 1999 and 2010. Data collection has been performed prospectively since 2004. Results: Median follow-up was 34.5 months and median age at diagnosis 56.4 years. Primary tumour localisations were pancreas (34.2%), midgut (5.8%), stomach (6.5%), bowel (6.9%), duodenum (4.8%) and neuroendocrine CUP (12.6%). Synchronous metastases were seen in 46% and second malignancies in 12%. From 860 patients, 402 (46.7%) had functional tumours with the following hormone excess syndromes: carcinoid syndrome (19.1%; n = 164), persistent hyperinsulinaemic hypoglycaemia (17.7%; n = 152), Zollinger- Ellison syndrome (7.1%; n = 61), glucagonoma (0.7%; n = 15), Verner-Morrison syndrome (0.4%; n = 8) and somatostatinoma syndrome(0.1%; n = 2). Surgical therapy was performed in 78%, therapy with somatostatin receptor analogues(SSA) in 28%, peptide radioreceptor therapy (PRRT) in 19%, chemotherapy in 18% and interferon therapy in 6.5%. Only surgery was done in 47%, whereas 53% received a second therapy. General mortality rate during follow-up was 14.9%. The tumour-specific survival rates for 2, 5 and 10 years were 94, 85 and 70%. The 5-year survival is dependent on the surgical or non-surgical therapy (82 versus 61%, p < 0.001) and also on the primary tumour site (90/30% for midgut, 85/65% for pancreas, p < 0.001). Grading (G1, G2, G3) based on proliferation index Ki-67 recommended by the ENETS guidelines and WHO classification is highly correlated to the 5-year survival rate (88, 82, 33%, p < 0.001). CONCLUSION: The German NET registry provides valid multicentric data on NET in Germany. Surgical therapy is the most frequent and important therapy with good clinical outcome. In non-resectable, metastatic tumours, systemic therapies are common. Continuation and evaluation of the new WHO and TNM classifications for NET and their therapies will be a future focus of the registry.

Encapsulation status of papillary thyroid microcarcinomas is associated with the risk of lymph node metastases and tumor multifocality.

The management of papillary microcarcinoma (PMC) of the thyroid is controversial, especially after partial thyroid resection for benign thyroid disease. In order to detect prognostic factors for PMC, we analyzed 116 patients with PMC for encapsulation status and lymph node metastases. Between 10/1992 and 12/2010, 116 patients with PMC have been operated in our department (87 females, 29 males, median age 49 years). Eighty per cent of PMCs were diagnosed postoperatively. Seventy-six patients (66%) received a more extended resection with either thyroidectomy, near total thyroidectomy, or Dunhill operation either primarily or after completion operation, whereas 40 patients (34%) had only partial resection. Fifty patients (43%) received radioiodine (RIA) ablation. Lymph node metastases were found in 21 patients (18%). Univariate analysis showed four risk factors to be significantly associated with the risk of lymph node metastasis (p<0.05): male gender, younger age, age group<50 years and nonencapsulation of the tumor. Multivariate analysis demonstrated statistical significance for gender and tumor capsulation status. The tumor capsulation status also correlated with tumor multifocality. Our data show that the risk of lymph node metastases is significantly higher in partially or nonencapsulated PMC than in encapsulated specimens. We therefore suggest that the WHO classification should be extended to a compulsory notification of the encapsulation status in PMC.

Secondary malignancy in patients with sporadic neuroendocrine neoplasia.

The incidence of neuroendocrine neoplasias (NENs), especially of the gastro-entero-pancreatic (GEP), system relatively increased over the past decades, as a result of advanced diagnostic tools, a better clinical awareness, and distinguished pathological diagnostic recognition. Previous reports hypothesized an increased risk for secondary malignancies in patients with NEN especially in GEP-NENs. The present study was designed to investigate the coincidence of NENs and secondary malignancies in a large patient collective. A retrospective analysis was performed on 161 patients (85 female and 76 male) with NEN of various origins. Clinical data of these patients, different classification systems (TNM/WHO), proliferations-based grading, and clinical follow-up were collected and analyzed. Out of 143 patients with a sporadic NEN, 15 (10.49 %) patients were identified with secondary malignant tumors. Median age at the time of the primary operation for NEN was 65 years, whereas the median age of initial diagnosis of associated tumors was 59 years. Mean follow-up time was 61 months. The risk of developing a secondary malignancy was most elevated for patients with an NEN of the lung, the stomach, and the ileum (60, 50 and 20 %, respectively). The spectrum of secondary malignancies included various types of cancer. Kaplan-Meier survival analysis shows a difference suggesting that patients with a secondary malignancy demonstrate a worse survival compared to patients without a secondary tumor; no significance was detected (p = 0.349). Our data suggest that secondary malignancies in patients with NEN's especially in GEP-NENs are found more frequently than in general population. Therefore, patients with NEN need a continuous and detailed follow-up. The reason for the increased incidence of secondary malignancies in patients with NENs remains to be elucidated.

Species-specific vesicular monoamine transporter 2 (VMAT2) expression in mammalian pancreatic beta cells: implications for optimising radioligand-based human beta cell mass (BCM) imaging in animal models.

AIMS/HYPOTHESIS: Imaging of beta cell mass (BCM) is a major challenge in diabetes research. The vesicular monoamine transporter 2 (VMAT2) is abundantly expressed in human beta cells. Radiolabelled analogues of tetrabenazine (TBZ; a low-molecular-weight, cell-permeant VMAT2-selective ligand) have been employed for pancreatic islet imaging in humans. Since reports on TBZ-based VMAT2 imaging in rodent pancreas have been fraught with confusion, we compared VMAT2 gene expression patterns in the mouse, rat, pig and human pancreas, to identify appropriate animal models with which to further validate and optimise TBZ imaging in humans. METHODS: We used a panel of highly sensitive VMAT2 antibodies developed against equivalently antigenic regions of the transporter from each species in combination with immunostaining for insulin and species-specific in situ hybridisation probes. Individual pancreatic islets were obtained by laser-capture microdissection and subjected to analysis of mRNA expression of VMAT2. RESULTS: The VMAT2 protein was not expressed in beta cells in the adult pancreas of common mouse or rat laboratory strains, in contrast to its expression in beta cells (but not other pancreatic endocrine cell types) in the pancreas of pigs and humans. VMAT2- and tyrosine hydroxylase co-positive (catecholaminergic) innervation was less abundant in humans than in rodents. VMAT2-positive mast cells were identified in the pancreas of all species. CONCLUSIONS/INTERPRETATION: Primates and pigs are suitable models for TBZ imaging of beta cells. Rodents, because of a complete lack of VMAT2 expression in the endocrine pancreas, are a 'null' model for assessing interference with BCM measurements by VMAT2-positive mast cells and sympathetic innervation in the pancreas.

Neuroendocrine neoplasms of the gastroenteropancreatic system: pathology and classification.

Neuroendocrine neoplasms (NEN) appear homogeneous in terms of morphology, but constitute a very heterogeneous group of tumors in terms of biological and clinical features. NEN may occur in any organ, but are most commonly observed in the lung and the gastroenteropancreatic system (GEP). The European Neuroendocrine Tumor Society (ENETS) developed guidelines in the last 5 years to standardize and improve the diagnosis and therapy of GEP-NEN. Taking these guidelines into account, the TNM classification of the Union for International Cancer Control (UICC) was introduced in 2009. The new GEP-NEN classification of the World Health Organization (WHO) was presented 1 year later. According to the guidelines of the ENETS, the UICC, and the WHO, the pathology classification of NEN of GEP consists of several basic components: (1) evidence of the neuroendocrine nature of the tumor, (2) histological distinction between well and poorly differentiated tumors, (3) proliferation-based grading. (4) TNM staging (including data about vascular invasion and resection margins), (5) with reference to the clinical question: evidence of hormones and biogenic amines, and (6) optional, especially in cases of initial diagnosis of NEN: expression of the somatostatin receptor type 2A. Based on these criteria, a standardized prognostic stratification of GEP-NEN can be performed in combination with other clinical parameters. The novel classifications constitute the basis for selecting the procedures of molecular and metabolic imaging as well as for tumor-specific treatments and permit comparisons of larger tumor populations. Close interdisciplinary cooperation is a prerequisite.

Global histone modification pattern predicts poor prognosis in organic hyperinsulinism.

Here we tested whether global histone modifications predict survival in organic hyperinsulinism and whether global histone modification pattern can be used to distinguish benign from malignant primary insulinoma. A tissue microarray (TMA) was built, using samples from 63 patients with organic hyperinsulinism. The TMA was classified according to the WHO classification of 2004 [WHO 1A: benign insulinoma (wdPET); WHO 1B: unknown behavior (wdPETub); WHO 2/3: malignant insulinoma (wdPEC/pdPEC)]. The TMA consisted of tissue cores from islands of Langerhans, primary insulinomas, lymph node metastases, and hepatic metastases. Immunohistochemistry was performed on consecutive TMA slides with antibodies against H3K9Ac, H3K18Ac, H4K12Ac, H3K4diMe, and H4R3diMe. The Remmele immunoreactive scoring system was used to classify the staining. The IHC staining results were correlated to the WHO-classification of 2004 as well as to clinical follow-up data (mean: 107 months; range: 1-312 months). A nuclear staining pattern was observed for all antibodies directed against histone H3 and H4 acetylation/methylation sites. We observed significant differences in the distribution of the medians across all investigated tissue types (H3K9Ac, p=0.004; H3K18Ac, p=0.001; H4K12Ac, p=0.006; H4R3diMe, p=0.002) except for H3K4diMe (p=0.183). Correlation of the histone modification with the WHO-classification and clinical follow-up data, showed in the dichotomized groups ["low" (score 0-3), "moderate" (4-7) vs. "high" (≥8)] that patients with lower H3K18Ac levels ("low + moderate") had a significantly decreased relapse-free survival vs. patients with high H3K18Ac levels (p=0.038). The WHO classification and age were also of significant prognostic impact upon univariate analysis. A backwards Cox proportional hazards model revealed the independent prognostic effekt of H3K18Ac levels. Our data revealed low K18 acetylation levels of histone H3 as independent prognostic factor in organic hyperinsulinism. This result warrants validation with independent data sets of organic hyperinsulinism, but is in line with several previous studies in different cancer entities. The broad applicability of this potential biomarker might lead to standardized diagnostic tests in near future and may help to manage insulinoma patients more effectively.

Loss of PTEN expression in neuroendocrine pancreatic tumors.

PTEN (phosphatase and tensin homologue deleted from chromosome 10) is a well established tumor suppressor gene, which was cloned to chromosome 10q23. PTEN plays an important role in controlling cell growth, apoptosis, cell adhesion, and cell migration. In various studies, a genetic change as well as loss of PTEN expression by different carcinomas has been described. To date, the role of PTEN as a differentiation marker for neuroendocrine tumors (NET) and for the loss of PTEN expression is still unknown. It is assumed that loss of PTEN expression is important for tumor progression of NETs. We hypothesize that PTEN might be used as a new prognostic marker. We report 38 patients with a NET of the pancreas. Tumor tissues were surgically resected, fixed in formalin, and embedded in paraffin. PTEN expression was evaluated by immunohistochemistry and was correlated with several clinical and pathological parameters of each individual tumor. After evaluation of our immunohistochemistry data using a modified Remmele Score, a widely accepted method for categorizing staining results for reports and statistical evaluation, staining results of PTEN expression were correlated with the clinical and pathological parameters of each individual tumor. Our data demonstrates a significant difference in survival with existence of lymph node or distant metastases. Negative patients show a significant better survival compared with positive patients. Furthermore, we show a significant difference between PTEN expression and WHO or TNM classification. Taken together, our data shows a positive correlation between WHO classification and the new TNM classification of NETs, and loss of PTEN expression as well as survival. These results strongly implicate that PTEN might be helpful as a new prognostic factor.

Coincidence of mature cystic teratoma and serotonin-producing neuroendocrine tumor of the ileum.

Mature cystic teratomas are often found in gonadal sites, but are very rarely located extragonadally, for example, in retroperitoneum, mediastinum, central nervous system, lung, or liver. In the literature, only 10 cases of cystic teratoma originating from the diaphragm have been reported. Here, we report for the first time a metachronous occurrence of a benign mature cystic teratoma in the left diaphragm together with a serotonin-producing neuroendocrine tumor of the ileum. The 51-year-old, female patient received a partial resection of the ileum due to a neuroendocrine tumor (pT3N1M0) 4 years ago. Furthermore, she was operated for a benign cystadenoma of the right ovary 3 years ago. In her past medical history, she had an appendectomy in her childhood and a subtotal thyroidectomy 10 years ago. To our knowledge, this is the first report describing the metachronous occurrence of benign mature cystic teratoma in the diaphragm and a highly differentiated neuroendocrine tumor of the ileum. The possible coincidence of both diseases is discussed.

The immune system in neuroendocrine tumors.

During the last 30 years the incidence of neuroendocrine tumors has increased considerably and the overall 5-year survival rate has not changed substantially. Conventional therapeutic approaches appear to show an unsatisfactory effect in the more insidious forms of malignancies. Hence, attempts were made to direct the patient's own immune system against cancer by vaccinating against different tumor antigens. Up to date, only sporadic achievements were demonstrated in the majority cases of vaccination trials. One of the main hindrances to a successful vaccination comprises tumor-immune-escape mechanisms. This review focuses on the current knowledge concerning tumor immunoevasion strategies and the immune system in neuroendocrine tumors.

[Diagnostics and treatment in functional pancreatic neuroendocrine tumours]. / Diagnostik und Therapie bei funktionell aktiven pankreatischen neuroendokrinen Tumoren.

Pancreatic neuroendocrine tumours (PNET) are rare entities with an annual incidence of < 100,000. About 1 - 2 % of pancreatic neoplasias are neuroendocrine tumours. About one third of these tumours secrete biologically active substances that lead to development of specific clinical syndromes. PNET may occur sporadically or in association with hereditary syndromes, such as multiple endocrine neoplasia type 1 (MEN1). Among the functional PNET, insulinomas and gastrinomas are the most common entities. In contrast, vasoactive intetinale peptide (VIP)-secreting tumours, glucagonomas, serotonin-secreting carcinoid tumors, and tumours with secretion of ectopic hormones, such as calcitonin, are extremely rare. Once diagnosis has been established on the basis of clinical and laboratory findings, localization of the source of pathologic hormone secretion is warranted. Imaging methods frequently used for localization of PNET comprise anatomical imaging modalities, computed tomography, and magnetic resonance imaging, endoscopic ultrasound, selective arterial catheterization with hepatic venous sampling, DTPA-octreotid scintigraphy and DOTA-D-Phe(1)-Tyr(3)-octreotid positron emission tomography. Therapy is based on the specific tumour entity and the extent of the disease. In the majority of patients, even in the case of malignant disease, a surgical approach is warranted, eventually combined with a medical treatment.

[Pathology of neuroendocrine neoplasms]. / Pathologie neuroendokriner Neoplasien.

During the last 5 years the European Neuroendocrine Tumor Society (ENETS) has developed basic recommendations for a standardized pathological diagnosis and classification of neuroendocrine neoplasms (NEN) of the gastroenteropancreatic system. These were included in the novel classification of tumors of the digestive system by the World Health Organization (WHO 2010) and the TNM classification of the union for international cancer control (2009). This review presents the pathology diagnosis regarding (1) basic diagnosis, (2) clinically relevant optional diagnosis, (3) proliferation-based grading, (4) nomenclature and (5) TNM classification. It is emphasized that a standardized diagnosis of NEN, together with clinical and radiological findings, is crucial for prognostic stratification and optimal therapy of patients with NEN. Therefore a close interdisciplinary collaboration is essential.

A new mutation in the menin gene causes the multiple endocrine neoplasia type 1 syndrome with adrenocortical carcinoma.

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant tumor syndrome that may be caused by mutations in the MEN1 gene on 11q13. Loss of function of the tumor suppressor gene MEN1 leads to synchronous or metachronous appearance of neuroendocrine tumors arising from neuroendocrine cells of the parathyroid and pituitary glands, the duodenum and pancreatic islets, and other endocrine organs such as the adrenal cortex. We here present a patient with MEN1 who developed hyperparathyroidism, multiple well differentiated functionally inactive neuroendocrine tumors of the pancreas and an adrenal carcinoma. We describe a new mutation at codon 443 in the coding region of exon 9 in the MEN1 gene, where a cytosine residue was exchanged for adenosine (TCC > TAC) and, consequently, serine for tyrosine (p.Ser443Tyr; c.1328C > A). [corrected] Also, we provide clinical data that may add to the genotype-phenotype discussion. We conclude that the novel mutation in the MEN1 gene described herein was clinically relevant.

6-18F-fluoro-L-dihydroxyphenylalanine positron emission tomography is superior to 123I-metaiodobenzyl-guanidine scintigraphy in the detection of extraadrenal and hereditary pheochromocytomas and paragangliomas: correlation with vesicular monoamine transporter expression.

CONTEXT: Pheochromocytomas (PHEOs) and paragangliomas (PGLs) may be better detected by (18)F-fluorodihydroxyphenylalanine-positron emission tomography (FDOPA-PET) than (123)I-metaiodobenzyl-guanidine (123-I-MIBG) scintigraphy. OBJECTIVE: The objective of the study was to correlate functional imaging results with immunohistochemical, molecular-genetic, and biochemical findings. DESIGN AND SETTING: Thirty consecutive patients with suspected PHEO/PGL presenting at a tertiary referral centre were investigated in a prospective study. PATIENTS: Twenty-five patients had confirmed PHEO/PGL. Thirteen of 25 patients had a hereditary PHEO/PGL syndrome (two multiple endocrine neoplasia II, six succinate dehydrogenase complex, subunit D, two succinate dehydrogenase complex, subunit B, one von Hippel Lindau tumor suppressor protein, two Neurofibromatosis-1), and 12 of 25 were classified as sporadic. Five patients had hormonally inactive adrenal incidentalomas. MAIN OUTCOME MEASURES: In all patients computed tomography scan and/or magnetic resonance imaging as well as both 123-I-MIBG scintigraphy and FDOPA-PET were performed. Resected tumors were examined by immunohistochemistry for expression of the vesicular monoamine transporter (VMAT)-1 and -2 and other markers. RESULTS: A total of 64 lesions were found with both functional imaging modalities. FDOPA-PET detected 62 lesions, whereas only 34 lesions were detected by 123-I-MIBG scintigraphy. This resulted in an overall sensitivity and specificity for FDOPA-PET of 98 and 100% and for MIBG of 53 and 91%, respectively. Comparable sensitivities were found for adrenal and extraadrenal abdominal lesions (94 vs. 97%), whereas in thoracic/cervical lesions, the sensitivity for 123-I-MIBG scintigraphy (15%) was inferior to that of FDOPA-PET imaging (100%). Immunohistochemistry demonstrated a lack of VMAT-1 expression in all MIBG-negative tumors. Clinical predictors for MIBG negativity were a predominant norepinephrine/normetanephrine secretion, an age less than 45 yr, and a hereditary cause. CONCLUSION: FDOPA-PET is superior to 123-I-MIBG scintigraphy in patients with extraadrenal, predominantly noradrenaline-secreting, and hereditary types of PHEO/PGL. The lack of VMAT-1 expression predicts negativity for MIBG-scintigraphy.

In vivo molecular imaging of somatostatin receptors in pancreatic islet cells and neuroendocrine tumors by miniaturized confocal laser-scanning fluorescence microscopy.

The aim of the study was to evaluate real time in vivo molecular imaging of somatostatin receptors (sstrs) using a handheld miniaturized confocal laser scan microscope (CLM) in conjunction with fluorescein-labeled octreotate (OcF) in healthy mice and murine models of neuroendocrine tumors. For CLM a small rigid probe (diameter 7 mm) with an integrated single line laser (488 nm) was used (optical slice thickness 7 mum; lateral resolution 0.7 mum). OcF was synthesized via Fmoc solid-phase peptide synthesis and purified by HPLC showing high-affinity binding to the sstr2 (IC(50) 6.2 nmol). For in vitro evaluation, rat and human pancreatic cancer cells were used and characterized with respect to its sstr subtype expression and functional properties. For in vivo confocal imaging, healthy mouse pancreatic islet and renal tubular cells as well as immunoincompetent nude mice harboring sstr-expressing tumors were evaluated. Incubation of sstr-positive cells with OcF showed a specific time- and dose-dependent staining of sstr-positive cells. CLM showed rapid internalization and homogenous cytoplasmatic distribution. After systemic application to mice (n = 8), specific time-dependent internalization and cytoplasmatic distribution into pancreatic islet cells and tubular cells of the renal cortex was recorded. After injection in tumor-harboring nude mice (n = 8), sstr-positive cells selectively displayed a cell surface and cytoplasmatic staining. CLM-targeted biopsies detected sstr-positive tumor cells with a sensitivity of 87.5% and a specificity of 100% as correlated with ex vivo immunohistochemistry. CLM with OcF permits real-time molecular, functional, and morphological imaging of sstr-expressing cell structures, allowing the specific visualization of pancreatic islet cells and neuroendocrine tumors in vivo.

VHL inactivation is an important pathway for the development of malignant sporadic pancreatic endocrine tumors.

A small subset of familial pancreatic endocrine tumors (PET) arises in patients with von Hippel-Lindau syndrome and these tumors may have an adverse outcome compared to other familial PET. Sporadic PET rarely harbors somatic VHL mutations, but the chromosomal location of the VHL gene is frequently deleted in sporadic PET. A subset of sporadic PET shows active hypoxia signals on mRNA and protein level. To identify the frequency of functionally relevant VHL inactivation in sporadic PET and to examine a possible prognostic significance we correlated epigenetic and genetic VHL alterations with hypoxia signals. VHL mutations were absent in all 37 PETs examined. In 2 out of 35 informative PET (6%) methylation of the VHL promoter region was detected and VHL deletion by fluorescence in situ hybridization was found in 14 out of 79 PET (18%). Hypoxia inducible factor 1alpha (HIF1-alpha), carbonic anhydrase 9 (CA-9), and glucose transporter 1 (GLUT-1) protein was expressed in 19, 27, and 30% of the 152 PETs examined. Protein expression of the HIF1-alpha downstream target CA-9 correlated significantly with the expression of CA-9 RNA (P<0.001), VHL RNA (P<0.05), and VHL deletion (P<0.001) as well as with HIF1-alpha (P<0.005) and GLUT-1 immunohistochemistry (P<0.001). These PET with VHL alterations and signs of hypoxia signalling were characterized by a significantly shortened disease-free survival. We conclude that VHL gene impairment by promoter methylation and VHL deletion in nearly 25% of PET leads to the activation of the HIF-pathway. Our data suggest that VHL inactivation and consecutive hypoxia signals may be a mechanism for the development of sporadic PET with an adverse outcome.

Mast cell reactivity at the margin of human skin wounds: an early cell marker of wound survival?

Detecting the vitality of mechanical skin wounds (antemortem versus postmortem injury) in human cadavers remains a specifically forensic problem. To determine whether skin mast cells (MCs) are activated during the very early phase of human wound healing we performed a histomorphometric evaluation of the extent of MC enzyme loss as an indication of MC degranulation at the wound margins of skin wounds in 64 human cadavers. We compared the number of tryptase-reactive MCs, which are said not to loose all of their enzyme activity during degranulation process, with the number of naphthol AS-D chloroacetate esterase (NAS-DClAE)-positive MCs, which loose their complete enzyme activity in the form of enzyme-positive granula after activation. The enzyme activity was evaluated on sequential histological sections after autopsy as an indirect quantification of the number of degranulated MCs. Most of the victims had died within 10-60 min after injury (n=50), 12 survived between 60 min and 24h, and only 2 victims survived more than 24h (12 days each). The number of enzyme-positive MCs were counted in six successive visual fields (0.785 mm(2)) on the one hand located parallel to and--on the other hand--at increasing distances outward from the wound margins. In victims surviving the injury less than 60 min the average number of NAS-DClAE-reactive MCs next to the wound margin was significantly lower than the number of tryptase-reactive MCs. The extent of the reduction in NAS-DClAE-reactive MC counts correlated inversely with the distance from the wound edges. Our findings show that MCs undergo very early loss of NAS-DClAE activity at wound margins, and thus appear to be an early cell marker of wound survival. However, definitive evidence that the enzyme loss (degranulation) represents a vital process can only be obtained by comparing MC enzyme loss induced by injury during intact circulation with the MC reaction to injury inflicted very shortly after cardiac arrest, a question that can only be answered by animal experiments.