mTOR inhibitors response and mTOR pathway in pancreatic neuroendocrine tumors

Medical therapy of pancreatic neuroendocrine tumors (P-NET) may take advantage of Everolimus treatment. However, the extent of therapeutic response cannot be predicted. This study was aimed to identify the possible predictive markers of response to Everolimus in P-NET. We found that Everolimus reduced the cell viability and induced apoptosis in primary cultures of 6 P-NET (P-NET-R), where the proliferative and antiapoptotic effects of IGF1 were blocked by Everolimus. On the contrary, 14 P-NET primary cultures (P-NET-NR) were resistant to Everolimus and IGF1, suggesting an involvement of PI3K/AKT/mTOR pathway in the mechanism of resistance. The response to Everolimus in vitro was associated with an active AKT/mTOR pathway and seemed to be associated with a greater clinical aggressiveness. In addition, a patient sensitive to Everolimus in vitro was sensitive to this drug in vivo also and showed a positive p-AKT immunohistochemistry (IHC) at tissue level. Similarly, a patient resistant to Everolimus treatment after surgery was not sensitive to the drug in vitro and had a negative p-AKT IHC staining. Therefore, present data confirm that P-NET primary cultures may be considered a model for testing medical treatment efficacy and that IHC characterization of p-AKT might help in identifying human P-NET who can benefit from Everolimus treatment. These data encourage conducting a prospective multicenter study involving different groups of P-NET patients treated with Everolimus.

PTEN alterations of the stromal cells characterise an aggressive subpopulation of pancreatic cancer with enhanced metastatic potential

BACKGROUND

Neoplastic stroma is believed to influence tumour progression. Here, we examine phosphatase and tensin homolog deleted on chromosome ten (PTEN) status in the tumour microenvironment of pancreatic ductal adenocarcinoma (PDAC) focussing especially at the stromal cells.

METHODS

We asses PTEN at protein, messenger RNA and DNA level using a well-characterised PDAC cohort (n = 117). miR-21, known to target PTEN, is assessed after RNA extraction from different laser-capture-microdissected cell populations, including cancer cells and juxta-tumoural and tumour-remote stroma.

RESULTS

PTEN deletion was the most frequent cause of PTEN protein loss in PDAC cells (71%) and correlated with vascular invasion (p = 0.0176) and decreased overall survival (p = 0.0127). Concomitant PTEN protein loss in tumour and juxta-tumoural stroma, found in 21.4% of PDACs, correlated with increased distant metastasis (p = 0.0045). Stromal cells with PTEN protein loss frequently showed PTEN genetic aberrations, including hemizygous PTEN deletion (46.6%) or chromosome 10 monosomy (40%). No alterations were found in the tumour-remote stroma. miR-21 was overexpressed by cancer- and juxta-tumoural stromal cells, in some cases without simultaneous PTEN gene alterations. No PTEN mutations or promoter methylation were detected.

CONCLUSIONS

We find various mechanisms of PTEN protein loss in the different tumour cell populations, including allelic PTEN deletions, gross chromosomal 10 aberrations and altered miR-21 expression. PTEN deletion is a major cause of PTEN protein loss in PDAC and correlates with aggressive characteristics and worse outcome. PTEN protein loss in juxta-tumoural stromal cells is mostly due to PTEN haplo-insufficiency and characterises a subgroup of PDACs with enhanced metastatic potential. In the tumour microenvironment of the invasive front, PTEN silencing by miR-21 in cancer and surrounding stromal cells acts not only cooperatively but also independently of the genetic aberrations to precipitate PTEN protein loss and promote further tumour growth.

New Genetics and Genomic Data on Pancreatic Neuroendocrine Tumors: Implications for Diagnosis, Treatment, and Targeted Therapies

The recent findings on the roles of death-associated protein 6/α-thalassemia/mental retardation X-linked (DAXX/ATRX) in the development of pancreatic neuroendocrine tumors (PanNETs) have led to major advances in the molecular understanding of these rare tumors and open up completely new therapeutic windows. This overview aims at giving a simplified view on these findings and their possible therapeutic implications. The importance of epigenetic changes in PanNET is also underlined by recent findings of a cross-species study on microRNA (miRNA) and messenger RNA (mRNA) profiles in PanNETs.

CK19 and CD99 Immunoexpression Profile in Goblet Cell (Mucin-Producing Neuroendocrine Tumors) and Classical Carcinoids of the Vermiform Appendix

The immunoexpression of CK19 recently has been identified as a marker of poor prognosis in pancreatic endocrine tumors and hepatocellular carcinoma. Conversely, the loss of expression of CD99 has been suggested to play a role in the tumorigenesis and dedifferentiation and is associated with poor outcome in some malignancies. The purpose of this study was to explore CK19 and CD99 immunostaining in mucin-producing neuroendocrine (goblet cell) and classical carcinoids of the appendix. Eighteen goblet cell carcinoids (GCCs) and 20 classic carcinoids were stained with CK19, CD99, and Ki-67, and these results were correlated with known pathological features of aggression: extent of invasion, mitoses, necrosis, and histological pattern. All 18 GCCs were CK19 strongly positive, whereas 16/20 classic carcinoids were also CK19 positive. Fourteen of 18 GCCs and 14/20 classic carcinoids were CD99 positive. CK19/CD99 immunoexpression did not correlate with extent of tumor invasion and mesoappendiceal extension, mitotic activity, Ki-67 labeling index, presence of extracellular mucinous pools dissecting muscle, and angiolymphatic and perineural/neural invasion. There is no difference in the immunostaining for CK19 and CD99 between GCCs and classic carcinoids, and both types of neuroendocrine tumor show the same extent of expression of both markers.

Successful Medical Treatment of Adult Nesidioblastosis With Pasireotide over 3 Years: A Case Report

Nesidioblastosis is a rare cause of endogenous hyperinsulinemic hypoglycemia in adults. Diagnosis is often challenging and therapeutic options are scarce.In 2009, a 46-year-old female patient presented with recurrent severe hypoglycemia and immediate recovery after glucose ingestion. Although 72-h-fasting test was positive, various imaging technologies (sonography, computed tomography, somatostatin receptor scintigraphy, dopamine receptor positron emission tomography [DOPA-PET]) were negative. Endoscopic ultrasound revealed a lesion in the pancreatic corpus, whereas selective arterial calcium stimulation test, portal venous sampling and GLP-1-receptor scintigraphy were indicative of a lesion in the pancreatic tail, which was surgically removed. The histopathologic examination revealed beta cell hyperplasia and microadenomas expressing glucagon. After surgery, the patient was free of symptoms for 6 months, after which hypoglycemic episodes recurred. After unsuccessful treatment with corticosteroids and somatostatin analogs, treatment with pasireotide, a novel somatostatin analog with high affinity to somatostatin receptor 5 and a possible side effect of hyperglycemia, was initiated (0.6 mg BID). To date, our patient has been free of severe hypoglycemic episodes ever since. Yearly repeated imaging procedures have shown no abnormities over the last 3 years.We report for the first time that pasireotide was successfully used in the treatment of adult nesidioblastosis.

Diagnosis and interdisciplinary treatment of a botryoid odontogenic cyst in the posterior mandible: report of a case

Botryoid odontogenic cysts (BOC) are considered to be rare polycystic variants of lateral periodontal cysts characterized by a multilocular growth pattern. The most frequent location of BOC is the mandible, predominantly the premolar-canine area, followed by the anterior region of the maxilla. The cyst shows a slight female predilection. This case report of a BOC demonstrates a treatment with initial fenestration and decompression of the cyst in order to prevent damage to adjacent structures such as the inferior alveolar nerve. The present case report emphasizes the importance of accurate clinical, radiographic, and histologic diagnostic procedures of unspecific radiolucent lesions in the jaws to establish a firm diagnosis and avoid inappropriate treatment strategies.

Histopathology of NET: Current concepts and new developments

The diagnosis of neuroendocrine tumors is based on their histopathologic appearance and immunohistochemical profile. With the WHO 2010 classification formal staging and grading was introduced for gastro-entero-pancreatic NET, however, the nomenclature for lung neuroendocrine tumors still relies on the carcinoid term. In this review we also focus on the situation of neuroendocrine carcinoma of unknown primary, tissue biomarkers and actual controversies in the histopathology of NEN.

Physical restraint in the ICU: does it prevent device removal?

BACKGROUND

Physical restraint is frequently used in the intensive care setting but little is known regarding its clinical scenario and effectiveness in preventing adverse events (AEs), defined as device removal.

METHODS

We carried out a prospective observational study in three Intensive Care Units on 120 adult high-risk patients. The effectiveness of physical restraint was evaluated using the propensity score methodology in order to obtain comparable groups.

RESULTS

Physical restraint was applied in 1371 of 3256 (43%) nurse shifts accounting for 120 patients. Substantial agitation, the nurse's judgement of insufficient sedation and sedative drug reduction were positively associated with physical restraint, whereas the presence of analgesics at admission, increased disease gravity and the treating hospital as the most substantial variable showed a negative association. Eighty-six AEs were observed in 44 patients. Quiet (SAS=1-4), unrestrained patients accounted for 40 cases, and agitated (SAS≥5) but physically restrained patients for 17 cases. The presence of any type of physical restraint had a protective effect against any type of AE (OR=0.28; CI 0.16-0.51). The observed AEs showed a limited impact on the patients' course of illness. No physical harm related to physical restraint was reported.

CONCLUSION

Physical restraint efficiently averts AEs. Its application is mainly driven by local habits. Typically, the almost recovered, apparently calm and hence unrestrained patient is at greatest risk for undesirable device removal. The control/interpretation of the patient's analgo-sedation might be inappropriate.

Construction of a business model to assure financial sustainability of biobanks

Biobank-suisse (BBS) is a collaborative network of biobanks in Switzerland. Since 2005, the network has worked with biobank managers towards a Swiss biobanking platform that harmonizes structures and procedures. The work with biobank managers has shown that long-term, sustainable financing is difficult to obtain. In this report, three typical biobank business models are identified and their characteristics analyzed. Five forces analysis was used to understand the competitive environment of biobanks. Data provided by OECD was used for financial estimations. The model was constructed using the business model canvas tool. The business models identified feature financing influenced by the economic situation and the research budgets in a given country. Overall, the competitive environment for biobanks is positive. The bargaining power with the buyer is negative since price setting and demand prediction is difficult. In Switzerland, the healthcare industry collects approximately 5600 U.S. dollars per person and year. If each Swiss citizen paid 0.1% (or 5 U.S. dollars) of this amount to Swiss biobanks, 45 million U.S. dollars could be collected. This compares to the approximately 10 million U.S. dollars made available for cohort studies, longitudinal studies, and pathology biobanks through science funding. With the same approach, Germany, the United States, Canada, France, and the United Kingdom could collect 361, 2634, 154, 264, and 221 million U.S. dollars, respectively. In Switzerland and in other countries, an annual fee less than 5 U.S. dollars per person is sufficient to provide biobanks with sustainable financing. This inspired us to construct a business model that not only includes the academic and industrial research sectors as customer segment, but also includes the population. The revenues would be collected as fees by the healthcare system. In Italy and Germany, a small share of healthcare spending is already used to finance selected clinical trials. The legal frameworks could serve as templates for the business model proposed here.

Abstract 447: Tumor microenvironment in pancreatic cancer (PDAC): interplay between tumor cells, stromal cells and immune cells

Introduction: Tumor budding is considered to be the morphologic correlate of epithelial-mesenchymal-transition (EMT) and is an independent prognostic factor in pancreatic ductal adenocarcinoma (PDAC). Here we explore the interactions between tumor budding cells, stromal cells and immune cells in the microenvironment of the tumor buds in PDAC.

Methods: Multi-punch tissue-microarrays (TMAs) containing punches from the tumor center and the tumor front, including tumor buds, from a well characterized cohort of 120 PDAC patients, were stained immunohistochemically and by mRNA-in-situ-Hybridization (mRNA-ISH)for the EMT markers E-cadherin, β-catenin, Snail, ZEB1, ZEB2, N-cadherin and Twist and for the immune cell markers CD8, CD4, Foxp3, M1- and M2-macrophages. Expression in budding- and stromal cells and immune-cell counts in the microenvironment of the tumor buds were compared with findings in the main tumor.

Results: Tumor buds showed loss of E-cadherin and b-catenin and overexpressed ZEB1 and ZEB2 compared with the neoplastic cells of the main tumor both at protein and mRNA level (p<0.0001 respectively). Stromal cells surrounding tumor buds showed increased protein and mRNA levels of the transcription factors Snail, ZEB1 and ZEB2. The immune microenvironment of the tumor buds composed of numerous Foxp3+cells and M1-macrophages while M2-macrophages were significantly reduced and CD8+cells were almost absent, in contrast to the main tumor.

Conclusions: Tumor budding cells show a shift towards EMT-promoting profiles at protein and mRNA level, compared with the neoplastic cells of the main tumor. Stromal cells surrounding tumor buds express high levels of Snail, ZEB1 and ZEB2 suggesting that some stromal cells may represent complete mesenchymally transformed tumor cells or alternatively that there is a special phenotype of cancer associated fibroblasts supporting EMT-Type tumor-budding through cellular crosstalk in the tumor microenvironment of PDAC. Moreover, there is a tumor favoring immune cell composition in the immediate microenvironment of the tumor buds. Our findings suggest a close interaction of the stromal and immune response with the EMT process in PDAC. The combined assessment of host-associated factors such as stromal and immune response and tumor-associated factors such as EMT-type tumor-budding could help us to achieve superior prognostication and patient stratification than either factor alone.

Citation Format: Eva Karamitopoulou, Martin Wartenberg, José A. Galván, Inti Zlobec, Alessandro Lugli, Aurel Perren. Tumor microenvironment in pancreatic cancer (PDAC): interplay between tumor cells, stromal cells and immune cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 447. doi:10.1158/1538-7445.AM2015-447

Tall cell papillary thyroid carcinoma: new diagnostic criteria and mutations in BRAF and TERT

The tall cell (TC) variant of papillary thyroid carcinoma (PTC) has an unfavorable prognosis. The diagnostic criteria remain inconsistent, and the role of a minor TC component is unclear. Molecular diagnostic markers are not available; however, there are two potential candidates: BRAF V600E and telomerase reverse transcriptase (TERT) promoter mutations. Using a novel approach, we enriched a collective with PTCs that harbored an adverse outcome, which overcame the limited statistical power of most studies. This enabled us to review 125 PTC patients, 57 of which had an adverse outcome. The proportion of TCs that constituted a poor prognosis was assessed. All of the tumors underwent sequencing for TERT promoter and BRAF V600E mutational status and were stained with an antibody to detect the BRAF V600E mutation. A 10% cutoff for TCs was significantly associated with advanced tumor stage and lymph node metastasis. Multivariate analysis showed that TCs above 10% were the only significant factor for overall, tumor-specific, and relapse-free survival. Seven percent of the cases had a TERT promoter mutation, whereas 61% demonstrated a BRAF mutation. The presence of TC was significantly associated with TERT promoter and BRAF mutations. TERT predicted highly significant tumor relapse (P<0.001). PTCs comprised of at least 10% TCs are associated with an adverse clinical outcome and should be reported accordingly. BRAF did not influence patient outcome. Nevertheless, a positive status should encourage the search for TCs. TERT promoter mutations are a strong predictor of tumor relapse, but their role as a surrogate marker for TCs is limited.

Pulmonary neuroendocrine (carcinoid) tumors: European Neuroendocrine Tumor Society expert consensus and recommendations for best practice for typical and atypical pulmonary carcinoids

BACKGROUND

Pulmonary carcinoids (PCs) are rare tumors. As there is a paucity of randomized studies, this expert consensus document represents an initiative by the European Neuroendocrine Tumor Society to provide guidance on their management.

PATIENTS AND METHODS

Bibliographical searches were carried out in PubMed for the terms 'pulmonary neuroendocrine tumors', 'bronchial neuroendocrine tumors', 'bronchial carcinoid tumors', 'pulmonary carcinoid', 'pulmonary typical/atypical carcinoid', and 'pulmonary carcinoid and diagnosis/treatment/epidemiology/prognosis'. A systematic review of the relevant literature was carried out, followed by expert review.

RESULTS

PCs are well-differentiated neuroendocrine tumors and include low- and intermediate-grade malignant tumors, i.e. typical (TC) and atypical carcinoid (AC), respectively. Contrast CT scan is the diagnostic gold standard for PCs, but pathology examination is mandatory for their correct classification. Somatostatin receptor imaging may visualize nearly 80% of the primary tumors and is most sensitive for metastatic disease. Plasma chromogranin A can be increased in PCs. Surgery is the treatment of choice for PCs with the aim of removing the tumor and preserving as much lung tissue as possible. Resection of metastases should be considered whenever possible with curative intent. Somatostatin analogs are the first-line treatment of carcinoid syndrome and may be considered as first-line systemic antiproliferative treatment in unresectable PCs, particularly of low-grade TC and AC. Locoregional or radiotargeted therapies should be considered for metastatic disease. Systemic chemotherapy is used for progressive PCs, although cytotoxic regimens have demonstrated limited effects with etoposide and platinum combination the most commonly used, however, temozolomide has shown most clinical benefit.

CONCLUSIONS

PCs are complex tumors which require a multidisciplinary approach and long-term follow-up.

Novel prognostic markers revealed by a proteomic approach separating benign from malignant insulinomas

The prognosis of pancreatic neuroendocrine tumors is related to size, histology and proliferation rate. However, this stratification needs to be refined further. We conducted a proteome study on insulinomas, a well-defined pancreatic neuroendocrine tumor entity, in order to identify proteins that can be used as biomarkers for malignancy. Based on a long follow-up, insulinomas were divided into those with metastases (malignant) and those without (benign). Microdissected cells from six benign and six malignant insulinomas were subjected to a procedure combining fluorescence dye saturation labeling with high-resolution two-dimensional gel electrophoresis. Differentially expressed proteins were identified using nano liquid chromatography-electrospray ionization/multi-stage mass spectrometry and validated by immunohistochemistry on tissue microarrays containing 62 insulinomas. Sixteen differentially regulated proteins were identified among 3000 protein spots. Immunohistochemical validation revealed that aldehyde dehydrogenase 1A1 and voltage-dependent anion-selective channel protein 1 showed significantly stronger expression in malignant insulinomas than in benign insulinomas, whereas tumor protein D52 (TPD52) binding protein was expressed less strongly in malignant insulinomas than in benign insulinomas. Using multivariate analysis, low TPD52 expression was identified as a strong independent prognostic factor for both recurrence-free and overall disease-related survival.