Expression of neuroendocrine markers in undifferentiated carcinomas of the gastrointestinal tract

The role of 68-Ga-DOTATOC CT-PET in surgical tactic for gastric neuroendocrine tumors treatment: our experience: a case report

Gastric neuroendocrine tumors (g-NETs), which originate from gastric enterochromaffin-like (ECL) mucosal cells and account for 2.4% of all carcinoids, are increasingly recognized due to expanding indications of upper gastrointestinal endoscopy. Often silent and benign, g-NETs may however, be aggressive and sometimes they mimic the course of gastric adenocarcinoma. Current nosography distinguishes those occurring in chronic conditions with hypergastrinemia, as the type 1 associated with chronic atrophic gastritis, and the type 2 associated with Zollinger-Ellison syndrome in MEN1. Conversely, type 3 and 4 (according to some authors) are unrelated to hypergastrinemia and are frequently malignant, with a propension to develop distant metastases. While there is a general agreement concerning the treatment of malignant gastric neuroendocrine tumors, for types 1 and 2, current possibilities include surveillance, endoscopic polypectomy, surgical excision, associated or not with surgical antrectomy, or total gastrectomy. This report, based on our clinical experience, discusses how the size, number, depth, histological grading, staging with CT, MRI, and the use of recently developed somatostatin receptor tracers (68Ga-DOTATATE, 68Ga-DOTA-TOC) could allow the correct identification of a benign or malignant propensity of an individual tumor, thus avoiding underestimation or overtreatment of these uncommon neoplasms.

[Neuroendocrine neoplasms of the appendix and colorectum]

Appropriate diagnosis and treatment of neuroendocrine neoplasms (NENs) of the appendix and colorectum requires a detailed knowledge of their proper classification according to the updated WHO and TNM systems. The WHO classification distinguishes well differentiated NEN, the neuroendocrine tumors (G1 and G2 NETs), from the poorly differentiated carcinomas (G3 NECs). While NETs are common in the appendix and rectum, NECs occur predominantly in the colon. G1 appendiceal and rectal NETs of 1 cm in size or below that do not invade either the muscular wall or vessels bear almost no metastatic risk and can be treated by appendectomy or endoscopic resection. G2 appendiceal and rectal NETs larger than 1 cm in size in combination with other risk factors have an increased risk of metastasis and need to be treated more aggressively. NECs of the colon usually require chemotherapy in addition to resection. Today, most patients with NETs of the appendix and rectum have an excellent prognosis when these diagnostic and therapeutic guidelines are borne in mind.

Neuroendocrine tumors of the small bowels are on the rise: Early aspects and management

Neuroendocrine tumors of the small bowel are on the rise. In the US they have increased by 300%-500% in the last 35 years. At the same time their prognosis is much improved. Today, most neuroendocrine tumors (NETs) of the duodenum are detected "incidentally" and therefore recognized at an early stage. Duodenal NETs which are well differentiated, not larger than 10 mm and limited to the mucosa/submucosa can be endoscopically resected. The management of duodenal NETs ranging between 10 and 20 mm needs an interdisciplinary discussion. Endoscopic ultrasound is the method of choice to determine tumor size and depth of infiltration. Surgery is recommended for well-differentiated duodenal NET tumors greater than 20 mm, for localized sporadic gastrinomas (of any size) and for localized poorly differentiated NE cancers. Surgery is recommended for any ileal NET. Advanced ileal NETs with a carcinoid syndrome are treated with long-acting somatostatin analogs. This treatment significantly improves (progression-free) survival in patients with metastatic NETs of the ileum. For optimal NET management, tumor biology, type, localization and stage of the neoplasm, as well as the patient's individual circumstances have to be taken into account.

PC-3 prostate carcinoma cells release signal substances that influence the migratory activity of cells in the tumor's microenvironment

Background

Tumor cells interact with the cells of the microenvironment not only by cell-cell-contacts but also by the release of signal substances. These substances are known to induce tumor vascularization, especially under hypoxic conditions, but are also supposed to provoke other processes such as tumor innervation and inflammatory conditions. Inflammation is mediated by two organ systems, the neuroendocrine system and the immune system. Therefore, we investigated the influence of substances released by PC-3 human prostate carcinoma cells on SH-SY5Y neuroblastoma cells as well as neutrophil granulocytes and cytotoxic T lymphocytes, especially with regard to their migratory activity.

Results

PC-3 cells express several cytokines and growth factors including vascular endothelial growth factors, fibroblast growth factors, interleukins and neurotrophic factors. SH-SY5Y cells are impaired in their migratory activity by PC-3 cell culture supernatant, but orientate chemotactically towards the source. Neutrophil granulocytes increase their locomotory activity only in response to cell culture supernantant of hypoxic but not of normoxic PC-3 cells. In contrast, cytotoxic T lymphocytes do not change their migratory activity in response to either culture supernatant, but increase their cytotoxicity, whereas supernatant of normoxic PC-3 cells leads to a stronger increase than that of hypoxic PC-3 cells.

Conclusions

PC-3 cells release several signal substances that influence the behavior of the cells in the tumor's microenvironment, whereas no clear pattern towards proinflammatory or immunosuppressive conditions can be seen.

Neuroendocrine carcinoma of unknown primary site

Neuroendocrine carcinomas of unknown primary site are uncommon, diverse tumors with variable clinical behavior, predicted by tumor grade or differentiation. Most of these carcinomas probably arise from an occult/clinically undetectable primary site in one of several locations (bronchus, pancreas, stomach, colon, rectum and several other sites). Patients with these tumors are a subset of unknown primary carcinoma with relatively favorable prognoses. Low-grade or well-differentiated tumors are frequently indolent and cases should be managed similar to advanced carcinoid tumors. Targeted therapies may have a role in the treatment of low-grade tumors. The high-grade or poorly differentiated carcinomas, including small cell and large cell neuroendocrine tumors, are rapidly growing and aggressive but responsive to platinum-based combination chemotherapy. Poorly differentiated large cell neuroendocrine tumors, first reported in 1988, are usually not recognized by routine hematoxylin and eosin light microscopy but require immunohistochemical stains or electron microscopy for their diagnosis. A review of cytotoxic chemotherapy for patients with high-grade neuroendocrine carcinomas, including a series of 99 patients, revealed an overall response rate of 70%, with a 20% complete response rate. The median survival was 15 months, and a minority of patients (13%) had long-term survival. Tumor grade/differentiation currently is an important determinant of the management of these patients, and therapy in the future will be based on a more precise knowledge of the unique biology of these tumors.

A ubiquitous membrane fusion protein αSNAP: a potential therapeutic target for cancer, diabetes and neurological disorders?

Alpha soluble NSF attachment protein (alphaSNAP) is a ubiquitous and indispensable component of membrane fusion machinery. Deletion of alphaSNAP is embryonically lethal. Yet, there is accumulating evidence that milder alterations in expression levels of alphaSNAP may be associated with a number of specific pathological conditions, such as several neurological disorders, Type 2 diabetes and aggressive neuroendocrine tumours. Here, the authors review the evidence available for animal models and for humans, and discuss possible therapeutic approaches that may target alphaSNAP.