Endocrine tumours of the hindgut

Clinicopathological hallmarks and biomarkers of colorectal neuroendocrine neoplasms

Chromogranin A (CgA) is a well-established marker for diagnosis and follow up of patients with gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN). Recently, it has been shown that plasma levels of CgA correlate with tumor load and predict survival of patients with NEN of the small bowel. It is assumed that this is as well valid for NEN of the colon and rectum, however, this is not supported by data. To evaluate this assumption, we analyzed 62 patients with NEN of the colon and rectum listed in the Marburg GEP-NEN registry for clinicopathological characteristics, expression and plasma levels of CgA. The present study demonstrates that immunohistochemical CgA and synaptophysin are good markers for histological diagnosis in patients with NEN of the colon and rectum. However, plasma CgA is a poor marker to follow-up these patients because only a minority exhibited increased levels which did not increase significantly during tumor progression. In contrast to NEN of the small bowel, there is no correlation of CgA plasma levels with tumor burden or survival. Patients with NEN of the colon and rectum displayed a relatively good prognosis resulting in a median survival of 8.5 years. However, a subset of patients affected by G3 neoplasms, exhibited a poorer prognosis with a median survival of 2.5 years. Taken together, CgA is a valuable marker for immunohistochemical diagnosis, but CgA plasma concentration is not suitable to mirror tumor burden or prognosis in patients with NEN of the colon and rectum.

Low BIN3 Expression is an Independent Predictor of Unfavorable Survival in Patients With Primary Colorectal Cancer

This study aimed to explore the mechanisms of bridging integrator-3 dysregulation, its prognostic value, and related signaling pathways in colorectal cancer . Bioinformatic analysis was performed based on the data from The Cancer Genome Atlas–colorectal cancer and Human Protein Atlas. Colorectal cancer cell lines, LoVo and HT29 cells, were used as in vitro cell model to assess the effect of demethylation on bridging integrator-3 expression. Results showed that bridging integrator-3 was downregulated in colorectal cancer tissues compared to normal colon and rectum tissues. Heatmap of bridging integrator-3 messenger RNA expression, exon expression, and DNA methylation indicated a negative correlation between bridging integrator-3 expression and methylation of some CpG sites within the coding sequence. Demethylation treatment significantly increased bridging integrator-3 expression in LoVo and HT29 cells. Low bridging integrator-3 messenger RNA and exon expression were associated with significantly worse overall survival (P = .015 and .013, respectively). Multivariate analysis confirmed that low bridging integrator-3 messenger RNA expression was an independent prognostic factor of unfavorable overall survival (Hazard Ratio (HR) = 1.596, 95% confidence interval: 1.024-2.486; P = .039). High bridging integrator-3 DNA methylation was also associated with significantly worse overall survival (P = .013). Kyoto Encyclopedia of Genes and Genomes analysis indicated that the genes correlated with bridging integrator-3 (absolute Pearson r ≥ 0.3, n = 121) were enriched in sphingolipid signaling pathway, natural killer cell-mediated cytotoxicity, p53 signaling pathway, and apoptosis. Based on these findings, we infer that DNA hypermethylation might be an important mechanism of suppressed bridging integrator-3 expression in colorectal cancer . Its low expression is an independent predictor of unfavorable survival in patients with primary colorectal cancer . Bridging integrator-3 might act as a tumor suppressor via modulating natural killer cell-mediated cytotoxicity, p53 signaling pathway, and apoptosis.

Rectal neuroendocrine neoplasms: a case report

The gastrointestinal neuroendocrine neoplasms (GI-NENs) are very rare, among which second most common type is the rectal NENs in China. Patients with rectal NENs may experience non-specific symptoms such as pain, perianal bulge, anemia, and bloody stools, and surgery is considered as the first treatment for rectal NENs. We report a case of rectal NENs in a 68-year-old male patient with bloody stools, who received surgery and postoperative pathology revealed an elevated well-differentiated neuroendocrine carcinoma.

Metastatic rectal neuroendocrine tumor presenting as an inguinal mass: A case report and review of literature

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Neuroendocrine tumors (NETs) are a heterogeneous and relatively rare group of neoplasms that often develop along the gastrointestinal tract.

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Rectal NETs are usually incidental findings on colonoscopy or present with metastatic disease.

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Treatment regimens for advanced metastatic rectal NETs are currently being developed.

Introduction

Neuroendocrine tumors (NET) are a heterogeneous group of rare carcinomas that most often manifest along the gastrointestinal tract. Some of these tumors have the ability to secrete vasoactive peptides and hormones.

Presentation of case

The present report describes the case of a previously healthy 52-year old man who presented with a painful right inguinal mass. Upon surgical exploration, a lymph node metastasis of a high-grade NET was found. Further investigations revealed a rectal NET with pulmonary, pelvic and penile metastases.

The patient was treated with 6 cycles of carboplatin and etoposide. Although initial follow-up imaging after 3 cycles of chemotherapy revealed stable disease, there was progression of the metastases after completion of systemic treatment. Second and third-line chemotherapy regimens were instituted along with pelvic and whole-brain radiation therapy extending the patient’s survival to 18 months after the initial diagnosis.

Discussion

This case highlights the aggressive nature high-grade NETs as described in the current literature. Treatment modalities of colorectal NETs include local excision for non-metastatic disease and systemic palliative chemotherapy for advanced disease. However, there are no controlled trials in favor of palliative chemotherapy.

Conclusion

Rectal NETs are rare tumors which often have an atypical presentation or present in advanced stages. Currently, surgical options exist for local disease while treatment modalities for more advanced disease is still under investigation.

The clinical implications and biologic relevance of neurofilament expression in gastroenteropancreatic neuroendocrine neoplasms

BACKGROUND

Although gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) exhibit widely divergent behavior, limited biologic information (apart from Ki-67) is available to characterize malignancy. Therefore, the identification of alternative biomarkers is a key unmet need. Given the role of internexin alpha (INA) in neuronal development, the authors assessed its function in neuroendocrine cell systems and the clinical implications of its expression as a GEP-NEN biomarker.

METHODS

Functional assays were undertaken to investigate the mechanistic role of INA in the pancreatic BON cell line. Expression levels of INA were investigated in 50 pancreatic NENs (43 primaries, 7 metastases), 43 small intestinal NENs (25 primaries, 18 metastases), normal pancreas (n = 10), small intestinal mucosa (n = 16), normal enterochromaffin (EC) cells (n = 9), mouse xenografts (n = 4) and NEN cell lines (n = 6) using quantitative polymerase chain reaction, Western blot, and immunostaining analyses.

RESULTS

In BON cells, decreased levels of INA messenger RNA and protein were associated with the inhibition of both proliferation and mitogen-activated protein kinase (MAPK) signaling. INA was not expressed in normal neuroendocrine cells but was overexpressed (from 2-fold to 42-fold) in NEN cell lines and murine xenografts. In pancreatic NENs, INA was overexpressed compared with pancreatic adenocarcinomas and normal pancreas (27-fold [P = .0001], and 9-fold [P = .02], respectively). INA transcripts were correlated positively with Ki-67 (correlation coefficient [r] = 0.5; P < .0001) and chromogranin A (r = 0.59; P < .0001). INA distinguished between primary tumors and metastases (P = .02), and its expression was correlated with tumor size, infiltration, and grade (P < .05).

CONCLUSIONS

INA is a novel NEN biomarker, and its expression was associated with MAPK signaling and proliferation. In clinical samples, elevated INA was correlated with Ki-67 and identified malignancy. INA may provide additional biologic information relevant to delineation of both pancreatic NEN tumor phenotypes and clinical behavior.

Diagnosis and treatment of colorectal carcinoid tumors with endoscopy: an analysis of 51 cases

AIM: To study endoscopic diagnosis and management of colorectal carcinoid tumors.

METHODS: Fifty one patients were certified by colonoscopy and pathology during April 1986 to August 2008. Morphologic characteristics, trans-endoscopic treatment and prognosis were documented for further analysis.

RESULTS: Male patients significantly outnumbered female patients with a ratio of 1.83. The average age was 53.0 ± 13.2 years. The most frequent occurrence location was rectum with almost 86.3 percents. Most carcinoid tumors, about 74.5%, were smaller than 1.0 cm in diameter. The classic characters were submucosal tumor with yellow color and rigid or tough texture, and always were lack of activities. There was metastasis of tumor when it was bigger than 2.0 cm, and there was no recurrence for smaller ones (≤ 1.0 cm) after EMR. Six patients had undergone endoscopic ultrasonic examination and it was very helpful for EMR.

CONCLUSION: Understanding the endoscopic characters of colorectal carcinoid tumors was helpful for correct diagnosis. Deep biopsy and EMR can help improve the correct diagnosis rate. EMR is safe and effective for carcinoid tumors with a diameter less than 1.0 cm.

Colonic crypt organization and tumorigenesis

An appreciation of colonic crypt organization has become essential to any understanding of tumorigenesis in the colon. Intestinal crypts house tissue-specific, multipotential stem cells, which are located in the niche at the base of the intestinal crypt and are capable of regenerating all intestinal cell types. Recent advances in our understanding of crypt biology, including how mutations in stem cells become fixed and expand within the epithelium, has led to new theories on the origins of colonic adenomas and cancers.

Anatomic and functional imaging of metastatic carcinoid tumors

Carcinoid tumors are a fascinating group of neuroendocrine neoplasms that develop either sporadically or as part of an inheritable syndrome. Many tumors arise in the bronchopulmonary or gastrointestinal tract, but a neuroendocrine tumor can arise in almost any organ. The tumors have varied malignant potential depending on the site of their origin, and the clinical manifestations often are nonspecific. Metastases may be present at the time of diagnosis, which often occurs at a late stage of the disease. Imaging plays a pivotal role in the localization and staging of neuroendocrine tumors and in monitoring the treatment response. Imaging is often challenging, and a combination of anatomic and functional techniques is usually required, depending on the tumor type and location. Techniques include ultrasonography, barium studies, endoscopy, computed tomography, magnetic resonance imaging, somatostatin receptor scintigraphy, iobenguane scintigraphy, and, in select cases, positron emission tomography. Coregistration of structural and functional images is often of incremental value for accurate localization of the primary tumor and any meta-static disease. Radiologists must understand the contribution of each imaging modality in the assessment of different neuroendocrine tumors. In addition, knowledge of the optimal technique for each radiologic and radionuclide imaging examination is essential. Familiarity with the protean imaging appearances of both primary and metastatic disease is essential for accurate staging, treatment monitoring, and surveillance. Finally, an understanding of the wide variety of treatment options for patients with carcinoid tumors is vital for optimal management.

Surgery on neuroendocrine tumours

Neuroendocrine tumours of the gastrointestinal tract and pancreas present a major challenge to physicians in their recognition and treatment requirements, and surgical treatment of these tumours has become increasingly important for symptom palliation and survival. For some carcinoid tumours the extent of surgery may depend on tumour size. Midgut carcinoid is the most common cause of the carcinoid syndrome, requiring surgery for primary and mesenteric tumours to minimize the risk for abdominal complications but also for removal of liver metastases to palliate hormonal symptoms. Among endocrine pancreatic tumours, insulinoma and gastrinoma often cause severe symptoms of hormone excess despite their inconspicuous size, but they can be successfully removed with improved pre- and intraoperative localization. Other tumours--glucagonoma, VIPoma, and non-functioning endocrine pancreatic tumours--are often large or metastasizing, but generally require surgical debulking to alleviate hormonal symptoms and have favourable survival.