Concordance of genetic alterations in poorly differentiated colorectal neuroendocrine carcinomas and associated adenocarcinomas

Targeted gene sequencing and bioinformatics analysis of patients with gallbladder neuroendocrine carcinoma: A case report

BACKGROUND

Gallbladder neuroendocrine carcinoma (NEC) represents a subtype of gallbladder malignancies characterized by a low incidence, aggressive nature, and poor prognosis. Despite its clinical severity, the genetic alterations, mechanisms, and signaling pathways underlying gallbladder NEC remain unclear.

CASE SUMMARY

This case study presents a rare instance of primary gallbladder NEC in a 73-year-old female patient, who underwent a radical cholecystectomy with hepatic hilar lymphadenectomy and resection of liver segments IV-B and V. Targeted gene sequencing and bioinformatics analysis tools, including STRING, GeneMANIA, Metascape, TRRUST, Sangerbox, cBioPortal and GSCA, were used to analyze the biological functions and features of mutated genes in gallbladder NEC. Twelve mutations (APC, ARID2, IFNA6, KEAP1, RB1, SMAD4, TP53, BTK, GATA1, GNAS, and PRDM3) were identified, and the tumor mutation burden was determined to be 9.52 muts/Mb via targeted gene sequencing. A protein-protein interaction network showed significant interactions among the twelve mutated genes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were used to assess mutation functions and pathways. The results revealed 40 tumor-related pathways. A key regulatory factor for gallbladder NEC-related genes was identified, and its biological functions and features were compared with those of gallbladder carcinoma.

CONCLUSION

Gallbladder NEC requires standardized treatment. Comparisons with other gallbladder carcinomas revealed clinical phenotypes, molecular alterations, functional characteristics, and enriched pathways.

Distinctive Phenotypic and Microenvironmental Characteristics of Neuroendocrine Carcinoma and Adenocarcinoma Components in Gastric Mixed Adenoneuroendocrine Carcinoma

This study aimed to conduct an in-depth examination of gene expression and microenvironmental profiles of gastric neuroendocrine carcinoma (NEC) and mixed adeno-NEC (MANEC). Tissue microarrays from 55 patients with gastric MANEC (N = 32) or NEC (N = 23) were analyzed using digital spatial profiling (GeoMx DSP, NanoString Technologies). Representative regions of interest were selected from the adenocarcinoma (ADC) portion (ADC-MANEC) and the NEC portion (NEC-MANEC) of the MANEC cores, and pure NEC (pNEC) cores. All regions of interest were separated into epithelial components and stromal components using the masking procedure in the GeoMx platform, followed by transcriptome analysis. Comparison of gene expression between ADC-MANEC and NEC-MANEC/pNEC identified several differentially expressed genes in the epithelial (including PEG10, MAP1B, STMN3, and AKT3) and stromal (FN1, COL1A1, SPARC, and BGN) components. Gene set enrichment analysis revealed that pathways related to the E2F target and G2M checkpoint were more enriched in NEC-MANEC and pNEC than in ADC-MANEC. Deconvolution analysis showed that the microenvironmental profile varied according to histologic differentiation. In ADC-MANEC, intraepithelial infiltrating immune cells were relatively more numerous, whereas fibroblasts in the stroma were more abundant in NEC-MANEC and pNEC. This study confirmed the distinct expression profile of each histologic component of MANEC according to its tumor vs stromal compartment using the DSP platform. Although each component of MANEC shares the same genetic origin, distinctive phenotypes should not be overlooked when managing patients with MANEC. This study provides a useful validation data set for future studies.

Triple synchronous malignancies of the stomach, bladder and thyroid in a previously treated prostate cancer patient: A Case Report

Cancers that develop within six months of the first primary cancer are referred to as synchronous malignancies. These malignancies are difficult to diagnose and treat, with treatment primarily based on case reports.

The genetic alterations of rectal neuroendocrine tumor and indications for therapy and prognosis: a systematic review

Neuroendocrine tumors (NETs) are a type of rare tumor that can occur at multiple organs. Rectal NETs are the most common NETs in gastrointestinal tract. Due to the rarity of rectal NETs in rectal cancer, the molecular features and the correlation with patient therapeutic response and prognosis have not been investigated in detail. In this review, we focused on the molecular features, potential therapeutic targets and prognosis of rectal NETs. By summarizing the relevant studies, we established the mutational landscape of rectal NETs and identified a series of large fragment variations. Driver genes including TP53, APC, KRAS, BRAF, RB1, CDKN2A and PTEN were found as the top mutated genes. Large fragment alterations mainly involved known driver genes, including APC, TP53, CCNE1, MYC, TERT, RB1 and ATM. Germline mutations of APC, MUTYH, MSH6, MLH1 and MSH2 associated with Lynch syndrome or FAP were also found in rectal NETs. The BRAF-V600E mutation was reported as an actionable target in rectal NETs, and the combined BRAF/MEK inhibitors were found to be effective targeting BRAF-V600E in advanced or metastatic NETs. The known prognostic risk factors of rectal adenocarcinoma, including a series of demographic and clinicopathological factors were also prognostic factors for rectal NETs. Furthermore, three types of markers, including genetic alterations, protein expression levels and methylation, were also suggested as prognostic factors for rectal NETs. In summary, we established the landscape of mutations and large-fragment alterations of rectal NETs, and identified potential therapeutic targets and a series of prognostic factors. Future studies may focus on the optimization of therapeutic strategies based on potential actionable biomarkers.

Unusual Microsatellite-Instable Mixed Neuroendocrine and Non-neuroendocrine Neoplasm: A Clinicopathological Inspection and Literature Review

BACKGROUND

Mixed neuroendocrine and non-endocrine neoplasms (MiNENs) are challenging to diagnose and manage clinically. The current understanding of MiNENs' pathobiology, molecular mechanisms, and management is incomplete. Though microsatellite instability (MSI) is known to impact carcinogenesis, reports examining MSI mechanisms for MiNENs are rare.

METHODS

We report an unusual colonic MSI-MiNEN uncovered in an 89-year-old woman and the review of the literature.

RESULTS

Pathologic inspection revealed a high-grade carcinoma composed of tumor cells with neuroendocrine histologic traits and immunophenotype intermixed with mucin-containing signet ring-like cells arranged in nested and micronodular patterns. Loss of MLH1 and PMS2 mismatch repair proteins was detected in tumor cells. INSM1 immunostaining highlighted about 50% of the tumour, further reinforcing the MiNEN diagnosis. Next-generation sequencing identified multiple carcinogenic mutations. Because of the advanced stage of the tumor and its adhesion to the adjacent organs, surgical resection was aborted; immunotherapy was initiated. The tumor is in remission 30 months following initiation of treatment, and the patient remains asymptomatic.

CONCLUSION

This unique MSI MiNEN was characterized by its immunohistochemical and molecular signatures and illustrated how correctly diagnosing MSI can strongly improve a patient's outcomes.

Long-term survival of gastric mixed neuroendocrine-non-neuroendocrine neoplasm: Two case reports

BACKGROUND

Gastric mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN), which consists of neuroendocrine and non-neuroendocrine components, is quite rare. Until now, most data on gastric MiNEN come from clinical cases, without large-scale retrospective studies or controlled clinical trials. Consequently, no consensus regarding the origin, molecular characteristics, or appropriate treatment of MiNEN has been reached so far. We conducted chemotherapy of irinotecan plus cisplatin (IP regimen) and surgery in two patients with gastric MiNEN, which had never been used in treating this kind of tumor, leading to their long-term survival for more than 3 and 7 years, respectively.

CASE SUMMARY

We present two patients (one male and one female) with gastric MiNEN, with the primary manifestation of recurrent upper abdominal pain. After they were referred to our hospital, a diagnosis of gastric MiNEN was defined with the help of CT scan, and histopathological and immunohistochemical examinations on the samples of gastrointestinal endoscopy or radical surgery. The male patient (case 1) were found to have metastases in the reginal lymph nodes and the left liver. He received four cycles of IP regimens first, then the gastrectomy and partial left liver resection, followed by additional two cycles of IP chemotherapy. The female patient (case 2) underwent a laparoscopic gastrectomy, and received six cycles of IP regimen. She was found to have metastatic lesions in the right lung 2 years after that, and underwent video-assisted thoracoscopic surgery (VATS) of the lower lobe of the right lung. The two patients have now survived for more than 3 years and 7 years, respectively, without any evidence of recurrence or metastases.

CONCLUSION

IP regimen, combined with curative-intent surgery if feasible, could be considered as the priority in the choice of front-line chemotherapy for gastric MiNEN.

Gastroenteropancreatic grade 3 neuroendocrine tumors: a single entity or a heterogeneous group? A retrospective analysis

PURPOSE

Grade 3 neuroendocrine tumor (NET G3) is a novel pathologic category within gastro-entero-pancreatic (GEP) neuroendocrine neoplasms (NENs) but its clinical behavior and therapeutic management still remain challenging. Prognostic and predictive factors aiding NET G3 management are needed.

PATIENTS AND METHODS

We performed a retrospective analysis from 2015 to 2020 of all patients with > 20% Ki-67, well-differentiated NETs evaluated within our NEN-dedicated multidisciplinary team. We divided the sample according the timing of NET G3 diagnosis, the radiotracers distribution and Ki-67. We analyzed the correlation between these NET G3 features and clinical outcomes.

RESULTS

Among 3238 multidisciplinary discussion reports, we selected 55 patients, 48 from GEP and 7 from an occult GEP origin. In 45 patients, NET G3 diagnosis occurred at the beginning of clinical history (upfront-NET G3), whereas in 10, during the NET G1-G2 clinical history (late-NET G3). Patients with ≤ 30% (34/55) vs. > 30% Ki-67 (21/55) had a better overall survival (OS) (p = 0.042); patients with a homogeneous vs. inhomogeneous/negative ⁶⁸Gallium(⁶⁸Ga)-DOTA-Peptide Positron Emission Tomography (PET)/computed tomography (CT) showed a trend to a better OS, and a significant better progression-free survival (PFS) (p = 0.033). A better OS was observed for negative/inhomogeneous vs. homogeneous 18-fluorodeoxyglucose (¹⁸FDG)-PET/CT (p = 0.027). A trend to a better OS was reported in late- vs. upfront-NET G3, while the latter showed a significantly better response rate (RR) (p = 0.048).

CONCLUSION

Our findings suggested that Ki-67 cutoff, functional imaging and the timing to NET G3 diagnosis may help clinicians in more accurate selection of NET G3 management. Prospective studies are needed.

Update in clinical management for gallbladder neuroendocrine carcinoma

BACKGROUND

Gallbladder neuroendocrine carcinoma (GB-NEC) is rare and there are few reports at present. We sought to review the current knowledge of GB-NEC and provide recommendations for clinical management.

METHODS

A systemic literature research was conducted in the websites of Pubmed, Medline, Web of Science, CNKI, Wanfang Data using the keywords including gallbladder combined with neuroendocrine carcinoma or neuroendocrine tumor or neuroendocrine neoplasm. Two reviewers independently screened the articles by reading the title, abstract and full-text.

RESULTS

In computed tomography (CT) and magnetic resonance imaging (MRI) examination, a well-defined margin, gallbladder replacing type with larger hepatic and lymphatic metastases could be helpful for differential diagnosis of GB-NEC and gallbladder adenocarcinoma (GB-ADC). Older age, unmarried status, large tumor size (>5 cm), positive margins, and distant Surveillance, Epidemiology and End result (SEER) stage are independently associated with poor survival. Surgical resection remains as the preferred and primary treatment. The potential survival benefit of lymphadenectomy for patients remains controversial. Platinum-based postoperative adjuvant chemotherapy may improve the survival. The efficacy of other treatments including immunotherapy, targeted therapy and somatostatin analogue needs further investigation.

CONCLUSION

Typical imaging features could be helpful for preoperative diagnosis. Age, margin status, tumor size, marital status, histopathologic subtype and SEER stage may be independent predictors for the survival. Remarkable advances regarding the treatment for GB-NEC have been achieved in recent years. Further studies are needed to investigate the survival benefit of lymphadenectomy for patients with GB-NEC.

Genomics of High-Grade Neuroendocrine Neoplasms: Well-Differentiated Neuroendocrine Tumor with High-Grade Features (G3 NET) and Neuroendocrine Carcinomas (NEC) of Various Anatomic Sites

High-grade neuroendocrine neoplasms (HG-NENs) are clinically aggressive diseases, the classification of which has recently been redefined. They now include both poorly differentiated NENs (neuroendocrine carcinoma, NECs) and high proliferating well-differentiated NENs (called grade 3 neuroendocrine tumors, G3 NETs, in the digestive system). In the last decade, the "molecular revolution" that has affected all fields of medical oncology has also shed light in the understanding of HG NENs heterogeneity and has provided new diagnostic and therapeutic tools, useful in the management of these malignancies. Considering the kaleidoscopic aspects of HG NENs in various anatomical sites, this review systematically addresses the genomic landscape of such neoplasm throughout the more common thoracic and digestive locations, as well as it will consider other rare but not exceptional primary sites, including the skin, the head and neck, and the urogenital system. The revision of the available literature will then be oriented to understand the translational relevance of molecular data, by analyzing conceptual issues, clinicopathological correlations, and unmet needs in this field.

Incidental morphological findings in colorectal adenomas

Owing to a sharp increase in the frequency of diagnosis of colorectal adenomas in the current era of population screening, distinctive morphological features are increasingly being observed. These may present diagnostic challenges and cause clinical management issues. Paneth cell metaplasia is a more common occurrence, but the incidence rates of squamous metaplasia, clear cell metaplasia, osseous metaplasia, neuroendocrine differentiation and signet‐ring cell‐like lesion are low, and they can be seen in <1% of colorectal adenomas. Their histomorphological characteristics are quite unique; ancillary studies are not very helpful and often not needed. In this review, we give an overview and describe the potential clinical consequences of such incidental and special morphological findings in colorectal adenomas.

Large cell neuroendocrine carcinoma of the colon with brain metastasis: A case report

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Large cell neuroendocrine carcinoma of the colon is rare and aggressive, and its prognosis is very poor.

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Effective treatment of large cell neuroendocrine carcinoma of the colon has not been established.

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If local Large cell neuroendocrine carcinoma is completely resected, the 5-year survival rate has been reported to be 61%.

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Most patients are metastatic and not candidates for curative resection.

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The efficacy of systemic chemotherapy is highest in patients with poorly differentiated neuroendocrine tumors with a combination of cisplatin and etoposide.

Background

Large cell neuroendocrine carcinoma of the colon is rare, and its prognosis is very poor especially when diagnosed at a metastatic stage. Early diagnosis can allow early curative surgery that can increase the survival for more than 5 years.

Case report

We report a 62-year-old man who presented for neurologic signs and symptoms followed by constipation. He was diagnosed with large cell neuroendocrine carcinoma of the colon with brain metastasis. Patient was treated with right hemi colectomy due to obstructive gastro-intestinal symptoms, followed by chemotherapy (cisplatin and etoposide).

Discussion

Because of its rarity, effective treatment of large cell neuroendocrine carcinoma of the colon has not been established. If local large cell neuroendocrine carcinoma is completely resected, the prognosis can be largely influenced, and patients can benefit from a 5-year survival rate of 61% compared to 0% in patients without curative surgery. However, most patients are metastatic and not candidates for curative resection. The efficacy of systemic chemotherapy is highest in patients with poorly differentiated neuroendocrine tumors with a combination of cisplatin and etoposide.

Conclusion

Patient with metastatic large cell neuroendocrine tumor have very poor prognosis with a 1 year survival rate of 10% without curative surgery. Increasing awareness of these types of cancer and their prognosis, may allow better comprehension of the importance of screening to allow early diagnosis and better outcomes. In case of late presentation, palliative surgery is always a must in patients with obstruction, bleeding or perforation.

Comparison of overall survival of gastric neoplasms containing neuroendocrine carcinoma components with gastric adenocarcinoma: a propensity score matching study

BACKGROUND

Gastric neoplasms containing neuroendocrine carcinoma (NEC) components are rare malignancies with highly aggressive behavior and a poor prognosis and include pure NEC and mixed tumors containing NEC components. We aimed to investigate whether there is a distinct difference in overall survival (OS) between gastric neoplasms containing NEC components and gastric adenocarcinoma.

METHODS

Surgically resected gastric neoplasms containing NEC components (n = 180) and gastric adenocarcinomas (n = 785) from January 2013 to December 2019 at Peking University Cancer Hospital were retrospectively analysed. Patients were categorized into a surgical group and a neoadjuvant group and adjusted using propensity score matching. In the two groups, gastric neoplasms containing NEC components were divided into pure NEC and mixed tumors with less than 30% (< 30% G-HMiNEN), between 30 and 70% (G-HMiNEN) and more than 70% (> 70% G-HMiNEN) neuroendocrine carcinoma components. OS was compared between these groups and the gastric adenocarcinoma group.

RESULTS

The OS of gastric neoplasms containing neuroendocrine NEC components was poorer than that of gastric adenocarcinomas in the surgical group, regardless of whether the percentage of neuroendocrine cancer components was less than 30%, between 30 and 70%, more than 70% or 100%. Cox multivariable regression analysis suggested that tumor category (neoplasms containing NEC components or gastric adenocarcinoma) was an independent risk factor for prognosis. Interestingly, among patients receiving neoadjuvant therapy, the difference was not significant.

CONCLUSIONS

Gastric neoplasms containing any proportion of NEC components had poorer overall survival than gastric adenocarcinoma in patients treated with surgery directly, indicating that these neoplasms are more malignant than gastric adenocarcinoma. Among the patients receiving neoadjuvant therapy, the difference in overall survival was not significant, which was in sharp contrast with the results of the surgery group, suggesting that neoadjuvant therapy may have a good effect in the treatment of these neoplasms.

Whole genome sequencing of colorectal neuroendocrine tumors and in-depth mutational analyses

Colorectal neuroendocrine tumors (NETs) are rare neoplasms and studies on colorectal NETs are relatively few compared to other tumors. To better understand the pathogenesis of this tumor, we performed whole-genome sequencing and follow-up verification using Sanger sequencing of the colorectal NETs and paired para-tumor tissue. We analyzed the features of the gene mutation spectrum and mutation signature patterns, and analyzed the four pathways that were altered by gene mutation in pancreatic neuroendocrine tumors, including DNA damage and repair, chromatin remodeling, telomere maintenance and mTOR signaling activation. We found that PARP4 which is related to the DNA damage and repair pathway; TSC2, which is related to the mTOR signaling activation pathway; and SLX1A, which is related to telomere maintenance, were mutated in colorectal NETs. Our data analyzed characteristics of gene mutation in colorectal NETs at the whole-genome level, and may help to better understand the pathogenesis of colorectal NETs and may be helpful for potential tumor therapy in the future.

Successful Treatment of a Mixed Neuroendocrine-Nonneuroendocrine Neoplasm of the Colon with Metastases to the Thyroid Gland and Liver

Patients with mixed neuroendocrine-nonneuroendocrine neoplasms (MiNENs) of the colon have poor prognosis. Herein, we report a patient with MiNEN of the colon with metastases to the liver and the thyroid gland, with long-term survival. A 45-year-old man presented with anterior neck swelling. Histopathological examination of the thyroid tumor revealed neuroendocrine carcinoma (NEC), suggesting that a primary NEC in another organ had metastasized to the thyroid gland. Computed tomography to identify a primary NEC revealed two tumors: one in the liver and one in the transverse colon. A biopsy revealed that the histopathology of the liver and colon tumors was NEC and adenocarcinoma, respectively. Thereafter, the patient underwent surgical resection of the colon tumor and was finally diagnosed as colon MiNEN with metastases to the thyroid and liver. The surgical resection of the metastatic liver tumor was performed after several courses of systemic chemotherapy, and the patient survives presently without any recurrence for approximately seven years after the diagnosis. Surgical resection of each metastatic lesion combined with systematic chemotherapy apparently improved the prognosis of MiNEN of the colon with distant metastases.

Combined Intestinal Adenomas/Microcarcinoids

The combined colonic adenoma/microcarcinoid tumor is a rare intestinal neoplasm featuring intermingled adenomatous and carcinoid components. A few case reports and small case series have suggested that this entity exhibits an indolent clinical course. Here, we report two cases with these tumors, and describe the morphological features and clinical follow-up. A 61-year-old male and 78-year-old male presented with heme-positive stools at their medical checkups. Colonoscopy revealed masses in the colons; we performed endoscopic mucosal resection. Both lesions featured low-grade adenomas and low-grade neuroendocrine tumors. We diagnosed combined colonic adenomas/microcarcinoids. The clinical courses of both patients were benign at follow-up at 2.5 and 6 years. Awareness of this rare colonic tumor should prevent potential diagnostic pitfalls and may help clarify the natural history of these tumors and their possible relationships with composite glandular/carcinoid tumors.

Updates on the Role of Molecular Alterations and NOTCH Signalling in the Development of Neuroendocrine Neoplasms

Neuroendocrine neoplasms (NENs) comprise a heterogeneous group of rare malignancies, mainly originating from hormone-secreting cells, which are widespread in human tissues. The identification of mutations in ATRX/DAXX genes in sporadic NENs, as well as the high burden of mutations scattered throughout the multiple endocrine neoplasia type 1 (MEN-1) gene in both sporadic and inherited syndromes, provided new insights into the molecular biology of tumour development. Other molecular mechanisms, such as the NOTCH signalling pathway, have shown to play an important role in the pathogenesis of NENs. NOTCH receptors are expressed on neuroendocrine cells and generally act as tumour suppressor proteins, but in some contexts can function as oncogenes. The biological heterogeneity of NENs suggests that to fully understand the role and the potential therapeutic implications of gene mutations and NOTCH signalling in NENs, a comprehensive analysis of genetic alterations, NOTCH expression patterns and their potential role across all NEN subtypes is required.

Neuroendocrine neoplasms of gastrointestinal tract and secondary primary synchronous tumors: A systematic review of case reports. Casualty or causality?

BACKGROUND

Neuroendocrine neoplasms (NENs) can arise in most of the epithelial organs of the body and are not a rare condition in the gastrointestinal tract (GIT). The presence of NENs in GIT associated with other secondary primary malignancies (SPM) has been considered an exotic event. This study aims to describe the case reports of NENs accompanied by synchronous primary tumors.

METHODS AND FINDINGS

We performed a systematic literature search of the databases Scopus, PubMed, Scielo and LILACS to identify case reports that described the presence of NENs in GIT with SPM. 78 case reports were included. The mean of age of the cases was 60.2 years. 60% were male. 95.4% were NENs G1. 17 cases of NENs had metastasis. 80% of SPM were recognized in the GIT (36% in stomach, 27% in large intestine, 11.2% in small intestine, and 5.6% in esophagus). The most common type of SPM was adenocarcinoma (49.4%), followed by GIST (13.5%), other NENs in different GIT segment (7.9%), lymphoma (6.8%), and squamous cell carcinoma (4.5%). The most common tumor in GIT was adenocarcinoma (97.6%) and the presence of adenocarcinoma in the same segment of GIT was found in 68.4% of the cases. Association between adenocarcinomas and NENs in GIT (p:<0.0001) and adenocarcinoma and tumor in the same segment of GIT location were observed (p<0.001).

CONCLUSION

These results demonstrate that NENs with SPM are not a rare condition. Several theories have been proposed to explain this association; one of these is the ability of NENs to generate synchronous tumors by autocrine and paracrine effect. We observed an association between adenocarcinomas and NENs in the same segment of GIT.

Mixed Adenocarcinomatous and Neuroendocrine Tumor of the Urinary Bladder With Concomitant Carcinoma In Situ: A Case Report With a Comprehensive Immunohistochemical Analysis and Review of the Literature

Mixed adenoneuroendocrine carcinomas are rare and usually occur in the gastrointestinal tract. Although there have been several investigations regarding their developmental mechanism, the molecular origin of these tumors remains unclear. In this article, we present an exceedingly rare case of a mixed tumor of the urinary bladder with an adenocarcinomatous and a neuroendocrine component and a concomitant urothelial carcinoma in situ (CIS). Due to this extraordinary combination of tumor components, our goal was to extensively examine the 3 tumor components with regard to a representable common origin. Therefore, a comprehensive immunohistochemical analysis and review of the literature was performed. Besides expected outcome, our examination also revealed surprising staining results. Urothelial CIS, like the adenocarcinomatous component, showed strong staining for CDX2. In addition, parts of the adenocarcinoma were positive for synaptophysin like the neuroendocrine tumor component. All 3 components showed a significant overexpression of p53 and a moderate to strong membranous and cytoplasmatic staining for β-catenin. To our knowledge, we are the first to describe a case of a mixed tumor of the urinary bladder with an adenocarcinomatous and a neuroendocrine component and a concomitant CIS. The components share striking molecular features that argue for a common clonal origin and a development of the invasive tumor via the urothelial precursor lesion.

Genetics and Epigenetics of Gastroenteropancreatic Neuroendocrine Neoplasms

Gastroenteropancreatic (GEP) neuroendocrine neoplasms (NENs) are heterogeneous regarding site of origin, biological behavior, and malignant potential. There has been a rapid increase in data publication during the last 10 years, mainly driven by high-throughput studies on pancreatic and small intestinal neuroendocrine tumors (NETs). This review summarizes the present knowledge on genetic and epigenetic alterations. We integrated the available information from each compartment to give a pathway-based overview. This provided a summary of the critical alterations sustaining neoplastic cells. It also highlighted similarities and differences across anatomical locations and points that need further investigation. GEP-NENs include well-differentiated NETs and poorly differentiated neuroendocrine carcinomas (NECs). NENs are graded as G1, G2, or G3 based on mitotic count and/or Ki-67 labeling index, NECs are G3 by definition. The distinction between NETs and NECs is also linked to their genetic background, as TP53 and RB1 inactivation in NECs set them apart from NETs. A large number of genetic and epigenetic alterations have been reported. Recurrent changes have been traced back to a reduced number of core pathways, including DNA damage repair, cell cycle regulation, and phosphatidylinositol 3-kinase/mammalian target of rapamycin signaling. In pancreatic tumors, chromatin remodeling/histone methylation and telomere alteration are also affected. However, also owing to the paucity of disease models, further research is necessary to fully integrate and functionalize data on deregulated pathways to recapitulate the large heterogeneity of behaviors displayed by these tumors. This is expected to impact diagnostics, prognostic stratification, and planning of personalized therapy.

Metastatic mixed adenoneuroendocrine carcinoma of the liver successfully resected by hepatic trisectionectomy following chemotherapy: A case report

The chemotherapy guidelines for mixed adenoneuroendocrine carcinoma (MANEC) remain poorly defined, and prognosis remains dismal. In this case, we successfully performed resection after FOLFOX for unresectable metastatic MANEC of the liver. Thus, chemotherapy for adenocarcinoma may be effective for MANEC.

Pancreatic neuroendocrine carcinomas reveal a closer relationship to ductal adenocarcinomas than to neuroendocrine tumors G3

Pancreatic neuroendocrine carcinoma is a rare aggressive tumor commonly harboring TP53 and RB1 alterations and lacking neuroendocrine-related genetic changes such as mutations in MEN1 and ATRX/DAXX. Little is known about its genetic profile with regard to that of pancreatic ductal adenocarcinoma. We therefore conducted a detailed genetic study in 12 pancreatic neuroendocrine carcinomas of large cell (n = 9) and small cell type (n = 3) using massive parallel sequencing applying a 409-gene panel on an Ion Torrent system. The genetic data were compared with known data of pancreatic ductal adenocarcinoma and correlated with exocrine lineage marker expression. A similar analysis was performed in 11 pancreatic neuroendocrine tumors G3. Neuroendocrine carcinomas harbored 63 somatic mutations in 45 different genes, affecting most commonly TP53 (8/12 cases), KRAS (5/12 cases), and RB1 (loss of expression with or without deletion in 4/12 cases). Five carcinomas had both TP53 and KRAS mutations. Neuroendocrine tumors G3 only shared singular mutations in 5 different genes with neuroendocrine carcinomas, including TP53, CDKN2A, ARID1A, LRP1B, and APC, affecting 5 different cases. Most KRAS-positive neuroendocrine carcinomas also expressed MUC1 (4/5) and carcinoembryonic antigen (3/5) as markers of ductal differentiation. Our data indicate that almost half of the pancreatic neuroendocrine carcinomas are genetically and phenotypically related to pancreatic ductal adenocarcinoma, and might therefore respond to chemotherapies targeting the latter carcinomas.

Multilayered heterogeneity as an intrinsic hallmark of neuroendocrine tumors

Neuroendocrine tumors (NETs) comprise a complex and highly heterogeneous group of neoplasms that can arise all over the body, originating from neuroendocrine cells. NETs are characterized by a general lack of symptoms until they are in advanced phase, and early biomarkers are not as available and useful as required. Heterogeneity is an intrinsic, pivotal feature of NETs that derives from diverse causes and ultimately shapes tumor fate. The different layers that conform NET heterogeneity include a wide range of distinct characteristics, from the mere location of the tumor to its clinical and functional features, and from its cellular properties, to the core signaling and (epi)genetic components defining the molecular signature of the tumor. The importance of this heterogeneity resides in that it translates into a high variability among tumors and, hence, patients, which hinders a more precise diagnosis and prognosis and more efficacious treatment of these diseases. In this review, we highlight the significance of this heterogeneity as an intrinsic hallmark of NETs, its repercussion on clinical approaches and tumor management, and some of the possible factors associated to such heterogeneity, including epigenetic and genetic elements, post-transcriptional regulation, or splicing alterations. Notwithstanding, heterogeneity can also represent a valuable and actionable feature, towards improving medical approaches based on personalized medicine. We conclude that NETs can no longer be viewed as a single disease entity and that their diagnosis, prognosis and treatment must reflect and incorporate this heterogeneity.

Ki67 proliferative index of the neuroendocrine component drives MANEC prognosis

Mixed adenoneuroendocrine carcinomas (MANECs) are composed of a poorly differentiated neuroendocrine carcinoma (NEC) and a non-neuroendocrine (non-NEC) neoplastic epithelial component, each representing at least 30% of the tumor. At present, prognostic factors for MANECs remain largely unexplored. We investigated the clinical-pathologic features of a large multicenter series of digestive system MANECs. Surgical specimens of 200 MANEC candidates were centrally reviewed; diagnosis was confirmed in 160 cases. While morphology, proliferation (mitotic count (MC), Ki67 index) and immunophenotype (p53, SSTR2a, beta-Catenin, Bcl-2, p16, Rb1, ALDH, mismatch repair proteins and CD117) were investigated separately in both components, genomic (TP53, KRAS, BRAF) alterations were searched for on the entire tumor. Data were correlated with overall survival (OS). MANEC sites were: 92 colorectal, 44 gastroesophageal and 24 pancreatobiliary. Median OS was 13.2 months. After adjustment for primary site, Ki67 index of the NEC component (but not of the non-NEC component) was the most powerful prognostic marker. At multivariable analysis, patients with Ki67 ≥ 55% had an 8-fold risk of death (hazard ratio (HR) 7.83; 95% confidence interval (CI) 4.17-14.7; P < 0.0001) and a median OS of 12.2 months compared to those with Ki67 < 55% (median OS 40.5 months). MC (HR 1.51; 95% CI 1.03-2.20, P = 0.04) was a weaker prognostic index. Colorectal primary site (HR 1.60; 95% CI 1.11-2.32; P = 0.01) was significantly associated with poorer survival. No single immunomarker, in either component, was statistically significant. This retrospective analysis of a large series of digestive system MANECs, showed that the NEC component, particularly its Ki67 index, was the main prognostic driver.

Gastroenteropancreatic neuroendocrine neoplasms: genes, therapies and models

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) refer to a group of heterogeneous cancers of neuroendocrine cell phenotype that mainly fall into one of two subtypes: gastroenteropancreatic neuroendocrine tumors (GEP-NETs; well differentiated) or gastroenteropancreatic neuroendocrine carcinomas (GEP-NECs; poorly differentiated). Although originally defined as orphan cancers, their steadily increasing incidence highlights the need to better understand their etiology. Accumulating epidemiological and clinical data have shed light on the pathological characteristics of these diseases. However, the relatively low number of patients has hampered conducting large-scale clinical trials and hence the development of novel treatment strategies. To overcome this limitation, tractable disease models that faithfully reflect clinical features of these diseases are needed. In this Review, we summarize the current understanding of the genetics and biology of these diseases based on conventional disease models, such as genetically engineered mouse models (GEMMs) and cell lines, and discuss the phenotypic differences between the models and affected humans. We also highlight the emerging disease models derived from human clinical samples, including patient-derived xenograft models and organoids, which may provide biological and therapeutic insights into GEP-NENs.

Composite neuroendocrine tumor and adenocarcinoma of the rectum

Background

Although adenocarcinomas showing neuroendocrine differentiation or those mixed with high-grade neuroendocrine carcinoma (NEC) are sometimes encountered, composite tumors comprising neuroendocrine tumor (NET) Grade 1 and adenocarcinoma are exceedingly rare.

Case presentation

A 64-year-old male presented after testing positive for fecal occult blood at a medical check-up. A biopsy demonstrated the presence of a NET and endoscopic submucosal dissection was undertaken. Histologic examination revealed that a well differentiated tubular adenocarcinoma was present in addition to the NET. Furthermore, histological transition between the two tumors was evident. Accordingly, this case was considered to be a composite tumor comprising NET and adenocarcinoma.

Conclusion

Composite tumors consisting of NET Grade 1 and adenocarcinoma are exceedingly rare, and only a few examples have been reported hitherto.

Unraveling molecular pathways of poorly differentiated neuroendocrine carcinomas of the gastroenteropancreatic system: A systematic review

BACKGROUND

Poorly differentiated neuroendocrine carcinomas (NECs) are rare and aggressive tumors. Their molecular pathogenesis is still largely unknown, and consequently, the best therapeutic management also remains to be determined. We conducted a systematic review on molecular alterations found in gastroenteropancreatic NECs (GEP-NECs) and discuss potential applications of targeted therapies in setting.

MATERIALS AND METHODS

Systematic review of studies about molecular features in tumor tissues of patients with GEP-NECs. The Medline, Lilacs, Embase, Cochrane, Scopus and Opengrey databases were sought, without time, study design or language restrictions.

RESULTS

Of the 1.564 studies retrieved, 41 were eligible: 33 were retrospective studies and eight were case reports. The studies spanned the years 1997-2017 and involved mostly colorectal, stomach and pancreas primary tumors. Molecular alterations in the TP53 gene and the p53 protein expression were the most commonly observed, regardless of the primary site. Other consistently found molecular alterations were microsatellite instability (MSI) in approximately 10% of gastric and colorectal NEC, and altered signaling cascades of p16/Rb/cyclin D1, Hedgehog and Notch pathways, and somatic mutations in KRAS, BRAF, RB1 and Bcl2. In studies of mixed adeno-neuroendocrine carcinomas (MANECs) the molecular features of GEP-NEC largely resemble their carcinoma/adenocarcinomas tumor counterparts.

CONCLUSIONS

Despite the paucity of data about the molecular drivers associated with GEP-NEC, some alterations may be potentially targeted with new cancer-directed therapies. Collaborative clinical trials for patients with advanced GEP-NEC are urgently needed.

Is neuroendocrine differentiation a prognostic factor in poorly differentiated colorectal cancer?

Background

To determine the prognostic relevance of neuroendocrine differentiation in poorly differentiated colorectal cancer.

Methods

The clinicopathological features and survival of 70 patients with poorly differentiated colorectal cancer were analyzed retrospectively. Chromogranin A and synaptophysin were used as neuroendocrine markers. Patients were followed-up for more than 3 years or until death.

Results

Of these 70 patients, 36 showed neuroendocrine differentiation. In univariate prognostic analysis, the patients with lymph node metastasis (P < 0.001), advanced TNM stage (P < 0.001), and neuroendocrine differentiation (P = 0.003) tended to have a poor prognosis. However, only lymph node metastasis was associated with a poor prognosis in multivariate analysis (P < 0.001). Patients with neuroendocrine differentiation were associated with lymph node metastasis (P = 0.006).

Conclusions

Neuroendocrine differentiation in poorly differentiated colorectal cancer was not a direct prognostic factor in these patients. Lymph node metastasis was a direct prognostic factor in these patients. Patients with neuroendocrine differentiation were associated with lymph node metastasis.

In-depth mutational analyses of colorectal neuroendocrine carcinomas with adenoma or adenocarcinoma components

Neuroendocrine carcinomas (NECs) of the colorectum are rare but highly aggressive neoplasms. These tumors show some shared genetic alterations with colorectal adenocarcinomas, and most of them have adjacent glandular adenoma or adenocarcinoma components. However, genetic data on colorectal NECs still are sparse and insufficient for definite conclusions regarding their molecular origin. Based on morphological characterization, panel and whole-exome sequencing, we here present results from an in-depth analysis of a collection of 15 colorectal NECs with glandular components, 10 of which by definition were mixed adenoneuroendocrine carcinomas (MANECs). Among shared genetic alterations of both tumor components, we most frequently found TP53, KRAS and APC mutations that also had highest allele frequencies. Mutations exclusive to glandular or neuroendocrine components outnumbered shared mutations but occurred at lower allele frequencies. Our findings not only provide additional evidence for a common clonal origin of colorectal NECs and adjacent glandular tumor components, but strongly suggest their development through the classical adenoma-carcinoma sequence. Moreover, our data imply early separation of glandular and neuroendocrine components during malignant transformation with subsequent independent mutational evolution.

Report of two cases of large cell neuroendocrine carcinoma of duodenal ampulla with contrasting outcomes following pancreaticoduodenectomy according to the use of adjuvant chemotherapy

INTRODUCTION

Large-cell neuroendocrine carcinoma (LCNEC) in the duodenal ampulla of Vater is a rare malignant tumor, with frequent postoperative recurrence and poor prognosis even following complete resection. Effective adjuvant chemotherapy is expected to offer longer survival.

PRESENTATION OF CASE

We present two patients with LCNEC accompanied by components of tubular adenocarcinoma/adenoma in the duodenal ampulla of Vater who underwent pancreaticoduodenectomy (PD), resulting in longer survival of 1 patient. The first patient was an 81-year-old man in whom a 14-mm protruding solid tumor of the ampulla was observed. Pylorus-preserving PD (PPPD) was performed for the diagnosis of adenocarcinoma of the ampulla, and the final histological diagnosis of the resected specimen was LCNEC with an adenoma component. The patient showed a liver metastasis 4 months after surgery and died of carcinoma after 11 months. The second patient was a 72-year-old man with a 24-mm ulcerative solid tumor of the ampulla. PPPD was also performed in this patient, and the final histological diagnosis was LCNEC with mixed adenocarcinoma component (21%). Adjuvant chemotherapy of cisplatin and etoposide was administered, and the patient survived without tumor relapse for 24 months after surgery.

CONCLUSION

In the surgical treatment of LCNEC of the ampulla showing malignant behaviour, an accurate preoperative diagnosis and effective adjuvant chemotherapy after curative resection are necessary for longer survival.

Mixed Neuroendocrine-Nonneuroendocrine Neoplasms (MiNENs): Unifying the Concept of a Heterogeneous Group of Neoplasms

The wide application of immunohistochemistry to the study of tumors has led to the recognition that epithelial neoplasms composed of both a neuroendocrine and nonneuroendocrine component are not as rare as traditionally believed. It has been recommended that mixed neuroendocrine-nonneuroendocrine epithelial neoplasms are classified as only those in which either component represents at least 30 % of the lesion but this cutoff has not been universally accepted. Moreover, since their pathogenetic and clinical features are still unclear, mixed neuroendocrine-nonneuroendocrine epithelial neoplasms are not included as a separate clinicopathological entity in most WHO classifications, although they have been observed in virtually all organs. In the WHO classification of digestive tumors, mixed neuroendocrine-nonneuroendocrine neoplasm is considered a specific type and is defined as mixed adenoneuroendocrine carcinoma, a definition that has not been accepted for other organs. In fact, this term does not adequately convey the morphological and biological heterogeneity of digestive mixed neoplasms and has created some misunderstanding among both pathologists and clinicians. In the present study, we have reviewed the literature on mixed neuroendocrine-nonneuroendocrine epithelial neoplasms reported in the pituitary, thyroid, nasal cavity, larynx, lung, digestive system, urinary system, male and female genital organs, and skin to give the reader an overview of the most important clinicopathological features and morphological criteria for diagnosing each entity. We also propose to use the term "mixed neuroendocrine-nonneuroendocrine neoplasm (MiNEN)" to define and to unify the concept of this heterogeneous group of neoplasms, which show different characteristics mainly depending on the type of neuroendocrine and nonneuroendocrine components.

On the Origin of Cells and Derivation of Thyroid Cancer: C Cell Story Revisited

We will highlight and put into perspective new lineage tracing data from genetic studies in mice indicating that the genuine progenitors to C cells arise in the endoderm germ layer. This overturns the current concept of a neural crest origin of thyroid C cells referred to in every textbook and dedicated paper to this very day. As will become apparent, except for a single experiment, the neural crest theory has little or no support when the evolution and development of calcitonin-producing cells in the entire chordate family are considered. Instead, a unifying origin of all cells of the ultimobranchial bodies reopens questions on the histogenesis of certain thyroid pathologies previously difficult to explain. On this aspect, medullary thyroid cancer shows a stronger connection to gut neuroendocrine tumours than previously recognized. It is envisaged that novel factors implicated in C cell-derived tumour growth and progression will be discovered as the mechanisms that regulate lineage expansion of embryonic C cell precursors from pharyngeal endoderm are uncovered. We will not discuss why C cells go to the bother of burying themselves in the thyroid - this remains a mystery.

Primary high-grade neuroendocrine carcinoma emerging from an adenomatous polyp in the setting of familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is a rare inherited syndrome that is characterised by innumerable adenomas of the colon and rectum, a high risk of colorectal cancer and a variety of extracolonic manifestations. FAP presents as hundreds to thousands of colonic adenomas beginning in adolescence. The syndrome is associated with less than 1% of all colorectal cancer cases, but there is a nearly 100% lifetime risk of colorectal cancer in individuals with FAP. This case demonstrates a 60-year-old man with FAP who developed high-grade neuroendocrine carcinoma with glandular and squamous differentiation, and regional lymph node and liver metastases. Early diagnosis of FAP is of the utmost importance to start screening colonoscopies to assess disease burden, perform polypectomies and to make management decisions. Neuroendocrine carcinomas rarely occur in patients with FAP, and awareness of this association among general medical physicians and pathologists is essential for the diagnosis and care of these patients.

Republished: gastric neuroendocrine neoplasms and related precursor lesions

Gastric neuroendocrine neoplasms (NENs) are a heterogeneous group of tumours showing different clinicopathological features and behaviour, implying a wide spectrum of therapeutic options. They are currently classified using the 2010 WHO classification of digestive neuroendocrine neoplasms into G1-neuroendocrine tumours (NETs), G2-NETs, neuroendocrine carcinomas (NECs) and mixed adenoneuroendocrine carcinomas (MANECs). However, most gastric NENs are composed of ECL-cells (ECL-cell NETs) that can be preceded by ECL-cell hyperplastic and dysplastic lesions, whose oncologic potential has not yet been completely elucidated. ECL-cell NETs differ considerably in terms of prognosis depending on the proliferative status and clinicopathological background. The integration of both aspects in the diagnostic pathway may help to better classify tumours in different prognostic categories, especially when diagnosing them in small bioptic specimens. NECs are all poorly differentiated, highly aggressive carcinomas, while MANECs can show different morphological features that are directly associated with different prognoses. Precursor lesions of such carcinomas are not entirely understood. In this review, the clinicopathological features of gastric NENs and related precursor lesions will be described to give the reader a comprehensive overview on this topic.

Endocrine cell carcinomas of the colon and rectum: a clinicopathological evaluation

PURPOSE

Endocrine cell carcinoma, according to the Japanese classification criteria for colorectal cancer, corresponds to neuroendocrine carcinoma (NEC) and mixed adenoneuroendocrine carcinoma (MANEC), as defined in the 2010 World Health Organization (WHO) classification. We retrospectively reviewed the clinical features of patients with these tumors diagnosed and treated at our institution.

METHODS

The clinicopathological features of endocrine cell carcinomas of the colon and rectum diagnosed by neuroendocrine markers from January 2000 to December 2012 were retrospectively evaluated in 12 patients.

RESULTS

Surgical specimens were obtained from eight of the 12 patients. MANEC was diagnosed in six patients and NEC in one. One tumor was unclassifiable. The tumors were not resected in four patients, and all died within 3 months. Of the eight patients who underwent resection, four received an R0 resection, two of whom underwent adjuvant chemotherapy and survived more than 5 years. One patient who underwent an R2 resection and continuous chemotherapy survived for 53 months. One patient with NEC underwent surgery and radiotherapy, and died 17 months later.

CONCLUSION

Most endocrine cell carcinomas of the colon and rectum reviewed were MANECs. Though their prognosis was generally poor, chemotherapy may be effective in some patients.

Colorectal poorly differentiated neuroendocrine carcinomas frequently exhibit BRAF mutations and are associated with poor overall survival

The molecular alterations in colorectal poorly differentiated neuroendocrine carcinoma remain incompletely characterized, particularly with respect to mutations in BRAF and KRAS. We analyzed 32 colorectal poorly differentiated neuroendocrine carcinomas and 40 colorectal poorly differentiated conventional adenocarcinomas for mutations in KRAS and BRAF and for DNA mismatch repair protein abnormalities to correlate histopathology with molecular alterations and survival. Compared with poorly differentiated conventional adenocarcinoma, poorly differentiated neuroendocrine carcinoma frequently harbored BRAF mutations (59% versus 5%; P < .001) and less frequently demonstrated KRAS codon 12 or 13 mutations (17% versus 43%; P = .03). BRAF mutations were identified in both pure poorly differentiated neuroendocrine carcinoma (60%) and poorly differentiated neuroendocrine carcinoma associated with a signet ring cell adenocarcinoma component (82%). Most (93%) poorly differentiated neuroendocrine carcinomas demonstrated proficient DNA mismatch repair by either microsatellite instability polymerase chain reaction or DNA mismatch repair immunohistochemistry. Patients with poorly differentiated neuroendocrine carcinoma had a significantly worse overall survival compared with patients with poorly differentiated conventional adenocarcinoma (P < .001). There was no significant difference in overall survival between patients with pure poorly differentiated neuroendocrine carcinoma and patients with both poorly differentiated neuroendocrine carcinoma and adenocarcinoma components (P = .5). In conclusion, colorectal poorly differentiated neuroendocrine carcinomas frequently harbor BRAF mutations and are associated with poor overall survival.

Molecular characteristics of colorectal neuroendocrine carcinoma; similarities with adenocarcinoma rather than neuroendocrine tumor

To further clarify the molecular features of colorectal neuroendocrine carcinomas (NECs), we immunohistochemically examined tumor samples from 25 NECs, including 9 small cell NECs (SCNECs) and 16 large cell NECs (LCNECs), 20 neuroendocrine tumors (NETs), and 21 poorly differentiated adenocarcinomas (PDCs) for the expression of several biomarkers (p53, β-catenin, Bcl-2, Rb, p16, p21, cyclin D1, and cyclin E) and used sequencing analysis to identify gene alterations of TP53, APC, CTNNB1, KRAS, and BRAF. The frequencies of aberrant p53 expression (88%), β-catenin nuclear expression (48%), and high expression of cyclin E (84%) were significantly higher in NECs than in NETs (0%, 5%, and 5%, P < .01, respectively). The immunohistochemical results of NECs and PDCs were similar. TP53, APC, KRAS, and BRAF gene mutations were variously detected in NECs and PDCs but not in any NETs. The frequencies of decreased expression of Rb (56%) and high expression of p16 (56%) and Bcl-2 (64%) were significantly higher in NECs than in PDCs (5%, 19%, and 5%, P < .05, respectively) or NETs (10%, 5%, and 5%, P < .01, respectively). Such immunohistochemical characteristics of NECs were more evident in SCNECs than in large cell NECs (P < .01). In conclusion, the molecular features of colorectal NECs are similar to those of adenocarcinomas and not to those of NETs. Decreased expression of Rb and high expression of p16 and Bcl-2 are characteristics of NECs, suggesting that Rb-p16 pathway disruption may contribute to the promotion of proliferative activity in colorectal NECs. SCNECs may be a prototype of NECs.

The Increasing Relevance of Tumour Histology in Determining Oncological Outcomes in Colorectal Cancer

Colorectal cancer is not just one type of cancer. Differences in outcome and reaction to treatment can at least be partly explained by different histological and molecular subtypes. Recognition of these differences may influence treatment decisions. However, there is huge variation in the amount of information that is available. Several tumour types such as mucinous carcinoma, signet ring cell carcinoma, neuroendocrine carcinoma and adenosquamous carcinoma have such a distinct phenotype that they are readily recognised. However, due to the rarity of signet ring cell carcinoma and adenosquamous carcinoma, limited data are available. More recently defined subtypes, like medullary carcinoma, serrated adenocarcinoma and micropapillary carcinoma, are not adequately diagnosed, which limits research possibilities using large-scale data from registries. In the current review, we systematically describe the histologic subtypes with the clinical and molecular background. We evaluate their prognosis compared to adenocarcinoma not otherwise specified and speculate about the clinical relevance.

Neuroendocrine Carcinomas of the Gastroenteropancreatic System: A Comprehensive Review

To date, empirical literature has generally been considered lacking in relation to neuroendocrine carcinomas (NECs), the highly malignant subgroup of neuroendocrine neoplasms. NECs are often found in the lungs or the gastroenteropancreatic (GEP) system and can be of small or large cell type. Concentrating on GEP-NECs, we can conclude that survival times are poor, with a median of only 4–16 months depending on disease stage and primary site. Further, this aggressive disease appears to be on the rise, with incidence numbers increasing while survival times are stagnant. Treatment strategies concerning surgery are often undecided and second-line chemotherapy is not yet established. After an analysis of over 2600 articles, we can conclude that there is indeed more empirical literature concerning GEP-NECs available than previously assumed. This unique review is based on 333 selected articles and contains detailed information concerning all aspects of GEP-NECs. Namely, the classification, histology, genetic abnormalities, epidemiology, origin, biochemistry, imaging, treatment and survival of GEP-NECs are described. Also, organ-specific summaries with more detail in relation to disease presentation, diagnosis, treatment and survival are presented. Finally, key points are discussed with directions for future research priorities.

Survival of patients with neuroendocrine carcinoma of the colon and rectum: a population-based analysis

BACKGROUND

High-grade neuroendocrine carcinoma is a rare colorectal pathology described in a case series. The role of surgery in this disease has been questioned.

OBJECTIVE

The purpose of this work was to describe the incidence, management, and outcomes of neuroendocrine carcinoma in comparison with high-grade adenocarcinoma.

DESIGN

This was a retrospective, population-based outcomes research study.

SETTINGS

The Survey of Epidemiology and End Results database was used.

PATIENTS

A total of 1367 patients with colorectal neuroendocrine carcinoma (distinguishing small-cell and non-small-cell subtypes) and 72,533 with high-grade adenocarcinoma diagnosed between 2000 and 2011 were included in this study.

INTERVENTIONS

Resection of the primary tumor was the main intervention.

MAIN OUTCOME MEASURES

Median overall and 5-year relative survival were measured. Trends were expressed as the annual percent change in incidence and relative survival.

RESULTS

The incidence rate increased for neuroendocrine carcinoma (annual percent change, +2.2%; p =0.035) and decreased for high-grade adenocarcinoma (annual percent change, -3.1%; p < 0.00001) during the study period. Relative survival at 5 years in neuroendocrine carcinoma was 16.3% overall and 57.4%, 56.4%, 26.3%, and 3.0% for stages I, II, III, and IV cancer. Small-cell tumors had worse survival (10% versus 19% for non-small cell). There was no improvement in the relative survival for neuroendocrine carcinoma (annual percent change, -1.1%; p =0.06) in contrast to adenocarcinoma (annual percent change, +0.7%; p < 0.00001). Patients with localized non-small-cell neuroendocrine carcinoma had better overall survival with surgery (median, 21 months) than without (6 months; log-rank, p < 0.0001), whereas those with small-cell neuroendocrine carcinoma did not (18 versus 14 months; p = 0.95). Prognosis in resected neuroendocrine carcinoma was worse with an increasing number of metastatic lymph nodes.

LIMITATIONS

Histology and grade assignments were not centrally verified. Data on chemotherapy use, patient performance status, and comorbidities were unavailable.

CONCLUSIONS

Neuroendocrine carcinoma did not benefit from advances in the prevention and treatment of colorectal adenocarcinoma over the past decade. Relatively poor survival in early stage neuroendocrine carcinoma warrants studies of adjuvant systemic therapy. The differences in outcomes between small-cell and non-small-cell neuroendocrine carcinomas indicate a need for histology-specific management.

Low-grade neuroendocrine tumors arising in intestinal adenomas: evidence for alterations in the adenomatous polyposis coli/β-catenin pathway

Low-grade neuroendocrine tumors (NETs) arising in intestinal adenomas are rare. They are occasionally observed in patients with familial adenomatous polyposis (FAP), suggesting a role for the adenomatous polyposis coli/β-catenin pathway. We identified 25 composite adenoma/low-grade NETs from colorectum (21) and duodenum (4) and evaluated their clinicopathological features, survival, and nuclear β-catenin expression by immunohistochemistry. β-catenin staining was scored as % positivity × intensity (weak, 1; moderate, 2; and strong, 3), for a total possible score of 300. Control groups included 1781 adenomas without NET, 63 composite adenoma/high-grade neuroendocrine carcinomas (NECs), and 32 sporadic NETs. Among 25 adenoma/low-grade NETs, 4 (16%) occurred in patients with FAP. Size of the NET component ranged from 0.01 to 0.9 cm (mean, 0.32 cm). Most (84%) arose in "advanced" adenomas (size >1 cm, villous architecture [72%], or high-grade dysplasia [56%]). In contrast, villous architecture and high-grade dysplasia were present in only 14% (P < .001) and 7% (P < .001), respectively, of adenomas without NET. Overall survival with adenoma/low-grade NET was significantly higher than adenoma/high-grade NEC but significantly lower than sporadic NET (P < .001). Higher β-catenin expression was seen in adenoma/low-grade NETs (mean score, 231) compared with sporadic NETs (mean score, 48; P < .0001) and adenoma/high-grade NEC (mean score, 173; P = .04). In summary, composite adenoma/low-grade NETs most commonly occur with advanced polyps, but the NET component itself is generally small and indolent. In contrast to sporadic NETs, the occurrence of these lesions in FAP and their high levels of nuclear β-catenin expression support a pathogenic role for the adenomatous polyposis coli/β-catenin pathway.

Gastric neuroendocrine neoplasms and related precursor lesions

Gastric neuroendocrine neoplasms (NENs) are a heterogeneous group of tumours showing different clinicopathological features and behaviour, implying a wide spectrum of therapeutic options. They are currently classified using the 2010 WHO classification of digestive neuroendocrine neoplasms into G1-neuroendocrine tumours (NETs), G2-NETs, neuroendocrine carcinomas (NECs) and mixed adenoneuroendocrine carcinomas (MANECs). However, most gastric NENs are composed of ECL-cells (ECL-cell NETs) that can be preceded by ECL-cell hyperplastic and dysplastic lesions, whose oncologic potential has not yet been completely elucidated. ECL-cell NETs differ considerably in terms of prognosis depending on the proliferative status and clinicopathological background. The integration of both aspects in the diagnostic pathway may help to better classify tumours in different prognostic categories, especially when diagnosing them in small bioptic specimens. NECs are all poorly differentiated, highly aggressive carcinomas, while MANECs can show different morphological features that are directly associated with different prognoses. Precursor lesions of such carcinomas are not entirely understood. In this review, the clinicopathological features of gastric NENs and related precursor lesions will be described to give the reader a comprehensive overview on this topic.

Gastroenteropancreatic high-grade neuroendocrine carcinoma

Gastroenteropancreatic (GEP) neuroendocrine neoplasms are classified as low-grade, intermediate-grade, and high-grade tumors based on morphologic criteria and the proliferation rate. Most studies have been conducted in patients with well differentiated (low-grade to intermediate-grade) neuroendocrine tumors. Data are substantially scarcer on poorly differentiated, high-grade neuroendocrine carcinoma (NEC), which includes the entities of small cell carcinoma and large cell NEC. A literature search of GEP-NEC was performed. Long-term survival was poor even among patients who presented with localized disease. Several studies highlighted heterogeneity within the high-grade NEC category and a need for the further identification of discreet prognostic and predictive groups. Tumors with a Ki-67 proliferation index <55% were less responsive to platinum-based chemotherapy, and patients with such tumors or with well differentiated morphology had better survival than patients who had tumors with poorly differentiated morphology or a higher Ki-67 index. Treatment options beyond platinum-based chemotherapy are emerging. A revision of the World Health Organization high-grade NEC classification seems to be necessary based on recent data. Platinum-based chemotherapy may not be the optimal treatment for patients who have GEP-NEC with a moderately high proliferation rate. Adequate diagnostic and prognostic stratifications constitute the basis for future progress.

Long term outcomes of neuroendocrine carcinomas (high-grade neuroendocrine tumors) of the colon, rectum, and anal canal

INTRODUCTION AND AIM

Neuroendocrine carcinomas (NEC) of the large intestine are rare and aggressive neoplasms. This study was designed to review the experience at a single institution and analyze the outcomes to improve our understanding of these tumors.

METHODS

The patients with NEC (high-grade neuroendocrine tumor) of the colon, rectum, and anal canal were identified from June 1993 to April 2011. Clinical features studied were patient demographics, presenting symptoms, tumor location, tumor stage, treatment status and length of follow-up.

RESULTS

Twenty-five patients were identified. Stages of the diseases were I (n=5), II (n=1), III (n=10) and IV (n=9). Locations of the tumors were: colon (36%); rectum (28%) and anal canal (36%). Rectal bleeding (36%) and pain (32%) were the most common symptoms but 16% of patients were asymptomatic. Among the patients with local or locally advanced disease, only five patients had surgery alone. The remainder of the patients underwent chemotherapy with/without radiation. Mean follow-up was 33.7 ± 8.4 months after diagnosis. NEC of the large bowel and anal canal has very distinctive pathologic features and a very poor prognosis. More than one third of the patients with NEC had metastatic disease at the time of diagnosis. When these tumors are in an advanced stage none of the treatment modalities impact on survival.

CONCLUSION

The present study showed the poor prognosis of these rare tumors.

Synchronous Small Cell Neuroendocrine Carcinoma and Adenocarcinoma of the Colon: A Link for Common Stem Cell Origin?

Synchronous carcinomas have been recognized for over a century, with synchronous primary adenocarcinoma of the colon reported to range from 2-11% of cases involving this type of malignancy. Small cell carcinomas occur frequently with colorectal adenomas; however, despite these reports and a known adenoma-to-carcinoma sequence, scarce literature exists on synchronous colorectal adenocarcinoma and small cell carcinomas. We present a rare cancer of synchronous small cell neuroendocrine carcinomas and discuss a possible link between these two cancers.

Immunohistochemical analysis of chromogranin A and p53 expressions in ulcerative colitis-associated neoplasia: neuroendocrine differentiation as an early event in the colitis-neoplasia sequence

Pancellular dysplasia involving neuroendocrine cells has been shown to be comparatively rare but crucially implicated in the development of neuroendocrine tumors in ulcerative colitis (UC). We attempted to clarify the prevalence of chromogranin A expression as a marker of neuroendocrine differentiation in UC-associated neoplasia by immunohistochemical analyses of 26 lesions of low-grade dysplasia (LGD), 32 high-grade dysplasias (HGDs) and 27 invasive cancers (INVs), along with p53 expression. We additionally assessed the utility of these proteins for differential diagnosis between LGD and HGD. Chromogranin A was considered positive when immunoreactive cells were more than 5% of neoplastic lesions, and the positivity tended to be higher in HGDs (57.7%) or INVs (46.7%) than LGDs (32.0%). Focal or diffuse nuclear staining for p53 was defined as positive. The positive rate for p53 was also higher in HGDs (59.4%; P = 0.037) or INVs (59.3%) than LGDs (30.8%). A similar trend was found in co-positivity for both proteins (HGDs, 30.7%/INVs, 26.7% versus LGDs, 12.0%). No positivity for both proteins was identified in the non-neoplastic mucosa. The combination of the two proteins improved the sensitivity (66.7%), specificity (80.0%), positive predictive value (72.7%) and negative predictive value (75.0%) for HGD as compared to p53 alone (sensitivity, 57.7%; specificity 68.0%; positive predictive value, 65.2%; negative predictive value, 60.7%). In conclusion, we show here that neuroendocrine differentiation is relatively common and represents an early event in the UC-neoplasia pathway in which p53 and chromogranin A are coordinately up-regulated. Immunohistochemical assessment of their expression might provide a useful adjunct tool for grading dysplasia in UC.

Proteomic and cytokine plasma biomarkers for predicting progression from colorectal adenoma to carcinoma in human patients

In the present study, we screened proteomic and cytokine biomarkers between patients with adenomatous polyps and colorectal cancer (CRC) in order to improve our understanding of the molecular mechanisms behind turmorigenesis and tumor progression in CRC. To this end, we performed comparative proteomic analysis of plasma proteins using a combination of 2DE and MS as well as profiled differentially regulated cytokines and chemokines by multiplex bead analysis. Proteomic analysis identified 11 upregulated and 13 downregulated plasma proteins showing significantly different regulation patterns with diagnostic potential for predicting progression from adenoma to carcinoma. Some of these proteins have not previously been implicated in CRC, including upregulated leucine-rich α-2-glycoprotein, hemoglobin subunit β, Ig α-2 chain C region, and complement factor B as well as downregulated afamin, zinc-α-2-glycoprotein, vitronectin, and α-1-antichymotrypsin. In addition, plasma levels of three cytokines/chemokines, including interleukin-8, interferon gamma-induced protein 10, and tumor necrosis factor α, were remarkably elevated in patients with CRC compared to those with adenomatous polyps. Although further clinical validation is required, these proteins and cytokines can be established as novel biomarkers for CRC and/or its progression from colon adenoma.