NKX2.2, PDX-1 and CDX-2 as potential biomarkers to differentiate well-differentiated neuroendocrine tumors

Extraskeletal Ewing Sarcoma of the Gastrointestinal and Hepatobiliary Tract: Deceptive Immunophenotype Commonly Leads to Misdiagnosis

Ewing sarcoma (ES) is an uncommon mesenchymal neoplasm that typically develops as a bone mass, although up to 30% arise in extraskeletal sites. ES of the gastrointestinal (GI) and hepatobiliary tract is rare and may be misdiagnosed as other, more common neoplasms that occur in these sites. However, the correct classification of extraskeletal ES is important for timely clinical management and prognostication. We reviewed our experience of ES in the GI and hepatobiliary tract in order to further highlight the clinicopathologic features of these neoplasms and document the potential for misdiagnosis in this setting. The archives and consultation files of 6 academic institutions were retrospectively queried for cases of ES occurring in the GI and hepatobiliary tract. The histologic slides and ancillary studies were reviewed and clinical data were retrieved for each case through the electronic medical records, when available. Twenty-three patients with ES in the GI and/or hepatobiliary tract were identified from 2000 to 2022. Of these, 11 were women and 12 were men with a median age of 38 years (range, 2 to 64). Tumor locations included the pancreas (n=5), liver (n=2), stomach (n=3), colorectum (n=3), and small intestine (n=5), as well as tumors involving multiple organs, pelvis and retroperitoneum (n=5). Tumor size varied between 2 cm and 18 cm. Twenty were primary and 3 were metastases. Of the 23 cases, only 17% were initially diagnosed as ES. The most common misdiagnoses involved various forms of neuroendocrine neoplasia due to expression of synaptophysin and other neuroendocrine markers (22%). A wide variety of diagnoses including GI stromal tumor was considered due to aberrant CD117 expression (4%). The diagnosis of ES was ultimately confirmed by detection of the EWSR1 rearrangement in 22 cases. The remaining case was diagnosed using traditional immunohistochemistry. Follow-up information was available in 20 cases, with follow-up time varying between 2 and 256 months. Six patients with follow-up died of disease between 6 and 60 months following initial presentation. Our data indicate ES in the GI and hepatobiliary tract is commonly misdiagnosed leading to a delay in therapy. In light of the attendant therapeutic and prognostic implications, ES should be considered in the differential diagnosis of any GI or hepatobiliary tumor with epithelioid and/or small round cell morphology.

PCSK2 can be Useful in a Panel Approach to Distinguish Foregut and Midgut Neuroendocrine Tumors

A number of immunohistochemical stains have been examined for utility in establishing the site of origin for metastatic well-differentiated neuroendocrine tumors (NETs). In the gastrointestinal (GI) tract, distinguishing metastatic duodenal NETs from jejunoileal and other GI NETs is important for clinical work-up, prognosis, and therapy. A recent study indicated that prohormone convertase 2 (PCSK2 or PC2) had broad expression in small intestine and appendiceal NETs. Because the study did not include duodenal NETs, we examined PCSK2 expression in duodenal and other GI NETs.

GI NETs (n = 69) and 13 corresponding lymph node metastases from stomach, duodenum, pancreas, ileum, appendix, and rectum were evaluated for the expression of PCSK2, along with ISL1, NKX2.2, CDX2, SATB2, and PAX8. Expression of each stain was evaluated using the H-score system, and differences in expression by site were evaluated by the chi square test.

PCSK2 was expressed at similar frequency in duodenal (50%), pancreatic (59%), and ileal NETs (40%). PCSK2 was infrequently expressed in stomach (0%), appendiceal (8%), and rectal (25%) NETs. However, incorporating PCSK2 into a panel including ISL1, NKX2.2, CDX2, and SATB2 allowed development of an algorithm which had 87% sensitivity and 93% specificity for classification of ileal NETs; and 68% sensitivity and 98% specificity for pancreaticoduodenal NETs.

In contrast to previous findings, PCSK2 does not show specificity for any particular GI site. An algorithmic approach incorporating the expression of PCSK2 with that of ISL1, NKX2.2, CDX2, and SATB2 is useful in discriminating pancreatic, duodenal, ileal, appendiceal, and rectal NETs.

Testicular Primary Well-Differentiated Neuroendocrine Tumor: Clinicopathologic, Immunohistochemical, and Molecular Characterization of Two Patients

Well-differentiated neuroendocrine tumor rarely occurs as a testicular primary tumor, accounting for less than 1% of all testicular cancers, and is rarely reported with sufficient molecular profiles. After searching our departmental database (2003-2023), two testicular primary well-differentiated neuroendocrine tumors were identified in a 35-year-old man and a 23-year-old man, respectively, both of whom had normal serum level of tumor markers. Both tumors grossly exhibited solid, yellow-tan, and homogeneous appearance and histologically displayed a mixture of growth patterns, including organoid, tubular, cribriform, nests, cords, and single cells, were composed of eosinophilic tumor cells with salt-and-pepper chromatin and indistinct cell borders. Immunoreactivity for chromogranin and synaptophysin were detected, with Ki-67 labeling 9% and 2% of tumor cells on counting of 500 tumor cells, respectively. There was no germ cell neoplasia in situ in the background testicular parenchyma. Furthermore, fluorescence in situ hybridization failed to identify the presence of isochromosome 12p in both tumors. A panel-based next-generation sequencing was done in one of tumors and showed no reportable pathogenic variants with a mutation burden of 0.5 mutations per megabase. Although elevated mitotic figures (up to 6 per 10 high power fields), lymphovascular invasion and marked nuclear pleomorphism were present in this tumor, there was no evidence of disease detected in this patient via Dotatate positron emission tomography/computed tomography scan after the surgery. This report expands the spectrum of testicular primary well-differentiated neuroendocrine tumor. Considering its rarity, it may pose a diagnostic challenge or pitfall in certain clinical circumstances. In addition, the literature pertaining to this entity is herein reviewed.

S100 Protein Expression in Primary and Metastatic Neuroendocrine Neoplasms: A Specific Marker of Pancreatic Origin

Neuroendocrine neoplasms can arise in a wide variety of anatomic sites including the gastrointestinal tract, pancreas, and lung, among others. Here, we report on the expression of S100 protein in a tissue microarray composed of 919 distinct primary and metastatic neuroendocrine neoplasms from 548 patients. S100 protein is a commonly used marker in many laboratories for the identification of neural and melanocytic neoplasms and occasionally used in the workup for neuroendocrine neoplasms when the diagnosis of paraganglioma is being considered. We show that strong S100 protein expression is highly specific to well-differentiated neuroendocrine tumors of pancreatic origin. This finding suggests potential diagnostic utility of this marker in cases of tumors of unknown origin, and emphasizes that S100 protein expression should not be an unexpected finding in neuroendocrine tumors of pancreatic origin.

Immunoreactivity of HOXB13 in Neuroendocrine Neoplasms Is a Sensitive and Specific Marker of Rectal Well-Differentiated Neuroendocrine Tumors

HoxB13 is a transcription factor involved in defining of posterior endodermal derivatives, including prostate and rectum. While it is used as a marker of prostatic adenocarcinoma, it has not been studied systematically in neuroendocrine neoplasms. Thus, we performed HoxB13 immunohistochemistry in tissue microarrays and the whole sections of 232 neuroendocrine neoplasms. These included 34 paragangliomas (PGs), 20 cauda equina neuroendocrine tumors (CENETs), 123 well-differentiated neuroendocrine tumors (WDNETs), and 55 neuroendocrine carcinomas (NECs). WDNETs were additionally analyzed with SATB2, and colorectal WDNETs with CDX2 and serotonin immunohistochemistry. In total, HoxB13 immunoreactivity was observed in 95% (19/20) CENETs, 10.6% (13/123) WDNETs, and 12.9% (7/54) NECs. No PGs were positive. Large intestine WDNETs expressed HoxB13 in 68.4% (13/19); five negative tumors originated in cecum and one in rectum. In rectum, 92.9% (13/14) WDNETs expressed HoxB13. HoxB13 was 92.9% sensitive and 100% specific, showing 100% positive predictive value for the rectal origin of WDNET. In NECs, HoxB13 was positive in 15.4% (2/13) GIT tumors and 80% (4/5) prostatic NECs, but in none of urinary bladder NECs (0/8). SATB2 was positive in 17.1% (21/123) WDNETs, including 78.9% (15/19) of colorectal WDNETs, 71.4% (5/7) appendiceal WDNETs, and 2.9% (1/34) small intestine WDNETs. All 4 SATB2-negative large bowel tumors originated in the cecum. When both markers combined, HoxB13+/SATB2+ immunoprofile was seen exclusively in rectal WDNETs (positive predictive value 100%), while HoxB13-/SATB2+ immunoprofile was highly suggestive of the appendiceal origin (positive predictive value 71.4%). Therefore, HoxB13 can be useful as an immunohistochemical marker of rectal WDNETs and prostatic NECs.

mRNA profiling of a well-differentiated G1 pancreatic NET correlates with immunohistochemistry profile: a case report

Background

Neuroendocrine neoplasms (NENs) are a complex group of tumours that occur in many organs. Routinely used IHC markers for NEN diagnosis include CgA, synaptophysin, Ki67 and CD56. These have limitations including lack of correlation to clinical outcomes and their presence in non-tumour tissue. Identification of additional markers and more quantitative analyses of tumour tissue has the potential to contribute to improved clinical outcomes. We used qRT-PCR to profile the expression levels of a panel of markers in tumour and matched non-tumour tissue from a patient with a G1 pancreatic neuroendocrine tumour. Differences in mRNA levels between tumour and non-tumour tissue were compared with IHC analyses of the same sample.

Case presentation

An elderly man presented with lower abdominal pain for 6 months. Histological analysis identified a low grade, well differentiated pancreatic endocrine neoplasm. Twenty-seven tumour markers for neuroendocrine status, proliferation, stem cell phenotype, angiogenesis, epithelial to mesenchymal transition, cell adhesion, differentiation and tumour suppression were selected from previous studies and mRNA levels of these markers were measured in tumour and adjacent non-tumour tissue sample using qRT-PCR. IHC was carried out on the same tissue to detect the corresponding marker proteins. Of the markers analysed, seven showed higher mRNA levels in tumour relative to non-tumour tissue while thirteen had lower expression in tumour relative to non-tumour tissue. Substantial differences in mRNA levels were a gain of CgA, CD56, β-catenin, CK20, PDX1 and p53 and loss of Ki67, PCAD, CK7, CD31, MENA, ECAD, EPCAM, CDX2 and CK6. Comparison of qRT-PCR data with IHC showed correlation between fifteen markers.

Conclusion

Our study is unique as it included matched controls that provided a comparative assessment for tumour tissue analysis, whereas many previous studies report tumour data only. Additionally, we utilised qRT-PCR, a relatively quantitative diagnostic tool for differential marker profiling, having the advantage of being reproducible, fast, cheap and accurate. qRT-PCR has the potential to improve the defining of tumour phenotypes and, in combination with IHC may have clinical utility towards improving tumour stratification or distinguishing tumour grades. The results need to be validated with different grades of NENs and related to clinical outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01705-9.

Predicting the Survival Probability of Neuroendocrine Tumor Populations: Developing and Evaluating a New Predictive Nomogram

Purpose

The purpose of this study was to develop and initially validate a nomogram model in order to predict the 3-year and 5-year survival rates of neuroendocrine tumor patients.

Methods

Accordingly, 348 neuroendocrine tumor patients were enrolled as study objects, of which 244 (70%) patients were included in the training set to establish the nomogram model, while 104 (30%) patients were included in the validation set to verify the robustness of the model. First, the variables related to the survival rate were determined by univariable analysis. In addition, variables that were sufficiently significant were selected for constructing the nomogram model. Furthermore, the concordance index (C-index), receiver operating characteristic (ROC), and calibration curve analysis were used to evaluate the performance of the proposed nomogram model. The survival analysis was then used to evaluate the return to survival probability as well as the indicators of constructing the nomogram model.

Results

According to the multivariable analysis, lymphatic metastasis, international normalized ratio (INR), prothrombin time (PT), tumor differentiation, and the number of tumor metastases were found to be independent predictors of survival rate. Moreover, the C-index results demonstrated that the model was robust in both the training set (0.891) and validation set (0.804). In addition, the ROC results further verified the robustness of the model either in the training set (AUC = 0.823) or training set (AUC = 0.768). Furthermore, the calibration curve results showed that the model can be used to predict the 3-year and 5-year survival probability of neuroendocrine tumor patients. Meaningfully, five variables were found: lymphatic metastasis (p = 0.0095), international standardized ratio (p = 0.024), prothrombin time (p = 0.0036), tumor differentiation (p = 0.0026), and the number of tumor metastases (p = 0.00096), which were all significantly related to the 3-year and 5-year survival probability of neuroendocrine tumor patients.

Conclusion

In summary, a nomogram model was constructed in this study based on five variables (lymphatic metastasis, international normalized ratio (INR), prothrombin time (PT), tumor differentiation, and number of tumor metastases), which was shown to predict the survival probability of patients with neuroendocrine tumors. Additionally, the proposed nomogram exhibited good ability in predicting survival probability, which may be easily adopted for clinical use.

Genome Methylation Accurately Predicts Neuroendocrine Tumor Origin: An Online Tool

PURPOSE

The primary origin of neuroendocrine tumor metastases can be difficult to determine by histopathology alone, but is critical for therapeutic decision making. DNA methylation-based profiling is now routinely used in the diagnostic workup of brain tumors. This has been enabled by the availability of cost-efficient array-based platforms. We have extended these efforts to augment histopathologic diagnosis in neuroendocrine tumors.

EXPERIMENTAL DESIGN

Methylation data was compiled for 69 small intestinal, pulmonary, and pancreatic neuroendocrine tumors. These data were used to build a ridge regression calibrated random forest classification algorithm (neuroendocrine neoplasm identifier, NEN-ID). The model was validated during 3 × 3 nested cross-validation and tested in a local and an external cohort (n = 198 cases).

RESULTS

NEN-ID predicted the origin of tumor samples with high accuracy (>95%). In addition, the diagnostic approach was determined to be robust across a range of possible confounding experimental parameters, such as tumor purity and array quality. A software infrastructure and online user interface were built to make the model available to the scientific community.

CONCLUSIONS

This DNA methylation-based prediction model can be used in the workup for patients with neuroendocrine tumors of unknown primary. To facilitate validation and clinical implementation, we provide a user-friendly, publicly available web-based version of NEN-ID.

NK homeobox 2.2 functions as tumor suppressor in colorectal cancer due to DNA methylation

Aim: The role of NK homeobox 2.2 (NKX2.2) in human colorectal cancer (CRC) remains to be unveiled. This study was designed to explore the epigenetic regulation and function of NKX2.2 in human CRC.

Methods: The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets were used to assess the methylation data of NKX2.2 in CRC. Six CRC cell lines (HCT116, SW480, HT29, LOVO, SW1116, SW640) and 20 pairs of primary CRC tumor and normal tissues were utilized to explore the function of NKX2.2 in CRC using Sequenom EpiTYPER®, verified by cloning-based bisulfite sequencing analysis, semi-quantitative reverse transcription PCR, western blot, cell viability assessment, plate clone formation assay , and transwell assays.

Results: Bioinformatic analysis showed that NKX2.2 was significantly hypermethylated in primary tumors compared to normal tissues (p < 0.05). Our study also found that NKX2.2 methylation was upregulated (p<0.05) in tumors than normal tissues. In vitro experiments demonstrated that 5-aza-2'-deoxycytidine downregulated the methylation of NKX2.2 and retrieved its expression of mRNA and protein levels (p<0.05). No significant association was found between the NKX2.2 methylation and sex, age, tumor differentiation, TNM stage, CEA, CA199, and fecal occult blood (p>0.05). Kaplan-Meier analysis indicated that NKX2.2 hypermethylation showed a trend but not statistical significance for predicting poor overall survival in CRC patients (p=0.33). NKX2.2 overexpression suppressed cell proliferation, colony formation, and inhibited tumor invasion and migration in CRC cells (both p<0.05).

Conclusions: This study indicates that NKX2.2 is a tumor suppressor in CRC due to hypermethylation.

Neuroendocrine Tumors of the Gastrointestinal Tract and Pancreas

Neuroendocrine neoplasms (NENs) of the gastrointestinal (GI) tract and pancreas are a rare and heterogeneous group of neoplasms characterized by common cellular features as well as unique site-specific traits. GI and pancreatic NENs are much rarer than the more common adenocarcinomas arising at these sites. However, the incidences of GI and pancreatic NENs have increased significantly, particularly in the stomach and common site, followed by rectum, appendix, colon, and stomach. Pancreatic NENs are also uncommon, with fewer than 1 per 100,000, accounting for 1% to 2% of all pancreatic neoplasms.

A primary neuroendocrine tumor of the left ventricle presenting with diarrhea-an unusual experience and literature review

Background

Neuroendocrine tumors (NETs) can secrete bioactive amines in the bloodstream, resulting in the carcinoid syndrome characterized by diarrhea and flushing. The frequency of occurrence of primary cardiac neuroendocrine neoplasms is lesser than that of metastases, and hence, metastases must be adequately ruled out before diagnosis. Cardiac tumors, both primary and metastatic, mainly result in heart-related symptoms, such as heart failure and acquired valvular dysfunction. Here, we report a unique case of a primary left ventricular neuroendocrine tumor presenting with diarrhea.

Case presentation

A 51-year-old female complaining of intermittent diarrhea for 2 years was admitted to our hospital. Enhancement of total abdominal computed tomography scan, echocardiography, and magnetic resonance imaging indicated a mass in the left ventricle. The indexes of myocardial enzymes were normal. Histologically, round cells with well-differentiated neuroendocrine morphology were arranged in typical pseudo-glandular, trabecular, ribbon-like, and solid nest patterns. Immunohistochemically, the tumor cells were positive for cytokeratin, chromogranin, synaptophysin, and CD56. However, they were negative for caudal type homeobox 2, S100, paired box gene 8, thyroid transcription factor 1, and CD20, which ruled out the origin of gastrointestinal, pancreatic, lung, and Merkel cell carcinomas. The symptoms of diarrhea disappeared after the operation. The patient was asymptomatic at the 9-month follow-up.

Conclusion

Cardiac neuroendocrine tumors with diarrhea are considerably rare and related clinical research is limited. We presented a case and reviewed related articles to improve the identification, diagnosis, and management of patients with cardiac neuroendocrine tumors. The site of origin of a neuroendocrine tumor is clinically vital, and identification of an occult primary tumor using imaging modalities is necessary. Immunohistochemistry is well-suited to indicate the origin of the tumor. Regular follow-up is necessary for both poorly differentiated and well-differentiated cardiac neuroendocrine tumors. It is suggested to detect some neuroendocrinal markers for patients with unexplained reasons of diarrhea.

Advances in the Diagnosis and Management of Well-Differentiated Neuroendocrine Neoplasms

Neuroendocrine neoplasms constitute a diverse group of tumors that derive from the sensory and secretory neuroendocrine cells and predominantly arise within the pulmonary and gastrointestinal tracts. The majority of these neoplasms have a well-differentiated grade and are termed neuroendocrine tumors (NETs). This subgroup is characterized by limited proliferation and patients affected by these tumors carry a good to moderate prognosis. A substantial subset of patients presenting with a NET suffer from the consequences of endocrine syndromes as a result of the excessive secretion of amines or peptide hormones, which can impair their quality of life and prognosis. Over the past 15 years, critical developments in tumor grading, diagnostic biomarkers, radionuclide imaging, randomized controlled drug trials, evidence-based guidelines, and superior prognostic outcomes have substantially altered the field of NET care. Here, we review the relevant advances to clinical practice that have significantly upgraded our approach to NET patients, both in diagnostic and in therapeutic options.

[Differential diagnostic value of the expression of the transcription factor PDX-1 in neuroendocrine and non-neuroendocrine tumors of the pancreas and other organs]

An important role in the differentiation of tissues in different organs is played by transforming factors (TFs); pancreatic and duodenal homebox 1 (PDX-1) is one of the earliest factors for pancreatic cells. Many malignant tumors, including neuroendocrine tumors (NETs), are similar in structure, and therefore the actual problem of oncomorphology is to search for narrow-specific markers and TFs.

AIM

to comparatively analyze and assess the value of the expression of the TF PDX-1 in NETs and non-NETs of different localization and histogenetic origin.

MATERIAL AND METHODS

Anti-PDX-1 antibodies were used to study 528 tumors divided into 3 groups: Group 1 included 394 NETs, among them there were those of the pancreas (n=173), stomach (n=46), bowel (n=65), lung (n=40), thymus (n=8), kidney (n=6), Merkel's cell carcinomas (n=14), NETs of the breast (n=3), larynx (n=2), trachea (n=2), bladder (n=1), and metastatic NETs (n=34) of unknown primary site; Group 2 consisted of 16 tumors, of them there were paragangliomas (n=6), medullary thyroid cancers (MTC) (n=6) and adrenal pheochromocytomas (APCC) (n=4); Group 3 comprised 118 non-NETs, among them there were tumors of the pancreas (n=54), stomach (n=26), bowel (n=17), lung (n=11), breast (n=3), kidney (n=4), adrenal glands (n=2), and bladder (n=1).

RESULTS

PDX-1 was positive in 75.1% (130/173) of pancreatic NETs, all insulinomas (50/50), gastrinomas (11/11), somatostatinomas (3/3), ACTH-producing tumors (2/2); PDX-1 was positive in the non-functioning pancreatic NETs, all PPomas (19/19), 76.1% (35/46) of NETs without the hormone detected, 50% (2/4) of calcitoninomas, and 21.1% (8/38) of silent glucagonomas. PDX-1 was positive in 32.4% (11/34) of carcinoids and 50% (6/12) of neuroendocrine carcinomas, all duodenal NETs (18/18), 90% (9/10) of rectal carcinoids and 30.8% (4/13) colonic carcinoids, 37.5% (3/8) of thymic/mediastinal carcinoids, 66.7% (4/6) of kidney carcinoids, and 37.5% (9/24) of metastatic NETs of unknown primary site. PDX-1 was negative in all carcinoids of the colon and sigmoid (0/5), ileum and jejunum (0/24), lung (0/40), trachea (0/2), larynx (0/2), Merkel's cell carcinoma (0/14), breast (0/3), bladder (0/1), as well as MTC (0/6), APCC (0/4), and paragangliomas (0/6). PDX-1-positive non-NETs included 81.8% (18/22) of adenocarcinomas (AC) and all serous cystic, mucinous cystic, intraductal and acinar cell tumors of the pancreas (4/4, 3/3, 2/2, and 3/3), 57.1% of AC (8/14) and 83.3% of signet ring cell carcinomas of the stomach (10/12), 56.2% AC of the bowel (9/17), bladder cancer (1/1). PDX-1 was negative in all anaplastic cancers (0/2) and solid pseudopapillary tumors of the pancreas (0/20), cancers of the lung (0/11), kidney (0/4), breast (0/3), and adrenal glands (0/2).

CONCLUSION

The expression of PDX-1 is very specific for most digestive tract NETs and non-NETs. Pancreatic ductal and acinar cell tumors and gastric signet ring cell carcinomas are most commonly PDX-1-positive. Most tumors that do not originate from the digestive tract have a PDX-1 negative immunophenotype.

Neuroendocrine Liver Metastasis-a Specific Set of Markers to Detect Primary Tumor Sites

The diagnosis of neuroendocrine neoplasia (NEN) is often made at an advanced stage of disease, including hepatic metastasis. At this point, the primary may still be unknown and sometimes cannot even be detected by functional imaging, especially in very small tumors of the pancreas (pan) and small intestinal (si) entities. The site of the primary may be based on biopsy specimens of the liver applying a specific set of markers. Specimens of liver metastases from 87 patients with NENs were studied. In retrospect, 50 patients had si and 37 pan NENs. Tissue samples were evaluated by immunohistochemistry. The markers applied were insulin gene enhancer protein Islet-1 (ISL-1), homeobox protein CDX-2 (CDX2), thyroid transcription factor 1 (TTF-1), and serotonin. Positive stains for CDX2 were documented in 43 (86%) and for serotonin in 45 (90%) of 50 siNENs. Three panNENs were positive for CDX2 and one for serotonin, respectively. ISL-1 was negative throughout in siNENs and also negative in 8 of 50 panNENs (21.6%). TTF-1 was negative in more than 90% of the specimens of either entity. Immunohistochemical markers in liver metastasis can lead the way to the site of the primary NEN. They should always be used in combined clusters.