Andrew M. Bellizzi

Aims: ASCL1, NEUROD1, POU2F3 and YAP1 are recently described markers of transcriptional subtypes in small cell lung carcinoma (SCLC), while DLL3, regulated by ASCL1, is a target of novel therapeutic agents in various neuroendocrine neoplasms. The expression of these markers in lung carcinoids is not well established. Methods and results: We examined these markers in 109 lung carcinoids and compared their expression with that in 191 enteropancreatic neuroendocrine tumours (EP‐NETs) and with lung carcinoid markers (OTP, TTF1). ASCL1, NEUROD1, OTP and TTF1 were positive in 56%, 0%, 84% and 35% of lung carcinoids, respectively. Of the OTP‐negative lung carcinoids ( n = 18), 4 (22%) were ASCL1‐positive, of which one was TTF1‐positive. In contrast, 59% of EP‐NETs were NEUROD1‐positive, whereas only rare tumours focally expressed ASCL1 (1.1%) and OTP (0.5%) and none expressed TTF1. DLL3 was positive in 57 (52%) lung carcinoids versus 5 (2.6%) EP‐NETs. All lung carcinoids and EP‐NETs were completely negative for POU2F3 and YAP1. We also analysed clinicopathologic correlates of ASCL1, OTP, TTF1 and DLL3 expression in lung carcinoids, expanding on several previously suggested associations, including ASCL1 and TTF1 with peripheral location, OTP with low Ki67 ( P = 0.002) and low stage ( P = 0.002) and DLL3 with high Ki67 ( P = 0.002). Conclusion: Unlike SCLC, lung carcinoids and EP‐NETs completely lack the expression of POU2F3 and YAP1, which offers diagnostic applications. Our findings also nominate ASCL1 and NEUROD1 as site of origin markers for lung versus digestive NETs/carcinoids, respectively. Finally, the divergent expression of DLL3 in lung carcinoids and EP‐NETs has therapeutic implications.

Aims: To describe the clinicopathological features of composite gangliocytoma/neuroma and neuroendocrine tumour (CoGNET) and possible risk factors for nodal metastasis. Methods and results: We compiled a cohort of 71 cases from 19 institutions. Mean patient age was 58 years. Thirty‐eight (54%) patients were male. Most patients (65%) had symptoms, including abdominal pain (20%) and gastrointestinal bleeding (19%). Most cases (70%) were described as a subepithelial mass/nodule, and nearly half (45%) were located in the 2nd portion of the duodenum. Mean tumour size was 2.2 cm, and most (87%) were well‐circumscribed. Nearly all cases (96%) demonstrated all three histologic components, with the epithelioid component being the most predominant overall (mean 59%). All cases involved the submucosa, with 7 (10%) additionally involving the muscularis propria. Solid areas of ganglion‐like cells were identified in 16/69 (23%) cases, glandular structure formation in 15/70 (21%), lymphovascular invasion (LVI) in 6/70 (9%) cases, and perineural invasion and necrosis in one case each. Nodal metastasis was identified at diagnosis in 8 (11%) cases; increased age, increased size, LVI and muscularis propria involvement were all significantly associated with nodal disease ( P < 0.05). Follow‐up data were available for 68 patients (mean 47 months); nearly all were alive without disease, though one patient developed liver metastasis after 8 months and died of the disease after 63 months. Conclusions: This largest series of CoGNET to date demonstrates that approximately 10% of cases develop nodal metastases. Large tumour size, muscularis propria involvement, advanced patient age and LVI appear to be risk factors for nodal metastasis.

Neuroendocrine neoplasms (NENs) are rare cancers originating in various organs and are further classified as well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). Commonly used drugs such as proton pump inhibitors can promote gastric NEN growth. Nowadays, incretin mimetic drugs such as glucagon-like peptide 1 receptor (GLP-1R) agonists have gained extensive popularity for the treatment of diabetes and obesity. These drugs target GLP-1R, and their use in neuroendocrine cancer patients with medullary thyroid carcinoma (thyroid NET) or multiple endocrine neoplasia syndrome type 2 is deemed contraindicated. Previous studies investigated GLP-1R expression in small subsets of NENs. Here, we assessed GLP-1R expression by immunohistochemistry in a large collection of 576 patient NENs from 13 sites of origin. We identified that 7% of NENs stained positive for GLP-1R. They were from five NEN types: duodenal NETs (dNETs), gastric NETs, pancreatic NETs, pheochromocytomas, and lung NETs. We then validated the dNET spheroids for response to an incretin mimetic drug and found activation of the MAPK pathway and growth. While GLP-1R agonists are contraindicated in patients with thyroid NETs, none of our 29 thyroid NETs expressed GLP-1R. Hence, in contrast to rodent studies, GLP-1R agonists may have little effect on human thyroid NETs since they do not express the receptor. Interestingly, ileal NETs also showed no expression of GLP-1R. More preclinical research examining potential oncogenic effects of incretin mimetics on the five subtypes of GLP-1R-positive NENs is needed to better understand their safety.

Functional copy-number alterations (fCNAs) are DNA copy-number changes with concordant differential gene expression. These are less likely to be bystander genetic lesions and could serve as robust and reproducible tumor biomarkers. To identify candidate fCNAs in neuroendocrine tumors (NETs), we integrated chromosomal microarray (CMA) and RNA-seq differential gene-expression data from 31 pancreatic (pNETs) and 33 small-bowel neuroendocrine tumors (sbNETs). Tumors were resected from 47 early-disease-progression (24 months) patients. Candidate fCNAs that accurately differentiated these groups in this discovery cohort were then replicated using fluorescence in situ hybridization (FISH) on formalin-fixed, paraffin-embedded (FFPE) tissues in a larger validation cohort of 60 pNETs and 82 sbNETs (52 early- and 65 late-disease-progression samples). Logistic regression analysis revealed the predictive ability of these biomarkers, as well as the assay-performance metrics of sensitivity, specificity, and area under the curve. Our results indicate that copy-number changes at chromosomal loci 4p16.3, 7q31.2, 9p21.3, 17q12, 18q21.2, and 19q12 may be used as diagnostic and prognostic NET biomarkers. This involves a rapid, cost-effective approach to determine the primary tumor site for patients with metastatic liver NETs and to guide risk-stratified therapeutic decisions.

Functional copy number alterations (fCNAs) are DNA copy number changes with concordant differential gene expression. These are less likely to be bystander genetic lesions and could serve as robust and reproducible tumor biomarkers. To identify candidate fCNAs in neuroendocrine tumors (NETs), we integrated chromosomal microarray (CMA) and RNA-seq differential gene expression data from 31 pancreatic (pNET) and 33 small bowel neuroendocrine tumors (sbNET). Tumors were resected from 47 early disease progression (24 months) patients. Candidate fCNAs that accurately differentiated these groups in this discovery cohort were then replicated using fluorescence in situ hybridization (FISH) on formalin-fixed, paraffin-embedded (FFPE) tissues in a larger validation cohort of 60 pNETs and 82 sbNETs (52 early and 65 late disease progression samples). Logistic regression analysis determined the predictive ability of these biomarkers as well as the assay performance metrics of sensitivity, specificity, and area under the curve. Our results indicate that copy number changes at chromosomal loci 4p16.3, 7q31.2, 9p21.3, 17q12, 18q21.2, and 19q12 may be used as diagnostic and prognostic NET biomarkers. This involves a rapid, cost-effective approach to determine primary tumor site for patients with metastatic liver NETs and to guide risk stratified therapeutic decisions.

Liver lesion, later diagnosed as moderately differentiated HCC. Notably, the patient had no history of well-established risk factors of HCC including viral hepatitis or liver cirrhosis. CLL/SLL was unexpectedly discovered in the surgical specimen during the hepatectomy. This case challenges traditional perceptions of HCC etiology, suggesting a potential link between HCC and CLL/SLL even without established risk factors....

Determining neuroendocrine tumor (NET) primary sites is pivotal for patient care as pancreatic NETs (pNETs) and small bowel NETs (sbNETs) have distinct treatment approaches. The diagnostic power and prioritization of fluorescence in situ hybridization (FISH) assay biomarkers for establishing primary sites has not been thoroughly investigated using machine learning (ML) techniques. We trained ML models on FISH assay metrics from 85 sbNET and 59 pNET samples for primary site prediction. Exploring multiple methods for imputing missing data, the impute-by-median dataset coupled with a support vector machine model achieved the highest classification accuracy of 93.1% on a held-out test set, with the top importance variables originating from the ERBB2 FISH probe. Due to the greater interpretability of decision tree (DT) models, we fit DT models to ten dataset splits, achieving optimal performance with k-nearest neighbor (KNN) imputed data and a transformation to single categorical biomarker probe variables, with a mean accuracy of 81.4%, on held-out test sets. ERBB2 and MET variables ranked as top-performing features in 9 of 10 DT models and the full dataset model. These findings offer probabilistic guidance for FISH testing, emphasizing the prioritization of the ERBB2, SMAD4, and CDKN2A FISH probes in diagnosing NET primary sites.

PURPOSE: To develop recommendations for systemic therapy for well-differentiated grade 1 (G1) to grade 3 (G3) metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NETs). METHODS: ASCO convened an Expert Panel to conduct a systematic review of relevant studies and develop recommendations for clinical practice. RESULTS: Eight randomized controlled trials met the inclusion criteria for the systematic review. RECOMMENDATIONS: Somatostatin analogs (SSAs) are recommended as first-line systemic therapy for most patients with G1-grade 2 (G2) metastatic well-differentiated GI-NETs. Observation is an option for patients with low-volume or slow-growing disease without symptoms. After progression on SSAs, peptide receptor radionuclide therapy (PRRT) is recommended as systematic therapy for patients with somatostatin receptor (SSTR)–positive tumors. Everolimus is an alternative second-line therapy, particularly in nonfunctioning NETs and patients with SSTR-negative tumors. SSAs are standard first-line therapy for SSTR-positive pancreatic (pan)NETs. Rarely, observation may be appropriate for asymptomatic patients until progression. Second-line systemic options for panNETs include PRRT (for SSTR-positive tumors), cytotoxic chemotherapy, everolimus, or sunitinib. For SSTR-negative tumors, first-line therapy options are chemotherapy, everolimus, or sunitinib. There are insufficient data to recommend particular sequencing of therapies. Patients with G1-G2 high-volume disease, relatively high Ki-67 index, and/or symptoms related to tumor growth may benefit from early cytotoxic chemotherapy. For G3 GEP-NETs, systemic options for G1-G2 may be considered, although cytotoxic chemotherapy is likely the most effective option for patients with tumor-related symptoms, and SSAs are relatively ineffective. Qualifying statements are provided to assist with treatment choice. Multidisciplinary team management is recommended, along with shared decision making with patients, incorporating their values and preferences, potential benefits and harms, and other characteristics and circumstances, such as comorbidities, performance status, geographic location, and access to care. Additional information is available at www.asco.org/gastrointestinal-cancer-guidelines .