MODERN APPROACHES AND RECENT ADVANCES IN NEUROENDOCRINE TUMORS

Modern Approaches and Recent Advances in Neuroendocrine Tumors-kapak

PATHOLOGICAL EXAMINATION, STAGING AND GENETIC MECHANISMS IN GASTROENTEROPANCREATIC NEUROENDOCRINE NEOPLASMS

Merve Cin

University of Health Sciences, İstanbul Training and Research Hospital, Department of Pathology, İstanbul, Türkiye

Cin M. Pathological Examination, Staging and Genetic Mechanisms in Gastroenteropancreatic Neuroendocrine Neoplasms. In: Gönüllü E, Karaman K, editors. Modern Approaches and Recent Advances in Neuroendocrine Tumors. 1st ed. Ankara: Türkiye Klinikleri; 2025. p.25-39.

ABSTRACT

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are heterogeneous epithelial tumors with endocrine characteristics, exhibiting considerable histopathological, genetic, and biological diversity. The diagnosis and assessment of these tumors necessitate a multidisciplinary approach that integrates morphological examination with immunohistochemical and molecular methodologies. Pathological evaluation constitutes the cornerstone of GEP-NEN diagnosis. The diagnostic process encompasses morphological parameters such as tumor localization, size, section characteristics (necrosis, hemorrhage), invasion pattern, and nuclear/cytoplasmic features of tumor cells. Microscopic examination with hematoxylin and eosin (H&E) staining is crucial in distinguishing neuroendocrine tumors (NETs) from neuroendocrine carcinomas (NECs). Low-grade NETs are characterized by an organoid, trabecular, or glandular growth pattern, with monomorphic cells and nuclei exhibiting a “salt-and-pepper” chromatin pattern. High-grade NETs, in contrast, display increased mitotic activity and a higher Ki-67 index. NECs are typically solid tumors with high mitotic activity and extensive necrosis, exhibiting either small-cell or large-cell morphology. Mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) are defined by the coexistence of neuroendocrine and non-neuroendocrine components, necessitating separate evaluation of each component. Molecular investigations play a pivotal role in understanding GEP-NEN biology and informing therapeutic decision-making. In pancreatic NETs, the presence of DAXX, ATRX, and MEN1 mutations is associated with poor prognosis. In jejunal-ileal NETs, CDKN1B mutations and chromosome 18 loss are frequently observed, whereas NECs share genetic similarities with adenocarcinomas arising in the same anatomical regions. Gastrointestinal NECs commonly harbor TP53, RB1, KRAS, and BRAF mutations, with pancreatic NECs exhibiting a particularly high mutational burden. Liquid biopsy techniques, including circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), and microRNA (miRNA) analysis, hold promise for clinical diagnosis, prognostic assessment, and therapeutic monitoring. However, their integration into routine clinical practice requires further validation through large-scale prospective studies.

Accurate classification of neuroendocrine neoplasms is essential for prognostication and clinical management, underscoring the necessity of a comprehensive pathological assessment. Pathological methodologies, spanning histomorphological examination, immunohistochemical markers, and molecular analyses, are critical in elucidating the heterogeneous nature of GEP-NENs and guiding clinical decision-making. This chapter will provide an in-depth discussion of the fundamental histopathological criteria, immunohistochemical markers, and molecular analyses relevant to the diagnosis and assessment of GEP-NENs.

Keywords: Gastroenteropancreatic neuroendocrine neoplasms; Pathological examination; Immunohistochemistry; Staging; Molecular pathology; Liquid biopsy

Referanslar

  1. Gheorghișan-Gălățeanu AA, Ilieșiu A, Lambrescu IM, Țăpoi DA. The Complex Histopathological and Immunohistochemical Spectrum of Neuroendocrine Tumors-An Overview of the Latest Classifications. IJMS. 2023;24(2):1418. [Crossref]  [PubMed]  [PMC]
  2. Fang JM, Li J, Shi J. An update on the diagnosis of gastroenteropancreatic neuroendocrine neoplasms. WJG. 2022;28(10):1009-1023. [Crossref]  [PubMed]  [PMC]
  3. Goldin SB, Aston J, Wahi MM. Sporadically occurring functional pancreatic endocrine tumors: review of recent literature: Current Opinion in Oncology. 2008;20(1):25-33. [Crossref]  [PubMed]
  4. BlueBooksOnline [Internet]. WHO Classification of Tumours Editorial Board. Digestive System Tumours. 5th ed [cited 2025 Feb 23]. Available from: cation.iarc.who.int/chaptercontent/31/139 [Link]
  5. Sigel CS. Advances in the cytologic diagnosis of gastroenteropancreatic neuroendocrine neoplasms. Cancer Cytopa thology. 2018;126(12):980-991. [Crossref]  [PubMed]
  6. Hirabayashi K, Zamboni G, Nishi T, Tanaka A, Kajiwara H, Nakamura N. Histopathology of gastrointestinal neuroendocrine neoplasms. Front Oncol. 2013;3:2. [Crossref]  [PubMed]  [PMC]
  7. Milione M, Maisonneuve P, Pellegrinelli A, Grillo F, Albarello L, Spaggiari P, et al. Ki67 proliferative index of the neuroendocrine component drives MANEC prognosis. Endocrine-Related Cancer. 2018;25(5):583-593. [Crossref]  [PubMed]
  8. Biancotti R, Dal Pozzo CA, Parente P, Businello G, Angerilli V, Realdon S, et al. Histopathological Landscape of Precursor Lesions of Gastro-Entero-Pancreatic Neuroendocrine Neoplasms. Dig Dis. 2023;41(1):34-48. [Crossref]  [PubMed]
  9. Mastracci L, Rindi G, Grillo F, Solcia E, Campora M, Fassan M, et al. Neuroendocrine neoplasms of the esophagus and stomach. Pathologica. 2021;113(1):5-11. [Crossref]  [PubMed]  [PMC]
  10. Sultana Q, Kar J, Verma A, Sanghvi S, Kaka N, Patel N, et al. A Comprehensive Review on Neuroendocrine Neoplasms: Presentation, Pathophysiology and Management. JCM. 2023;12(15):5138. [Crossref]  [PubMed]  [PMC]
  11. Van Velthuysen MF, Couvelard A, Rindi G, Fazio N, Hörsch D, Nieveen Van Dijkum EJ, et al. ENETS standardized (synoptic) reporting for neuroendocrine tumour pathology. J Neuroendocrinology. 2022;34(3):e13100. [Crossref]  [PubMed]  [PMC]
  12. Tao Z, Xue R, Wei Z, Qin L, Bai R, Liu N, et al. The assessment of Ki-67 for prognosis of gastroenteropancreatic neuroendocrine neoplasm patients: a systematic review and meta-analysis. Transl Cancer Res. 2023;12(8):1980-1991. [Crossref]  [PubMed]  [PMC]
  13. Bellizzi AM. Immunohistochemistry in the diagnosis and classification of neuroendocrine neoplasms: what can brown do for you? Human Pathology. 2020;96:8-33. [Crossref]  [PubMed]  [PMC]
  14. Alexander ES, Ziv E. Neuroendocrine Tumors: Genomics and Molecular Biomarkers with a Focus on Metastatic Disease. Cancers. 2023;15(8):2249. [Crossref]  [PubMed]  [PMC]
  15. Uccella S. Molecular Classification of Gastrointestinal and Pancreatic Neuroendocrine Neoplasms: Are We Ready for That? Endocr Pathol. 2024;35(2):91-106. [Crossref]  [PubMed]  [PMC]
  16. Reid MD, Bagci P, Ohike N, Saka B, Erbarut Seven I, Dursun N, et al. Erratum: Calculation of the Ki67 index in pancreatic neuroendocrine tumors: a comparative analysis of four counting methodologies. Modern Pathology. 2016;29(1):93. [Crossref]
  17. Tang LH, Gonen M, Hedvat C, Modlin IM, Klimstra DS. Objective Quantification of the Ki67 Proliferative Index in Neuroendocrine Tumors of the Gastroenteropancreatic System: A Comparison of Digital Image Analysis With Manual Methods. American Journal of Surgical Pathology. 2012;36(12):1761-1770. [Crossref]  [PubMed]
  18. Ordóñez NG. Broad-spectrum immunohistochemical epithelial markers: a review. Hum Pathol. 2013;44(7):1195-1215. [Crossref]  [PubMed]
  19. Bräutigam K, Rodriguez-Calero A, Kim-Fuchs C, Kollár A, Trepp R, Marinoni I, et al. Update on Histological Reporting Changes in Neuroendocrine Neoplasms. Curr Oncol Rep. 2021;23(6):65. [Crossref]  [PubMed]  [PMC]
  20. Couvelard A, Cazes A, Cros J. Updates in histopathological classification and tissue biomarkers of digestive neuroendocrine neoplasms: What the clinician should know. Best Practice & Research Clinical Endocrinology & Metabolism. 2023;37(5):101795. [Crossref]  [PubMed]
  21. Bellizzi AM. Assigning site of origin in metastatic neuroendocrine neoplasms: a clinically significant appli cation of diagnostic immunohistochemistry. Adv Anat Pathol. 2013;20(5):285-314. [Crossref]  [PubMed]
  22. College of American Pathologists [Internet]. Cancer Protocol Templates. [cited 2025 Feb 23].
  23. AJCC Staging Online. [Internet]. [cited 2025 Feb 23].
  24. enets.org [Internet]. Standardised Reports. [cited 2025 Feb 23].
  25. Androsova A, Orlova R, Gordiev M, Ivanova A, Belyak NP, Kutukova S. Molecular genetic sequencing of neuroendocrine tumors of the gastrointestinal tract. JCO. 2023;41(4_ suppl):651-651. [Crossref]
  26. Öberg K. Management of functional neuroendocrine tumors of the pancreas. Gland Surg. 2018;7(1):20-27. [Crossref]  [PubMed]  [PMC]
  27. Chen Z, Forman LW, Miller KA, English B, Takashima A, Bohacek RA, et al. Protein kinase C inactivation inhibits cellular proliferation and decreases survival in human neuroendocrine tumors. Endocrine-Related Cancer. 2011;18(6):759-771. [Crossref]  [PubMed]  [PMC]
  28. Dong M, Sangai T, Zhao Q, Rashid A, Meric-Bernstam F, Yao JC. Activation of hedgehog pathway in neuroendocrine tumors. JCO. 2012;30(15_suppl):e14662-e14662. [Crossref]
  29. Tirosh A, Kebebew E. Genetic and epigenetic alterations in pancreatic neuroendocrine tumors. J Gastrointest Oncol. 2020;11(3):567-577. [Crossref]  [PubMed]  [PMC]
  30. Chen S, Sun L, Chen H, Li J, Lu C, Yang Y, et al. Clinicopathological and genetic characteristics of gastric neuroendocrine tumour (NET) G3 and comparisons with neuroendocrine carcinoma and NET G2. Histopathology. 2023;83(5):700-711. [Crossref]  [PubMed]
  31. Park HY, Kwon MJ, Kang HS, Kim YJ, Kim NY, Kim MJ, et al. Targeted next-generation sequencing of well-differentiated rectal, gastric, and appendiceal neuroendocrine tumors to identify potential targets. Human Pathology. 2019;87:83-94. [Crossref]  [PubMed]
  32. Rindi G, Wiedenmann B. Neuroendocrine neoplasia of the gastrointestinal tract revisited: towards precision medicine. Nat Rev Endocrinol. 2020;16(10):590-607. [Crossref]  [PubMed]
  33. Rinke A, Auernhammer CJ, Bodei L, Kidd M, Krug S, Lawlor R, et al. Treatment of advanced gastroenteropancreatic neuroendocrine neoplasia, are we on the way to personalised medicine? Gut. 2021;70(9):1768-1781. [Crossref]  [PubMed]
  34. Webster AP, Thirlwell C. The Molecular Biology of Midgut Neuroendocrine Neoplasms. Endocrine Reviews. 2024;45(3):343-350. [Crossref]  [PubMed]  [PMC]
  35. Australian Pancreatic Cancer Genome Initiative, Scarpa A, Chang DK, Nones K, Corbo V, Patch AM, et al. Whole-genome landscape of pancreatic neuroendocrine tumours. Nature. 2017;543(7643):65-71. [Crossref]  [PubMed]
  36. Schmitt AM, Schmid S, Rudolph T, Anlauf M, Prinz C, Klöppel G, et al. VHL inactivation is an important pathway for the development of malignant sporadic pancreatic endocrine tumors. Endocrine-Related Cancer. 2009;16(4):12191227. [Crossref]  [PubMed]
  37. Navale P, Chatterjee D, Itani M, Trikalinos NA. Tuberous sclerosis complex mutations in patients with pancreatic neuroendocrine tumors. Observations on phenotypic and treatment-related associations. Virchows Arch. 2023;483(2):167-175. [Crossref]  [PubMed]
  38. Kim JY, Brosnan-Cashman JA, An S, Kim SJ, Song KB, Kim MS, et al. Alternative Lengthening of Telomeres in Primary Pancreatic Neuroendocrine Tumors Is Associated with Aggressive Clinical Behavior and Poor Survival. Clinical Cancer Research. 2017;23(6):1598-1606. [Crossref]  [PubMed]  [PMC]
  39. Singhi AD, Liu TC, Roncaioli JL, Cao D, Zeh HJ, Zureikat AH, et al. Alternative Lengthening of Telomeres and Loss of DAXX/ATRX Expression Predicts Metastatic Disease and Poor Survival in Patients with Pancreatic Neuroendocrine Tumors. Clinical Cancer Research. 2017;23(2):600-609. [Crossref]  [PubMed]  [PMC]
  40. Chan CS, Laddha SV, Lewis PW, Koletsky MS, Robzyk K, Da Silva E, et al. ATRX, DAXX or MEN1 mutant pancreatic neuroendocrine tumors are a distinct alpha-cell signature subgroup. Nat Commun. 2018;9(1):4158. [Crossref]  [PubMed]  [PMC]
  41. Di Domenico A, Pipinikas CP, Maire RS, Bräutigam K, Simillion C, Dettmer MS, et al. Epigenetic landscape of pancreatic neuroendocrine tumours reveals distinct cells of origin and means of tumour progression. Commun Biol. 2020;3(1):740. [Crossref]  [PubMed]  [PMC]
  42. Cejas P, Drier Y, Dreijerink KMA, Brosens LAA, Deshpande V, Epstein CB, et al. Enhancer signatures stratify and predict outcomes of non-functional pancreatic neuroendocrine tumors. Nat Med. 2019;25(8):1260-1265. [Crossref]  [PubMed]  [PMC]
  43. Jiao Y, Shi C, Edil BH, De Wilde RF, Klimstra DS, Maitra A, et al. DAXX/ATRX, MEN1, and mTOR Pathway Genes Are Frequently Altered in Pancreatic Neuroendocrine Tumors. Science. 2011;331(6021):1199-1203. [Crossref]  [PubMed]  [PMC]
  44. Cao Y, Gao Z, Li L, Jiang X, Shan A, Cai J, et al. Whole exome sequencing of insulinoma reveals recurrent T372R mutations in YY1. Nat Commun. 2013;4(1):2810. [Crossref]  [PubMed]
  45. Hong X, Qiao S, Li F, Wang W, Jiang R, Wu H, et al. Whole-genome sequencing reveals distinct genetic bases for insulino mas and non-functional pancreatic neuroendocrine tumours: leading to a new classification system. Gut. 2020;69(5):877887. [Crossref]  [PubMed]  [PMC]
  46. Lee JE, Hong SH, Jung HI, Son MW, Ahn TS, Han SW, et al. Small-cell neuroendocrine carcinoma of the ileum: case report and literature review. BMC Surg. 2019;19(1):135. [Crossref]  [PubMed]  [PMC]
  47. Chopin-Laly X, Walter T, Hervieu V, Poncet G, Adham M, Guibal A, et al. Neuroendocrine neoplasms of the jejunum: a heterogeneous group with distinctive proximal and distal subsets. Virchows Arch. 2013;462(5):489-499. [Crossref]  [PubMed]
  48. Dasari A, Shen C, Halperin D, Zhao B, Zhou S, Xu Y, et al. Trends in the Incidence, Prevalence, and Survival Outcomes in Patients With Neuroendocrine Tumors in the United States. JAMA Oncol. 2017;3(10):1335. [Crossref]  [PubMed]  [PMC]
  49. Kojima M, Ikeda K, Saito N, Sakuyama N, Koushi K, Kawano S, et al. Neuroendocrine Tumors of the Large Intestine: Clinicopathological Features and Predictive Factors of Lymph Node Metastasis. Front Oncol. 2016;6. [Crossref]  [PubMed]  [PMC]
  50. Nesti C, Bräutigam K, Benavent M, Bernal L, Boharoon H, Botling J, et al. Hemicolectomy versus appendectomy for patients with appendiceal neuroendocrine tumours 1-2 cm in size: a retrospective, Europe-wide, pooled cohort study. The Lancet Oncology. 2023;24(2):187-194. [Crossref]  [PubMed]
  51. Blažević A, Hofland J, Hofland LJ, Feelders RA, De Herder WW. Small intestinal neuroendocrine tumours and fibrosis: an entangled conundrum. Endocrine-Related Cancer. 2018;25(3):R115-R130. [Crossref]  [PubMed]
  52. Banck MS, Kanwar R, Kulkarni AA, Boora GK, Metge F, Kipp BR, et al. The genomic landscape of small intestine neuroendocrine tumors. J Clin Invest. 2013;123(6):25022508. [Crossref]  [PubMed]  [PMC]
  53. Francis JM, Kiezun A, Ramos AH, Serra S, Pedamallu CS, Qian ZR, et al. Somatic mutation of CDKN1B in small intestine neuroendocrine tumors. Nat Genet. 2013;45(12):14831486. [Crossref]  [PubMed]  [PMC]
  54. Simbolo M, Vicentini C, Mafficini A, Fassan M, Pedron S, Corbo V, et al. Mutational and copy number asset of primary sporadic neuroendocrine tumors of the small intestine. Virchows Arch. 2018;473(6):709-717. [Crossref]  [PubMed]  [PMC]
  55. Van Riet J, Van De Werken HJG, Cuppen E, Eskens FALM, Tesselaar M, Van Veenendaal LM, et al. The genomic landscape of 85 advanced neuroendocrine neoplasms reveals subtype-heterogeneity and potential therapeutic targets. Nat Commun. 2021;12(1):4612. [Crossref]  [PubMed]  [PMC]
  56. Nieser M, Henopp T, Brix J, Stoß L, Sitek B, Naboulsi W, et al. Loss of Chromosome 18 in Neuroendocrine Tumors of the Small Intestine: The Enigma Remains. Neuroendocrinology. 2017;104(3):302-312. [Crossref]  [PubMed]
  57. How-Kit A, Dejeux E, Dousset B, Renault V, Baudry M, Terris B, et al. DNA Methylation Profiles Distinguish Different Subtypes of Gastroenteropancreatic Neuroendocrine Tumors. Epigenomics. 2015;7(8):1245-1258. [Crossref]  [PubMed]
  58. Karpathakis A, Dibra H, Pipinikas C, Feber A, Morris T, Francis J, et al. Prognostic Impact of Novel Molecular Subtypes of Small Intestinal Neuroendocrine Tumor. Clinical Cancer Research. 2016;22(1):250-258. [Crossref]  [PubMed]
  59. Takizawa N, Ohishi Y, Hirahashi M, Takahashi S, Nakamura K, Tanaka M, et al. Molecular characteristics of colorectal neuroendocrine carcinoma; similarities with adenocarcinoma rather than neuroendocrine tumor. Human Pathology. 2015;46(12):1890-1900. [Crossref]  [PubMed]
  60. Chen L, Liu M, Zhang Y, Guo Y, Chen M hu, Chen J. Genetic Characteristics of Colorectal Neuroendocrine Carcinoma: More Similar to Colorectal Adenocarcinoma. Clinical Colorectal Cancer. 2021;20(2):177-185.e13. [Crossref]  [PubMed]
  61. Kimura T, Miyamoto H, Fukuya A, Kitamura S, Okamoto K, Kimura M, et al. Neuroendocrine carcinoma of the pancreas with similar genetic alterations to invasive ductal adenocarcinoma. Clin J Gastroenterol. 2016;9(4):261-265. [Crossref]  [PubMed]
  62. Makuuchi R, Terashima M, Kusuhara M, Nakajima T, Serizawa M, Hatakeyama K, et al. Comprehensive analysis of gene mutation and expression profiles in neuroendocrine carcinomas of the stomach. Biomed Res. 2017;38(1):19-27. [Crossref]  [PubMed]
  63. Uccella S, La Rosa S. Looking into digestive mixed neuroendocrine nonneuroendocrine neoplasms: subtypes, prognosis, and predictive factors. Histopathology. 2020;77(5):700717. [Crossref]  [PubMed]
  64. Venizelos A, Elvebakken H, Perren A, Nikolaienko O, Deng W, Lothe IMB, et al. The molecular characteristics of highgrade gastroenteropancreatic neuroendocrine neoplasms. Endocrine-Related Cancer. 2022;29(1):1-14. [Crossref]  [PubMed]  [PMC]
  65. Yachida S, Totoki Y, Noë M, Nakatani Y, Horie M, Kawasaki K, et al. Comprehensive Genomic Profiling of Neuroendocrine Carcinomas of the Gastrointestinal System. Cancer Discovery. 2022;12(3):692-711. [Crossref]  [PubMed]  [PMC]
  66. Wu H, Yu Z, Liu Y, Guo L, Teng L, Guo L, et al. Genomic characterization reveals distinct mutation landscapes and therapeutic implications in neuroendocrine carcino mas of the gastrointestinal tract. Cancer Communications. 2022;42(12):1367-1386. [Crossref]  [PubMed]  [PMC]
  67. Kasajima A, Konukiewitz B, Schlitter AM, Weichert W, Klöppel G. An analysis of 130 neuroendocrine tumors G3 regarding prevalence, origin, metastasis, and diagnostic features. Virchows Arch. 2022;480(2):359-368. [Crossref]  [PubMed]  [PMC]
  68. Tang LH, Basturk O, Sue JJ, Klimstra DS. A Practical Approach to the Classification of WHO Grade 3 (G3) Well-differentiated Neuroendocrine Tumor (WD-NET) and Poorly Differentiated Neuroendocrine Carcinoma (PDNEC) of the Pancreas. American Journal of Surgical Pathology. 2016;40(9):1192-1202. [Crossref]  [PubMed]  [PMC]
  69. Umetsu SE, Kakar S, Basturk O, Kim GE, Chatterjee D, Wen KW, et al. Integrated Genomic and Clinicopathologic Approach Distinguishes Pancreatic Grade 3 Neuroendocrine Tumor From Neuroendocrine Carcinoma and Identifies a Subset With Molecular Overlap. Modern Pathology. 2023;36(3):100065. [Crossref]  [PubMed]
  70. Kalligeros M, Diamantopoulos L, Toumpanakis C. Biomarkers in Small Intestine NETs and Carcinoid Heart Disease: A Comprehensive Review. Biology. 2021;10(10):950. [Crossref]  [PubMed]  [PMC]
  71. Barriuso J, Custodio A, Afonso R, Alonso V, Astudillo A, Capdevila J, et al. Prognostic and predictive biomarkers for somatostatin analogs, peptide receptor radionuclide therapy and serotonin pathway targets in neuroendocrine tumours. Cancer Treatment Reviews. 2018;70:209-222. [Crossref]  [PubMed]
  72. Zakka K, Nagy R, Drusbosky L, Akce M, Wu C, Alese OB, et al. Blood-based next-generation sequencing analysis of neuroendocrine neoplasms. Oncotarget. 2020;11(19):17491757. [Crossref]  [PubMed]  [PMC]
  73. Fernandez CJ, Agarwal M, Pottakkat B, Haroon NN, George AS, Pappachan JM. Gastroenteropancreatic neuroendocrine neoplasms: A clinical snapshot. WJGS. 2021;13(3):231-255. [Crossref]  [PubMed]  [PMC]
  74. Öberg K, Califano A, Strosberg JR, Ma S, Pape U, Bodei L, et al. A meta-analysis of the accuracy of a neuroendocrine tumor mRNA genomic biomarker (NETest) in blood. Annals of Oncology. 2020;31(2):202-212. [Crossref]  [PubMed]
  75. Yang J, Zhang Y, Gao X, Yuan Y, Zhao J, Zhou S, et al. Plasma-Derived Exosomal ALIX as a Novel Biomarker for Diagnosis and Classification of Pancreatic Cancer. Front Oncol. 2021;11:628346. [Crossref]  [PubMed]  [PMC]