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

Cancer Treat Rev. 2017 May:56:28-35. doi: 10.1016/j.ctrv.2017.04.002. Epub 2017 Apr 17.


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.

Keywords: Cancer; Microsatellite Instability; Molecular; Neuroendocrine Carcinoma; Neuroendocrine tumors; p53.

Publication types

  • Review
  • Systematic Review

MeSH terms

  • Cell Differentiation / physiology
  • Gastrointestinal Neoplasms / genetics*
  • Gastrointestinal Neoplasms / metabolism
  • Gastrointestinal Neoplasms / pathology
  • Humans
  • Microsatellite Instability
  • Mutation
  • Neuroendocrine Tumors / genetics*
  • Neuroendocrine Tumors / metabolism
  • Neuroendocrine Tumors / pathology
  • Pancreatic Neoplasms / genetics*
  • Pancreatic Neoplasms / metabolism
  • Pancreatic Neoplasms / pathology