Gastroenteropancreatic (GEP) Neuroendocrine Neoplasia G3 (NEN G3) According to 2019 WHO Classification: A Comprehensive Clinicopathological Characterization Including Mismatch Repair (MMR) Proteins, PDL1 Expression and KRAS/BRAF Status


Introduction: In the 2019 WHO FOR NEN’S classification NETG3 have been distinguished from poorly differentiated neuroendocrine carcinoma (NEC). They are heterogeneous group concerning prognosis and treatment benefit.

Aim(s): To describe clinical, histological, innmunohistochemical and molecular characteristics in a cohort of high grade GEP-NEN with emphasis in morphological differences between NEC and NET G3 and correlate de findings with the clinical outcome

Materials and methods: From 2006 to 2018, 64 pts with GEP NENc G3 with available tumor tissue samples were identified at our institution. Clinical data were retrospectively extracted from medical records. Samples were evaluated by three physicians with expertise in gastrointestinal pathology to determine inter-observer differences to identify NET G3 and NEC. We studied the immunohistochemistry expression of MMR (MLH1, PMS2, MSH2, MSH6), PDL1,Rb and p53 by optic microscopy. KRAS/BRAF status was tested in 17 patients.

Conference: 17th Annual ENETSConcerence (2020)

Presenting Author:

Authors: Ruiz G, Graselli J, Golubicki M, Rizzol M,


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