When It Comes to the Diagnostic of Neuroendocrine Neoplasms (NEN), Not All Markers and Clones Were Made Equal. Assessment of 5 Makers in 466 NEN from 10 Anatomical Sites

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Introduction: Histological diagnostic of neuroendocrine neoplasms (NEN) relies on morphological criteria and expression of several neuroendocrine marker assessed by immunohistochemistry. Systematic large evaluation of classical (chromogranin A (chrA), synaptophysin (Syn), CD56) and emerging (chromogranin B (chrB), INSM1) markers are lacking.

Aim(s): Assess the diagnostic value of these 5 neuroendocrine markers across a large series of NEN from multiple origins.

Materials and methods: Expression of ChrA (2 most commonly used clones DAK-A3 and LK2H10), Syn, CD56, ChrB and INSM1 was assessed on 466 NEN (including thymus (11), lung (106), digestive system (301) and Merkel cell carcinomas (48). Pancreatic NEN-look alike were also tested (serous cystadenomas (14), acinar cell carcinomas (21), solid pseudopapillary tumors (31). Markers were defined as positive if expressed by at least 10% of the tumor cells.

Conference: 17th Annual ENETSConcerence (2020)

Presenting Author: Cros J

Authors: Mamodaly M, Chen R, Cazes A, Guedj N, Deschamps L,

Keywords: Neuroendocrine markers, Chromogranin A, Chromogranin B, INSM1,