PD1 and PDL1 Expression in Midgut Neuroendocrine Tumors

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Introduction: PD1/PDL1 inhibitors have shown promising results in different carcinomas, and correlation between PDL1 expression and response to immunotherapy has been reported. No studies thus far have investigated the expression of PD1 or PDL1 in midgut NETs.

Aim(s): To investigate the expression of PD1/PDL1 in midgut NETs, and its relation to the presence of peritumoral lymphoid cell aggregates containing germinal centers (lymph node-like structures; LLS).

Materials and methods: PD1 and PDL1 expression was assessed by immunohistochemistry in 32 patients with midgut NET. All cases with moderate or strong staining by Allred score were considered positive. The presence or absence of LLS was evaluated on H/E stained sections, and characterized by immunohistochemistry.

Conference: 13th Annual ENETSConcerence (2016)

Presenting Author:

Authors: Cives M, Strosberg J, Coppola D,

Keywords: midgut NETs, PD1, PD-L1, lymph node-like structures,