Evaluation of the impact of indoleamine 2,3-deoxygenase (IDO) enzyme activity in neuroendocrine tumors (NETs)

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Introduction: Indoleamine 2,3-deoxygenase (IDO) enzyme, by inducing L-tryptophan (Trp) depletion and L-kynurenine (kyn) accumulation, contributes to the formation of an immunosuppressive microenvironment. Some studies highlighted that patient with cancer in treatment with immune checkpoint inhibitors (ICI) and with low Kyn/Trp values showed a better PFS and OS, but there are no data for NETs.

Aim(s): Aims: 1) to assess the enzymatic activity of IDO (Kyn/Trp ratio) in NETs, 2) to correlate it with the clinical course of the disease, 3) to compare it with the literature data of non-NETs.

Materials and methods: Patients with NETs referred to ENETS center Sant'Andrea Hospital (within 6 month). Clinical and pathological characteristics were evaluated.

Conference:

Presenting Author: Mancini C

Authors: Mancini C, Mazzilli R, Zamponi V, Motta C, Salerno G,

Keywords: neuroendocrine tumor, IDO enzyme, Kyn/Trp ratio, immunotherapy,