Pit and pitfalls of tumor mutational burden assessment in well-differentiated pancreatic neuroendocrine tumors: Two case reports from University of Verona

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Introduction: The hypermutated phenotype is used as a predictive parameter for immune-checkpoint inhibitors (ICI). However, the relationship between high TMB, the underlying mutational drivers and response to ICI is still unclear.

Aim(s): We present 2 patients (BS and DM) affected by advanced pancreatic NET (pNET), that underwent NGS on baseline tissue and after CAPTEM and radio-ligand therapy (4 cycles both). BS had liver metastasis at diagnosis, DM developed metachronous liver and extra-liver metastasis after surgery. BS underwent NGS on liver biopsy both at baseline and after treatment, DM on the surgical sample and then on liquid and liver biopsies.

Materials and methods: We collected clinical and molecular data. Only ACMG/AMP1 class IV-V pathogenic alterations were considered.

Conference:

Presenting Author: Trevisani E

Authors: Torresan I, Reni A, Trevisani E, Borghesani M, Rossi A,

Keywords: Neuroendocrine tumor, NGS, Tumor Mutational Burden, Alkylating agent, DNA Damage Repair, Liquid biopsy,