TY - JOUR T1 - Molecular characterisation of pancreatic ductal adenocarcinoma with <em>NTRK</em> fusions and review of the literature JF - Journal of Clinical Pathology JO - J Clin Pathol DO - 10.1136/jclinpath-2021-207781 SP - jclinpath-2021-207781 AU - Michael J Allen AU - Amy Zhang AU - Prashant Bavi AU - Jaeseung C Kim AU - Gun Ho Jang AU - Deirdre Kelly AU - Sheron Perera AU - Rob E Denroche AU - Faiyaz Notta AU - Julie M Wilson AU - Anna Dodd AU - Stephanie Ramotar AU - Shawn Hutchinson AU - Sandra E Fischer AU - Robert C Grant AU - Steven Gallinger AU - Jennifer J Knox AU - Grainne M O'Kane Y1 - 2021/09/28 UR - http://jcp.bmj.com/content/early/2022/02/22/jclinpath-2021-207781.abstract N2 - Aims The majority of pancreatic ductal adenocarcinomas (PDACs) harbour oncogenic mutations in KRAS with variants in TP53, CDKN2A and SMAD4 also prevalent. The presence of oncogenic fusions including NTRK fusions are rare but important to identify. Here we ascertain the prevalence of NTRK fusions and document their genomic characteristics in a large series of PDAC.Methods Whole genome sequencing and RNAseq were performed on a series of patients with resected or locally advanced/metastatic PDAC collected between 2008 and 2020 at a single institution. A subset of specimens underwent immunohistochemistry (IHC) analysis. Clinical and molecular characterisation and IHC sensitivity and specificity were evaluated.Results 400 patients were included (resected n=167; locally advanced/metastatic n=233). Three patients were identified as harbouring an NTRK fusion, two EML4-NTRK3 (KRAS-WT) and a single novel KANK1-NTRK3 fusion. The latter occurring in the presence of a subclonal KRAS mutation. Typical PDAC drivers were present including mutations in TP53 and CDKN2A. Substitution base signatures and tumour mutational burden were similar to typical PDAC. The prevalence of NTRK fusions was 0.8% (3/400), while in KRAS wild-type tumours, it was 6.25% (2/32). DNA prediction alone documented six false-positive cases. RNA analysis correctly identified the in-frame fusion transcripts. IHC analysis was negative in the KANK1-NTRK3 fusion but positive in a EML4-NTRK3 case, highlighting lower sensitivity of IHC.Conclusion NTRK fusions are rare; however, with emerging therapeutic options targeting these fusions, detection is vital. Reflex testing for KRAS mutations and subsequent RNA-based screening could help identify these cases in PDAC.No data are available. ER -