Abstract 4792: Comprehensive molecular pathology analysis of small bowel adenocarcinoma reveals novel targets with clinical utility

Small bowel accounts for only 0.5% of cancer cases in the US; a third of which are adenocarcinomas. But incidence rates have been rising at a rate of 2.4% per year over the last decade. Because of the rarity of this cancer, little is known about its molecular pathology and there are no molecular markers for diagnosis, predicting prognosis or therapeutic intervention. The aim of this study was therefore to look into this disease at a molecular level to better understand its biology and identify biomarkers and potential points of therapeutic intervention. Using a retrospective 28 patient matched normal-tumor cohort next generation sequencing (NGS) was performed using a 50 gene cancer hotspot panel, gene expression arrays were used to profile ∼29,000 RNA transcripts and 450k CpG methylation arrays were used to carry out DNA methylation analysis. We also looked at microsatellite instability (MSI), HER2 and p53 expression. NGS identified novel mutations in IDH1, CDH1, KIT, NRAS, FGFR2, FLT3, NPM1, PTEN, MET, AKT1, RET, NOTCH1 and ERBB4. Previously known mutations such as high-frequency KRAS and TP53 and low-frequency HER2 were also confirmed in our cohort. The average patient had 2.6 mutations with eight patients having only a single mutation to one having seven. Array data revealed 17% of CpGs and 5% of RNA transcripts assayed to be differentially methylated and expressed respectively (p This study has for the first time highlighted the extent of molecular changes taking place in SBA. The clinical potential of TP53 mutations and Kazald1 hypomethylation as prognostic biomarkers and CHN2 as a diagnostic biomarker are focus areas for further research by our group. Citation Format: Muhammad A. Alvi, Darragh G. McArt, Paul Kelly, Marc-Aurel Fuchs, Matthew Alderdice, Clare M. McCabe, Victoria Bingham, Claire McGready, Stephen McQuaid, Perry Maxwell, Peter Hamilton, Jacqueline A. James, Richard Wilson, Manuel Salto-Tellez. Comprehensive molecular pathology analysis of small bowel adenocarcinoma reveals novel targets with clinical utility. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4792. doi:10.1158/1538-7445.AM2015-4792