Oral Presentation Australian Society for Medical Research Annual Scientific Meeting 2016

High resolution mass spectrometry to identify new colorectal cancer biomarkers from sequentially collected plasma samples (#12)

Juhura (Trisha) G Al-mazi 1 , Nicole M Verrills 1 2 , Nathan D Smith 3 , Peter Pockney 4 , Hubert Hondermarck 1 , Matthew D Dun 1 2
  1. Hunter Medical Research Institute, Cancer Research Program, School of Biomedical Sciences and Pharmacy Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia
  2. Priority Research Centre for Cancer Research, Innovation and Translation, , University of Newcastle, Callaghan, NSW, Australia
  3. Analytical and Biomolecular Research Facility Advanced Mass Spectrometry Unit, University of Newcastle, Callaghan, NSW, Australia
  4. School of Medicine and Public Health, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia

Colorectal cancer (CRC) is the 2nd most common cause of cancer related mortality. Despite progress in treatment options for advanced staged disease 5 year survival is only 13%. Several plasma biomarkers are currently used for diagnosis, including carcinoembryonic antigen (CEA) however, the significance of CEA over-expression in CRC and its abundance in plasma remains controversial due to its expression in benign tumours. Therefore, improved detection and monitoring techniques coupled to better diagnostic and prognostic biomarkers are needed to improve the survival of these patients.

We tested the quality of proteins isolated from liquid biopsies using 2 types of blood collection tubes (BCT); STRECK and EDTA. STRECK BCT is the most efficient tube type for maintaining the quality of nucleic acids to be used in genomic prognostic analysis. Using high-resolution mass spectrometry we have tested the quality of proteins to be used as new biomarkers from patient plasma samples pre- and post-surgery and in both collection tubes. Plasma samples were obtained from the Hunter Cancer Biobank and digested using Trypsin/LysC enzyme mix. Sequence data was obtained using the Q-Exactive Plus mass spectrometer.

We have quantitatively identified >2000 plasma proteins and ~6000 unique peptides across 20 samples. Known CRC biomarkers, such as; ORM1, LUM, and GELS were identified. Interestingly, we have identified novel and potential new CRC plasma markers such as FCN3, HTR2A and SERPING1 which showed increased abundance in patient samples pre-resection that no longer showed elevated expression post-surgery. Label-free targeted analysis (PRM) revealed additional biomarkers not identified using by our labelling approach (CEACAM5 (CEA) and the novel marker UPAR).

Our study provides quantitative data for the best method of collection and storage of blood samples for proteomics. Future directions will resolve the clinical utility of these potentially new biomarkers which may improve the diagnosis and subsequent selection of personalised therapies.