Abstract 1562: Proteomic changes observed in colon cancer tumors by label-free differential profiling of paired tumor versus normal FFPE samples

Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA Colorectal cancer (CRC) is the third most common cancer and if caught early enough has a good prognosis. Mass screening of the adult population is advisable to reduce CRC mortality rate as well as reduce the cost of treating advanced CRC cases. A blood-based biomarker panel with the ability to diagnose CRC as well as determine prognosis and predict the response to drug therapy is desired. However, blood biomarker discovery is hampered by problems of complexity and dynamic range of protein abundance. Formalin-fixed and paraffin-embedded (FFPE) tissue is an ideal sample type for cancer biomarker analysis due to its ubiquitous use in cancer diagnosis in the clinic and consequent availability in oncology hospitals and clinics as well as biobanks. Biomarker discovery to date using FFPE have used only very few patient samples, making clinically relevant biomarker discovery difficult due to large patient-to-patient variation. As a part of our Biospecimen Research Network (BRN) program we funded a proteomic biomarker study of a large number of colorectal cancer and adjacent normal tissue samples. The investigators employed two platforms for biomarker discovery: label-free intensity based discovery using high resolution tandem mass spectrometry and targeted quantitation using multiple reaction monitoring. These two techniques allowed them to dig deeper into the proteome and to profile phosphopeptides. Paired tissue from 40 patients was profiled and of the 2875 proteins quantified, 367 proteins changed significantly in patients whose tumor size was greater than 50%. Large changes in secreted proteins were observed and many of these proteins were also observed in blood, offering promise for a potential blood-based biomarker for colorectal cancer. A blood-based biomarker assay for colorectal cancer could ultimately reduce the number of colonoscopies required, reducing cost and discomfort. Citation Format: Lokesh Agrawal, Fiona McAlister, Sushmita Roy, Florian Unger, Kerstin David, Harmut Juhl, Daniel Chelsky, Helen Moore. Proteomic changes observed in colon cancer tumors by label-free differential profiling of paired tumor versus normal FFPE samples. [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 1562. doi:10.1158/1538-7445.AM2015-1562