Enrichment methods for revealing lower molecular weight biomarkers in human breast plasma proteome

Abstract

Breast cancer is the most common malignancy in women, comprising about 18% of all female cancers. The most important tools in screening and early detection are imaging techniques: mammography, ultrasonography and magnetic resonance imaging. However, up to 20% of new breast cancer incidents cannot be detected by these methods. Up to now, poor diagnosis of breast cancer is due to a lack of specific biomarkers. Therefore, there is much interest in identifying useful pathological markers that can help in detection and treatment of this disease. Up to now, detecting minor proteins in human plasma is a difficult strategy due to the presence of several highly abundant proteins such as albumin and haptoglobins. The objective of this study was to develop a reproducible method that depletes high-abundant proteins and improves detection of minor ones. For this purpose, we evaluated the impact of using Affi-gel blue affinity columns and organic solvent (acetonitrile) precipitation on the removal of high abundant proteins. Fractionated plasma protein extracts were subsequently analyzed by SDS-PAGE and two dimensional gel electrophoresis. Our findings confirm that Affi-gel blue can enhance detection of minor plasma proteins and could thus be a useful strategy in the discovery of new breast cancer markers. Key words: Affigel blue, albumin, acetonitrile, plasma, proteomic separation, breast cancer.