Human Albuminome: Reflections of Neoplastic Transformation and Cancer Detection Through Albumin-Associated Biomarkers

Abstract

Human serum albumin is the most abundant protein in blood plasma. High abundance of albumin obscures the identification of low-abundance proteins using currently available proteomic technologies, and thus a pre-fractionation step is desired. At the same time, long shelf life of albumin makes it most important carrier protein molecule in the circulatory proteome. Albumin has six binding sites and can interact with a variety of intact and truncated proteins and peptides. In circulation, albumin binding can enrich the low molecular weight proteins by protecting them from renal clearance. This enriched albumin fraction is a valuable source for identification of cancer-specific potential biomarkers of high specificity and sensitivity along with other proteins that are involved in neoplastic growth and transformation. Identification of such albumin-associated biomarkers may aid in early detection of tumors and thus influence the outcome of treatment. Albumin along with its associated proteins is collectively called albuminome. We analyze and summarize the potential of human albuminome, technical challenges in its study, and its role in understanding molecular signatures of tumor progression and biomarker discovery.