So far research has been focused almost exclusively on searching individual proteins as protein biomarkers for cancer detection and diagnosis. The level change of an individual protein target in biological systems and fluids is most commonly studied to identify their potential association with cancer. Using a nanoparticle aggregation immunoassay, we discovered several proteins that are substantially more complexed/aggregated in different cancer than normal tissue. The level of protein complex/aggregate in a biological system can serve as a biomarker for disease detection and as a target of therapy. In one particular example, prostate cancer is clearly distinguishable from normal prostate and prostate with benign conditions according to the complex/aggregate level of a unique biomarker protein
