Methods for detecting cancer as well as methods of diagnosis of cancer by detecting proteins secreted into biological fluids are disclosed The invention was first applied to detecting proteins secreted into serum and urine However, it is understood that the methods have broader application to developing tools and systems for detecting proteins secreted into other biological fluids such as, but not limited to, saliva, spinal fluid, seminal fluid, vaginal fluid, and ocular fluid Reliable detection of proteins secreted into biological fluids provided by embodiments of the methods will enable more timely and accurate detection and diagnosis of cancer.