Table 5.

Sample selection for biomarker discovery. Table adapted from [5].

	Tissue Biopsy, Needle biopsy	Serum and Plasma	Urine	Prostatic Fluid and Seminal Plasma
Advantages	Direct analysis of tumor protein expression/activation	Non-invasive collection	Non-invasive collection	Slightly invasive collection
	Diagnostic markers	Fast and low-cost sample preparation	High volume	Abundant in prostate-derived proteins
	Prognostic markers	Diagnostic markers	Rich in prostate-derived proteins	Quick and low-cost sample preparation
	Most useful for patient stratification in terms of response to therapy	Prognostic markers	Fast and low-cost sample preparation	Diagnostic markers
			Diagnostic markers	Prognostic markers
			Prognostic markers
Limitations	Invasive collection	Low abundance of potential biomarkers	Low abundance of potential biomarkers	Minimal abundance of potential biomarkers
	Limited quantity	Dynamic concentration range	Dynamic concentration range	Dynamic concentration range
	Must be snap-frozen within 30 min of collection	Intra- and inter-patient variability in composition	Intra- and inter-patient variability in composition	Intra- and inter-patient variability in composition
	Complex sample preparation Tissue sampling errors		Variability in sample collection