Common confounders when evaluating noninvasive protein biomarkers

Noninvasive protein biomarkers are becoming an increasingly important factor in medical practice and clinical trial design. Such quantifiable molecular biomarkers can serve as early surrogate endpoints of an eventual clinical outcome and/or identify patients most likely to respond to a specific therapy. Noninvasive biomarkers offer several advantages over tissue-based markers; however, it is important to be familiar with potential common confounders that may impact the interpretation of the results and hence the clinical decision-making.