Translating metastasis-related biomarkers to the clinic--progress and pitfalls

In the context of metastatic disease, preclinical models have been used primarily to decipher different steps of the metastatic cascade. Numerous molecular processes operate in these model systems, but none of these has been successfully translated to the clinic. We discuss some of the successes and failures of preclinical models in metastasis research and suggest some of the clues for more clinically relevant research. These potential avenues of research include: the use of adequate statistical methods and well-annotated cohorts in biomarker discovery; an objective assessment of the level of evidence provided by each biomarker; the development of robust molecular or cellular surrogates of metastasis in patients; and original designs for clinical trials.