OBJECTIVES: New biomarkers are being developed to identify individuals at risk for cancer, detect disease earlier, determine prognosis, detect recurrence, predict response to particular agents, and monitor response to treatment. This article attempts to address some of the challenges facing the research and medical communities in the delivery of new biomarkers for individualized medicine. METHODS: A variety of issues and barriers can affect the transfer of clinical tests from research to clinical practice. Differences in sample collection, handling or storage, and profiling techniques may influence the protein profile obtained by any method. RESULTS: Standard procedures and quality check schemes are necessary because there is a lack of definition to guarantee reproducibility of new procedures. From technical and economic viewpoints, the assay has to be sufficiently robust to be completed in community-based hospitals. Although traditionally cancer patients were treated with drugs of low toxicity or of high tolerance regardless of their efficacy in a given patient if the benefits of that drug are proven in both experimental and clinical conditions, recent advances have provided opportunities to adapt "tailored" treatment modalities. The evolving trend is the usage of patterns of markers instead of a single marker. Further challenges in biomarker development are in finding the relevant markers that have the right degree of specificity and sensitivity and a reliable test to measure the outcome. CONCLUSIONS: Discovery, testing, and validation of clinically appropriate and commercially useful tumor markers should permit individualization of therapy.
