[Innovations in biomarker development: a pathway towards individualized cancer therapy?]

Despite multiple medical and scientific achievements, cancer remains a leading cause of death worldwide. Next to imaging technologies, molecular methods for early detection and for monitoring of the course of disease are of increasing interest. Thus, over the past years numerous studies have focused on the identification of biomarkers for cancer diagnosis, prognosis and response to therapy. The study of biomarkers seems to pose a high degree of complexity because many different types of molecules may, in principle, serve as potential biomarkers. In addition, these molecules can be produced either by the tumor or by the tumor-host in response to the presence of cancer. In this review the authors will address several major topics encompassed by the field of biomarker research. They will discuss the primary sources from which biomarker candidates can be 'mined' as well as the technological or methodological challenges associated with identification of biomarkers. Furthermore, the review will focus on current biomarker candidates for head and neck squamous cell carcinoma (HNSCC), with particular interest on several molecules yielding potential relevance for detection and prognosis of this type of cancer. Finally, several biomarker candidates with predictive potential for the response to therapy of HNSCC patients will be discussed, since identifying such molecules is crucial for developing individually-tailored and improved therapeutic strategies.