Microfluidics for Cancer Biomarker Discovery, Research, and Clinical Application.

Currently, cancer is the leading cause of death and its incidence and mortality is growing rapidly all over the world. One of the confounding factors contributing to the failure of conventional cancer diagnostics and treatment strategies is a high degree of intratumoral and intertumoral heterogeneity at the single-cell and molecular levels. Recent innovations in microfluidic techniques have revolutionized single-cell and single-molecule research and challenged the conventional definition of a "biomarker." Alongside classic cancer biomarkers such as circulating tumor DNA or circulating tumor cells (CTC), tumor cell heterogeneity, transcriptional and epigenetic cell states and their abundance in the tumor microenvironment have been demonstrated to impact disease progression and treatment response. Utilizing high-throughput, robust microfluidic techniques for the detection, isolation, and analysis of various cancer biomarkers, valuable information about the tumor can be obtained for clinical decision-making. This chapter presents clinically relevant advances of cancer biomarker research using microfluidics technology and identifies the emerging applications for disease diagnosis, monitoring, and personalized treatment.