Biomimetic tumor microenvironment on a microfluidic platform.

Tumor microenvironment is a highly complex system consisting of non-cancerous cells, soluble factors, signaling molecules, extracellular matrix, and mechanical cues, which provides tumor cells with integrated biochemical and biophysical cues. It has been recognized as a significant regulator in cancer initiation, progression, metastasis, and drug resistance, which is becoming a crucial component of cancer biology. Modeling microenvironmental conditions of such complexity in vitro are particularly difficult and technically challenging. Significant advances in microfluidic technologies have offered an unprecedented opportunity to closely mimic the physiological microenvironment that is normally encountered by cancer cells in vivo. This review highlights the recent advances of microfluidic platform in recapitulating many aspects of tumor microenvironment from biochemical and biophysical regulations. The major events relevant in tumorigenesis, angiogenesis, and spread of cancer cells dependent on specific combinations of cell types and soluble factors present in microenvironmental niche are summarized. The questions and challenges that lie ahead if this field is expected to transform the future cancer research are addressed as well.