3D bioprinting technology to mimic the tumor microenvironment: tumor-on-a-chip concept

Despite many advances in cancer treatment, cancer still remains a major global health problem owing to its high rate of recurrence, the tendency to metastasize, and the development of drug resistance. In addition to animal models, cancer researchers can employ in vitro tumor models to mimic in vivo tumor microenvironment with the purpose of discovering new therapeutic approaches. In order to engineer a realistic tumor microenvironment that can recapitulate not only cancer progression but also angiogenesis and metastasis, many complex interacting factors must be taken into account. Strategies based on 3D bioprinting are now being investigated, which could simulate the tumor microenvironment by bioprinting living human cells. These approaches allow the accurate placement of the normal cancer cells and bioactive macromolecules to monitor cancer progression, facilitate drug screening, and provide to design new generations of anticancer therapies. The present review summarizes progress in the area of 3D bioprinting utility for mimicking the tumor microenvironment, and studying the physicochemical/biological factors for new and improved therapeutic and diagnostic applications.