Dear Colleagues:

Cancerous tumors are among the most fatal diseases worldwide, claiming nearly 10 million lives in 2020. Due to their complex and dynamic nature, modeling tumors accurately is a challenging task. Current models suffer from inadequate translation between in vitro and in vivo results, mainly because of  isotropic nature of tumors and their microenvironment's relationship. To address these limitations, 3D bioprinting is privileged as an emerging technique to mimic cancer development and behavior. Bioprinting of polymers and their composites would be a solution. In this Special Issue our topics will be related to modeling methods used so far and their limitations, such that the significance of bioprinting, its applications in cancer modeling, and the importance of biomaterials selection will be highlighted.