Why do we need to print more tumors

Murine tumor models, while extremely useful for studying biological processes during tumor growth, and for preclinical development of antitumor therapies, also have well characterized limitations. As a result, numerous anti-tumor immunotherapy drugs, although efficacious in mice, have proved unusable against human tumors. Other drugs may have been missed due to a lack of response in tumor models, which fail to capture tumor structure complexity. Recent work revealed that various human cancers have regions within the tumor composed of dense areas of antigen-presenting cells that resemble the T cell zone of secondary lymphatic tissues. These regions are enriched with stem-like CD8 T cells, which provide the proliferative burst following checkpoint blockade therapy that is correlated with better prognosis. Unfortunately, traditional two-dimensional (2D) cell culture techniques lack the necessary complexity to replicate such an architecture. Here we propose the use of a novel three-dimensional (3D) in vitro bioprinted methodology to generate tumors with immune niches. This model will allow different treatments to be evaluated, and provide an opportunity to examine how spatial relationships between different cells (both immune and non-immune) can impact T cell differentiation and function. I will discuss our recent advances and future goals working with this innovative technology.