The case for cancer-associated fibroblasts: essential elements in cancer drug discovery?

Recent advances in cancer research have improved our understanding of disease progression; however, the number of drugs failing in clinical trials remains high and therefore, present a critical challenge for cancer drug discovery. Although the interactions of the tissue surrounding the tumor, the tumor microenvironment, are now considered key targets for new interventions in cancer, the role of microenvironment is largely absent in drug discovery pipelines. Here we explore the role of the most prominent cell type in the tumor microenvironment, cancer-associated fibroblasts (CAFs), in altering cancer therapy response and ultimately patient outcome. To provide new perspectives for future studies, we draw attention to key complications of CAF biology and highlight emerging technologies that could be used to address this. We believe including CAFs in drug discovery, whether for targeting cancer cells or the microenvironment, will allow for a better understanding of therapeutic efficacy and ultimately improve clinical outcome.