Estrogen receptor positive breast cancer patient derived xenograft models in translational research

Abstract Estrogen receptor (ER) positive patient derived xenograft (PDX) models of breast cancer are important translational tools in our pursuit for a better understanding of treatment resistance and for the preclinical evaluation of novel therapies. PDX modelling of ER+ breast cancer is traditionally associated with caveats such as low engraftment rates and absence of immune components, leading to a paucity of ER+ models and an inability to assess immune-related effects. Furthermore, with the increased demand for modelling of therapy-resistant metastatic ER+ disease, our approach to propagating these models needs to evolve to ensure accurate recapitulation of the clinical features observed in patients with treatment-resistant breast cancer. In this review, we discuss recent major advancements in this field and the increasing utility of these models for high throughput screening of novel therapeutics.