Dan Regan

Associate Professor Microbiology, Immunology, and Pathology

ACC252 Flint Cancer Center

(970) 297-4034

About Dan

Dr. Regan received his DVM degree from the University of Georgia in 2011, and subsequently completed his residency training in veterinary anatomic pathology (2014) and PhD (Comparative Pathology; 2017) in the Department of Microbiology, Immunology, and Pathology (MIP) at Colorado State University. In 2018 he accepted his current faculty position in the Flint Animal Cancer Center and MIP in the College of Veterinary Medicine and Biomedical Sciences at Colorado State University. Tumors co-evolve in the presence of a complex micro-environment composed of a mixture of resident and recruited host cells. The focus of Dr. Regan’s laboratory is to increase our understanding of the interplay between the immune system and (non-immune) tumor stroma, and how these compartments of the tumor microenvironment promote metastasis as well as respond to and mediate extrinsic mechanisms of resistance to anti-cancer therapy. To investigate this area of cancer biology, his laboratory utilizes a combination of in vitro 3-dimensional tumor co-culture models and animal models, focusing on breast and bone cancer (osteosarcoma). Dr. Regan also has a strong interest in comparative oncology and leveraging naturally occurring cancers in dogs as both a surrogate and intermediary model to evaluate and validate his laboratory’s investigations into the tumor microenvironment. In collaboration with the laboratory of Dr. Steve Dow, we recently targeted an innate immune cell subset known as inflammatory monocytes as an immunotherapy for tumor metastasis, via identification of a small molecule compound that could be re-purposed to effectively inhibit monocyte recruitment. We confirmed the translational potential of these findings by utilizing this drug for monocyte-targeted immunotherapy clinical studies conducted in dogs with spontaneous osteosarcoma. Results from these translational studies have led to a phase I clinical trial in children with osteosarcoma. Our continued long-term research goal is to fully elucidate the mechanisms by which tumors prime non-malignant host stromal cells of distant organs to promote their metastasis and chemo-resistance, in order to identify novel targets for host-directed stromal therapies which “poison the soil” for effective combination with conventional tumor cell targeted drugs.


American College of Veterinary Pathologists