Titles and Affiliations

Professor, Department of Pathology
University of Colorado Anschutz Medical Campus
Denver, Colorado

Research area

Discovering ways to improve treatment response in patients with estrogen receptor-positive breast cancer.


Breast cancers that are driven by estrogen, called estrogen receptor (ER)-positive, have the best five-year prognosis of any breast cancer. Despite effective therapies to treat ER-positive breast cancer, one-quarter to one-third of patients will experience a breast cancer recurrence. The goal of Drs. Sartorius’ and Horwitz’s BCRF research is to identify and test vulnerabilities in a common but understudied group of cells in ER-positive tumors that may be responsible for drug resistance and recurrence. By understanding how these cells drive tumor growth and identifying their weaknesses, they hope to identify strategies to turn them off and prevent recurrence.

Progress Thus Far

In the last year, Drs. Sartorius and Horwitz finished developing new models of ER-positive breast cancer that have several mutations prevalent in human breast cancer but not typically found in most laboratory models. They have made progress on their work to understand the function of a group of proteins that are prevalent in stem cell-like cancer cells and are now extending this work to include triple-negative breast cancers. 

What's next

The team will use state-of-the-art technologies to identify factors that activate or repress the genes that give rise to cancer stem cell-like properties and/or that switch off the estrogen receptor, leading to resistance to anti-estrogen treatments. They hope to understand how cancer stem cells affect tumors and how to prevent the switch to stem cell-like states.


Dr. Sartorius earned her bachelor’s degree from the University of Michigan and PhD from the University of Colorado Health Sciences Center, both in Molecular Biology. She did her postdoctoral work at the University of Colorado Boulder and is currently a Professor of Pathology at the University of Colorado Anschutz Medical Campus (UC-AMC).

Dr. Sartorius’s research studies the biology, progression, and endocrine resistance of hormone receptor positive breast cancer. Her laboratory seeks to understand the molecular basis of transcriptional regulation by progesterone receptors (PR) and how this impacts estrogen receptors (ER) and tumor cell phenotype. Current research topics include hormone regulation of cancer stem cells and tumor heterogeneity, hormone regulation of metastasis, hormone control of translation and protein synthesis, and how host obesity and metabolic syndrome specifically affect ER-positive breast cancer and endocrine resistance. Dr. Sartorius’s team also specializes in developing hormone-dependent breast cancer models. She is the co-founder and co-director (with Dr. Peter Kabos) of the breast cancer patient-derived xenograft (PDX) bank at UC-AMC. Their collection emphasizes ER and PR-positive tumors. These tumor models are being characterized by genomic and proteomic techniques to discover novel hormone receptor interactions that can be leveraged for treatment. The goal is to improve hormone-directed therapies for breast cancer.

She is an active member of the Cancer Biology Training Program at UC-AMC with an interest in training the next generation of scientists in the field of hormones and cancer. Her laboratory trains predoctoral students, and postdoctoral and clinical fellows.

BCRF Investigator Since


Areas of Focus