Hallgeir Rui MD, PhD

Wisconsin Breast Cancer Showhouse (WBCS) Endowed Chair in Basic Breast Cancer Research

Professor of Pathology

Hallgeir Rui MD, PhD

Hallgeir Rui MD, PhD


Hallgeir Rui, MD, PhD is internationally recognized for his research on hormone signaling in breast cancer, and has a strong track record of leadership, mentoring and collaboration. He is the WBCS Endowed Professor of Breast Cancer Research at the Medical College of Wisconsin (MCW), with his primary appointment in the Department of Pathology, and a secondary appointment to the Department of Pharmacology & Toxicology. In addition, Dr. Rui serves as the Associate Director of Basic Science and Shared Resources at the MCW Cancer Center. With his past experience as a Program Leader and Shared Resource Director at the NCI-designated Sidney Kimmel Cancer Center at Thomas Jefferson University, Dr. Rui brings valuable experience to the MCW Cancer Center efforts toward NCI-designation. Dr. Rui serves on the Breast Cancer Translational Research Committee of NRG Oncology.

Research Interests
  • Breast Cancer
  • Cytokine receptors
  • Hormones: Estrogen, growth, glucocorticoid, steroid
  • Endocrinology
  • Prolactin and Prolactin receptors
  • Jak2, Stat5, Stat5a, Stat5b
  • Immunohistochemistry
  • Pathology
  • Biomarkers
  • Early detection
  • tissue microarray
  • mouse modeling
  • EGFR, Her2, ErbB2
Professional Background
  • Dr. Rui leads an inter-institutional consortium of multidisciplinary investigators to classify malignant breast tumors based on the expression of druggable target proteins for improved personalized cancer care, an effort initiated by a prestigious Promise Grant from the Susan G. Komen Foundation. Advanced quantitative immunofluorescence-based immunohistochemistry technologies are being used and developed. Programmatic efforts are being pursued using novel patient-derived breast cancer xenograft lines to find more effective strategies combination for metastatic breast cancer. Dr. Rui holds several patents that include high-density tissue arraying technology.
  • Dr. Rui has made a series of contributions to increased understanding of the molecular mechanisms of signal transduction by cytokine receptors and hormones, with a research focus on breast cancer. Dr. Rui was the first to isolate a prolactin receptor-associated tyrosine kinase, and to identify this molecule as Janus kinase-2. Dr. Rui’s laboratory has maintained a focus on cytokine and hormone receptor function with a primary goal of understanding the role of downstream Jak-Stat pathways and their aberrations in breast cancer.
  • Activation of Stat5 is a strong favorable prognostic marker in breast cancer and an invasion-suppressive role of Stat5 in human breast cancer may represent a biological mechanism. Loss of Stat5 in estrogen-receptor-positive breast cancer is associated with increased risk of antiestrogen resistance. Dr. Rui and his team have invented and patented cutting-edge matrix assembly technology for generation of high density tumor tissue arrays for high-through-put molecular profiling.
Educational Background
  • MD, University of Oslo, Oslo, Norway
  • PhD, Pathology, University of Oslo, Oslo, Norway
Board Certifications
  • Anatomic and Clinical Pathology (2008)


Contact Information

Office Address
8701 Watertown Plank Road
TBRC Suite C4980
Milwaukee, WI 53226