Director, Dan L. Duncan Cancer Center
Professor of Medicine and Molecular and Cellular Biology
Baylor College of Medicine
Although there are effective treatments for estrogen receptor-positive (ER+) and HER2+ breast cancers, many tumors are, or become resistant to these therapies. Drs. Schiff and Osborne are collaborating to develop new models of resistance that can be used for a variety of scientific studies to identify key molecules responsible for treatment resistance and to develop new treatments that will improve patient outcome. Their BCRF research suggests that drug resistance occurs because of the cooperative influence of compensatory and/or adaptive mechanisms and the evolution of rare tumor cells with unique mutations and/or non-genetic modifications to DNA (epigenetic features). Mechanisms of resistance to endocrine treatments, which include changes in growth factor signaling as well as in the estrogen receptor gene or other co-regulators, have guided several new drug combinations. Drs. Schiff and Osborne are currently testing these combinations to identify the most effective regimens for ER+ breast cancer. Similarly, they have identified several resistance mechanisms to anti-HER2 therapies, which include an increase in the activity of the cholesterol synthesis and the ER pathways, mutations in the HER2 protein itself, increased levels of other signaling molecules, and alterations in various components of the patient’s immune system. In 2015-2016, they will continue to investigate these and additional pathways involved in resistance to endocrine and anti-HER2 therapy using various preclinical models and clinical trial samples.
Dr. Osborne was born in St. Louis, Missouri and received his AB and his MD from the University of Missouri, both with honors. He completed his internship and residency at Johns Hopkins and followed this with three years as a Clinical Associate at the Medicine Branch of the National Cancer Institute. He was a faculty member at the University of Texas Health Science Center from 1977 until 1999 and became Chief of Medical Oncology in 1992. In 1999, Dr. Osborne moved to Baylor College of Medicine to direct a new Breast Center and in 2004 he, in addition, was named Director of the Dan L. Duncan Cancer Center at Baylor.
Dr. Osborne's research interests have focused on the biology and treatment of breast cancer. He has published extensively on the role of growth factors in breast cancer pathogenesis, and he has also investigated the mechanisms of action and resistance to ER and HER2 targeted therapies in breast cancer. Dr. Osborne currently directs the Baylor Breast Cancer Specialized Program of Research Excellence Grant. Dr. Osborne has authored more than 400 manuscripts dealing with the biology and treatment of breast cancer.