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Katherine L. Nathanson, MD

University of Pennsylvania
Philadelphia, Pennsylvania

Titles and Affiliations

Pearl Basser Professor of BRCA-Related Research
Medicine, Translational Medicine and Human Genetics
Deputy Director, Abramson Cancer Center
Perelman School of Medicine

Research area

Refining breast cancer risk assessment by examining moderate risk genes and common inherited gene variations in families with a high risk of breast cancer.


The most common hereditary risk factors are mutations in the BRCA1 or BRCA2 genes, but these account for only 5-10 percent of inherited breast cancers. There are additional breast cancer risk genes, though mutations in these genes are not as potent as BRCA mutations. Dr. Nathanson’s studies have demonstrated the frequency of mutations in high and moderate penetrance genes, their distribution around the world, and the penetrance and risk of cancers associated with these mutations. Her team is utilizing novel methods of gene sequencing to assess mutations and variants in multiple genes associated with increased risk of breast cancer. The results of their studies will lead to a better understanding of hereditary breast cancer, specifically, the factors that increase the risk of breast cancer in those patients with negative standard genetic testing results.

Progress Thus Far

Dr. Nathanson and her team have shown that women with breast cancer and a second primary cancer have an increased likelihood of carrying an inherited mutation in a cancer susceptibility gene and should be eligible for genetic testing regardless of the age of breast cancer diagnosis. Her team launched a study of very high-risk women with early-onset breast cancer to identify what drives their risk of breast cancer, who should be offered genetic testing, as well as the genes that should be included on multi-gene panels.

What’s next

Dr. Nathanson and her colleagues will continue to characterize the pathogenic variants in known and novel breast cancer susceptibility genes that can be correlated to an increased risk of the disease. In addition, they will analyze the data they have collected from high-risk women—those with both early onset breast cancer and multiple family members with breast cancer—to identify the drivers of risk in the absence of mutations in known predisposition genes. The results of her studies will be used to develop and refine models to yield accurate estimates of breast cancer risk and minimize inconclusive genetic testing results and provide greater benefit for patients and their families.


Dr. Nathanson is a cancer geneticist, boarded in Internal Medicine and Clinical Genetics; she runs a research laboratory and has a busy clinical practice. Currently she is Professor at the Perelman School of Medicine at the University of Pennsylvania, and at the Abramson Cancer Center is the co-Leader of the Cancer Control Program and Chief Oncogenomics Physician.

Dr. Nathanson has had extensive experience with molecular genotyping and analysis of genetic variants in relationship to cancer susceptibility and somatic genetics of cancer. She runs a translational research laboratory and has had a long term interest and published extensively on breast cancer genetics on topics including the identification of novel breast cancer susceptibility genes, characterization of cohorts that carry mutations in BRCA1/2 and genetic modifiers of breast cancer penetrance in BRCA1/2 mutation carriers, among others. Dr. Nathanson is a key contributor to the development of a large collection of DNA and tissue samples from high-risk family breast cancer cohorts, participating in several national and international consortium, including the Consortium of Identifiers of Modifiers of BRCA1/2 (CIMBA) and Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA). She has had a longstanding interest in the identification and characterization of moderate to high penetrance breast cancer susceptibility genes, which is the focus of her BCRF funded project.

BCRF Investigator Since


Donor Recognition

The Ulta Beauty Award