Spotlight On: Curtis C. Harris, MD

Issue 24 Winter/Spring 2015

At the heart of any exploration into the origins – and prevention – of cancer is the relationship between a cell's genetics and its environment.

That relationship has also been the focus of Dr. Curtis Harris' award-winning research over the past few decades. In presenting him with the annual AACR-American Cancer Society Award for Cancer Epidemiology and Prevention in 2014, the AACR said Harris "is particularly renowned for his pioneering studies of gene-environment interactions."

"Cancer researchers are interested in what causes cancer – why one person has an increased risk versus another," Harris explained. "The more susceptible people are those who will benefit the most by both preventive activities and cancer screening."

Sometimes, as Harris' groundbreaking work has helped discover, certain DNA variants may be key. For example, he and his colleagues have published important findings on p53, a gene that helps regulate the senescence of healthy cells. However, this genetic barrier to cancer development is bypassed by cancer cells, which proliferate unchecked.

The p53 example shows how genes and the environment can combine to encourage cancer development. In one study conducted in Qidong, China — an area with a high incidence of liver cancer — Harris' team uncovered a relationship between the disease and a p53 gene damaged by the environmental carcinogen aflatoxin B1, which is a key to residents' cancer risk and prognosis.

In other work, Harris and his colleagues helped identify an inherited variant of the MBL2 gene that boosts the odds of lung cancer in people exposed during childhood to another environmental carcinogen, secondhand tobacco smoke. "The combination of these two factors increased the risk of lung cancer — even though these people never smoked," Harris noted.

Harris is also a proponent of Precision Medicine, described in a report by the Institute of Medicine, National Academy of Science. The goal: to integrate data from state-of-the-art analysis — including the structure and function of genes, tumor metabolism, and the immune system — with traditional medicine, to improve cancer care and guide prevention and biomedical research.

Preventing tumor recurrence is another major focus of Harris' research. "In cancers such as lung cancer, the surgeon completely removes a small, early stage cancer and the lymph nodes are negative," he explained. "And yet we know that about 30 percent of these people will have undetected micro-metastases and will frequently die of recurrent cancers if we don't intervene."

Work by Harris and his colleagues has also been instrumental in identifying "biomarkers" — expression of certain types of genetic material called microRNAs and pro-inflammatory genes — that may lead to tests that identify people with micro-metastases and a high risk of cancer recurrence.

These, and many more discoveries spearheaded by Harris, have "significantly impacted the field of cancer risk assessment and our understanding of the molecular pathogenesis of human cancer," the AACR said.

Along the way, Harris has received numerous awards, including the Distinguished Service Medal (the highest honor of the U.S. Public Health Service); the Alton Ochsner Award relating to smoking and health from the American College of Physicians; the Nelson Fausto Award from the International Liver Cancer Association; and two outstanding mentor awards from the NCI. He has published more than five hundred papers and is currently editor-in-chief of the journal Carcinogenesis.

Harris received his medical degree from Kansas University School of Medicine in Kansas City, and completed his clinical training at the University of California, Los Angeles and the NCI. He has led the Laboratory of Human Carcinogenesis at the NCI's Center for Cancer Research since 1981, and also is an Adjunct Professor in the Department of Oncology at Georgetown University Medical Center in Washington, DC.

Curtis C. Harris, Ph.D.

Curtis C. Harris, MD
Chief, Laboratory of Human Carcinogenesis
Head of Molecular Genetics & Carcinogenesis Section
Center for Cancer Research
U.S. National Cancer Institute
Bethesda, MD