VERMILLION, S.D. | Dr. Dong Zhang doesn't just talk a good genetic game with his students at the University of South Dakota.

He rolls up the sleeves in his lab coat and digs in.

Zhang, a assistant professor of basic biomedical sciences at USD's Sanford School of Medicine, spends half his time researching DNA when he's not teaching DNA repair to first-year medical students. His lab is just behind his office in the Lee Medical School on campus.

Zhang works with other researchers from the University of Michigan, The Ohio State University and the University of Texas MD Anderson Cancer Center. Their work involves examining DNA damage and repair. Of particular interest is the BRCA1 gene, the "faulty" gene that sharply increases the risk of developing breast cancer and ovarian cancer for those who carry it.

Actress Angelina Jolie carries the BRCA1 gene. She directed a national spotlight on this DNA research with her decision to have a preventive double mastectomy. She wrote an opinion piece in The New York Times in May, one that makes Zhang's work seem even more pertinent to his students.

"If you have the BRCA1 gene mutation, you have 80 percent risk of developing breast cancer and a 50 percent risk of developing ovarian cancer," says Zhang.

Jolie's mother, who also carried the "faulty" gene, fought breast cancer for nearly 10 years before losing her battle at age 56.

"The gene mutation fascinates me," says Zhang, who works with cultures in the lab adjacent to his office.

Narrowing the source of the cancer, he says, allows researchers to work on what's called targeted therapy. Zhang's quest is to one day find drugs that only kill cancer cells, not healthy cells in a patient's body.

"Many chemotherapy drugs are DNA damagers and they damage the DNA of a tumor," he says. "But general drugs like that can also damage other DNA."

That's why, in many cases, those fighting cancer lose their hair or suffer other negative reactions such as nausea.

The future of the fight against cancer involves targeted therapy, or synthetic lethals. Zhang keeps working in hopes of making breakthroughs to help people like Jolie and future generations.

"President Nixon declared a war on cancer in 1974," says Zhang, a native of Shandong Province, on the east coast of China. "We could make cancer chronic and elongate peoples' lives 20 to 30 years."

Doctors and patients have higher success rates with pediatric cancers as those diseases often involve just one or two gene mutations. For adults, there are many more mutations to attempt to isolate. It makes the fight that much more difficult.

Still, researchers like Zhang keep plugging away, thankful for the opportunities grants and institutions like USD provide for that invaluable time in the lab.

Zhang, who trained as an undergraduate in medical chemistry, earned his doctorate in molecular biology and biochemistry at Brandeis University in Boston, Mass. After earning his doctorate, he served at the Baylor College of Medicine in Houston, Texas and for three years at Harvard Medical School.

For three years he worked in private industry, doing research for a company that developed Advil. He came to USD in 2010 and continues to teach while conducting DNA research.