This Doctor Linked Genes to Breast Cancer
After two decades of research, geneticist Mary-Claire King, Ph.D., theorized in 1990 that mutated genes cause some forms of breast cancer.
That revolutionary finding was later confirmed by other researchers, who pinpointed breast-cancer-triggering genes called BRCA1 and BRCA2.
Although genetic mutations cause just 5 to 10 percent of the 192,000 annual U.S. cases of breast cancer, Dr. King's discovery showed the importance of understanding how gene-linked proteins help trigger many types of breast cancer.
Dr. King's decision to study genetics was influenced by tragedy: At age 15, she watched a friend die of a kidney tumor. "It seemed so unfair," she says. "It wasn't a conscious decision, but I said to myself: 'Something needs to be done.'"
Since 1995, Dr. King has served as American Cancer Society Research Professor in the University of Washington Departments of Medicine and Genetics. She has also studied genetic factors in deafness, lupus and AIDS.
"I love to work on puzzles," she says, "and genetic puzzles are especially challenging, because they're so wonderfully complex!"
Q. How did you go about proving some breast cancers are genetically inherited?
Dr. King: Back in 1974... I began doing mathematical and statistical studies aimed at finding a connection between inherited genetic traits and breast cancer. I wanted to test the idea that mutated genes might be causing some types of breast cancer.
After I got some positive results from the statistical surveys, I started working in the lab. With the help of many colleagues, I began searching for genetic markers [nearby proteins] that might point us toward the location of genes involved in the development of breast cancer.
That work opened the door to the eventual identification of BRCA1 and BRCA2. But our work has really only begun. Now we have to move from what we're learning about normal cells and malignant cells to what we can do about them.
Q. What was the toughest hurdle in making this discovery?
Dr. King: I think the hardest part is the heterogeneity of cancer, because cancer is so many different diseases and it involves so many different conditions. The problem is that there are multiple [cellular] pathways that can go awry, and trying to identify all of them is essential to trying to understand all of normal cellular biology.
Q. The nation has been making gains against breast cancer. Your thoughts?
Dr. King: Well, I think it's enormously important that survivors of breast cancer and families of women with breast cancer have become involved in the fight against the disease. They've focused public attention on it, and they've saved an enormous number of lives, because women have gotten themselves tested with mammograms regularly.
Q. Regular mammograms are a good idea, then?
Dr. King: Yes, I am absolutely in favor of regular mammographic screening for women.
Q. Are we seeing practical results from this theoretical research?
Dr. King: Yes, there have been some absolutely practical advances. Breast cancers are detected earlier today, and survival among women who do develop breast cancer is better at every stage.
In terms of being able to attack breast cancer using the biology of breast cancer itself, we still haven't gotten there yet. That's why understanding the biology of breast cancer itself is so absolutely critical.
Q. What's next?
Dr. King: What's coming, I hope, will be compounds we can target at individual [cancer] cells. Right now, chemotherapy is targeted at all cells....But the science involved is absolutely mind-boggling -- and that's why basic research in this field is so vitally important!