2 sisters diagnosed with breast cancer use genetic testing to determine different treatments

A Menlo Park woman is crediting a genetic test with helping her family learn more about their genetic make-up and said it can help others make informed decisions about their medical care.

For Kim Garlinghouse-Jones, cancer has been a thread weaved throughout her life.

“I started as an oncology nurse because that was an interest of mine,” she said. “I was so interested in understanding why diseases happened to certain people at certain times.”

Garlinghouse-Jones holds a master’s degree and studied breast and cancer in families for a research position at Stanford. She had no idea she would eventually develop breast cancer years later at age 40. The mother of four girls was nursing her youngest when she felt a lump.

“It turned out that I was advanced enough to need a double mastectomy and chemo and radiation,” she said. “I'd been so healthy my whole life and how could I have breast cancer. I'd done everything right.”

After a second diagnosis of tongue cancer, Garlinghouse-Jones took a genetic test. It showed she had a "CHEK2" gene mutation. Then two years ago, her sister Meg, was diagnosed with breast cancer. She urged Meg to take a genetic test through a company called Color Genomics.

Color, based in Burlingame, is a physician-ordered genetic test available online. The at-home saliva test looks for gene mutations linked to hereditary cancers and heart conditions.

“She did testing through Color Genomics to determine that she did not actually carry the mutation,” Garlinghouse-Jones said.

That information saved Meg from having a double mastectomy like doctors initially recommended. Instead, Meg had the lump removed. 

“She is incredibly relieved and grateful that she had that information and she wouldn't have that information if I hadn't pushed to have genetic testing done in the first place,” she said.

Amie Blanco, Director of the Cancer Genetics and Prevention Program at UCSF, said Color is a diagnostic genetic test.

“What Color is doing, is looking at these genes that are not common, but associated with very high risk,” Blanco said.

She noted that Color does is different than other companies that sell direct-to-consumer tests, which only look at low risk, very common, differences amongs people.

Arguably the most popular direct-to-consumer test, 23andMe, recently received FDA authorization to test for genetic risk, cancer risk, medication response, and carrier status. For example, the Mountain View based company, provides customers with information on the three most common genetic variants found on the BRCA 1 and BRCA 2 genes known to be associated with higher risk for breast, ovarian, and prostate cancer in people of Ashkenazi Jewish descent.

Emily Drabant Conley, Vice President of Business Development for 23andMe, said her company's technology is groundbreaking.

“We've been able to show to the FDA that people could understand this info,” she said. “That was part of the authorization process. We just get tremendous feedback and high ratings from our customers.”

But, some customers are downloading their raw data and taking it to a third party service for interpretation. A recent study by the American College of Medical Genetics and Genomics revealed a 40% false positive rate in the results from direct-to-consumer genetic tests, and misinterpretations when analyzed by third party services. The concern is that this could create false reassurances or lead to unnecessary medical treatment.

“We have significant disclaimers when people download that raw data,” Conley said. “That data is processed in a different way. We're not standing by any interpretation of that info, but people are taking that and getting these third party interpretations of it and that's where the confusion lies.”

23andMe notes it's not a substitute for visits to a health care provider.

Blanco agrees and said anyone with a concern about a specific inherited risk should seek a genetic counselor or specialist.

“I think it's important for people to read the fine print when they're signing up for any kind of direct to consumer test so they can understand what they're getting into,” Blanco said. “There's all kinds of direct-to-consumer genetic tests out there and as long as people realize that for entertainment purposes, that's fine. It's unlikely to really be useful for true health care.”

Kim’s sister Meg was required to speak with a Color genetic counselor, per company policy, to interpret the results.

“Genetic testing is going to revolutionize health care,” Garlinghouse-Jones said. “We don't need to be afraid of it. It would be like saying we need to be afraid of MRI's because that would show so much micro detail.”

She said knowing our genetic make-up is just another piece of the puzzle to who we are.

“I think it's changed the trajectory of my health and the health of my family,” she added.