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27th November 2015

Cancer Treatment Gets Personal with DNA Sequencing

When identical twin sisters were diagnosed with different forms of cancer, they began to wonder if cancer was “in their genes.” They discovered that gene sequencing could provide answers, but it could also raise some difficult questions.

Kathy Giusti was an otherwise healthy 37-year-old when she was diagnosed with multiple myeloma, a rare and incurable cancer of the plasma cells. This was in 1996, before many of today’s treatments were available.  “Back then, the prognosis was grim,” Kathy says. “I was given three years to live.”

She remembers the shock of her diagnosis. “Despite the fact that one in every two men and one in every three women will be diagnosed with cancer in their lifetime, no one expects it  would happen to them. I surely didn’t,” she says.  “I had many moments of despair where I was certain my battle was over even before it had begun. But the thought of my beautiful little girl, just a year-old, gave me the determination to live.”

Kathy educated herself on cancer, myeloma, and her treatment options. Two years after the  diagnosis, she  started the Multiple Myeloma Research Foundation together with her identical twin sister, Karen Andrews. After years of treatments, Kathy received a stem cell transplant from Karen in 2006, and finally went into remission. But the family’s fight against cancer didn’t end there.

Looking for asnwers…

In fact, the disease seemed to follow Kathy and Karen’s family. Their father died of kidney cancer at the age of 63. Their mother, Elizabeth, was diagnosed with melanoma. A grandmother had breast cancer, and a grandfather also had multiple myeloma. When Karen was diagnosed with breast cancer in 2014, Kathy wondered how two identical twin sisters could get two different types of cancer. She wanted answers.

So she decided to contact A. Keith Stewart, the director of Mayo Clinic’s Center for Individualized Medicine, and asked him to do a gene sequence on her entire family.  Gene sequencing takes a look at the six billion DNA letters found in an individual’s chromosomes. By studying the order and length of each string of letters, researchers gain insights into how the individual’s body works.

Gene sequencing is used to see why certain healthy cells turn into cancer cells. Small changes in genetic letters can differentiate one form of cancer from another, or identify a subtype of cancer. Understanding the cancer genome can also help a doctor select the best treatment for a patient.As gene sequencing information is highly valuable in the research community, there is a push for individuals to share their sequencing data and health information. This type of “data donation” became a national priority in the United States in September, when President Obama announced a $215 million investment in the Precision Medicine Initiative, a push to collect the genetic data for one million Americans.

…in her family’s genes

This is what Kathy had in mind when she suggested sequencing her immediate family. She and Dr. Stewart hoped to create a valuable pool of data to explain why certain family members developed cancer, and if others were at risk. However, not everyone was thrilled about the idea.

Kathy and Karen’s mother, Elizabeth, volunteered to participate. “I don’t think there’s too much more to learn about myself that would be surprising. But I’m willing to do anything that could be helpful.” Kathy’s husband and son also volunteered. Kathy’s daughter, Nicole, now 21 years old, was hesitant. She felt too young to have the results hanging over the head. Also, Karen was worried that there may be unintended consequences for her or her children if  this kind of data was widely known. Having just recently completed chemotherapy and radiation treatments for her breast cancer, Karen worried that gene sequencing may uncover information she was not be prepared to hear.

Kathy still plans to get sequenced, and her mother will as well. Nearly 20 years after being given 3 years to live, Kathy has seen a number of new treatments developed for myeloma, and she credits a lot of this success to gene sequencing.

“Thanks to advances in sequencing technologies, we have gained unprecedented insights into the genetic drivers of cancer,” she says. “We now have an arsenal of breakthrough treatments that take into account these genetics and patients’ other unique characteristics, personalizing care and giving patients their very best chance of beating the odds.”


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