JOLIET – Dr. Nafisa Burhani, with Joliet Oncology-Hematology Associates in Joliet and Morris, said doctors have known about cancer genes for some time, but many of the clinical implications are being seen just now.
Burhani said our bodies have the ability to repair DNA when it is damaged, but sometimes mutations arise that impair that process, resulting in cancer. Testing is available for inherited genetic mutations in such cancers as breast, ovarian and colon, Burhani said.
“These are powerful tests,” Burhani said. “We can prevent cancer in some of these people who test positive.”
This knowledge of genetics is helping to lead to new cancer treatments. For instance, in December 2014, the U.S. Food and Drug Administration approved a new treatment for certain types of ovarian cancer. Olaparib, which will be marketed as Lynparza, may cause cancer cells to die because it interferes with their ability to repair DNA.
However, olaparib is only for women who test positive for the BRCA gene mutation and who have undergone three lines of chemotherapy, said Ron Rogers, executive vice president of corporate communications for Myriad Genetics Inc., based in Utah.
The FDA also approved a blood test called BRACAnalysis CDx, which finds BRCA gene mutations in potentially eligible patients, taking genetic testing to a new level, Rogers said.
“When you do genetic testing on women and learn information on the tumor,” Rogers said, “then you can target the best drugs for treating that tumor.”
Genetic testing also can tell people if they are more likely to develop a condition, said Kisha Johnson-Isidore, a geneticist with Myriad Genetics, who works with Burhani regarding conditions based on gene mutations.
Johnson-Isidore believes that is useful information to have.
“The point of genetic testing,” Johnson-Isidore said, “is that you can do something differently to decrease the risk of developing it or to manage it better if you have it.”
Just two years ago, Johnson-Isidore said, the cause of Kabuki syndrome – which is associated with developmental delays – was not known. With a genetic technique called whole exome sequencing, the gene was found.
“There are more than 25,000 genes in our body that we know of, but we don’t know what the function of all of them are,” Johnson-Isidore said. “With the technology of five years ago, we could only look at one gene at a time. Now with next-generation sequencing, we can look at panels of genes at a time. It’s very fast, very cheap and very accurate.”
Alive because of genetic test
Heather Meyer of rural Marseilles believes getting tested for the breast cancer gene saved her life. Meyer’s mother died from ovarian cancer; and then her sister, Jodi – after being diagnosed with breast cancer – urged Meyer and several family members to undergo the testing.
Jodi died within a year of her diagnosis, but Meyer took her sister’s advice and learned she was positive for the BRCA1 genetic mutation, Meyer said.
According to the American Cancer Society, www.cancer.org, BRCA are genes that everyone has and naturally suppress tumors. When one mutates, cancer is more likely to develop. There are hundreds of different BRCA mutations. Some raise the risk for breast, ovarian, pancreatic or stomach cancers.
Meyer decided to have a complete hysterectomy before cancer could develop. She and her husband previously decided not to have children. Soon afterward, Meyer consulted with her surgeon about having a double mastectomy. During that appointment, the doctor found a lump in Meyer’s breast.
“It was about a week after my mother had died,” Meyer said. “It had already gone into one of my sentinel lymph nodes. This was an extremely aggressive type of cancer.”
It also was the same type her sister had. At the time of her sister’s diagnosis, the cancer had spread to 15 of her nodes, as well as her spine. Meyer had a double mastectomy and eight rounds of chemotherapy in November 2008. Today, Meyer said, her health is good.
How to use the results
Dr. Nafisa Burhani, Heather Meyer’s oncologist, said testing involves a blood sample or mouth swab, which is sent to a special laboratory. Burhani believes people should ask their doctors if they are at risk for cancer and if they are candidates for genetic testing. They also should have their doctors keep updated medical histories on them.
In addition to cancers, genetic testing is available today for thousands of conditions, including:
• Fragile X syndrome
• Duchenne muscular dystrophy
• Down syndrome
• Huntington’s disease
• Grave’s disease
• Spina bifida
• Kabuki syndrome
• Some types of cardiac myopathy
• Some types of developmental delays
• Variants of early-onset Alzheimer’s disease
Source: Centers for Disease Control and Prevention and Myriad Genetic Laboratory geneticist Kisha Johnson-Isidore