Myriad myRisk test solves overlap dilemma between hereditary cancer syndromes

Myriad Genetics, Inc. (Nasdaq: MYGN) today presented several clinical studies on the Myriad myRisk- Hereditary Cancer test at the 2014 American Society of Clinical Oncology (ASCO) annual meeting in Chicago, Illinois. Among the important new findings is that the myRisk test detects significantly more deleterious mutations than single cancer tests and helps solve the overlap dilemma that exists among hereditary cancer syndromes.

"There is robust evidence that hereditary cancers are caused by mutations in many genes and testing for only one hereditary cancer syndrome may lead to missed mutations," said Richard J. Wenstrup, M.D., chief medical officer of Myriad. "The Myriad myRisk test solves this dilemma by evaluating 25 clinically significant genes, which detects more deleterious mutations and people at risk for hereditary cancers."

The Myriad myRisk Hereditary Cancer test uses next-generation sequencing technology to evaluate 25 clinically significant hereditary cancer genes associated with eight major hereditary cancers including: breast, colon, ovarian, endometrial, pancreatic, prostate, gastric cancers and melanoma. The myRisk test results are combined with a patient's personal and family history of cancer and medical society guidelines into a single comprehensive report for the physician, which makes it easier for physicians to tailor treatment plans for patients depending on their level of risk. A summary of the key Myriad studies featured at ASCO follows.

Multi-gene panel testing in patients suspected to have Lynch syndrome

Matthew Yurgelun. (Podium Presentation; S100a).

This study evaluated the outcomes of testing with the myRisk test in 1,260 patients with a history of hereditary colon cancer. Results show that 27 percent of mutation carriers identified by the myRisk test had mutations in genes not normally associated with hereditary colon cancer. Importantly, more than one third of the additional mutations found were in the BRCA1 and BRCA2 genes, which further demonstrates the overlap that exists between the hereditary breast and colon cancer syndromes.

A study of ovarian cancer patients tested with a 25-gene panel of hereditary cancer genes. Lucy Langer. (Podium Presentation; Location S100a)

Results from this study of 648 patients show that 15.4 percent of patients with ovarian cancer had a mutation that was detected by the Myriad myRisk Hereditary Cancer 25-gene panel. Of these, 59.6% percent of patients had mutations in BRCA1 and BRCA2, 34.6% had mutations in the other hereditary cancer genes in the panel, including hereditary colon cancer genes Testing patients with the myRisk Hereditary Cancer panel increased the number of positive test results in ovarian cancer patients by 63 percent over BRCA1 and BRCA2 testing alone.

Analysis of patients with two hereditary cancers (breast/ovarian or colon/endometrial) who met NCCN genetic testing criteria after their first cancer. Jennifer Saam (Poster 1542).

In this study, patients with a history of two associated cancers were evaluated to determine what percentage of patients met National Comprehensive Cancer Network (NCCN) criteria for genetic testing after their first cancer diagnosis, but who did not receive a test result until after their second cancer diagnosis. The majority of patients in this study had at least 5 years between their first and second cancers. For 9,982 patients with breast and ovarian cancer who were evaluated, the overall rate of BRCA1 and BRCA2 mutations was 22 percent. Of these, only 56 percent of patients diagnosed with breast and ovarian cancer met the NCCN criteria for genetic testing after their first cancer. Among 941 patients with colon and endometrial cancer who were evaluated, 28 percent had mutations in the genes associated with hereditary colon cancer. Of these, 65 percent of patients met NCCN criteria for genetic testing after their first cancer. These findings underscore the importance of diagnosing patients with hereditary cancer syndromes after their first cancer so that a second cancer can be prevented or identified early.