NCCC physicians use new gene sequencing equipment for testing abnormal DNA in cancerous tumor cells

Clinical laboratory experts and physicians at Dartmouth-Hitchcock Norris Cotton Cancer Center (NCCC) achieved 100 percent accuracy in testing for abnormal DNA in cancerous tumor cells with its new gene sequencing equipment and panels. The results, published in the journal Clinical Chemistry and Laboratory Medicine, confirm the precision of the test for routine patient care so physicians can tailor treatment to an individual person's DNA, improving the chances of a successful outcome.

"We evaluated next generation tools for gene sequencing in our clinical laboratory," said Gregory Tsongalis, PhD, director, molecular pathology. "The equipment and approach we are using is faster, more sensitive, and more reliable than previous approaches. It paves the way for routine genetic testing in personalizing cancer care here at the Norris Cotton Cancer Center."

The genomic sequencing test, called the Ion Torrent AmpliSeq Cancer Hotspot Panel, is often used in research settings. Now the clinically certified and accredited pathology laboratory at NCCC has put in place the ability to routinely perform this test on patient tumor tissue. The NCCC Department of Pathology clinical laboratory, where this testing is performed, is in compliance with the Clinical Laboratory Improvement Amendment (CLIA), which certifies laboratories to federal standards of quality, proficiency, and safety. It is also accredited by the College of American Pathologists, the gold standard in laboratory accreditation.

"This takes genetic sequencing information or molecular profiling of tumors and puts it into the hands of physicians treating patients today," said Tsongalis.

The laboratory has run over 400 patient samples, about 80 percent of which have identified genetic mutations. About 50 to 60 percent of the tests identify genetic mutations that change the course of treatment. Turnaround time for the test is one week to 10 days. Physicians and scientists test tumor samples from metastatic colon cancer, melanoma, gliomas, and non-small cell lung cancers. In the months to come, they will add testing for breast cancer, leukemia, and lymphoma. Patients' insurance companies reimburse for testing on known mutations as single-gene tests. The Norris Cotton Cancer laboratory, however, runs each sample against a wide panel of genetic mutations. The Cancer Hotspot Panel tests for mutations in 50 common cancer genes as part of a molecular profiling strategy to personalize therapy for an individual patient.

DNA is supposed to be well ordered, and it is considered damaged or mutated when there is an extra or missing section. Genetic mutations can be inherited or caused by environmental factors such as exposure to sunlight, cigarette smoke, or other carcinogens. Damaged DNA can send out the wrong messages to cells: telling them to multiply and grow in ways that can lead to tumors. By identifying the specific mutations in a tumor, physicians can chose medications that precisely target that location for treatment.