The panel represents loss of a powerful tumor suppressor gene, SYK, as well as genetic alterations in 51 other genes that are directly affected by the loss of a copy of the SYK gene and the absence of its protein.
“Without SYK, the protein it makes, and genetic disruption in a set of genes thought also to be controlled by SYK, cancer invades and metastasizes,” says the study’s senior investigator, Susette C. Mueller, PhD, professor of oncology emeritus at Georgetown Lombardi.
Mueller and her colleagues examined the loss of SYK in tissue from breast ductal carcinoma in situ (DCIS), a cancer contained within the breast ducts that sometimes morphs and invades surrounding tissue. Samples that had a loss of one copy of the SYK also had evidence of invasive ductal carcinoma nearby. None of the normal breast tissue samples, or of the DCIS-only tissue, had loss of SYK.
“This was the first time that a loss of a SYK gene was found in DCIS breast tissue, but we needed information about the outcomes of these cases to determine the significance of this finding,” says Mueller.
So the scientists turned to The Cancer Genome Atlas at the National Institutes of Health, a catalogue containing gene sequencing and gene mutations from cancer patients with invasive disease, along with outcome information.
When they matched changes in the 55 genes to the patients’ outcomes, the researchers found that the panel was predictive of which breast cancer patients fared better, Mueller says.
“Survival was much better in the invasive ductal carcinoma patients who did not have any change in the 55 genes,” she adds.
At the end of more than 18 years of follow-up, an estimated 80 percent of patients without gene changes were still alive. In contrast, about 20 percent of patients with changes in one or more of the genes were alive.
“The panel is not ready for use as a prognostic tool in the clinic, and much work is required to test it in that way,” Mueller cautions.
The study was supported by Georgetown Lombardi, and by grants from the U.S. Public Health Service (2P30-CA-51008, 1S10 RR15768-01, and 1 S10 RR019291-01A2; and 9R01 CA112673).
Researchers participating in the study are from the University of the District of Columbia, The Ohio State University, the Affiliated Pathologists Medical Group in California, the Armed Forces Radiobiology Research Institute in Maryland and the Victor Babes University of Medicine and Pharmacy in Romania.
About Georgetown Lombardi Comprehensive Cancer Center
Georgetown Lombardi Comprehensive Cancer Center, part of Georgetown University Medical Center and MedStar Georgetown University Hospital, seeks to improve the diagnosis, treatment, and prevention of cancer through innovative basic and clinical research, patient care, community education and outreach, and the training of cancer specialists of the future. Georgetown Lombardi is one of only 41 comprehensive cancer centers in the nation, as designated by the National Cancer Institute, and the only one in the Washington, DC area. For more information, go to http://lombardi.georgetown.edu.
About Georgetown University Medical Center
Georgetown University Medical Center is an internationally recognized academic medical center with a three-part mission of research, teaching and patient care (through MedStar Health). GUMC’s mission is carried out with a strong emphasis on public service and a dedication to the Catholic, Jesuit principle of cura personalis – or “care of the whole person.” The Medical Center includes the School of Medicine and the School of Nursing & Health Studies, both nationally ranked; Georgetown Lombardi Comprehensive Cancer Center, designated as a comprehensive cancer center by the National Cancer Institute; and the Biomedical Graduate Research Organization (BGRO), which accounts for the majority of externally funded research at GUMC including a Clinical and Translational Science Award from the National Institutes of Health.