An initial validation study presented by Exagen Diagnostics at the San Antonio Breast Cancer Symposium suggests it may soon be possible to distinguish good prognosis from poor prognosis in any newly diagnosed breast cancer patient based on DNA changes in the patient's tumor.
Those patients identified as having a very good prognosis may do well without chemotherapy or hormonal therapy after their tumors have been removed.
In a retrospective study of 308 patients conducted with the University of New Mexico Cancer Research and Treatment Center at the Health Sciences Center, Exagen Diagnostics, an emerging leader in the rapid identification and productization of practical, genomic markers for prognostic testing, reported the discovery of two, 3-gene sets of markers that were prognostic in testing archived specimens from hormone receptor (HR)-positive and hormone receptor-negative patients, respectively. These two sets of markers form a panel for use in testing tumor tissue from breast cancer patients, providing a same- or next-day result.
In independent test sets, each of the 3-gene markers accurately identified 91 percent of HR-negative and HR-positive specimens from patients that did not experience recurrence of disease. In patients that were also node negative, the negative predictive value was 100 percent (e.g., 100 percent of patients identified by these tests had a good prognosis clinically).
The study population consisted of white and Hispanic patients with invasive ductal carcinoma that were diagnosed between 1986 and 1999 at the University of New Mexico Health Sciences Center. A minimum of four years of follow-up clinical information was available for each of the patients, with an average follow-up of 8.9 years. Poor prognosis was clinically defined as development of recurrence, as evidenced by either distant metastasis or death from breast cancer. Good prognosis was clinically defined as the absence of recurrence (or death from breast cancer) as of the last date of follow-up.
"With this approach, we are seeking to define a new standard of care by becoming the first company to offer a prognostic panel of tests that examines the patient's tumor tissue to detect changes in DNA copy number in any patient. This is a more practical method than currently available tests using RNA," said Waneta Tuttle, Ph.D., Exagen CEO.