OncoHealth Corp, San Jose, Calif, reports that three new studies demonstrate the effectiveness of assays using its proprietary HPV E6 and E7 biomarkers to distinguish clinically meaningful cervical disease from insignificant HPV infections.
The studies, presented recently in two oral presentations and a poster at the 28th International Papillomavirus Conference, suggest that the company’s biomarkers and technology platform can be used to develop tests that may help clinicians better determine which women with abnormal cervical cancer screening results require additional testing or procedures.
Previous studies have demonstrated that Pap testing lacks sensitivity, while testing for high-risk human papillomavirus (HPV), the cause of cervical cancer, lacks specificity, the company notes. As a result, millions of women with abnormal screening results undergo unnecessary repeat testing and/or additional procedures, such as colposcopy and biopsy, each year. The company’s tests are based on E6 and E7 oncoproteins, which are scientifically known to be associated with progression of HPV infection to cervical cancer.
In one presentation, titled “The Potential Use of Direct E6E7 cELISA for Triage of Patients with Abnormal Test Results,” Shuling Cheng, PhD, the company’s chief scientific officer, presented data showing that, when applied to samples with abnormal Pap and HPV-positive test results, an E6E7 whole-cell ELISA assay demonstrated a specificity of 76% for pre-cancerous cervical disease (CIN3). The positive predictive value (PPV) of the E6E7 cELISA assay for CIN3 was three times greater than the PPV of Pap or HPV DNA testing. The findings, part of an ongoing study involving more than 1,700 liquid-based abnormal cervical cytology samples, were based on an initial 158 cases with known histology results from patients who had biopsies.
“Each year, approximately four million women in the US have mildly abnormal cervical cancer screening results that reflect conditions that will typically resolve on their own,” said Teresa M. Darragh, MD, professor of pathology, Department of Pathology, University of California, San Francisco (UCSF). “Because clinicians do not know which cases will spontaneously resolve, most of these women undergo inefficient repeat testing or invasive, costly procedures. The findings suggest the potential for the E6E7 cELISA assay to help millions of women avoid unnecessary procedures each year, while focusing resources on the women who will benefit the most from intervention.”
In a study titled “Detection of HPV-E6E7 Oncoproteins in Cytology Samples Using Flow Cytometry Assay,” researchers demonstrated the ability of OncoHealth’s technology to accurately detect E6 and E7 oncoproteins in single cells and correlate their expression levels with disease state using a flow cytometry testing platform. The study involved more than 1,500 liquid-based cervical cytology samples.
While cervical cancer mortality rates have decreased substantially over the last few decades due to early detection and intervention, over-diagnosis of minimal abnormalities and over-treatment are critical problems leading to unnecessary anxiety, pain, expense, and inconvenience, according to the company.