Presence of Protein E6 Predictive of Oropharyngeal Cancer Risk in HPV16-Infected Persons
in individuals infected with HPV16, the protein E6 is produced by chronically infected cells.
Researchers at the German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ) in Heidelberg, in collaboration with researchers from the International Agency for Research on Cancer (IARC) and the US National Cancer Institute, believe they found the first ever easy-to-analyze biomarker to detect if a person is at a high risk of developing HPV-associated cancer of the oropharynx.
When a person is infected with HPV16, the protein E6 is produced by chronically infected cells. The body responds to the infection by producing antibodies against E6. The researchers postulated that these antibodies could be used as early indicators of oropharyngeal cancer risk.
The researchers analyzed blood samples from approximately 150,000 healthy participants in the US Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial from 1993 to 2001. The cancers that developed over time were recorded. The researchers analyzed 198 blood samples from patients with oropharyngeal cancer and 924 control samples from patients without cancer.
The researchers detected HPV16 E6 antibodies in 42.3% of patients with oropharyngeal cancer using blood samples that were taken long before their diagnosis. Only 0.5% of patients from the control group tested positive for the biomarker. "This pretty much corresponds to the percentage of HPV-related cases of oropharyngeal cancer that we expected to find for that time in the American population," explained lead researcher Tim Waterboer.
However, Waterboer cautions that the test is not currently appropriate for larger populations. "The occurrence of new cases of oropharyngeal cancer is rather low at about 5 cases per 100,000 inhabitants. That means that although the test is highly specific, very many healthy people would receive false positive results. However, in certain high-risk groups, up to 10 times more people can develop the disease. HPV16 E6 antibody detection is the first ever easy-to-analyze biomarker that enables us to narrow down the circle of individuals who are at an extremely high risk of developing the cancer."
1. Kreimer AR, Johansson M, Yanik EL, et al. Kinetics of the human papillomavirus type 16 E6 antibody response prior to oropharyngeal cancer [published online March 22, 2017]. J Natl Cancer Inst. doi:10.1093/jnci/djx005