(HealthDay News) — In patients with head and neck cancer, human papillomavirus (HPV) infection predicts survival when determined by viral load and viral gene expression rather than the presence of viral DNA or expression of the p16 tumor suppressor gene, according to two studies published online Sept. 18 in Cancer Research.
Dana Holzinger, Ph.D., from Heidelberg University in Germany, and colleagues analyzed HPV DNA, viral load, RNA expression patterns typical of cervical carcinomas (CxCaRNA+), and expression of p16INK4a in 199 oropharyngeal squamous cell carcinomas. The researchers found the risk of death to be lowest in tumors with CxCaRNA+ (hazard ratio [HR], 0.28) and in those with high viral load (HR, 0.32). There was a weaker inverse association for tumors that were HPV positive and p16INK4a high (HR, 0.55; 95 percent confidence interval, 0.29 to 1.08).
In the second study, Caihua Liang, Ph.D., from Brown University in Providence, R.I., and colleagues analyzed patients with head and neck squamous cell carcinoma for HPV serology (488 patients), HPV16 DNA (subset of 179 cases) and p16 protein expression (subset of 233 cases). The researchers found improved survival in patients seropositive for the E6 and E7 oncoproteins (HR, 0.1), while the presence of HPV DNA or p16 protein alone was not associated with survival.
“What can be stated from these two studies and others is that p16INK4a status, particularly if dichotomized, should be interpreted with caution,” Eduardo Méndez, M.D., from the University of Seattle in Washington, writes in an accompanying editorial. “Further testing to confirm HPV active infection may be warranted, particularly in consideration of de-escalation regimens.”
Several authors from both studies disclosed financial ties to the pharmaceutical industry. The author of the editorial disclosed a proctoring/honorarium agreement with Intuitive Surgical.