p16 IHC/DNA qPCR proves to be best predictor of oropharyngeal squamous cell carcinoma outcome
TUESDAY, Oct. 4 (HealthDay News) -- Diagnostic tests for human papillomavirus-16 (HPV16) in oropharyngeal squamous cell carcinoma (OPSCC) differ in accuracy and prognostic value, with a combination of p16 immunohistochemistry (p16 IHC) and DNA quantitative polymerase chain reaction (qPCR) proving to be the best discriminator of favorable outcome, according to a study published in the Oct. 1 issue of Clinical Cancer Research.
Andrew G. Schache, B.D.S., MB., Ch.B., from the University of Liverpool in the United Kingdom, and colleagues assessed the sensitivity, specificity, and prognostic ability of eight possible assays and assay combinations for HPV16, including the gold standard of RNA qPCR, in 108 cases of OPSCC. Fixed and fresh-frozen tissues were evaluated using p16 IHC, in situ hybridization for high-risk HPV (HR HPV ISH), RNA qPCR, DNA qPCR, or combinations of these assays.
The investigators found that HPV16-positive patients with OPSCC were younger and smoked less than HPV-negative patients, and the proportion of HPV16-positive cases increased from 15 to 57 percent between 1988 and 2009. When compared to RNA qPCR, p16 IHC/DNA qPCR showed sensitivity and specificity of 97 and 94 percent, respectively, and proved to be the best discriminator of favorable outcome. The p16 IHC/HR HPV ISH had a specificity of 90 percent, but reduced sensitivity of 88 percent affected the prognostic utility. Used in isolation, p16 IHC, HR HPV ISH, or DNA qPCR were not specific enough to be recommended for use in clinical trials.
"Caution must be exercised in applying HPV16 diagnostic tests because of significant disparities in accuracy and prognostic value," the authors write.
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