Performance of HPV E6/E7 mRNA RT-qPCR for screening and diagnosis of cervical cancer with ThinPrep Pap test samples

Recent research has shown that oncogenic human papillomavirus (HPV) DNA, which is currently used in the screening and diagnosis of cervical cancer, can be detected not only in high-grade cervical lesions, but also in low-grade cervical lesions and normal tissues. For this reason, HPV tests targeting the E6 and E7 mRNA of five oncogenic HPV strains (HPV genotypes 16, 18, 31, 33, and 45), which are known to be responsible for the oncogenesis of cervical cancer, have been commercialized using a real-time nucleic acid sequence based amplification (NASBA) assay. Previous data has shown that the real-time NASBA assay has higher clinical specificity than HPV DNA testing (97.1% vs. 53.7%). However, the sensitivity of the real-time NASBA assay was lower than that of HPV DNA testing (41.1% vs. 100%). Despite the fact that there are more than 16 oncogenic HPV genotypes known to cause cervical cancer (HPV genotypes 16, 18, 31, 33, 35, 39, 45, 51, 52, 53, 56, 58, 59, 66, 68, and 69), the commercialized real-time NASBA kit was designed to detect only five genotypes (16, 18, 31, 33, and 45). Therefore, in the present study, CervicGen HPV RT-qDX (Optipharm), a commercial diagnostic kit targeting a HPV E6/E7 mRNA based on RT-qPCR assay was evaluated with RNA extracted from ThinPrep Pap samples, and the results were compared to real-time NASBA data. The sensitivity and specificity of the RT-qPCR assay were 91% and 98.6%, respectively, for the detection of cervical intraepithelial neoplasia CIN2(+) high-grade cervical lesions. Therefore, the CervicGen HPV RT-qDX assay showed a significantly higher sensitivity (91.1%) compared to the real-time NASBA assay (41.1%). In normal cytohistology cases, the specificity was 98.6% and 53.7% for HPV mRNA RT-qPCR and HPV DNA testing, respectively. These results demonstrate that HPV mRNA RT-qPCR better reflects clinical diagnosis. In conclusion, it is suggested that HPV mRNA RT-qPCR overcomes the shortcomings of lower specificity seen in the DNA assay and the lower sensitivity of the commercialized HPV mRNA real-time NASBA assay when testing from ThinPrep Pap samples.