Clinical Performance of the PreTect HPV-Proofer E6/E7 mRNA Assay in Comparison with That of the Hybrid Capture 2 Test for Identification of Women at Risk of Cervical Cancer

Abstract

Human papillomavirus (HPV) DNA testing has a higher clinical sensitivity than cytology for the detection of high-grade cervical intraepithelial neoplasia or worse (CIN 2؉). However, an improvement in specificity would be desirable. As malignant transformation is induced by HPV E6/E7 oncogenes, detection of E6/E7 oncogene activity may improve specificity and be more predictive of cervical cancer risk. The PreTect HPVProofer assay (Proofer; Norchip) detects E6/E7 mRNA transcripts from HPV types 16, 18, 31, 33, and 45 with simultaneous genotype-specific identification. The clinical performance of this assay was assessed in a crosssectional study of women referred for colposcopy in comparison with the Hybrid Capture 2 (HC2; Qiagen) test, which detects DNA of 13 high-risk oncogenic HPV types collectively. Cervical specimens were collected in PreservCyt, and cytology was performed using the ThinPrep method (Hologic). The samples were processed for HPV detection with Proofer and HC2 and genotyping with the Linear Array method (Roche Molecular Systems). Histology-confirmed CIN 2؉ served as the disease endpoint to assess the clinical performance of the tests. A total of 1,551 women were studied, and of these, 402 (25.9%) were diagnosed with CIN 2؉ on histology. The Proofer assay showed a sensitivity of 78.1% (95% confidence interval [CI], 74.1 to 82.1) versus 95.8% (95% CI, 93.8 to 97.8) for HC2 (P < 0.05) and a specificity of 75.5% (95% CI, 73.0 to 78.0) versus 39.6% (95% CI, 36.8 to 42.4), respectively (P < 0.05). The lower sensitivity and higher specificity of Proofer for detection of CIN 2؉ can be attributed to the fact that this test detects the expression of E6/E7 genes beyond a threshold from a limited number of oncogenic HPV types. In conclusion, Proofer is more specific than HC2 in identifying women with CIN 2؉ but has a lower sensitivity.Numerous nonrandomized studies (19), and more recently randomized clinical trials (3,24,31,34), have clearly established that testing for human papillomavirus (HPV) DNA is significantly more sensitive than Pap cytology for detection of high-grade cervical intraepithelial neoplasia (CIN 2 and CIN 3) or worse (CIN 2ϩ; i.e., CIN 2, CIN 3, squamous cell carcinoma, endocervical adenocarcinoma in situ, and endocervical adenocarcinoma). There are also indications that testing for HPV might be the most effective method of cervical cancer screening in developing countries (36). Moreover, HPV testing would be warranted as a primary screening tool in the era of HPV vaccination (14). While the use of HPV testing in primary cervical cancer screening and triage of borderline cytologic abnormalities have been recommended (37,43,44), HPV testing lacks specificity due to the ubiquitous and transient nature of HPV infection in women, and therefore, the positive predictive value (PPV) tends to be lower than that of cytology (11,19). Most studies on primary screening have evaluated HPV DNA detection tests, especially the Hybrid Capture 2 (HC2; Qiagen) test (10,19). HC2 utilizes a full genomic prob...

E6/E7 proteins are potential markers for the screening and diagnosis of cervical pre‑cancerous lesions and cervical cancer in a Chinese population

“…According to the present results, the application of E6/E7 protein detection in CC screening could reduce the limitations of other recent technologies, such as the Pap test and HC2 test, and the indicators (E6/E7 proteins) for both cervical pre-cancer and progression to CC could be quantified with the standard detection method established in the present study (17,21). However, not all types of anti-E6/E7 monoclonal antibodies exhibit high specificity currently (8,38).…”

“…Histology is recognized as the gold standard for diagnosing the pathological process of CC. CIN2 + is considered a precancerous lesion and, if left untreated, this may progress to cervical cancer; therefore, if a patient exhibits a CIN2 + lesion, this should be treated (17,29). However, it is unknown which kind of lesions will finally lead to infiltrative cancers.…”

“…According to previous studies, the sensitivity of E6 protein detection by OncoE6 Cervical Test was only 42.4%, which is lower than the 71.3% of HPV E6/E7 protein detection, but it exhibited 99.1% specificity for E6 protein detection (18). The sensitivity of E6/E7 mRNA detection gradually increases when the number of HR-HPV types increases (17,19,20). When the number of HR-HPV types was >9, the sensitivity was >90%, with a satisfactory specificity (19,20).…”

“…Histologic diagnosis, which is deemed as the gold standard for the diagnosis of CC, was used in the present study to clarify the stage of CIN with CIN2 + serving as the disease endpoint (17). The main steps were performed according to the procedure described by Ratnam et al (17).…”

Sensitivity, Specificity, and Clinical Value of Human Papillomavirus (HPV) E6/E7 mRNA Assay as a Triage Test for Cervical Cytology and HPV DNA Test

“…Commercially available robust assays for HPV mRNA detection can be performed in reflex after liquid based cytology or the HPV DNA test (4,9,22,26,28,30,33,38). We compared here the clinical performance of the PreTect HPVProofer E6/E7 mRNA assay (Norchip, Klokkarstua, Norway) as a triage test to that of the HPV DNA test and cytology for detecting high-grade cervical intraepithelial neoplasia or worse (CIN2ϩ).…”