A low-cost HPV immunochromatographic assay to detect high-grade cervical intraepithelial neoplasia

Objective To evaluate the reproducibility and accuracy of the HPV16/18-E6 test. Methods The study population was comprised of 448 women with a previously abnormal Pap who were referred to the Barretos Cancer Hospital (Brazil) for diagnosis and treatment. Two cervical samples were collected immediately before colposcopy, one for the hr-HPV-DNA test and cytology and the other for the HPV16/18-E6 test using high-affinity monoclonal antibodies (mAb). Women with a histologic diagnosis of cervical intraepithelial neoplasia grade 2 or 3 were considered to be positive cases. Different strategies using a combination of screening methods (HPV-DNA) and triage tests (cytology and HPV16/18-E6) were also examined and compared. Results The HPV16/18-E6 test exhibited a lower positivity rate compared with the HPV-DNA test (19.0% vs. 29.3%, p<0.001) and a moderate/high agreement (kappa = 0.68, 95% CI: 0.60-0.75). It also exhibited a significantly lower sensitivity for CIN2+ and CIN3+ detection compared to the HPV-DNA test and a significantly higher specificity. The HPV16/18-E6 test was no different from cytology in terms of sensitivity, but it exhibited a significantly higher specificity in comparison to ASCH+. A triage test after HPV-DNA detection using the HPV16/18-E6 test exhibited a significantly higher specificity compared with a triage test of ASCH+ to CIN2+ (91.8% vs. 87.4%, p = 0.04) and CIN3+ (88.6% vs. 84.0%, p = 0.05). Conclusion The HPV16/18-E6 test exhibited moderate/high agreement with the HPV-DNA test but lower sensitivity and higher specificity for the detection of CIN2+ and CIN3+. In addition, its performance was quite similar to cytology, but because of the structural design addressed for the detection of HPV16/18-E6 protein, the test can miss some CIN2/3+ lesions caused by other high-risk HPV types.Cancer Prevention Department, Center for the Researcher Support and Pathology Department of the Barretos Cancer Hospital. This study was supported by CNPq 573799/2008-3 and FAPESP 2008/57889-1info:eu-repo/semantics/publishedVersio

Examples of specimens using the HPV16/18-E6 test.

<p>(C) Control line; (16) HPV16-E6 line; (18) HPV-18-E6 line. Strip on left side (1): cervical sample HPV16 positive; Strip in the middle (2): cervical sample HPV18 positive; Strip on the right side (PC): positive control (HPV16/18 positive).</p

Number and percentage of cases according to cervical cytology, histology diagnosis, HPV-DNA test and HPV16/18-E6 test.

<p>Number and percentage of cases according to cervical cytology, histology diagnosis, HPV-DNA test and HPV16/18-E6 test.</p

Performance of different strategies for the detection of CIN2+.

<p>CI, confidence interval; AUC, area under ROC curve; ASCH+, Atypical Squamous Cells of Undetermined Significance or worse; HSIL, High-grade Squamous Intraepithelial Lesion.</p

Performance of HPV16/18-E6 test, HPV-DNA test and cytology for the detection of CIN3+.

<p>CI, confidence interval; AUC, area under ROC curve; ASCH+, Atypical Squamous Cells of Undetermined Significance or worse; HSIL, High-grade Squamous Intraepithelial Lesion. CIN3+: CIN3, carcinoma in situ, invasive carcinoma, carcinoma not otherwise specified.</p

Performance of different strategies for the detection of CIN3+.

<p>CI, confidence interval; AUC, area under ROC curve; ASCH+, Atypical Squamous Cells of Undetermined Significance or worse; HSIL, High-grade Squamous Intraepithelial Lesion.</p