Pitfalls of commercially available HPV tests in HPV68a detection

Human Papillomavirus E7 and p16INK4a mRNA Multiplexed Quantification by a QuantiGeneTM Proof-of-Concept Assay Sensitively Detects Infection and Cervical Dysplasia Severity

Background: Persistent infection with human papillomavirus (HPV) can lead to cervical cancer (CxCa). During the progression to CxCa, the expression of HPV oncogenes E6 and E7 is upregulated. In turn, cellular proteins such as p16INK4a are also modulated. The combined detection of HPV oncogenes and cellular biomarkers indicative for dysplasia could be informative and convey better specificity than the current HPV tests that cannot discriminate transient infection from dysplastic changes. Methods: The QuantiGeneTM 2.0 Plex Assay platform was chosen for the effective multiplexing and quantitative detection of seven HPV-E7 mRNA targets (HPV6, 16, 18, 31, 45, 59, and 68) and the cellular mRNA of p16INK4a as a biomarker for HPV-induced transformation. Actin-beta (ACTB) and hypoxanthine-guanine phosphoribosyltransferase 1 (HPRT1) were included as reference markers. Sequences for the specific capture and detector probes were customized and developed by ThermoFisher and formulated as a QuantiGene proof-of-concept (QG-POC) plex-set. The crude lysates of the HPV-positive cervical cancer cell lines CaSki (HPV16), HeLa (HPV18), MRHI-215 (HPV45), Erin59 (HPV59), ME180 (HPV68), and the HPV-negative cell line C33A, as well as liquid-based cytology smear samples (n = 441) were analyzed. The study was a proof-of-concept evaluating the feasibility of the platform. Logistic regression and receiver operating characteristic (ROC) analyses were performed to test for the sensitivity and specificity of HPV detection and dysplastic stage discrimination. Results: A QG-POC assay specifically and sensitively detects the HPV-E7 mRNA of seven different genotypes with an assay linearity between 20 and 13,000 cells. Cellular mRNA was detected from the crude lysates of cell lines and of cellular material from clinical liquid-based cytology smear samples. By combining HPV-E7 and p16INK4a expression normalized to ACTB, high-grade dysplasia (HCIN) and invasive cervical cancer (CxCa) were detectable, discriminable, and correlated to the biomarker expression strength. The ROC analysis from the multivariate logistic regression model including HPV-E7 and p16 INK4a resulted in an AUC of 0.74, at the optimal cut-off (sensitivity: 70.4%; specificity: 66.0%) for HCIN detection. CxCa was detected with an AUC of 0.77 (sensitivity: 81.8%, specificity: 77.4%). Conclusions: The QG-POC assay is sufficiently sensitive to detect and quantify HPV-E7 and cellular mRNA species. Multiplexing allows the specific detection of at least 10 analytes in a single reaction. Determining the abundance of E7 and p16INK4a transcripts when normalized to ACTB is informative about the presence of cervical dysplasia and potentially discriminates between low-grade and high-grade dysplasia and invasive cervical cancer. Further studies including more HPV genotypes and biomarkers are warranted.

Novel concepts in cervical cancer screening: a comparison of VIA, HPV DNA test and p16INK4a/Ki-67 dual stain cytology in Western Kenya

BACKGROUND

Screening of unvaccinated women remains essential to mitigate the high morbidity/mortality of cervical cancer. Here, we compared visual inspection with acetic acid (VIA), recommended by WHO as the most cost-effective screening approach in LMICs, with HPV-based screening, and usage of p16INK4a/Ki-67 dual stain cytology.

METHODS

We prospectively enrolled women participating in a VIA-based cervical cancer screening program in two peri-urban health centers of Kenya. Consenting women had a VIA examination preceded by collection of a liquid-based cytology sample from the cervix stored in PreservCyt medium (Hologic®). Analysis of all samples included a hrHPV DNA test and evaluation of a p16INK4a /Ki-67 (CINtecPLUS®) dual stained slide that was prepared using the ThinPrep® 2000 Processor and evaluated by a pathologist trained in the methodology.

RESULTS

In 701 of a total of 800 women aged 18-64 years, all three investigations were performed and data could be analyzed. The HPV, VIA and dual stain cytology positivity were 33%, 7%, and 2% respectively. The HPV positivity rate of VIA positive cases was 32%. The five most common HPV types were HPV16, 52, 68, 58 and 35. The OR among HIV infected women of an HPV infection, VIA positivity and positive dual stain cytology were 2.6 (95%CI 1.5-4.3), 1.9 (95%CI 0.89-4.4) and 3.4 (95%CI 1.07-10.9) respectively. The sensitivity of VIA to detect a p16INK4a/Ki-67 positive transforming infection was 13% (95%CI 2-38).

CONCLUSIONS

Primary HPV testing appears feasible and should be considered as a primary screening test also in LMICs. The poor sensitivity of VIA renders it unsuitable as a triage test for HPV positive women. The utility of p16INK4a/Ki-67 dual stain cytology as a triage test for HPV positive women in LMICs should be further studied.

Negative Roche cobas HPV testing in cases of biopsy-proven invasive cervical carcinoma, compared with Hybrid Capture 2 and liquid-based cytology

INTRODUCTION

The objective of this study was to conduct a retrospective analysis of results of cytology and Roche cobas (RC) and Hybrid Capture 2 (HC2) human papillomavirus (HPV) screening tests in cases of biopsy-proven invasive cervical carcinoma.

MATERIALS AND METHODS

The clinical data were obtained at a university hospital in New York, NY, between 2004 and 2017. Results of cytology, reported per Bethesda classification system, and HPV screening in 177 identified cases with cytology and biopsy-proven diagnosis of cervical carcinoma were included in the analysis.

RESULTS

Two cohorts were analyzed. Of the 177 identified cases, cotesting was performed for 100 patients. Among these 100, cotesting screening results would not trigger immediate colposcopy in 6%; HPV screening results were reported as negative in 16% (16% of all RC, 16% of all HC2, 16% total) and, if HPV was the only screening modality, would not trigger a colposcopy. Of the 177 total cases, 128 patients underwent cytology screening prior to biopsy, with a cytology diagnosis that, alone, would not trigger immediate colposcopy in 14%.

CONCLUSIONS

The HPV DNA screening and cytology screening alone were negative for 16% and 14%, respectively, of patients with biopsy-proven diagnoses of invasive carcinoma of cervical origin, without a significant difference in failure rates between cytology, HC2, and RC. The cotesting approach had a significantly lower failure rate (6%) compared with the 2 other screening modalities alone.