Negative HPV Test Results on Infinity/GeneXpert® With the Presence of a Late Amplification Signal: What Does This Mean ? (PaPCR)

Cervical cancer is the fourth most common cancer in women worldwide, with 660,000 new cases and 350,000 related deaths by 2022. Papillomavirus (HPV) infection is the most common sexually transmitted infection in the world, and is transmitted by mucocutaneous contact. Incidence is particularly high in low- and middle-income countries, due to inadequate access to screening, treatment and vaccination against human papillomavirus (HPV). Numerous genotypes exist worldwide, some of which have oncogenic potential, principally genotypes 16, 18 and 45 (77% of all cervical cancers), and which should be screened as a priority by PCR.

In France, screening varies according to women's age: between the ages of 25 and 29, cytological examination is recommended every 3 years, following two initial tests carried out 1 year apart with normal results. Between the ages of 30 and 35, PCR detection of HPV at high risk of malignancy (HPV-HR) replaces cytological testing. This test is performed 3 years after the last normal cytological examination, and repeated every 5 years. If the PCR is positive, a cytological examination is performed. If the result is negative, a new PCR test is performed 1 year later.

The HPV test based on Cepheid® GeneXpert® technology detects HPV DNA, distinguishing between HPV 16 and 18/45, as well as other high-risk HPVs (31, 33, 35, 52, 58, 51, 59, 39, 56, 66, 68). The test targets E6/E7 oncogenes, and includes a sample adequacy check confirming the presence of human DNA in the sample. This quantitative real-time PCR test can provide quantitative information on viral load. A high viral load is a marker of persistent HPV infection, as well as a risk indicator for squamous intraepithelial lesions (SILs). However, the significance of low viral loads remains unclear.

GeneXpert® technology can produce "negative" results when late amplification (Ct approx. >37) is visible on qPCR curves.

It is difficult for medical biologists to biologically validate an uncertain result, so the aim of this study was to determine the significance of these late amplification curves using cytology results, as well as comparing GeneXpert® technology with in-house real-time PCR and genotyping in the event of positive samples.

Inclusion criteria

• Patients whose cervico-uterine swab was initially rendered negative by the GeneXpert® system when a late Ct signal (>35) was present in the raw result.

Exclusion criteria

• Patients with a positive cervico-uterine swab for Papillomavirus.
• Patients with a negative test with no amplification signal.
• Patients who have expressed opposition to inclusion in the study.
• Patients under legal protection (guardianship, curatorship, etc.).