HPV73 in cervical cancer and distribution of HPV73 variants in cervical dysplasia

HPV73 is classified as possibly oncogenic and is not recognized by most commercial primary HPV screening platforms. The aim was to determine the prevalence of HPV73 among invasive cervical cancers, formalin-fixed paraffin embedded (FFPE) samples (N = 69), from southern Sweden during 2009 to 2010. Another aim was to determine proportions of HPV73 among Aptima HPV assay negative cervical cancers (N = 9, out of 206 cancers) and of high-grade cytological cervical diagnosis (N = 75, out of 5807 high grade lesions) in liquid-based cytology (LBC) samples collected between 2016 and 2019. We also investigated the distribution of HPV73 variants A1, A2 and B among HPV73-positive cases. HPV73 was detected by multiplex MGP-PCR and Luminex, and HPV73 variants were identified by sequencing PCR amplicons. HPV73 was detected in 2.9% (2/69, 95% CI: 0.18-9.9) of the FFPE cervical cancer series. Among the Aptima HPV-negative LBC samples, HPV73 was present in 55.5% (5/9) of the cancers and 29.3% (22/75) of the different grades of cervical diagnosis. The A1, A2 and B variants were present in 6.9% (2/29), 82.7% (24/29) and 10.3% (3/29) of the HPV73-positive women, respectively. Among the seven HPV73 cancer cases (two FFPE samples and five LBC samples), six A2 and one A1 isolate were detected. In summary, the A2 variant of HPV73 was most common in our region. In addition, the observed prevalence of HPV73 (2.9%) in cervical cancers and its relative high occurrence (55.5%) among Aptima HPV-negative cancers urge that detection of HPV73 should be included in future primary HPV screening programs.