The study is to test a liquid biopsy assay for screening and classifying anal dysplasia from blood.

Anal squamous cell carcinoma, despite being considered as a rare cancer, has seen a steady rise in incidence over the past three decades. Recent evidence from the Anal Cancer-HSIL Outcomes Research (ANCHOR) study demonstrated benefits of treating anal high-grade squamous intraepithelial lesion (HSIL), highlighting the importance of screening anal cancers and high-grade precancers. Current anal cancer screening starts with HPV testing and/or cytology for primary screening, followed by high-resolution anoscopy (HRA) with biopsy for confirmatory diagnosis. However, the poor specificity of HPV testing and the extremely limited capacity of HRA urges the development of new screening approaches for identifying anal high-grade precancers and cancers. Blood circulating tumor HPV DNA (ctHPVDNA) is an emerging non-invasive biomarker for screening and treatment monitoring of HPV-associated cancers, but its significance in anal cases remains underexplored. Here the investigators use an ultrasensitive HPV whole genome sequencing assay to test the hypothesis that anal precancers are detectable in the blood.

Inclusion Criteria:

• Past or current anal HPV-positive population undergone anal dysplasia screening.
• Control patients from the general population.

Exclusion Criteria:

• Not meeting inclusion criteria.

Patients undergone screening for anal dysplasia and control patients from the general population.