Enhanced detection of high-risk human papillomavirus by in situ hybridization with expansion from 7 to 18 genotypes in anal biopsies.

OBJECTIVES

High-risk human papillomavirus (HPV) plays a central role in the pathogenesis of anal high-grade squamous intraepithelial lesions (HSILs). In situ hybridization (ISH) is commonly used for high-risk HPV detection in surgical specimens. Recently, ISH panels with expanded HPV genotype cocktails have become available. This study evaluated the detection rate of an expanded ISH probe cocktail targeting 18 high-risk HPV genotypes (HR18) compared with a 7-HPV genotype panel (HR7) in anal tissue microarray samples.

METHODS

A retrospective study was performed on 245 patients with anal biopsy samples collected from 2017 to 2023 at a tertiary-care medical center. Tissue microarrays were constructed with 1 to 3 cores per case. In situ hybridization was performed with an HR18 probe for comparison with the reported HR7 result. The detection rate of high-risk HPV was assessed.

RESULTS

Among 55 patients with HSIL, HR18 demonstrated a positivity rate of 93% (51/55) compared with 73% (40/55) for HR7 (P = 2.6 × 10-3). The HR18 panel detected high-risk HPV in 3 patients with histologically low-grade and 1 previously ungraded SIL. No high-risk HPV was detected in patients without SIL by HR18.

CONCLUSIONS

Expansion of the ISH panel from 7 to 18 genotypes improved detection for high-risk HPV in anal HSIL and identified high-risk HPV in additional patients without HSIL.