Retrospective Analysis of the Utility of Polymerase Chain Reaction–Reverse Sequence-Specific Oligonucleotide (GENOSEARCH HPV31) and Human Papillomavirus Immunohistochemistry (BSB-66) in the Diagnosis of Digital Papillary Adenocarcinoma

Digital papillary adenocarcinoma (DPA) is a rare malignant sweat gland tumor associated with human papillomavirus genotype 42 (HPV42). Currently, the only established test for detecting HPV42 in DPA is RNAscope in situ hybridization. However, this test incurs extremely high acquisition and running costs. To find an alternative method for the detection of human papillomavirus (HPV) in DPA, we evaluated the utility of polymerase chain reaction-reverse sequence-specific oligonucleotide (PCR-rSSO) (GENOSEARCH HPV31) and immunohistochemistry (IHC) using an anti-HPV antibody (BSB-66) for the detection of HPV in DPA. A total of 6 cases of DPA and 16 cases of other cutaneous tumors were reviewed, all of which had been practically performed by GENOSEARCH HPV31 using formalin-fixed paraffin-embedded (FFPE) tissues. The results revealed the presence of HPV42 in all 5 available cases of DPA (5/5, 100%) in GENOSEARCH HPV31. However, 1 case of DPA could not be processed because of poor DNA quality. HPV42 was not detected in the remaining 16 controls. IHC for HPV (BSB-66) showed no reactivity in any of the 6 DPA tumors. For the detection of HPV42 in the FFPE tissue of DPA, GENOSEARCH HPV31 can be used as an alternative to RNAscope in situ hybridization, unless the DNA quality in the FFPE tissue is poor. A notable advantage of GENOSEARCH HPV31 is its lower financial burden, both regarding purchase and operational costs, compared with RNAscope. Furthermore, GENOSEARCH HPV31 can identify additional 30 major genotypes of HPV, other than HPV42. By contrast, HPV (BSB-66) IHC cannot be used to detect HPV in DPA.