Detection of <i>Felis catus</i> papillomavirus-derived genes in squamous cell carcinoma tissues in cats in Japan

Felis catus papillomavirus (FcaPV) was first discovered in 2002. Seven genotypes (FcaPV-1/-2/-3/-4/-5/-6/-7) have been reported to date, at least one of which (FcaPV-2) is suggested to be implicated in squamous cell carcinoma (SCC); however, relevant epidemiological data on Japanese cats are limited. There is one report on relatively low FcaPV-2 prevalence in cats with SCC, largely in the Tokyo region. In this study, we investigated the prevalence of each FcaPV genotype in cats with SCC largely drawn from a peripheral region of Japan (Kyushu). Formalin-fixed paraffin-embedded (FFPE) specimens from 107 cats with SCC were subjected to DNA extraction for type-specific PCR assays, followed by confirmatory nucleotide sequencing. Overall, 16 cases (15.0%) were positive for FcaPV, and the results detected for FcaPV-1/-2/-3/-4/-5/-6/-7 were 0/107 (0.0%), 7/107 (6.5%), 4/107 (3.7%), 1/107 (0.9%), 3/107 (2.8%), 1/107 (0.9%), and 1/107 (0.9%), respectively. Our results suggest that FcaPV-2 is the prevalent papillomavirus type in cats with SCC across Japan, but the figure is lower than in other countries. This is also the first report on the detection of FcaPV-6 and FcaPV-7 in Japan, which previously have only been reported in Australia and New Zealand, respectively.