Subtype HPV38b[FA125] demonstrates heterogeneity of human papillomavirus type 38

The human papillomaviruses (HPVs) exist as more than 100 distinct types. While variants of HPV are common, only few HPV subtypes have been reported. HPV type 38 has been proposed to be associated with nonmelanoma skin cancer (NMSC), with reported prevalences of up to 55%. A subtype of HPV38 was cloned, completely sequenced and found to have a 96% sequence similarity to prototype HPV38 in the L1 open reading frame. The presence of prototype HPV38 and HPV38b[FA125] was examined in paired biopsies of tape-stripped skin lesions and healthy skin from 269 immunocompetent patients by real-time PCR. Prototype HPV38 and HPV38b[FA125] were present in seven (3%) and five (2%) lesions, respectively, in viral loads ranging from one copy per 150 cells to one copy per 70,000 cells. In summary, we found that HPV38 is heterogeneous and is one of so far only few HPVs that contain subtypes. The heterogeneity needs to be considered in studies of the biology of this virus.