Taking into account the low HPV DNA concentration detected only for types 6 and 11, as well as the immunohistochemical detection of HPV L1 in the tumor stromal lymphocytes and macrophages and some basal epitheliocytes in individual cases, it can be assumed that HPV does not play a crucial role as an etiological factor for IP. PCR revealed oncogenic HPV types 16 and 35 in sinonasal carcinoma associated with IP only in one case, which makes it untimely to claim that this virus plays a very special role in the etiology of this carcinoma. Epstein-Barr virus was not found in any case.