Anal warts are irregular, verrucous lesions caused by human papilloma virus. The human papilloma virus (HPV) is strongly associated with vaginal cancer. These structures are distinctly different from squamous papilloma and benign teratoma. Most cases of anal cancer are related to infection with the human papilloma virus (HPV). Cervical cancer risk in those infected with human papilloma virus is increased. HeLa cells have also been instrumental in the development of Human papilloma virus (HPV) vaccines. It has also been linked to a virus called Human Papilloma Virus (HPV type HPV16). Rabbit Papilloma displays tropism for the cutaneous epithelium. A 2014 study indicates that lopinavir is effective against the human papilloma virus (HPV). Examples include encephalocele, glioma, inverted papilloma, and cancer. Rats having stomach tumour (papilloma) also had nematodes and their eggs. It can also be associated with other types of infections, such as human papilloma virus. It is caused by the human papilloma virus types 13 and 32. There are about 130 known types of human papilloma viruses.