Human papilloma virus (HPV) particle, illustration. HPV particles (virions) consist of a protein capsid enclosing DNA (deoxyribonucleic acid), the genetic material of the virus. Attached to the capsid are many surface proteins (blobs). HPV causes warts, which mostly occur on the hands and feet. Certain strains also infect the genitals. Although most warts are non-malignant (not cancerous), some strains of HPV have been associated with cancers, especially cervical cancer.