HPV diversity and cancer risk

Abstract

HPV evolution is closely related to viral tropism and carcinogenic potential. HPVs from the alpha-papillomavírus genus infect the anogenital and anal mucosas, and some HPV types of this genus cause approximately all cases of cervical cancer and tumors from other anogenital and extragenital regions. These HPV types, classified as high oncogenic risk, belong to 5 different species: alpha-5, -6, -7, -9 e -11. Moreover, among each species, type-specific behavior of persistence and carcinogenesis is observed. In a more detailed taxonomic level, HPV-16 molecular variants evolved in a manner to obtain clear differences concerning viral DNA persistence and risk of developing high grade cervical lesions. Nevertheless, little is known about the natural history of molecular variants of HPV types other than HPVs-16 and -18.Thus, the aim of this project is to characterize HPV genome diversity among genital and head and neck tumor samples. More specifically we aim to: (1) Identify the prevalence of HPV types in a series of genital and head and neck tumor samples; (2) Identify molecular variants detected in the cases of infection by some HPV of the high risk species alpha-9 (HPV-16, -31, -35, -52 e -58), alpha-7 (HPV-18 e -45), and alpha-6 (HPV-56) in these samples; (3) Identify HPV types and variants associated with specific histological types; and (4) Verify if the prevalence of the diverse HPV types and variants changed throughout the last 4 decades (1970-2010). The information regarding HPV prevalence and type-specific distribution is highly desired in order to evaluate the impact of HPV type-specific prophylactic vaccines. (AU)