Biology and natural history of human papillomavirus infection

Abstract

Human papillomavirus (HPV) is one of the most common causes of sexually transmitted diseases worldwide. It has been proposed that the great majority of women and men have been infected with HPV at least once during their lifetime. HPV infection is associated with a variety of clinical conditions, ranging from benign lesions to cervical cancer. In most cases, the infection is transient, where most of the individuals are healing, eliminating the virus without the presence of any clinical manifestation. Actually, more than 120 HPV types have been cataloged, of which approximately 40 can infect the mucosa of the anogenital tract and are collectively known as mucosal HPV, which are classified based on their oncogenic potential as either low-or high-risk HPV types. The low-risk HPV type causes benign hyperproliferative lesions or genital warts, with a very limited tendency for malignant progression, while the high-risk HPV type is strongly associated with premalignant and malignant cervical lesions. The HPV cycle initiates when the virus gains access to undifferentiated cells of the basement membrane of the squamous columnar junction epithelium of the ectocervix, after these regions are exposed to mechanical or chemical trauma. The basal cells in the transformation zone retain the ability to differentiate, a property required for virion production. Cervical infection with high-risk HPV typically lasts from 12 to 18 months and in most cases is cleared spontaneously. However, in some women the immune response is insufficient to eliminate the virus, resulting in a persistent, long-term infection that may progress to a malignant lesion. In this review, we discuss the biology and natural history of HPV infection and its association with cervical cancer.

Genetic polymorphisms of glutathione S transferase and cervical intraepithelial neoplasia

“…Since it is very difficult to realize a longitudinal study that might include patients without any cytological anomalies for decades in order to see the relationship between GST M1 and T1 genetic polymorphisms and HPV HR infections, the present study has included HPV-HR positive patients with LSIL, HSIL or in situ carcinoma, which, accordingly to the known HPV natural history (1,2,4,5,22,23), are due to persistent HPV-HR that cause significant squamous cell modifications.…”

“…The molecular study of HPV carcinogenesis has been a major research topic trying to identify the genetic predisposing factors involved in the etiopathogenesis of cervical cancer (5). There are a number of studies demonstrating that personal genetic particularities are important when defining higher susceptibility to HPV infections and cervical neoplasia, particularly the effect of the viral oncoproteins E6 and E7, the loss of heterozygosity in some chromosomal region, and, last but not least, different polymorphisms of the MHC, p53, immune response and detoxifying genes (6,7).…”

Current studies on human papillomavirus in Saudi Arabia

“…Over 120 subtypes of HPVs are classified as either low-risk (LR-HPV) or high-risk (HR-HPV) based on their oncological potential for transforming cells. The LR-HPV types cause benign hyperproliferative lesions, or genital warts, while the HR-HPV types are strongly associated with premalignant and malignant cervical lesions [15]. An HPV type is defined as an HPV isolate with an L1 gene sequence that is at least 10% unique when compared with any other type.…”

Atividade mucosotrópica do Papilomavírus Humano (HPV) no processo carcinogênico em diferentes sítios de infecção.

“…Os genes da região E correspondem a 50% do genoma, codificam três oncoproteínas, E5, E6 e E7, onde a proteína E5 está envolvida na transformação celular, participa da replicação do DNA viral e contribue para a evasão do sistem imune na célula infectada (FERNANDES et al, 2013;MORSHED et al, 2014). As proteínas E6 e E7 têm um papel central na transformação maligna por ação do HPV e causam danos na regulação do controle do ciclo celular (MORSHED et al, 2014).…”

“…É um vírus pequeno, pertencente à família Papillomaviridae (SHUKLA et al, 2009 (FERNANDES et al, 2013), dessa forma são classificados em mucosos ou cutâneos.…”