Human papillomavirus 52 positive squamous cell carcinoma of the conjunctiva
The virus infects basal epithelial cells of stratified squamous epithelium. HPV E6 and E7 oncoproteins are the critical molecules in the process of malignant tumour formation. Interacting with various cellular proteins, E6 and E7 influence fundamental cellular functions like cell cycle regulation, telomere maintenance, susceptibility to apoptosis, intercellular adhesion and regulation of immune responses.
High-risk E6 and E7 bind to p53 and pRb and inactivate their functions with dysregulation of the cell cycle.
Uncontrolled cell proliferation leads to increased risk of genetic instability. Usually, it takes decades for cancer to develop. This review presents the main mechanisms of HPV genome in the carcinogenesis of the uterine cervix. Virusul infectează epiteliile bazale, celule de epiteliu scuamos stratificat.
Proteinele celulare E6 și E7 influențează fundamental funcțiile celulare, cum ar fi reglarea ciclului celular, întreținerea telomerilor, susceptibilitatea la apoptoză, adeziunea intercelulară și reglarea răspunsurilor imune.
E6 și E7 cu grad ridicat de risc se leagă la p53 și PRB și inactivează funcțiile lor cu dereglarea ciclului celular. Proliferarea necontrolată a celulelor conduce la un risc crescut de instabilitate genetică.
Involvement of Human Papillomavirus genome in oncogenesis of cervical cancer
De obicei, este nevoie de zeci de ani pentru a dezvolta un cancer. Acest review prezintă principalele mecanisme ale genomului HPV în carcinogeneza colului uterin. The most important risk factor in the ethiology of cervical cancer is the persistent infection with a high-risk strain of human papillomavirus.
Materials and methods This general review was conducted based on the AngloSaxone literature from PubMed and Medline to identify the role of HPV genome in cervical cancer not hpv related development of cervical cancer. Discussions Genital human papillomavirus HPV is the most common sexually transmitted infection.
Although the majority of infections cause no symptoms and are self-limited, persistent infection with high-risk types of HPV is the most important risk factor for cervical cancer precursors and invasive cervical cancer.
Implicarea genomului papiloma virusului uman (hpv) în oncogeneza cancerului cervical
The presence of HPV in They are also responsible for others genital neoplasias like vaginal, vulvar, anal, and penian. HPV is a non-enveloped, double-stranded DNA virus from the family of Papillomaviridae, with an 8 kb circular genome composed of six early ORFs open reading frames with role in viral transcription and replication E1, E2, E4, E5, E6, E7two late ORFs L1,2-capsid proteins and a non-coding long controlled region LCR that contains a variety of cis elements, which regulate viral replication and gene expression.
More than HPV types have been identified, and about 40 can infect the genital tract. Based on their association with cervical cancer and precursor lesions, HPVs are grouped to high-risk 16, 18, 31, 33, 34, 35, 39, 45, 51, 52, 56, 58, 59, 66, 68, 73, 82 and low-risk HPV types 6, 11, 42, 43, 44, 54, 61, 70, 72, Natural history Most genital HPV infections are benign, subclinical, and self-limited, and a high proportion of infections associated with low-grade cervical dysplasias also regress spontaneously 1.
By contrast, persistent cervical infection infection detected more than once in an interval of 6 que es cancer linfatico or longer cervical cancer not hpv related an oncogenic HPV type, especially HPV 16 and HPV 18, is the most important risk factor for progression to high-grade dysplasia, papilloma virus bovino precancerous lesion that should be treated to prevent the development of invasive cervical cancer not hpv related 2.
HPV is cervical cancer not hpv related necessary but not a sufficient condition for the development of cervical cancer. Cofactors associated with cervical cancer include: cigarette smoking, increased parity, increased age, other sexually transmitted infections, immune suppression, long-term oral contraceptive use, and other host factors. Figure 1. Schematic representation of the HPV double-stranded circular DNA genome Journal of Virology Nov HPV integration into the host genome and Papillomavirus life cycle To establish infection, the virus cervical cancer not hpv related infect basal epithelial cells of stratified squamous epithelium, that are long lived or have stem cell-like properties.
Cervical cancer not hpv related of the suprabasal epidermal cells enables the virus to infect the cell within the basal layer. Cervical cancer not hpv related inside the host cell, HPV DNA replicates as the basal cells differentiate and progress to the surface of the epithelium.
The viral genome maintains itself as an episome in basal cells, where the viral genes are poorly expressed.
In the differentiated keratinocytes of the suprabasal layers of the epithelium, the virus switches to a rolling-circle mode of DNA replication, amplifies its DNA to high copy number, synthesizes capsid proteins, and causes viral assembly to occur 3. HPV needs host cell factors to regulate viral transcription and replication.
Their function is to subvert the cell growth-regulatory pathways by binding and inactivating tumor suppressor proteins, cell cyclins, and cyclin-dependent kinases and modify the cellular environment in order to facilitate viral replication in a cell that is terminally differentiated and has exited the cell cycle 4.
Cell growth is regulated by cervical cancer not hpv related cellular proteins: the tumor suppressor protein, p53, and the retinoblastoma gene cervical cancer not hpv related, pRB.
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Unlike in many other cancers, the p53 in cervical cancer is usually wild type and is not mutated. E6 binds to p53 via a cellular ubiquitin ligase named E6AP, so that it becomes ubiquitinated, leading to degradation and down-regulation of pathways involved in cycle arrest and apoptosis.
This degradation has the same effect as an inactivating mutation.
Department of Ophthalmology, Grigore T. E-mail: moc. We report the detection of HPV 52 in a sample taken from a year-old patient with squamous cell carcinoma of the conjunctiva of the left eye. The method used for the detection of HPV was real time polymerase chain reaction.
It is likely that ubiquitin ligase E6AP is a key player not only in the degradation of p53 but also in the activation of telomerase and cell transformation by E6 5. The E7 binds to retinoblastoma RBphosphorylating and therefore inactivating it 4. Also it binds to other mitotically interactive cellular proteins such as cyclin E.
Rb prevents inhibiting progression from the gap phase to the synthesis phase of the G1 mytotic cycle. When E7 binds to and degrades Rb protein, it is no longer functional and cell proliferation is left unchecked. The outcome is stimulation of cellular DNA synthesis and cell proliferation. The net result of both viral products, E6 and E7, is dysregulation of the cell cycle, allowing cells with genomic defects to enter the S-phase DNA replication phase.
These oncoproteins have also been shown to promote chromosomal instability as well as to induce cell growth and immortalize cells.
The changing epidemiology of HPV and cervical cancer
Next, the E5 gene product induces an increase in mitogen-activated protein kinase activity, thereby enhancing cellular responses to growth and differentiation factors. This results in continuous proliferation and delayed differentiation of the host cervical cancer not hpv related. The E1 and E2 gene products are synthesized next, with important role in the genomic replication. Through its interaction with E2, E1 is recruited to the replication origin oriwhich is essential for the initiation of cervical cancer not hpv related DNA replication.
E2 also contributes to the segregation of viral DNA in the cell division process by tethering the viral DNA to the host chromosome through interaction with Brd4.