Cervical Cancer Cure
Cervical Cancer Cure
A human papillomavirus ( HPV ) is a member of the papillomavirus family of viruses that is capable of infecting humans. Like all papillomaviruses, HPVs establish productive infections only in the stratified epithelium of the skin or mucous membranes. While the majority of the nearly 200 known types of HPV cause no symptoms in most people, some types can cause warts (verrucae), while others can – in a minority of cases – lead to cancers of the cervix, vulva, vagina, and anus in women or cancers of the anus and penis in men.
More than 30 to 40 types of HPV are typically transmitted through sexual contact and infect the anogenital region. Some sexually transmitted HPV types may cause genital warts. Persistent infection with "high-risk" HPV types—different from the ones that cause warts—may progress to precancerous lesions and invasive cancer. HPV infection is a cause of nearly all cases of cervical cancer; however, most infections with these types do not cause disease.
Most HPV infections in young females are temporary and have little long-term significance. 70% of infections are gone in 1 year and 90% in 2 years. But when infection persists—in 5% to 10% of infected women—there is high risk of developing cervical precancer (lesions on the cervix), which can progress to invasive cervical cancer. This process usually takes 15–20 years, providing many opportunities for detection and treatment of the pre-cancerous condition, often with high cure rates.
In the US and other high-resource countries, a cervical Papanicolaou (Pap) test is used to detect abnormal cells which may develop into cancer. A cervical examination also detects warts and other abnormal growths which become visible as white patches of skin after they are washed with acetic acid (visual inspection). Abnormal and cancerous areas can be removed with a simple procedure, typically with a cauterizing loop or—more common in the developing world—by freezing (cryotherapy). New HPV DNA tests are more sensitive than Pap or visual inspection and a lower-cost HPV test suitable for low-resource settings may become available soon, potentially making high-sensitivity screening feasible where it currently does not exist in Africa, Asia and Latin America.
Pap smears have reduced the incidence and fatalities of cervical cancer in the developed world, but even so there were 11,000 cases and 3,900 deaths in the U.S. in 2008. Cervical cancer has substantial mortality in resource-poor areas; worldwide, there are 490,000 cases and 270,000 deaths. In large part because Pap is difficult to sustain in low-resource settings, eighty to 85 percent of cervical cancer deaths occur in the developing world.
HPV vaccines, Cervarix and Gardasil, which prevent infection with the HPV types (16 and 18) that cause 70% of cervical cancer, may lead to further decreases.
History
In 1976 Harald zur Hausen published the hypothesis that human papilloma virus plays an important role in the cause of cervical cancer. In 1983 and 1984 zur Hausen and his collaborators identified HPV16 and HPV18 in cervical cancer. In 1972, the association of the Human papilloma viruses with skin cancer in epidermodysplasia verruciformis was proposed by Stefania Jablonska in Poland. In 1978 Jablonska and Gerard Orth at the Pasteur Institute discovered HPV-5 in skin cancer.
Prevalence
United States of America
HPV is estimated to be the most common sexually transmitted infection in the United States. Most sexually active men and women will probably acquire genital HPV infection at some point in their lives. The American Social Health Association reported estimates that about 75-80% of sexually active Americans will be infected with HPV at some point in their lifetime. By the age of 50 more than 80% of American women will have contracted at least one strain of genital HPV.
It was estimated that in the year 2000, there were approximately 6.2 million new HPV infections among Americans aged 15–44; of these, an estimated 74% occurred to people between ages 15–24. Of the STDs studied, genital HPV was the most commonly acquired.
Estimates of HPV prevalence vary from 14% to more than 90%. One reason for the difference is that some studies report women who currently have a detectable infection, while other studies report women who have ever had a detectable infection. Another cause of discrepancy is the difference in strains that were tested for.
One study found that, during 2003–2004, at any given time, 26.8% of women aged 14 to 59 were infected with at least one type of HPV. This was higher than previous estimates. 15.2% were infected with one or more of the high-risk types that can cause cancer. However only 3.4% were infected with one or more of the four types prevented by the Gardasil vaccine, which was lower than previous estimates.
Note that prevalence decreases with age. This may be due to HPV infection being cleared by the immune system, or sinking to undetectable levels while still present in the body. HPV will probably remain in the infected person's cells for an indefinite time—most often in a latent state, but occasionally producing symptoms or disease. Recent studies from the Albert Einstein College of Medicine and from the University of Washington suggest that HPV may eventually be cleared in most people with well functioning immune systems. It appears that in some cases the virus does remain in the body indefinitely, producing symptoms if the immune system weakens.
Cervical cancer
The American Cancer Society estimates that in 2008, about 11,070 women in the United States will be diagnosed with invasive cervical cancer, and about 3,870 US women will die from this disease.
Life cycle
The HPV life cycle strictly follows the differentiation program of the host keratinocyte. It is thought that the HPV virion infects epithelial tissues through micro-abrasions, whereby the virion associates with putative receptors such as alpha integrins and laminins, leading to entry of the virions into basal epithelial cells through clathrin-mediated endocytosis and/or caveolin-mediated endocytosis depending on the type of HPV. At this point, the viral genome is transported to the nucleus by unknown mechanisms and establishes itself at a copy number between 10-200 viral genomes per cell. A sophisticated transcriptional cascade then occurs as the host keratinocyte begins to divide and become increasingly differentiated in the upper layers of the epithelium.
E6/E7 proteins
The viral oncogenes, E6 and E7 are thought to modify the cell cycle so as to retain the differentiating host keratinocyte in a state that is favourable to the amplification of viral genome replication and consequent late gene expression. E6 in association with host E6 associated protein, which has ubiquitin ligase activity, act to ubiquitinate p53, leading to its proteosomal degradation. E7 (in oncogenic HPVs) acts as the primary transforming protein. E7 competes for retinoblastoma protein (pRb) binding, freeing the transcription factor E2F to transactivate its targets, thus pushing the cell cycle forwards. All HPV can induce transient proliferation, but only 16 and 18 can immortalise cell intes (in vitro). It has also been shown that HPV 16 and 18 cannot immortalise primary rat cells alone; there needs to be activation of the ras oncogene. In the upper layers of the host epithelium, the late genes L1 and L2 are transcribed/translated and serve as structural proteins which encapsidate (Encapsidation is the process of incorporating a nucleic acid sequence (e.g., a vector, or a viral genome) into a viral particle) the amplified viral genomes. Once the genome is encapsidated, the capsid appears to undergo a redox-dependent assembly/maturation event which is tied to a natural redox gradient that spans both suprabasal and cornified epithelial tissue layers. This assembly/maturation event stabilizes virions, and increases their specific infectivity. Virions can then be sloughed off in the dead squames of the host epithelium and the viral lifecycle continues.
Latency period
Once an HPV viron invades a cell, an active infection occurs, and the virus can be transmitted. Several months to years may elapse before squamous intraepithelial lesions (SIL) develop and can be clinically detected. The time from active infection to clinically detectable disease makes it difficult for someone who has become infected to establish which partner was the source of infection.
Types and associated diseases
Over 100 HPV types have been identified and are referred to by number. Types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, and 59 are "high-risk" sexually transmitted HPVs and may lead to the development of cervical intraepithelial neoplasia (CIN), vulvar intraepithelial neoplasia (VIN), penile intraepithelial neoplasia (PIN), and/or anal intraepithelial neoplasia (AIN).
Cancers
See also: Cervical cancerAbout a dozen HPV types (including types 16, 18, 31 and 45) are called "high-risk" types because they can lead to cervical cancer, as well as anal cancer, vulvar cancer, penile cancer and lung cancer Several types of HPV, particularly type 16, have been found to be associated w
PATH | RHO Cervical Cancer | Kill or Cure? Cervical ...
Kill or Cure? Cervical Cancer. This seven-minute film shows how simple screening tests and community mobilization are saving lives across India.
ACS :: Overview: Cervical Cancer
Overview: Cervical Cancer Get an overview of each of the topics by clicking the document title. Choose another cancer topic
Cervical cancer protocol by Dr. Simoncini
Cervical cancer protocol - Simoncini Sodium bicarbonate cancer therapy
PATH | RHO Cervical Cancer | Kill or Cure? Cervical Cancer
Kill or Cure? Cervical Cancer. This seven-minute film shows how simple screening tests and community mobilization are saving lives across India.
Symptoms of Cervical Cancer - CureResearch.com
Symptoms of Cervical Cancer including signs, symptoms, incubation period, duration, and correct diagnosis.
Cervical Cancer Symptoms, Treatments And Cures
Learn the seven easiest ways to spot symptoms of cervical cancer. Click here before it's too late!
HPV Cure - Is There a Cure for HPV?
Answer to a common question about whether the human papillomavirus (HPV) can be cured or not.
ICT Results - Pooled data towards cervical cancer cure
Pooled data towards cervical cancer cure ... Half of all the 60,000 new cases of cervical cancer diagnosed in Europe this year will prove ...
Pooled Data Towards Cervical Cancer Cure
Every year, tens of thousands of women die in the EU from cervical cancer because the disease is not detected and treated at an early enough stage. A multidisciplinary European ...
Cervical Cancer : Cafe Cure
Awareness t shirts and gifts for Cancer, support our troops, child abuse, and more. Where there is an awareness there can be a cure!
