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Cervical Canser Causes The human papillomavirus (HPV) has been detected in virtually all invasive cervical cancers and has been confirmed as the major cause of this cancer. How HPV Is Transmitted. HPV is spread primarily by having sex with an infected partner. Most sexually active young women become infected with this virus, but only 10% remain infected for more than 5 years. Only those infected for longer than 5 years have a higher risk (about 50% above normal). Other factors are then needed to trigger the disease. How HPV Contributes to Cervical Cancer. Researchers believe that most cervical cancers develop when various aggressive genetic HPV strains activate certain oncogenes (cancer-causing genes). Oncogenes called E6 and E7 are particularly important because they interfere with certain protective proteins, such as p53 and pRb, respectively. Under normal conditions, these proteins limit cell growth. Once they are blocked, cell growth can run rampant, leading to tumor development and cancer. HPV Genetic Types. More than 30 genetic variants of human papillomaviruses can be passed through sexual contact form one person to another. The severity, however, varies widely according to genetic type. (Women initially infected by one type of HPV are still at risk for infection from other types.) In women with cervical intraepithelial neoplasia I , the HPV viruses that are present are often types 6 and 11, which are low risk. Other low-risk HPV genetic types are 40, 42, 43, 44, 54, 61, 70, 72, and 81. These viral types often produce genital warts (condylomata) that rarely lead to cancer. (These warts usually affect the woman's genitals, the vagina, and vulva, rather than the cervix.) Of the high-risk types, HPV types 16 and 18 have long been known to be particularly dangerous. These two genetic types and six others (31, 33, 35, 45, 52, and 58) account for 95% of HPV-related cervical cancers. Other high-risk types are 39, 51, 56, 59, 68, 73, and 82. All are associated with moderate cervical intraepithelial neoplasia II and cervical intraepithelial neoplasia III. Types 26, 53, and 66 are also considered high-risk. In 2007, several studies indicated that HPV-16 infection in the mouth is associated with increased risk for oropharyngeal cancer. (Oropharyngeal cancer develops in the throat, just behind the mouth. It includes the base of the tongue, soft palate, tonsils, and side and back walls of the throat.) Prior to this research, alcohol and tobacco were thought to be the main risk factors for this type of cancer. According to the studies, oral sex (both fellatio and cunnilingus) significantly increases the risk of HPV-16 transmission and, therefore, the risk of developing oropharyngeal cancer. While the risk of HPV-16 causing oropharyngeal cancer is lower than the risk of it causing cervical cancer, experts think that the HPV vaccine may help reduce the incidence of throat, tonsil, and tongue cancers, as well as cervical cancer. High-risk types of HPV have also been associated with an increased risk for other cancers, including other genital and lung cancers. The high-risk viruses generally produce flat and nearly invisible growths, compared to the usually harmless warts caused by low-risk HPV viruses.

Other Sexually Transmitted Diseases Herpes viruses. Certain herpes viruses, including herpes simplex virus 6, 2, 7, and cytomegalovirus, have been detected in women with cervical cancer. herpes simplex virus 6 is under particular suspicion for playing a role in activating the papilloma virus gene. The presence of these very common viruses, however, may simply be coincidental, and they may serve no purpose other than being bystanders. Chlamydia Trachomatis. Studies are finding an especially strong association between the incidence of Chlamydia trachomatis, a sexually transmitted infection, and HPV. (Chlamydia trachomatis should not be confused with Chlamydia pneumoniae, a common cause of mild pneumonia in young adults. Chlamydia pneumonia e is not associated with cervical cancer.) Other Sexually Transmitted Diseases. Other sexually transmitted diseases that have been associated with cervical cancer include HIV and gonorrhea. These infections, however, also may only be markers of increased sexual activity and may not themselves cause cancer. View & Print In-Depth Report »

Review Date: 6/10/2008 Reviewed By: James R. Mason, MD, Oncologist, Director, Blood and Marrow Transplantation Program and Stem Cell Processing Lab, Scripps Clinic, Torrey Pines, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (www.hon.ch). A.D.A.M. Copyright The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -they do not constitute endorsements of those other sites. © 1997- 2008 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.