From the National Cancer Institute
What is the association between HPV infection and cancer?
Persistent HPV infections are now recognized as the major cause of cervical cancer. In 2007, it was estimated that 11,000 women in the United States would be diagnosed with this type of cancer and nearly 4,000 would die from it. Cervical cancer strikes nearly half a million women each year worldwide, claiming a quarter of a million lives. Studies also suggest that HPVs may play a role in some cancers of the anus, vulva, vagina, and penile cancer (cancer of the penis) (2).
Studies have also found that oral HPV infection is a strong risk factor for oropharyngeal cancer (cancer that forms in tissues of the oropharynx, which is the middle part of the throat and includes the soft palate, the base of the tongue, and the tonsils) (2, 3). Researchers found that an oral HPV infection and past HPV exposure increase the risk of oropharyngeal squamous cell cancer, regardless of tobacco and alcohol use, two other important risk factors for this disease. However, combining HPV exposure and heavy tobacco and alcohol use did not have an additive effect (3).
Are there specific types of HPV that are associated with cancer?
Some types of HPV are referred to as “low-risk” viruses because they rarely cause lesions that develop into cancer. HPV types that are more likely to lead to the development of cancer are referred to as “high-risk.” Both high-risk and low-risk types of HPV can cause the growth of abnormal cells, but only the high-risk types of HPV lead to cancer. Sexually transmitted, high-risk HPVs include types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, 68, and 73 (4). These high-risk types of HPV cause growths on the cervix that are usually flat and nearly invisible, as compared with the external warts caused by low-risk types HPV–6 and HPV–11. HPV types 16 and 18 together cause about 70 percent of cervical cancers (4, 5). It is important to note, however, that the great majority of high-risk HPV infections go away on their own and do not cause cancer (5).
What are the risk factors for HPV infection and cervical cancer?
Having many sexual partners is a risk factor for HPV infection. Although most HPV infections go away on their own without causing any type of abnormality, infection with high-risk HPV types increases the chance that mild abnormalities will develop and progress to more severe abnormalities or cervical cancer. However, even among the women who do develop abnormal cell changes with high-risk types of HPV, only a small percentage would develop cervical cancer if the abnormal cells were not removed. As a general rule, the more severe the abnormal cell change, the greater the risk of cancer. Studies suggest that whether a woman develops cervical cancer depends on a variety of factors acting together with high-risk HPVs. The factors that may increase the risk of cervical cancer in women with HPV infection include smoking and having many children (5).
Ignorance of this relationship will cause many to contact cancer. We need to teach this in our schools, families, and churches. Few realize that STDs can cause cancer.