Cervical cancer starts in the cells lining the cervix—the lower part of the uterus (womb). This is sometimes called the uterine cervix. The fetus grows in the body of the uterus (the upper part). The cervix connects the body of the uterus to the vagina (birth canal). The part of the cervix closest to the body of the uterus is called the endocervix. The part next to the vagina is the ectocervix. The 2 main types of cells covering the cervix are squamous cells (on the ectocervix) and glandular cells (on the endocervix). These 2 cell types meet at a place called the transformation zone. The exact location of the transformation zone changes as you age and if you give birth.
Most cervical cancers begin in the cells in the transformation zone. These cells do not suddenly change into cancer. Instead, the normal cells of the cervix first gradually develop pre-cancerous changes that turn into cancer and this is due to infection with the human papillomavirus (HPV).
Types of Cervical Cancer
Cervical cancers and cervical pre-cancers are classified by how they look under a microscope. The main types of cervical cancers are squamous cell carcinoma and adenocarcinoma.
Most (up to 9 out of 10) cervical cancers are squamous cell carcinomas. These cancers form from cells in the ectocervix and the cancer cells have features of squamous cells under the microscope. Squamous cell carcinomas most often begin in the transformation zone (where the ectocervix joins the endocervix).
Most of the other cervical cancers are adenocarcinomas. Adenocarcinomas are cancers that develop from gland cells. Cervical adenocarcinoma develops from the mucus-producing gland cells of the ectocervix. Cervical adenocarcinomas seem to have become more common in the past 20 to 30 years.
Less commonly, cervical cancers have features of both squamous cell carcinomas and adenocarcinomas. These are called adenosquamous carcinomas or mixed carcinomas.
Although cervical cancers start from cells with pre-cancerous changes (pre-cancers), only some of the women with pre-cancers of the cervix will develop cancer. It usually takes several years for cervical pre-cancer to change to cervical cancer, but it can happen in less than a year. For most women, pre-cancerous cells will go away without any treatment. Still, in some women pre-cancers turn into true (invasive) cancers. Treating all cervical pre-cancers can prevent almost all true cervical cancers.
Although almost all cervical cancers are either squamous cell carcinomas or adenocarcinomas, other types of cancer also can develop in the cervix. These other types, such as melanoma, sarcoma, and lymphoma, occur more commonly in other parts of the body.
Cervical Cancer & HPV
Infection by the human papillomavirus (HPV) is the biggest risk factor for cervical cancer. HPV is a group of more than 150 related viruses.
HPV can spread from one person to another through skin-to-skin contact. One way HPV spreads is through sexual activity, including vaginal, anal, and even oral sex.
Different types of HPV cause warts on different parts of the body. Some cause common warts on the hands and feet; others tend to cause warts on the lips and tongue. Certain types of HPV may cause warts on or around the female and male genital organs and in the anal area. These are called low-risk types of HPV because they are seldom linked to cancer.
Other types of HPV are called high-risk types because they are strongly linked to cancers, including cancer of the cervix, vulva and vagina in women, penile cancer in men, and cancers of the anus, mouth and throat in both men and women.
Infection with HPV is common, and in most people, the body can clear the infection by itself. Sometimes, though, the infection does not go away and becomes chronic. Chronic infection, especially when it is caused by certain high-risk HPV types, can eventually cause certain cancers, such as cervical cancer.
Content was created using EBSCO’s Health Library. Edits to original content made by Rector and Visitors of the University of Virginia. This information is not a substitute for professional medical advice.