Part of the female reproductive system, the cervix is a muscular ring of tissue that joins the uterus to the vagina. Cervical cancer occurs when cells that make up the cervix grow abnormally and out of control. Most cervical cancers — 99% of them — are caused by infection with certain types of human papillomavirus (HPV), a group of very common viruses, which can now be largely prevented by vaccination.
Although the cervix is considered part of the uterus, cancers that begin in other parts of the uterus or uterine lining (endometrium) are diagnosed and treated differently. Learn more about these other cancer types at Roswell Park’s section on uterine cancer.