Understanding HPV

What Is HPV?

  • Human papillomavirus (HPV) is the most common sexually transmitted infection in the United States
  • If left untreated, high-risk HPV infection can cause precancerous cells
  • Two of these high-risk viruses (HPV 16/18) are responsible for 70% of HPV-related cancers

How does HPV infection cause precancerous cells of the cervix?

  • High-risk HPV infects cells on the surface of the cervix
  • Often the body fights the high-risk HPV infection and causes it to go away, but when it does not, the infection can cause the cells to grow abnormally
  • If the body’s immune system does not fight these changes, the abnormal growth can lead to precancerous cells, which are referred to as HSIL
  • Precancerous cells can progress to cancer over time

What are some medical terms for precancerous cells of the cervix?

  • “High grade” means that these changes are serious because they may turn into cervical cancer if not treated
  • HSIL is identified by a Pap test (Pap smear) and/or cervical biopsy
  • CIN is graded on a scale of 1 to 3, based on how abnormal the cells look under a microscope and how much of the cervical tissue is affected
  • CIN 1 is not considered to be precancerous, and represents a response to HPV infection that usually goes away on its own without treatment. CIN 1 can be defined as “mild”
  • CIN 2 and CIN 3 are considered to be precancerous, and may progress to cancer if they go untreated. CIN 2 can be defined as “moderate” and CIN 3 can be defined as “severe.” CIN 2 and/or CIN 3 might also be referred to as cervical dysplasia
  • CIN is identified by a cervical biopsy