The occurrence of cervical cancer is closely related to HPV virus infection, especially high-risk HPV infection, such as HPV16, HPV18, HPV31, HPV33, HPV45, HPV51, HPV52, HPV56 and other types. The two most common subtypes, HPV16 and HPV18, are the most directly cancer-causing subtypes. HPV viruses, or human papillomaviruses, are divided into high-risk HPV viruses and low-risk HPV viruses.