HPV is a species-specific epitheliotropic virus. It is a small double-stranded closed-loop DNA virus containing approximately 8,000 base pairs. Structural diagram of human papillomavirus (HPV). These include 8 early open reading frames (E1-E8), 2 late reading frames and 1 non-coding long control region. In the early open reading frame, E6 and E7 genes are most important for stimulating cell growth. The E6 and E7 proteins encoded by E6 and E7 cause the immortalization of cervical epithelial cells. The late reading frame L1 and L2 genes encode the major and minor capsid proteins of HPV respectively, which are assembled into the capsid of HPV.
When HPV is "dissected", you will find that it is composed of a protein capsid coat and a wrapped core. The "raw materials" of the capsid are mainly capsid protein (L1) and minor capsid protein (L2); after removing the capsid, the core is the true body that can cause human diseases - a small double-stranded ring without an envelope. of DNA. In 1949, Strauss first observed HPV particles under an electron microscope. They were spherical in shape, with icosahedral symmetry and a diameter of about 45-55 nm.
Based on the different structures of HPV gene sequences, HPV is divided into nearly 130 genotypes, of which the gene sequences of nearly 100 types have been identified. Humans are the only host of HPV. It prefers to make its home in the skin and mucous membranes, so it has a high degree of host-specific affinity. [1] [Edit this paragraph] Transmission route HPV is a sexually transmitted microorganism. It can enter the skin and mucous membranes of contacts through tiny injuries in the skin or mucous membranes. HPV stimulates epidermal basal cells to divide, causing proliferative damage to the epidermis. In 1954, HPV was confirmed to be one of the causes of sexually transmitted diseases, related to urogenital genital warts, and is contagious.
In addition, HPV can also be transmitted from mother to child through close contact between mother and baby. In daily life, a very small number of cases may also be infected by contact with household items containing HPV, such as underwear, bathtubs or bath towels.
Medical research shows that many factors can affect HPV infection. For example, women after the age of 30 have a low HPV infection rate. If the husband's penis has HPV, his wife's risk of cervical infection with HPV will increase by nine times. Even the number of male sexual partners is related to women's HPV infection. Among women with a single male sexual partner, the cervical and vulvar HPV detection rate is only 17%-21%; among women with more than five male partners, the HPV infection rate is as high as 69%-83%.
Research by the International Association for Research on Cancer shows that after circumcision, men not only reduce their own HPV infection rate by 14%, but also reduce the risk of cervical cancer in their female sexual partners. There is no consensus on whether using contraceptives can reduce HPV infection.
The mechanism by which HPV causes cervical cancer is complex. Integration of viral DNA into the host chromosome, abnormal expression of HPV E6 and E7 proteins, oncogenes, telomerase, etc. are all involved. [1] [Edit this paragraph] Basic classification: HPV infection has high-risk and low-risk types. The so-called high-risk type means that such people are more likely to develop cervical cancer. If you are infected with low-risk HPV, it may cause cervical precancerous lesions in the future, or lesions such as genital warts are more likely, and the possibility of causing cancer is relatively small.
According to the strength of its pathogenicity, HPV is divided into high-risk and low-risk types. "Whether it can cause cancer" is the main indicator of the risk. Data from the International Association for Research on Cancer (IARC) show that 13 low-risk HPV types mainly cause genital warts and low-grade cervical intraepithelial neoplasia in the skin around the genital tract and anus; 15 high-risk HPV types, especially types 16 and 18 , mainly leading to the occurrence of high-grade cervical intraepithelial neoplasia and cervical cancer.
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Virus classification
Classification by infection site
Epithelial HPV types 1, 5, 8, 14, 20, 21, 25, 47 and mucosal types HPV6,11,16,18,31,33,35,39,41,45,51,52,56,58,59,68,70 are classified according to cancer risk
Low risk group 6 , Type 11, 41, 42, 43, 44 high-risk group 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68, 70 type [edit this paragraph] HPV-induced diseases Infection is not only the culprit of cervical cancer. Cervical cancer is only part of the "broad cancer spectrum" caused by HPV. It can be considered that some vaginal cancers or vulvar cancers may have the same cause, which is HPV infection. This is not the same as Cervical cancer is completely unambiguous, but that's basically it. In the United States, in 2000, there were 4,000 cases of vaginal cancer and 900 deaths, which is a very high mortality rate. There were 2,000 cases of vaginal cancer and 800 deaths. They are believed to be closely related to HPV infection, so HPV can be detected very early. As important as dealing with it is, the early detection of precancerous lesions is also very important. In the UK, her overall medical level is relatively high. The number of CIN3 diagnosed in 2003, including carcinoma in situ, is 10 times that of invasive cancer. It is easy to understand that most invasive cancers have not developed, and precancerous lesions, especially in the CIN3 stage, are It has been diagnosed and treated, which is a considerable achievement. It should be said that it has saved many women's lives, including their health and life.
Another concept is that HPV infection is not uncommon in sexually active young women under 30 years old (18-28 years old), and is even relatively common. There have been corresponding reports in China, which is more than ten percent, 15% in Guangdong, and 10% in other regions. The probability of lifetime accumulation can reach 40%, which is quite high.
Only persistent HPV infection will develop into different levels of CIN or cervical cancer. Generally speaking, if an HPV infection is not cleared, it can develop into different levels of CIN within one or two years: CIN1, CIN2, and CIN3. After about 10 years, it may develop into invasive cancer. This timetable is very clear. . If you are HPV positive, you have a 28% chance of developing CIN1 or CIN2; if you are HPV negative, there is almost no chance, only 3%; if HPV infection continues, you may have a 1 to 2% chance of developing CIN1 or CIN2. Cervical cancer. HPV infection is a very common reproductive tract infection, but the development of cancer is only an accidental event. It does not happen to most people, but previous CIN is very common. [1] [Edit this paragraph] Influencing factors These influencing factors still play a certain role. For example, the chance of HPV infection from a single sex partner is small, less than 20%; if there are many sex partners and you don’t know how to investigate, it is not easy to ask 5, but it can be as high as 70%. Immunocompromise, such as HIV infection, or Hodgkin's disease. I am dealing with a very severe condyloma, a genital wart, a large cauliflower on the cervix, and a large cauliflower on the vulva. This is because the patient is taking immunosuppressants for kidney transplantation. Although it is low-grade HPV, it is uncontrollable. Genital warts grow, so immune status is important. Viral load is very important. If the patient has a low viral load, the chance of infection is 3 times higher than that of an HPV-negative patient; but if the patient has a high viral load, the chance of infection is 43 times higher than that of an HPV-negative patient. Therefore, HPV load is an independent factor affecting the occurrence of CIN.
This is the International Agency for Research on Cancer (IARC), which clearly stated in 2004 that HPV infection is a necessary factor in the occurrence of cervical intraepithelial neoplasia and cervical cancer. It can be considered that, Women who do not have persistent HPV infection have almost no risk of cervical cancer.
[2] [Edit this paragraph] There are more than 200 types of HPV discovered in HPV categories. The known types include low-risk and high-risk types. The low-risk types are well-known as 6 and 11, and the high-risk types 16 and 18. In various countries and regions, The cancer-causing HPV varies by region. In China, the next highest number is 58. Of course, 51 and 52 are also more common. For example, in Taiwanese and Japanese, 52 is relatively high. In China, it is 16, 18, and 58. There is one type of 58 that is more common than 18. trend. This is very important. We can talk about vaccines. The vaccines are 16 and 18. In the future, if the vaccine comes to China, there will be quite a lot of 58 in China, and this problem will not be covered. As for the detection method, PCR has made a great contribution to the detection of HPV. Starting from PCR, the types can be distinguished and there is a better detection method. However, PCR is actually used for research and not for clinical use, so it is With the US FDA approval of the so-called hybrid capture generation 1 and especially generation 2, this is a very important milestone. [2] [Edit this paragraph] Detection method It is important to understand PCR, but due to contamination, PCR has the problem of false positives. But hybrid capture is a very good method. Hybrid capture 2 generation is a very good HPV DNA detection method approved by the US FDA. Almost more than 60,000 people take HC2 testing every year. This is a very big change and shows that everyone attaches great importance to and applies HPV testing. The HC2 test has a very good sensitivity, especially a very good negative predictive value of more than 99%; that is to say, if the HC2 test is negative, it can be considered that the person does not have HPV infection, which is very important. HC2 detection is highly automated and standardized, with very few human factors. Unlike looking at cells, which is different for everyone, a lot can be done. [2] [Edit this paragraph] Development status Sexually transmitted infections caused by the human papilloma virus (HPV) are extremely common, with 20 million people in the United States alone infected with the disease.
HPV (Human Papilloma Virus) is an incurable sexually transmitted disease following AIDS, the “terminal disease of the century”. Both men and women may be infected with HPV, and it can even lead to cervical cancer in women. Since HPV is transmitted directly through the skin, condoms cannot prevent it.
440 million people worldwide are infected with HPV, and at least half a million women are diagnosed with cervical cancer every year, mostly in developing countries. HPV is the culprit that causes cervical cancer and genital warts, commonly known as "cauliflower". Among more than 100 types of HPV, 37 are known to be transmitted through sexual contact and can cause sexually transmitted diseases. They are widespread among adults, come and go without a trace, and show no symptoms. Types 6 and 11 can cause genital warts in both men and women. The wart itself is not cancer, but the pain and trauma it causes are beyond words.
However, indirect infection with high-risk HPV types can lead to cervical cancer, other genital cancers, or anal cancer. There are approximately 19 types of these high-risk types, with types 16 and 18, which cause cervical cancer, being the most common. Since the 19th century, the medical community has long observed that cervical cancer is closely related to social, economic, cultural, and behavioral factors. Virgins, nuns and nuns are protected from cervical cancer throughout their lives. Women who get married early are more likely to get cervical cancer early. In the past, the medical community believed that smegma on men's penis was a carcinogen and advocated circumcision. The medical community emphasizes the importance of personal hygiene such as descaling and smoking cessation, and believes that HPV is the cause of cervical cancer in women and the main cause of penile cancer in men.
Cervical cancer is an infectious disease that can be prevented, treated, cured and eliminated. Cervical cancer is caused by infection with the human papillomavirus. If HPV infection can be prevented, it can be said that cervical cancer can be prevented; if there is no HPV infection, it can be said that cervical cancer will not occur. This has been concluded and was recognized at the meeting. The cervical cancer mentioned here refers to invasive cancer of the cervix, referred to as CC. Generally speaking, cervical cancer is invasive cancer; other precancerous lesions are called CIN, including carcinoma in situ of the cervix, which is classified as CIN3. If it is invasive cancer, it is called cervical cancer. [1] [Edit this paragraph] Prevention: You should go to the hospital for a cervical scraping examination every 6 months. In daily life, we should pay attention to improving our own resistance. Second, pay attention to avoid cross-infection between husband and wife. It is best to wear condoms during sex.
[3] [Edit this paragraph] There is no specific medicine to treat HPV infection, whether it is traditional Chinese medicine or Western medicine. Treatment is mainly to improve the body's immunity and resistance. Therefore, from the perspective of Western medicine treatment, it is to increase local resistance. For example, use drugs such as interferon. Traditional Chinese medicine also provides treatment through the auxiliary implementation of traditional Chinese medicine.
There is no specific drug treatment for HPV. In fact, there is no treatment drug for the virus. Interferon and other drugs improve immunity and do not directly respond to the virus. HPV spreads easily, but HPV is not equal to cancer, especially in the blood. The presence of HPV antibodies only indicates that you have been infected with HPV. If HPV is found in secretions or shedding of the cervix, most people will recover within one or two years. STDs are generally considered to be transmitted through sexual contact or contact with the secretions (including sweat) of STD patients. They are not transmitted through the air. This is because human resistance is limited and may not be able to withstand an invasion that is too strong. This does not mean that all All viruses can cause disease. Sexually transmitted warts, commonly known as "cauliflower", are caused by HPV infection. Women may develop cervical cancer after warts occur. In three steps, the HPV infection will heal itself or develop into warts or may be latent and long-term infection. The possibility of cervical cancer occurs, so it is recommended that patients infected with HPV should check HPV and cancer cells every year for early treatment of cervical cancer. After all, in addition to life, women also hope to maintain normal functions. Early treatment, minimal damage, and no impact on life at all. At the same time, it should also be pointed out that sexual life-infection with HPV-cervical cancer is not the cause of cervical cancer. Unmarried women may also suffer from cervical cancer, but of course the chance will be much smaller. [4]