Causes of nasopharyngeal cancer

Nasopharyngeal cancer can bring a lot of harm and cause considerable trouble to patients. In life, we must pay attention to nasopharyngeal cancer, especially the causes that can cause nasopharyngeal cancer. So what factors cause the occurrence of nasopharyngeal cancer? Let me introduce them to friends here.

Causes of nasopharyngeal cancer:

1. Genetic factors, family clustering phenomenon Many NPC patients have a family history of cancer. NPC has a vertical and horizontal family tendency. Racial susceptibility NPC is mainly seen in yellow people and rarely in white people; ethnic groups with high incidence rates have moved to other places (or lived abroad), and their descendants still have a high incidence rate. Regional concentration NPC mainly occurs in the five southern provinces of my country, namely Guangdong, Guangxi, Hunan, Fujian and Jiangxi, accounting for the first place in local head and neck malignant tumors. Southeast Asian countries are also high-incidence areas. Susceptibility genes In recent years, molecular genetic studies have found that the main chromosomes that undergo chromosomal changes in NPC tumor cells are chromosomes 1, 3, 11, 12 and 17. The discovery of multiple chromosome heterozygous loss regions (1p, 9p, 9q, 11q, 13q, 14q and 16q) in NPC tumor cells may indicate that there are multiple tumor suppressor gene mutations in the development of NPC.

2. Environmental factors. Reports show that the mortality rate of nasopharyngeal cancer among Chinese who have emigrated abroad gradually decreases with the number of generations. On the contrary, the risk of nasopharyngeal cancer among white people born in Southeast Asia has increased. This suggests that environmental factors may play an important role in the pathogenesis of nasopharyngeal cancer. Epidemiological surveys have found that infants in high-incidence areas of nasopharyngeal cancer in Guangdong Province first come into contact with salted fish after weaning. In addition, dried fish and Guangdong cured meat are also related to the incidence of nasopharyngeal cancer. These foods contain nitrites, the precursor of nitrosamines, during the pickling process. When the pH value of human gastric juice is between 1 and 3, nitrite or nitrate (which needs to be reduced to nitrite by cells) can synthesize nitrosamine compounds with secondary amines in cells. These substances have a strong carcinogenic effect. Excessive levels of certain trace elements, such as nickel, in the environment may also induce nasopharyngeal cancer.

3. Viral infection. In 1964, a lymphoblastoid cell line that can be propagated was first established from the biopsy tissue of African childhood lymphoma (Burkitt lymphoma). Herpes-type virus particles can be seen under an electron microscope. Because it has different characteristics from other members of the herpes virus family, it is named Epstein-Barr virus, or EB virus. Lymphoblastoid cell lines carrying the virus can be isolated from nasopharyngeal carcinoma tissues, and a few of them have visible virus particles under an electron microscope. Immunological and biochemical studies have confirmed that EB virus is closely related to nasopharyngeal carcinoma. The dynamic changes and monitoring of EB virus antibody titers can be used as indicators for clinical diagnosis, prognosis estimation, and follow-up monitoring. In addition to EB virus, other viruses such as coronaviruses are also believed to be involved in the occurrence and development of nasopharyngeal carcinoma.