Do We Know What Causes Nasopharyngeal Cancer?
The exact cause of most cases of nasopharyngeal cancer (NPC) is not known. But scientists have found that the disease is linked with certain diets, infections, and inherited characteristics, which are described in the section called “ What are the risk factors for nasopharyngeal cancer? Research is being done to learn more about these causes.
In recent years, scientists have studied how the Epstein-Barr virus (EBV) may cause cells in the nasopharynx to become cancerous, but much still remains to be learned. In developed countries, most people infected with EBV develop only infectious mononucleosis (mono), and their immune system is able to recognize and destroy the virus. These people recover without any long-term problems. But in some cases, pieces of viral DNA mix with the DNA of cells in the nasopharynx.
DNA is the chemical in each of our cells that makes up our genes, the instructions for how our cells function. We usually look like our parents because they are the source of our DNA. But DNA affects more than how we look. Some genes contain instructions for controlling when cells grow and divide into new cells. Viruses such as EBV also contain DNA. When a cell is infected with the virus, the viral DNA may mix with the normal human DNA. EBV DNA may instruct the cells of the nasopharynx to divide and grow in an abnormal way.
But EBV infection only rarely results in NPC, so other factors probably play a role in whether or not it causes cancer. Eating a diet high in salt-cured fish and meat seems to increase the ability of EBV to cause NPC. Studies show that foods preserved in this way may produce chemicals that can damage DNA. The damaged DNA alters a cell’s ability to control its growth and replication.
Some studies suggest that inheriting certain tissue types may contribute to a person’s risk of developing NPC. Because the tissue type plays a role in the function of the immune system, some scientists suspect that an abnormal immune reaction to EBV infection may be involved. The details of how certain tissue types might increase NPC risk are still being worked out.
Last Medical Review: January 15, 2015 Last Revised: August 8, 2016