What Causes Nasopharyngeal Cancer?

The exact cause of most cases of nasopharyngeal cancer (NPC) is not known. But scientists have found links with certain diets, infections, and inherited factors. (See Risk Factors for Nasopharyngeal Cancer.)

Epstein-Barr virus infection

Scientists have studied how the Epstein-Barr virus (EBV) may cause cells in the nasopharynx to become cancer, but there's still a lot to learn. In developed countries, most people infected with EBV have 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 EBV 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 work. For instance, we often look like our parents because they're the source of our DNA. But DNA affects more than how we look. Some genes contain instructions that control when cells grow and divide into new cells. Viruses like EBV also contain DNA. When a cell is infected with the EBV virus, the viral DNA may mix with the normal human DNA. Then the EBV DNA may tell the cells of the nasopharynx to divide and grow in an abnormal way. Still, EBV infection rarely leads to NPC, so other factors, such as smoking and genetic factors, probably play a role in whether or not it causes cancer.

Eating certain foods

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 then changes a cell’s ability to control its growth and reproduction.

Inherited Factors

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.