Multiple Sclerosis (MS ) is an autoimmune disorder that strips nerve cells in the brain and spinal cord of their coverings (sheaths) which results in impaired messaging. A 2022 article published in Science suggested that the Epstein-Barr virus (EBV) could be one cause of MS and other autoimmune disorders (such as lupus and Rheumatoid Arthritis). Interestingly, having an EBV infection is also an established risk factor for developing certain types of cancers (such as stomach, nasopharyngeal cancer and different types of lymphoma).
EBV is a very common human herpes virus. In fact, some studies show that greater than 90 percent of the population globally has been exposed to the virus at some point in their lives even though they may have had no symptoms. Sometimes EBV infects the lining of the mouth and throat (called mono) while at other times it can remain dormant (inactive).
The connection between EBV and certain cancers was made when the virus was found in cancer cells. Even so, the number of EBV-related cancers is small (less than 1 percent of all cancers). Researchers suggest that is the combination of exposure to EBV, genetics, and environmental exposures that increases the risk of cancer.
So what is the connection between MS and cancer? The jury is still out. Some studies have found no increased risk from having MS while others have found an increased number of certain cancers in MS patients, such as bladder cancer and cancer of the brain and spinal cord (the central nervous system). Further, at least one study showed an increased risk of blood cancers in the siblings of MS patients-including cancers with proven association with EBV infection.
The immune system functions abnormally in MS, both attacking the cells in the brain and spinal cord AND not fighting viruses and cancer as it should.
Some of the increased risk of cancer in MS patients may actually be due to the medications used to treat MS. This is because the immune system normally acts as scavengers of cancer cells. The same MS drugs suppress the immune system to decrease the attacks on the nervous system may increase the chance of some cancer cells remaining unchecked.
The best ways to prevent cancer if you have MS are the same as for the general population-avoiding excess sun exposure, not smoking, limiting alcohol and pursuing a healthy lifestyle.