What Causes Salivary Gland Cancer?

Although we know a few things that can raise a person’s risk of salivary gland cancer, it’s not clear exactly what causes most of these cancers. And while there is no clear relationship between certain genes and the development of salivary cancers, here is some information that might be helpful.

DNA is the chemical in our cells that makes up our genes, which control how our cells work. We look like our parents because they are the source of our DNA. But DNA affects more than just how we look. It also can influence our risk for developing certain diseases, such as some kinds of cancer.

Some genes control when cells grow, divide, and die: 

• Genes that help cells grow, divide, and stay alive are called proto-oncogenes. If something causes a proto-oncogene to mutate (change), the gene becomes abnormal and is then called an oncogene. 
• Genes that help keep cell growth under control or make cells die at the right time are called tumor suppressor genes.

Cancers can be caused by DNA mutations (gene changes) that turn on oncogenes or turn off tumor suppressor genes. This leads to cells growing out of control. Changes in many different genes are usually needed to cause salivary gland cancer.

Researchers don’t yet know all of the DNA changes that result in salivary gland cancer, but they have found some gene changes that are often found in these cancers.

• Most mucoepidermoid cancers have the MECT1-MAML2 fusion oncogene
• More than half of adenoid cystic salivary gland cancers have the MYB-NFIB oncogene

Identifying these gene changes is helping to find new targeted drug therapies for some salivary gland cancers.

For more about how gene changes can lead to cancer, see Genes and Cancer.

Inherited and acquired gene mutations: Salivary gland cancer does not usually run in families, so most of the DNA changes that lead to this cancer are not likely to be inherited from a person’s parents.

Gene changes related to these cancers usually happen during a person’s lifetime, rather than being inherited. These acquired mutations often result from exposure to cancer-causing chemicals, like those found in tobacco smoke or chemicals at work, but others might just be random events that happen inside cells, without having an outside cause. Several different gene changes are probably needed for cancer to develop, and not all of these changes are understood at this time.

Inherited mutations of oncogenes or tumor suppressor genes rarely cause these cancers, but some people seem to inherit a poor ability to detoxify (break down) certain types of cancer-causing chemicals. These people are more sensitive to the cancer-causing effects of tobacco smoke, and certain industrial chemicals.