Our endocrine glands produce hormones, which are like the body’s messengers—they move through the bloodstream until they reach their target organ, and then they deliver instructions telling that organ exactly how to behave. These “messages” trigger important processes, like metabolism, growth, reproduction and even mood.

Occasionally, in one of the endocrine glands, a change in the DNA (known as a mutation) causes abnormal cells to grow, and a tumor forms. Most endocrine tumors are benign (not cancerous), but a few will become cancerous. Collectively, endocrine cancers are much less common than other kinds of cancer.