ON THIS PAGE: You will find out more about what factors increase the chance of this type of tumor. To see other pages in this guide, use the colored boxes on the right side of your screen, or click “Next” at the bottom.
A risk factor is anything that increases a person’s chance of developing cancer. Although risk factors often influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. However, knowing your risk factors and talking about them with your doctor may help you make more informed lifestyle and health care choices.
The following factors can raise a person's risk of developing a neuroendocrine tumor:
Age. Pheochromocytoma is most common between the ages of 40 and 60. Merkel cell cancer is most common in people older than 70.
Gender. Men are more likely to develop pheochromocytoma than women. For every two women who develop pheochromocytoma, three men will develop the disease. Men are also more likely to develop Merkel cell cancer than women.
Race/ethnicity. White people are most likely to develop Merkel cell cancer; however, some black people and people of Polynesian descent have developed the disease.
Family history. Ten percent of pheochromocytomas are linked to hereditary causes. Multiple endocrine neoplasia type 1 (MEN1)  is a hereditary condition that increases the risk of developing a tumor of three glands: pituitary, parathyroid, and pancreas. Multiple endocrine neoplasia type 2 (MEN2)  is a hereditary condition associated with medullary thyroid cancer and other types of cancer, including pheochromocytoma.
Immune system suppression. People with human immunodeficiency virus (HIV), the virus that causes acquired immune deficiency syndrome (AIDS), and people whose immune systems are lowered because of organ transplantation have a higher risk of developing a neuroendocrine tumor.
Arsenic exposure. Exposure to the poison arsenic may increase the risk of Merkel cell cancer.
Sun exposure. Because Merkel cell cancer often occurs on the sun-exposed areas of the head and neck, many doctors think that sun exposure may be a risk factor for this type of cancer. Learn more about protecting your skin from the sun .
Choose “Next” (below, right) to continue reading this guide to learn about what symptoms this type of tumor can cause. Or, use the colored boxes located on the right side of your screen to visit any section.