What You Need to Know About Melanoma

Introduction

Melanoma is the most serious type of cancer of the skin. Each year in the United States, more than 53,600 people learn they have melanoma. In some parts of the world, especially among Western countries, melanoma is becoming more common every year. In the United States, for example, the percentage of people who develop melanoma has more than doubled in the past 30 years.

The National Cancer Institute (NCI) has written this booklet (NIH Publication No. 02-1563) to help people with melanoma and their families and friends better understand this disease. We hope others will read it as well to learn more about melanoma. This booklet discusses risks and prevention, symptoms, diagnosis, treatment, and follow-up care. It also has information about resources and sources of support to help patients cope with melanoma.

Research continues to teach us more about melanoma. Scientists are learning more about its causes. They are exploring new ways to prevent, find, and treat this disease. Because of research, people with melanoma can look forward to a better quality of life and less chance of dying from this disease.

Information specialists at the NCI's Cancer Information Service at 1-800-4-CANCER can answer questions about melanoma and can send NCI materials. They can also send up-to-date treatment information from NCI's PDQ® database. In addition, many NCI publications and fact sheets are on the Internet at http://cancer.gov/publications. People in the United States and its territories may use this Web site to order publications. This Web site also explains how people outside the United States can mail or fax their requests for NCI publications.

What is Melanoma

Melanoma is a type of skin cancer. It begins in cells in the skin called melanocytes. To understand melanoma, it is helpful to know about the skin and about melanocytes-what they do, how they grow, and what happens when they become cancerous.

The Skin

The skin is the body's largest organ. It protects against heat, sunlight, injury, and infection. It helps regulate body temperature, stores water and fat, and produces vitamin D.

The skin has two main layers: the outer epidermis and the inner dermis.

• The epidermis is mostly made up of flat, scalelike cells called squamous cells. Round cells called basal cells lie under the squamous cells in the epidermis. The lower part of the epidermis also contains melanocytes.
• The dermis contains blood vessels, lymph vessels, hair follicles, and glands. Some of these glands produce sweat, which helps regulate body temperature. Other glands produce sebum, an oily substance that helps keep the skin from drying out. Sweat and sebum reach the skin's surface through tiny openings called pores.

Melanocytes and Moles

Melanocytes produce melanin, the pigment that gives skin its natural color. When skin is exposed to the sun, melanocytes produce more pigment, causing the skin to tan, or darken.