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 followup 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. 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.

Sometimes, clusters of melanocytes and surrounding tissue form noncancerous growths called moles. (Doctors also call a mole a nevus; the plural is nevi.) Moles are very common. Most people have between 10 and 40 moles. Moles may be pink, tan, brown, or a color that is very close to the person's normal skin tone. People who have dark skin tend to have dark moles. Moles can be flat or raised. They are usually round or oval and smaller than a pencil eraser. They may be present at birth or may appear later on-usually before age 40. They tend to fade away in older people. When moles are surgically removed, they normally do not return.
Understanding Cancer

Cancer begins in cells, the building blocks that make up tissues. Tissues make up the organs of the body. Normally, cells grow and divide to form new cells as the body needs them. When cells grow old, they die, and new cells take their place.

Sometimes this orderly process goes wrong. New cells form when the body does not need them, and old cells do not die when they should. These extra cells can form a mass of tissue called a growth or tumor. Not all tumors are cancer.

Tumors can be benign or malignant:

• Benign tumors are not cancer:

  • They are rarely life threatening.

  • Usually, benign tumors can be removed, and they seldom grow back.

  • Cells from benign tumors do not spread to tissues around them or to other parts of the body.

• Malignant tumors are cancer:

  • They are generally more serious and may be life threatening.

  • Malignant tumors usually can be removed, but they can grow back.

  • Cells from malignant tumors can invade and damage nearby tissues and organs. Also, cancer cells can break away from a malignant tumor and enter the bloodstream or lymphatic system. That is how cancer cells spread from the original cancer (the primary tumor) to form new tumors in other organs. The spread of cancer is called metastasis. Different types of cancer tend to spread to different parts of the body.

Melanoma

Melanoma occurs when melanocytes (pigment cells) become malignant. Most pigment cells are in the skin; when melanoma starts in the skin, the disease is called cutaneous melanoma. Melanoma may also occur in the eye (ocular melanoma or intraocular melanoma). Rarely, melanoma may arise in the meninges, the digestive tract, lymph nodes, or other areas where melanocytes are found. Melanomas that begin in areas other than the skin are not discussed in this booklet. The Cancer Information Service (1-800-4-CANCER) can provide information about these types of melanoma.

Melanoma is one of the most common cancers. The chance of developing it increases with age, but this disease affects people of all ages. It can occur on any skin surface. In men, melanoma is often found on the trunk (the area between the shoulders and the hips) or the head and neck. In women, it often develops on the lower legs. Melanoma is rare in black people and others with dark skin. When it does develop in dark-skinned people, it tends to occur under the fingernails or toenails, or on the palms or soles.

When melanoma spreads, cancer cells may show up in nearby lymph nodes. Groups of lymph nodes are found throughout the body. Lymph nodes trap bacteria, cancer cells, or other harmful substances that may be in the lymphatic system. If the cancer has reached the lymph nodes, it may mean that cancer cells have spread to other parts of the body such as the liver, lungs, or brain. In such cases, the cancer cells in the new tumor are still melanoma cells, and the disease is called metastatic melanoma, not liver, lung, or brain cancer.
Melanoma: Who's at Risk?

No one knows the exact causes of melanoma. Doctors can seldom explain why one person gets melanoma and another does not.

However, research has shown that people with certain risk factors are more likely than others to develop melanoma. A risk factor is anything that increases a person's chance of developing a disease. Still, many who do get this disease have no known risk factors.

Studies have found the following risk factors for melanoma:

• Dysplastic nevi: Dysplastic nevi are more likely than ordinary moles to become cancerous. Dysplastic nevi are common, and many people have a few of these abnormal moles. The risk of melanoma is greatest for people who have a large number of dysplastic nevi. The risk is especially high for people with a family history of both dysplastic nevi and melanoma.

• Many (more than 50) ordinary moles: Having many moles increases the risk of developing melanoma.

• Fair skin: Melanoma occurs more frequently in people who have fair skin that burns or freckles easily (these people also usually have red or blond hair and blue eyes) than in people with dark skin. White people get melanoma far more often than do black people, probably because light skin is more easily damaged by the sun.

• Personal history of melanoma or skin cancer: People who have been treated for melanoma have a high risk of a second melanoma. Some people develop more than two melanomas. People who had one or more of the common skin cancers (basal cell carcinoma or squamous cell carcinoma) are at increased risk of melanoma.

• Family history of melanoma: Melanoma sometimes runs in families. Having two or more close relatives who have had this disease is a risk factor. About 10 percent of all patients with melanoma have a family member with this disease. When melanoma runs in a family, all family members should be checked regularly by a doctor.

• Weakened immune system: People whose immune system is weakened by certain cancers, by drugs given following organ transplantation, or by HIV are at increased risk of developing melanoma.

• Severe, blistering sunburns: People who have had at least one severe, blistering sunburn as a child or teenager are at increased risk of melanoma. Because of this, doctors advise that parents protect children's skin from the sun. Such protection may reduce the risk of melanoma later in life. Sunburns in adulthood are also a risk factor for melanoma.

• Ultraviolet (UV) radiation: Experts believe that much of the worldwide increase in melanoma is related to an increase in the amount of time people spend in the sun. This disease is also more common in people who live in areas that get large amounts of UV radiation from the sun. In the United States, for example, melanoma is more common in Texas than in Minnesota, where the sun is not as strong. UV radiation from the sun causes premature aging of the skin and skin damage that can lead to melanoma. Artificial sources of UV radiation, such as sunlamps and tanning booths, also can cause skin damage and increase the risk of melanoma. Doctors encourage people to limit their exposure to natural UV radiation and to avoid artificial sources.

People who are concerned about developing melanoma should talk with their doctor about the disease, the symptoms to watch for, and an appropriate schedule for checkups. The doctor's advice will be based on the person's personal and family history, medical history, and other risk factors.

Melanoma is basically a skin disease typical to youth, but Melanoma may occur to the people at any age. Melanoma is a type of skin cancer hich usually starts in the skin, either in a mole or in normal-looking skin. About 7000 people in the UK are diagnosed with melanoma each year . It begins in skin cells called melanocytes. Melanocytes produce the substance that gives your skin its color. Although the number of people who develop melanoma is rising, it is still an uncommon type of cancer. The body is made up of many types of cells. Normally, cells grow, divide and die. Sometimes, cells mutate (change) and begin to grow and divide more quickly than normal cells. 

Causes of Melanoma:- 

the main causes of Melanoma are: UV radiations and skin cancer - UV radiation is one of the prime cause in formation aof this disease. 

Other factors in melanoma 

1) Tanning salons also expose your body to UV radiation and increase your risk of developing melanoma 
2) Heredity. A small percentage of people who develop melanoma have a family history of the disease. Having a parent, child or sibling with melanoma greatly increases your risk. In addition, some families are affected by a condition called familial atypical multiple mole melanoma (FAMMM) syndrome. 
3) Combination of environmental and genetic factors. 
4) Atypical moles 
5) an impaired immune system, especially if you have had an organ transplant, leukemia, or lymphoma.