Melanoma is a type of cancer that starts in cells in the skin called melanocytes. These cells make a pigment called melanin which gives skin its natural colour. Melanin helps to protect the body from ultraviolet light (UV radiation) from the sun.1

The most common sign of melanoma is the appearance of a new mole or a change in an existing mole. 2

People with darker skin tones are generally less likely to get melanoma than people with fairer skin. This is because their skin produces more melanin, which protects against the harmful effects of UV radiation.3

In women, the most common place for melanoma to develop is on the legs. In men, melanoma is most commonly found on the chest and back. Melanomas are uncommon in areas which are protected from sun exposure. However, in dark-skinned people, melanoma is more commonly found under the nails of the fingers or toes, on the palms of the hands, or soles of the feet.5

The number of people developing melanoma is rising and it is now the 5th most common cancer in the UK. Approximately 16,000 people in the UK are diagnosed with melanoma each year, though 86% of melanoma cases in the UK are preventable.6

In the UK, the risk of melanoma increases with age, however the number of melanoma cases diagnosed in young people is disproportionately high. In fact, melanoma is one of the most common cancers in people aged 15–34.7

When melanoma has spread around the body it is known as stage 4 or metastatic melanoma.  When the disease gets to this stage, it is sadly notoriously difficult to treat. The standard treatment is only effective in a small number of cases and is highly unlikely to produce a cure.

In recent years, scientists have been working tirelessly in trying to find a cure for melanoma.  Sadly, we have not reached this point yet, but in November 2012 after many appraisals that we were a part of, two new drugs, Ipilimumab and Vemurafenib were given approval for use on the NHS.  These drugs, whilst not a cure, have been proven to extend the lives of late-stage melanoma patients.  This will make a huge difference in the lives of patients and their families.

Following further NICE appraisals, Pembrolizumab is another approved treatment for advanced melanoma patients, you will often hear this referred to as a ‘PD1″ and at the beginning of 2016 Nivolumab received a positive decision from NICE.   Decisions like this provide much more hope for patients living with a diagnosis of advanced melanoma.

If you have queries about anything you see on our site, drugs, treatments or clinical trials, please let us know and we will do our best to help and put you in contact with the correct people.  It could be that you are not being treated at a cancer center and you would like the opportunity to explore that possibility.

The skin 8

The skin has many purposes, it:

  • acts as a barrier to protect the body from injury and harm from the outside world
  • protects the body from the harmful effects of UV light
  • helps to control the body’s temperature
  • stores water, fat, hormones and other essential molecules that are important for the whole body

The skin is made up of three main layers, the epidermis, the dermis and the subcutaneous tissue.

The epidermis (the outer layer) is the thin top layer of skin, which you see. Several cell types make up the epidermis. Cells are the microscopic building blocks that make up tissues, such as skin.

Melanocytes are a type of cell in the epidermis with a special function - the production and storage of a pigment called melanin, which gives skin its colour. Melanin protects us from the sun’s harmful UV rays. When skin is exposed to UV light, melanocytes make more melanin - making the skin look darker.

The dermis (the middle layer) is the layer of skin below the epidermis. The dermis contains several types of cells and structures, in particular, tough, elastic collagen fibres which make the skin strong and robust, as well as allowing the skin to stretch.

The dermis also contains a network of nerve fibres and blood vessels, the latter of which carry nutrients and oxygen to the skin and remove waste products. Other cell types in the dermis include sensory (feeling) cells, sweat glands, sebaceous glands (which produce sebum, an oily substance that helps protect skin from drying out) and hair follicles.

The subcutaneous tissue (the deepest layer) lies beneath the dermis. It attaches the skin to the muscle underneath and contains connective tissue and fat. The subcutaneous tissue stores body heat and absorbs shock to protect the body, as well as producing hormones such as vitamin D.

The lymphatic system 10

The lymphatic system helps to protect us from infection and disease. It also drains lymph fluid from the tissues of the body before returning it to the blood. The lymphatic system is made up of thin tubes called lymph vessels or lymphatic vessels that connect to groups of lymph nodes throughout the body. As the lymph fluid travels round the body, it is filtered by lymph nodes before passing back into the bloodstream.

Lymph nodes (sometimes called lymph glands) are small and bean-shaped. They filter the lymph fluid as it passes through them. White blood cells attack any bacteria or viruses they find in the lymph. When you have an infection, lymph nodes often swell as they fight the infection.

Cancer cells can sometimes grow in the lymph nodes. This occurs if cancer cells break away from a tumour, and become stuck in one or more of the nearest lymph nodes. Doctors will check the lymph nodes when they are working out how far a cancer has grown or spread. 

Melanocytes 11

Melanocytes are a type of skin cell that produce a pigment called melanin. Melanin is responsible for the natural colour of our skin, and also protects skin from the harmful effects of the sun.

When our skin is exposed to sunlight, our melanocytes increase the amount of melanin. This is to absorb more potentially harmful UV rays. This makes the skin darker and gives it a suntanned appearance. A suntan is a sign that the skin is trying to protect itself.

If you have naturally dark (brown or black) skin, you have the same number of melanocytes as people with white skin, but your melanocytes make more melanin. This means you have more natural protection from UV rays.

Moles are clusters of melanocytes that are close together. Most people with white skin have about 10–50 moles on their skin, some people can have as many as 100. 

How melanoma develops

Normal, healthy skin cells continually grow, divide and mature, before eventually dying and being shed from the skin. However, sometimes the cells develop damage to their DNA (the part of a cell that carries genetic information and passes it from one generation to the next). This damage is called a mutation and can lead to inappropriate growth or survival of the cells. Because a cell copies its own DNA before it divides to make new cells, any mutations in the original cell will be passed along to the cells that follow.12

Melanoma develops from melanocytes that inherit or experience a mutation which allows the melanocyte to grow and divide more quickly than usual.12  In melanoma, the melanocytes also start to spread into the surrounding surface layers of skin.13

If not diagnosed and treated, melanoma will grow and spread along the epidermis before penetrating deeper layers of the skin and eventually coming into contact with lymph and blood vessels.13

If the melanoma breaks through into a blood vessel then this allows the melanoma to spread to distant sites or distant organs. This is called ‘metastatic melanoma’. Metastatic melanoma most commonly occurs in the liver, lungs, bones or brain.14

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