Melanoma - everything you need to know

10th May 2023

Melanoma, a type of skin cancer, is the 5th most common cancer in the UK – almost 20,000 people were diagnosed in 2020. Like all cancers, it’s important to know the earliest signs of melanoma, but what causes melanoma? What increases your risk of melanoma? How do you treat melanoma? And what are we doing to make a difference?

Melanoma is a serious type of skin cancer that appears as a mole or dark patch on the skin.

Skin cancer is normally categorised as either melanoma or non-melanoma skin cancer, depending on what type of cell the cancer starts in.

Melanoma starts in melanocytes, a type of cell in the skin and eyes that produces pigment. Melanocytes are found in the deepest layer of the epidermis, which is the outermost layer of the skin. By producing melanin, which gives skin its colour, melanocytes help to protect us from UV damage. If the DNA in a melanocyte becomes too damaged, for example because of too much UV exposure, it can begin growing out of control.

What increases your risk of melanoma?


Older people are more likely to develop melanoma. In general, cancer becomes more likely to occur as we age because mutations in our DNA build up - this makes cancer more likely to occur.

However, melanoma is relatively more common in younger people compared to some other types of cancer. This means it is important to look for the signs of melanoma no matter your age, and protect yourself from too much UV exposure (another key risk factor).

UV exposure

UV rays (radiation), which cause sunburn, can cause DNA damage. The sun is the most important source of UV, however sunbeds also emit high levels of UV radiation. If enough DNA damage accumulates, cancer can occur.

This means it is important to reduce your exposure to UV to prevent melanoma and other skin cancers occurring. It will not prevent every case, however it is estimated that 85% of cases in the UK are caused by too much UV exposure.

Skin type

Some people may be more likely to develop melanoma due to differences in their skin. People with fair or very fair skin are more at risk of developing melanoma. You are also more at risk if you have freckles or have lots of moles.

In general, if you tend to burn in the sun you are more at risk of skin cancer. People with deeper skin tones can also develop melanoma. It is less common depending on skin tone and how much UV exposure a person has, and most commonly occurs on lighter areas of skin (e.g. palms of the hands and soles of the feet) or under a nail.

Family history

As with many types of cancer, a family history of melanoma may increase your risk of developing melanoma at some stage in your life. A genetic condition, called familial atypical multiple mole melanoma (FAMMM), can cause more moles that are unusually shaped and different sizes, and increase your risk of melanoma.

What does melanoma look like?

Melanoma usually looks like a dark mole anywhere on the skin or eyes. It can appear as a new mole or an existing mole may change size or shape. A helpful way to remember the key signs of melanoma is to use the “ABCDEmethod:

  • Asymmetry – Is the mole asymmetrical? Meaning it is not a neat, mirrored shape.
  • Border – Does the mole have an uneven border?
  • Colour – Is the colour of the mole uneven, or is there more than one colour in the mole?
  • Diameter – Is the mole larger than 5mm across?
  • Elevation – Is the mole elevated or becoming raised?

Other symptoms of melanoma include moles that are itchy, painful, inflamed, or bleeding. A dark area under a nail, not caused by injury, can also be a sign of melanoma, as can an unusual mark on your skin that has not gone away after a few weeks.

Some melanomas may lack colour – called “amelanotic” melanomas, these cases are missing the melanin that give most moles and melanomas their colour.

If you have a mole that matches any of these descriptions, you should speak to your GP. In many cases, it may not be melanoma or another type of skin cancer, but it is always better to check with a health professional – catching melanoma early (before it has spread) is extremely important for successful treatment.


How is melanoma diagnosed?

If your doctor suspects you may have melanoma, they normally refer you to a dermatologist. This skin specialist will take a closer look at the mole under a dermascope (a kind of handheld microscope) to look for signs of cancer.

If they suspect the mole is cancerous, they might remove the mole, along with a margin of healthy skin around the mole, and send it away to be tested in the lab to see if it is cancerous.


Why is it important to catch melanoma early?

If caught early, melanoma can often be treated successfully by removing the mole and a margin of healthy skin around it. However, if left untreated, it can grow down into the skin and spread around the body.

Melanoma can be much harder to treat once it has spread, and some types of melanoma tend to reach this stage faster than others. That means it is important to get any new or changing moles checked by a health professional to catch it early.

You can make a difference to the lives of those affected by melanoma. Become a Curestarter today.

What different types of melanoma are there?

Superficial spreading melanoma

This is the most common type of melanoma. This type of melanoma tends to spread on the surface of the skin for a while before it starts spreading down into the skin. It can appear almost anywhere of the body, most commonly on places that are more often exposed to the sun – the legs in women, the torso in men, and the upper back in both.

Lentigo maligna

This type also tends to spread on the surface of the skin. It often develops in older patients, typically on sun-damaged skin. It can look like a flat or raised, blotchy patch with uneven borders, and either blue-black or tan-brown in colour.

Acral lentiginous melanoma

This type of melanoma often appears in hard-to-spot places like under nails and on the soles of the feet or palms of the hands. It is the most common type in people of colour, and may appear as a black or brown area.

Nodular melanoma

This is the most aggressive type of melanoma. It spreads down into the skin more quickly than other types, and unfortunately is often found to have already spread when first diagnosed. It is often found on the torso, legs, and arms, and the scalp in older men. It can look like a blue-black coloured lump, but sometimes a pink or red bump.

Melanoma stages

Melanoma can be categorised as stages 0 – 4:

Stage 0 – Melanoma in situ, meaning the cancerous cells are only on the surface of the skin

Stage 1 – Melanoma at an early (less than 2mm thick) with no sign of spread to other areas

Stage 2 – Melanoma that hasn’t spread from the skin, but has become thicker and may be ulcerated (skin covering the tumour looks broken)

Stage 3 – Melanoma that has spread to nearby lymph nodes, or to an area between the melanoma and lymph nodes.

Stage 4 – Melanoma that has spread to other parts of the body and nearby lymph nodes.

How do you treat melanoma?


Melanoma can often be effectively treated with surgery, if caught before it has spread. In fact, most people with localised melanoma that have the tumour removed with surgery make a full recovery. To make sure that all of the cancerous cells are removed, a margin around the tumour will usually also be removed.

Surgery may also be used to remove more tissue if the cancer has spread, or if it returns following a previous surgery. This can involve removing large areas of skin or nearby lymph nodes. Depending on how significant the surgery is, aftercare can be important to avoid infection, and skin grafts may be used to replace the skin that was removed.


Radiotherapy, which uses bursts of radiation to kill cancer cells, is sometimes used to reduce the size of large melanomas.


If melanoma has spread, sometimes chemotherapy is used to kill cancer cells as they have spread around the body. However, it does not tend to work as well for melanoma as some other treatments.

Targeted medicines and immunotherapy Modern medicines, which work by targeting s

Modern medicines, which work by targeting specific parts of the biology of cancer cells, can be used to treat melanoma in some cases. Similarly, immunotherapy, which harnesses the power of the immune system to kill cancer cells, can be an option for some patients.

These medicines are at an early stage and, while some patients respond well, others do not respond or may stop responding after initially having some benefit. A significant amount of research is being done to find new targeted treatments or improve those we have developed already.


What are we doing to make a difference to the lives of those affected by melanoma?

Many of our researchers sit at the forefront of efforts to find new ways to help patients with melanoma.

We need new discoveries about how melanoma starts, how it changes, or why treatments don’t work for some patients, to make it possible to find new ways to prevent, diagnose, and treat melanoma.

Thanks to our Curestarters, we were able to fund Dr Giulia Casorati and her team in Italy to carry out their research on melanoma. The team were able to engineer a type of immune cell in mice to detect different types of cells, including melanoma cells.

As they had hoped, the engineered cells were able to kill the melanoma cells, either slowing the growth of the cancer or curing it completely. With an extra boost from a drug delivered by nanotechnology, the cells did an even better job at destroying melanoma.

With further testing, these remarkable findings could go on to benefit patients with many types of cancer including melanoma.

Click to learn more about Dr Casorati's incredible breakthrough

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