What is skin cancer?

There are two types of skin cancer: melanoma cancer and non-melanoma cancer, which include basal and squamous.

Melanoma skin cancer

Melanoma is a life-threatening skin cancer, often requiring heavy treatment such has chemotherapy.  

According to the CDC, over 76,000 people were diagnosed with melanoma in 2014 in the US and nearly 10,000 died.

Squamous and basal skin cancer

This is the most common form of skin cancer, affecting 3 million people per year in the US.

These cancers are curable but are very serious for immunosuppressed people. They can also cause disfigurement (basal) and spread to other parts of the body (squamous).

What are the signs of skin cancer?

It is crucial to catch skin cancer early. You should consult a dermatologist regularly and keep an eye on your moles and all skin lesions. Dermatologists have developed a visual system to help you identify suspect moles.

A = Asymmetry.

Asymmetrical moles have a higher likelihood of being cancerous.

B = Borders

Notice moles with outer edges that are uneven.

C = Color

Look for moles that are dark black or have multiple colors.

D = Diameter

A mole with a diameter greater than 6mm may be suspect.

E = Evolving

Note any changes in size, shape, or color.

Sources of harmful UV exposure

There are two types of UV: UVB and UVA. UVB usually leads to visible burns and UVA rarely burns, but it still is associated with skin aging, cancer risk, and other UV-triggered immune reactions.

Tanning beds

Tanning beds are used by people for aesthetic purposes. Tanning beds use very high doses of UVA, much higher than what sunlight delivers. There is no "safe" tanning bed.


Sunlight is essential to our social life, happiness, mood, and even vitamin D. Sunlight is a complex combination of UVB and UVA.

How much UV exposure is too much?

Intuition about UV light levels is often wrong. Without measuring UV exposure, you must always be extremely cautious to minimize your UV exposure.