What is cancer?

What is Skin Cancer? 

The most common cancer in the United States, skin cancer is cancer that has developed in any area of the skin. Skin cancer can develop in anyone on any portion of the body, but it is most common in those who have had frequent exposure to ultraviolet light whether the source be the sun, or from an artificial source such as a tanning bed. It most commonly develops in areas of the body that are frequently exposed to UV light, such as the face, arms, neck. However, it can also develop in less exposed areas, such as your palms.

How it Begins

Skin, which is the body’s largest organ, has several layers. The epidermis, or the outer layer of the skin, is where skin cancer begins to develop. Skin cancer begins when a cell in the epidermis with damaged DNA begins to duplicate at a rapid rate due to the damage, usually initiated and accelerated by exposure to ultraviolet light. 


The epidermis is made up of three cell types. These three cell types correspond with the three main types of skin cancer, as each cell type can develop into a different type of skin cancer.  

  • Basal cells are round and are formed in a layer underneath the layer of squamous cells.  
  • Squamous cells are thin and flat and form the outermost layer of the epidermis. 
  • Melanocytes are cells that make melanin, which is the pigment that gives skin its color. Melanocytes make more pigment when the skin is exposed to ultraviolet light, which causes the skin to darken. 

Three Main Types of Skin Cancer

Depending on which type of skin cancer is developing, the signs and symptoms will vary.

The two most common types of skin cancer are basal cell carcinoma, pictured middle, then squamous cell carcinoma cell carcinoma, pictured left. Both are curable, but the treatments may be disfiguring or expensive. Melanoma is the third most common type of skin cancer and is the deadliest, pictured right.

Basal cell carcinoma is the most common type of skin cancer and most commonly forms in sun-exposed areas of your body. Areas include the neck, face, and arms. Basal cell carcinoma may appear as: 

  • A pearly skin-colored bump with waxy appearance
  • A flat scaly patch with raised edges
  • A brown, black, or blue scar-like lesion
  • A bleeding or scabbing sore that returns after healing

Squamous cell carcinoma occurs most commonly on sun-exposed areas, like the face, ears, and hands. Those with darker complexions are more likely to develop squamous cell carcinoma in areas that are not as commonly exposed, like the palms of their hands or bottoms of the feet. Signs of squamous cell carcinoma include:  

  • A firm, red nodule developed or developing on the skin  
  • A flat lesion that is scaly or crusty in appearance 
  • A wart-like growth that crusts and bleeds 
  • An open sore that bleeds or crusts 

Melanoma is the third most common type of skin cancer but causes the most deaths because it is most likely to metastasize, or travel to other portions of the body. Melanoma can develop anywhere on the body but is commonly seen in cases on the face. It develops on otherwise healthy skin (70-80% of cases), or in moles that become cancerous (20-30% of cases). In men, this cancer is commonly seen on the trunk, and in women, the lower legs. Melanoma can affect individuals of any skin tone; in those of darker complexions cases of melanoma develop most commonly on the palms or soles. Symptoms of melanoma may include:  

  • A large brown colored spot with darker specs within it 
  • A mole that changes in size, shape, feel, or color, or bleeds 
  • A small lesion that appears red, pink, white, blue, or blue-black that has an irregular border 
  • A painful lesion that is itchy or burns 
  • Dark lesions on areas with less light exposure, like the palms, soles, fingertips, or toes, or on mucous membranes lining the mouth, nose, vagina, or anus 

Less Common Skin Cancers  

There are various other types of skin cancer that are less common than the previously named. Some examples include:  

  • Kaposi sarcoma forms in the skin’s blood vessels, causing red or purple spots on the skin or mucous membranes.  
  • Merkel cell carcinoma causes nodules on or beneath the skin that are firm and appear shiny.  
  • Sebaceous gland carcinoma is uncommon yet aggressive. It originates in the oil glands in the skin and appears as hard, painless nodules.  

Risk Factors  

It is important to remember when considering the following risk factors that anyone can develop skin cancer. However, these risk factors are just that – factors that elevate your risk of skin cancer.



  • Skin type is the first factor to consider. Those naturally with fair skin are at an increased risk. This is due to decreased melanin in the skin. Melanin provides protection from UV radiation, and if you have less of it, you have less protection. 
  • Sunburn history. It is common to experience sunburn in your life, but the more times that you develop a sunburn, the higher you elevate your risk of developing skin cancer. Bad sunburn, such as blistering burns and burns that result in peeling skin increases your risk. Sunburns in childhood and as a teenager increase your risk, but sunburns in adulthood also pose a risk.  
  • Ultraviolet light exposure elevates your risk as well. Excessive exposure elevates your risk, whether this be from the sun itself or from tanning lamps and tanning beds. Attaining a tan, or darkening the skin, is your body’s response to excessive UV exposure, and indicates skin damage.  
  • Living in sunny areas, or areas of high altitude are exposed to more sunlight than those in cloudier areas. High elevations are where the sunlight is the strongest also increases your UV exposure.  
  • Having many moles or abnormal moles elevates your risk. If this applies to you, have them frequently checked and monitor them yourself for changes.  
  • Precancerous skin lesions appear as rough, scaly patches that range from brown to deep pink, commonly found on the face, head, and hands of those with sun damage.  
  • A family history of skin cancer may increase your risk.  
  • A personal history of skin cancer increases your risk, as you are likely to develop it again. 
  • Having a weakened immune system have an elevated risk, which includes individuals living with HIV/AIDS as well as those prescribed immunosuppressant drugs following an organ transplant.  
  • Individuals who have received radiation treatment for skin conditions like eczema or acne are at an increased risk. 
  • Exposure to carcinogens, such as arsenic.  

Prevention – Ultraviolet Safety 

Skin cancer can be prevented by taking care of your skin. These skin cancer prevention tips will decrease your risk of developing skin cancer, and should be practiced routinely:  

  • Avoid direct sunlight during midday. Between 10 am and 4 pm, the sun’s rays are the strongest. When planning outdoor activities, schedule them outside of this period to limit your sun exposure. Avoiding the sun at its strongest helps you avoid sunburn, as sun exposure accumulated over time increases your risk of skin cancer.  
  • Wear sunscreen year-round. Sunscreen cannot provide full protection, unfortunately, but it plays a significant role in sun safety. Use a broad-spectrum sunscreen with an SPF of at minimum 30 and reapply at minimum every 2 hours. If you are doing an activity like swimming or are sweating, reapply more frequently. Use a generous amount and be sure to cover all exposed skin- including the lips, ears, backs of your hands, and your neck.  
  • Wear protective clothing that covers exposed skin. Cover your skin with dark, tightly woven clothing for the best protection year-round.  
  • In addition, add a wide-brimmed hat to your wardrobe and wear that when outdoors. This hat type provides maximum protection from the sun. 
  • Photoprotective clothing is an option to consider when purchasing clothing, and wearing sunglasses is also recommended when outdoors.
  • Invest in sunglasses that contain UVA and UVB ray protection, as this is the best for your eyes.
  • Avoid tanning beds. The lights in tanning beds emit UV rays and increase your risk of developing skin cancer.
  • Be aware of medications that may increase your exposure. Sun-sensitizing medications increase your sensitivity to sunlight, and many common prescription and over-the-counter drugs are in this category. Ask your doctor about the side effects of medications you take to ensure you take appropriate steps to take extra precautions in the sun.  


Self-exams and self-skin checks are the first step in skin cancer prevention. Monitor your skin regularly and examine for new growths or changes in existing moles, freckles, bumps, and birthmarks. In addition, monitor the skin itself for new abnormalities that may indicate pre-cancerous growth.  


Utilize mirrors to assess every area of your skin for these changes, as any portion of the skin can develop skin cancer. If you notice abnormalities or changes, reach out to your doctor for them to investigate the area and if needed, biopsy.  

During a screening exam by a doctor or nurse, the provider checks the skin for the same abnormalities we have mentioned previously. Regular checks by a doctor are important for individuals that have already had skin cancer, and for those at an elevated risk.  

If the doctor does discover a concerning area, a biopsy is usually completed. A biopsy is completed by the doctor removing a sample of cells for examination and sending the sample to a pathologist to study the tissue to identify if it is cancerous. If the sample does indicate cancer is present, further treatment will be pursued to treat the cancer.