May 17, 2024 - Health + Traits

23andMe and Colorectal Cancer Alliance Team Up on Cancer Research

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Summer is almost here, and along with all the sun and fun, it’s important to remember how best to protect your skin. 

So, for Skin Cancer Awareness Month, we’re offering some helpful information and suggestions because skin cancer is the most common form of cancer; it’s also one of the most preventable. 

Skin Cancer in the United States

In the U.S. alone, an estimated 3.3 million people are diagnosed with basal cell or squamous cell cancers each year, according to the American Cancer Society. Melanoma makes up a small percentage of all skin cancers. Still, it is the most lethal, contributing to the vast majority of skin cancer-related deaths. These are three of the most common types of skin cancer.

Understanding your likelihood of developing one of these types of cancer and learning about what to look for goes a long way toward preventing them from developing. Sun exposure, either because you live in a sunnier climate or you spend a lot of time outdoors, plays a role. 

We looked at where in the United States 23andMe customers who consented to participate in our research reported having been diagnosed with basal or squamous cell carcinomas. 

We do not have enough data to generate results for every state, but for the states we do have data, we see a higher prevalence of basal cell and squamous cancers in sunnier states. For instance, the highest prevalence is in Florida, Arizona, South Carolina, North Carolina, Alabama, and New Mexico. However, we also see a high prevalence in Delaware, which may be related to the age of the population there. The prevalence for both cancers increases with age, and Delaware has an aging population. We have not adjusted our data for age.

Genetics and Skin Cancer

The likelihood of developing skin cancer is influenced not just by geography and sun exposure but also by a person’s ethnicity, lifestyle, and genetics. Skin cancer can develop in people of all ethnicities, but people of European descent with lighter skin tones have a much higher risk. 

The lifetime risk for melanoma is about two percent for people of European descent but only about 0.1 percent among those of African descent. It’s a little more than half a percent for people of Latino or Hispanic descent. 

But people with darker skin are more likely to be diagnosed with melanoma at a later stage when it can be harder to treat. In addition, people with darker skin are much more likely to develop melanoma in parts of the body that get less sun, such as the palms of the hands, soles of the feet, beneath the fingernails, or even inside the mouth.

The ABCDEs of melanoma

A: Asymmetry. Does one half look different than the other?

B: Border. Does it have an irregular edge?

C: Color. Does it have multiple colors?

D: Diameter. Is it longer than 6mm across or about the diameter of a pencil eraser?

E: Evolving. Is it changing over time?

That’s why both prevention and skin self-exam are so important. Experts recommend knowing the ABCDEs of melanoma (see sidebar) and performing a skin self-exam about once a month. It’s essential to monitor your skin and talk to a healthcare professional, like a dermatologist, if you notice any changes, including new or changed moles, bumps, or sores.

Early detection — often through self-exam and regular mole checks by a dermatologist — can also go a long way toward ensuring healthy outcomes. There’s another tool for assessing one’s risk, and that’s looking at your genetics.

23andMe+

As part of 23andMe+ Premium, members can access two reports to assess their genetic likelihood of developing one of these three common types of skin cancer. 

The service offers a Skin Cancer (Melanoma) report and a Skin Cancer (Basal and Squamous Cell Carcinomas) report. Both reports use polygenic risk scores (PRS) to assess a member’s likelihood of developing one of these cancers. These statistical models consider a person’s genetic ancestry and birth sex. 

The reports also include some prevention tips. Some of these tips are obvious but also bear repeating. For instance, knowing that repeated sunburns substantially increase the risk is a reminder to use sunscreen and protect yourself from too much sun. However, research has also found that genetic factors and specific traits play a role. 

Not long ago, using data from 23andMe customers who consented to participate in research, researchers from Indiana University found genetic variants associated with squamous cell carcinomas. A few years before, researchers at Stanford, also using 23andMe data, found genetic variants associated with the risk of melanoma. Most recently, a team of researchers in Australia, with the help of 23andMe data, found more than 70 genetic variants associated with melanoma and identified correlations between melanoma and autoimmune diseases such as psoriasis and rheumatoid arthritis. 

What You Can Do

Being vigilant, especially for new moles or discolored skin, and protecting your skin from the sun can all help lower the likelihood of developing skin cancer.

A self-examination is a little more challenging for areas like the back, so having a partner, doctor, or a dermatologist take a look is a good idea.

Everyone should be aware of the risk of skin cancer, but some individuals have more risk than others. Individuals with lighter skin, many moles, who sunburn easily, or who have a family history of skin cancer should be particularly vigilant. 

Wearing sun protection (like “broad spectrum” sunscreen and protective clothing) outdoors is essential—even when it’s cloudy. Avoiding tanning beds is also important. 

More

23andMe’s skin cancer reports are available to all annual 23andMe+ Premium Membership subscribers.  Premium members can view your report here and here

Are you still waiting to be a23andMe+ Premium member?

Find out more here.


FAQ

What is melanoma?

Melanoma is a common and serious form of skin cancer that can originate from moles. Early detection offers the best chance for treatment, so it’s essential to get familiar with your moles to notice changes that could signal that a mole is becoming cancerous. Only about two percent of skin cancers are melanoma, but this aggressive form of cancer is responsible for most skin cancer deaths. Melanomas are more likely than other skin cancers to be lethal because they can spread locally or metastasize to different parts of the body. While ultraviolet radiation from sun exposure and skin characteristics like moles, freckles, or light skin tones are key factors in the risk for melanoma, genetic factors also play a role. Again, this is why early detection is so important so that they can be treated before cancer can spread.

What is basal cell carcinoma?

Basal cell carcinoma is very common. This form of cancer begins in basal cells found in the skin’s outer layer. The most common cause of basal cell carcinoma is too much exposure to ultraviolet (UV) light from the sun. This can happen even on a cloudy day or through a glass window. In addition, UV light exposure from tanning beds and sun lamps increases the risk. Basal cell carcinoma also most often occurs in areas of the skin that are most exposed, such as the face, head, and neck, but it can happen anywhere. For people with darker skin, squamous and basal cell carcinomas often appear more like a dark brown or black bump that might be glossy and have a rolled border. The first sign is typically a bump, growth, or sore that doesn’t heal. Basal cell carcinoma is very treatable and tends to grow slowly.

What is squamous cell carcinoma?

Like basal cell carcinoma, squamous cell carcinoma often occurs due to too much exposure to UV light from the sun or other sources like tanning beds or sun lamps. Like basal cell carcinoma, it most often occurs in areas of the skin that are most exposed, but squamous cell carcinoma is more likely to happen on the scalp, the backs of hands, ears, and lips. However, as with basal cell carcinoma, it can develop in other areas. For example, among people with darker skin, squamous cell carcinoma commonly appears on the legs and other areas that typically get less sun exposure. For people with darker skin, squamous and basal cell carcinomas often seem more like a dark brown or black bump that might be glossy and have a rolled border. The first sign is typically a bump, growth, or sore that doesn’t heal. Squamous carcinoma is very treatable and tends to grow slowly.


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