New genetic variants found to influence skin cancer risk

With summer upon us many are hitting the beach or pool and taking in some rays. Of course we’re also slathering Sunon sunscreen, since with sun exposure comes risk for skin cancer.

In the largest-to-date study of the most common form of skin cancer, basal cell carcinoma,  researchers at Stanford University School of Medicine identified 31 genetic associations for the disease, 14 of which were identified for the first time.

Skin cancer is the most common type of cancer and there are three main types — basal cell carcinoma, squamous cell carcinoma, and melanoma, all named after the affected cell types. Basal cell carcinoma, the most common, affects more than four million people annually in the United States alone — and although it can be disfiguring it is rarely life-threatening. Squamous cell carcinoma  affects more than one million people annually and leads to about nine thousand deaths each in year in the United States. Melanoma is extremely rare, but it is also deadly.

The new basal cell study follows another recent study by the same group at Stanford that focused on squamous cell carcinoma. Both studies were carried out in a similar two stage fashion. In collaboration with 23andMe, scientists first conducted a large genome-wide association study using 23andMe customers who consented to participate in research and had reported having either basal cell carcinoma or squamous cell carcinoma. Then, a confirmatory genome-wide association study was performed using data from a different cohort of research participants, either from the Nurses’ Health Study or the Health Professionals Follow-Up Study.

Roughly 17,000 cases and nearly 290,000 controls were included in the new basal cell study. The researchers confirmed 17 previously reported genetic associations and identified 14 novel susceptibility regions. Some of the genetic associations are with genes or gene regions thought to regulate skin cells. Other regions are involved in maintaining telomeres — the ends of chromosomes that either become too long or too short in many cancers — regulating the immune system, and tumor progression. The 31 genetic associations identified in this study are estimated to explain almost 11 percent of the familial relative risk for basal cell carcinoma.

Interestingly, many of the regions associated with basal cell carcinoma appeared to exert a bigger effect in younger individuals, which suggested that environmental factors for basal cell carcinoma might become more influential with age. When the scientists tested for interactions between the genetic markers and UV exposure, hair color, number of sunburns, and tanning ability, they found a significant interaction between a genetic marker in a gene called LPP and hair color, specifically light brown and dark brown/black hair groups. This finding suggests that the LPP marker is exerting a bigger effect on risk for basal cell carcinoma in people with brown or black hair.

Overall, the new basal cell carcinoma study expands our knowledge of the genetic factors that contribute to the most common form of skin cancer. Understanding what drives cancer, both the genetic and environmental factors, and the combination of the two, will ultimately help researchers predict who is at risk, make diagnoses quicker, and develop more precise treatments.

The study appeared in the journal Nature Communications.

  • Patricia Riley

    The impact of immuno suppressive conditions and transplantss is not noted. I do not believe this data is collected by 23 & me BUT papers have been published by others who note this correlation. Immunosuppressive drugs are necessary fo a life time fot transplants plus the other factors noted make the probability increase dramatically

  • Bonnee Price Linden

    Recently I was diagnosed with squamous cell carcinoma at the point of a fracture near my toes left side of my left foot. Surgery was performed immediately. I knew I had a family history of skin cancer particularly on my hands but this was shocking. What is the relationship if any between bone fractures, heredity and squamous cell carcinoma? What is the prognosis?

    • 23blog

      Hi Bonnee,
      Sorry to hear about your health problems. We do not diagnose conditions or give prognosis. I also do not know the relationship between fractures and squamous cell carcinoma. That is a good question to pose to our researchers and I can convey that for you.

      • Bonnee Price Linden

        Thank you I look forward to hearing reaponse

        • 23blog

          Hi Bonnee,
          I talked to our researchers and they were unaware of an association.

        • Bonnee Price Linden

          Excellent the dermatologist and surgeon both felt that there was no connection, also. Thank you

  • Butch

    I am told a lot of general things about basal cell carcinoma, and that my input helped the study. But How do I find out the specific snip that exposes me to a greater chance of BCC.

    • 23blog

      Hi Butch,
      For genetic health risk information, there are several steps we have to take before being able to report back health risks. Currently we do not have a genetic health risk report for BCC. If you’d like to learn more about the specific variants that are part of this report you can find them in the paper:

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