Basal cell skin cancers aren’t usually thought of as dangerous—anything but…but researchers now suspect that they can be the “canary in the coal mine” for more deadly cancers.

Your skin is constantly exposed to ultraviolet rays from the sun that cause DNA breakdown. When your body can’t repair this damage, skin cells can start to grow out of control and form basal cell skin cancers, the most common type of cancer, diagnosed in more than three million Americans each year.

We know that some people inherit genes that make it harder for them to repair DNA and who, because of this, are at higher risk than others for cancers such as breast cancer and colon cancer. So researchers at Stanford University wanted to look for a connection between basal cell skin cancer in people with a high inherited general cancer risk and other, more serious cancers.

They recruited 61 patients who had been diagnosed with six or more basal cell skin cancers over a 10-year period and tested them for gene mutations known to be associated with serious cancers. While just 3% of the general public would test positive for these mutations, almost 20% of these participants did.

The researchers also found that the 61 participants were three times more likely to have already had other cancers, compared with their peers in the general population (primarily people 40 to 59 years old). The most frequent other cancer was the deadly skin cancer melanoma, followed by blood, colon, breast and prostate cancers.

To apply their theory to a larger pool of people, the researchers then looked at health insurance records of about 13,000 patients who had also had six or more basal cell skin cancers and found the same results. The same additional cancers that the original 61 participants had and in numbers again three times the amount seen in the general public.

Key takeaways: While it’s unlikely that getting one or two basal cell skin cancers significantly raises the risk for a more serious form of cancer, if you’ve had numerous ones, consider talking to your health-care provider and possibly a genetics counselor to assess your overall cancer susceptibility and whether having increased cancer screenings makes sense for you. Also, because of the number of cases of melanoma seen among the study’s participants, have a skin cancer screening by a dermatologist annually at the least, said Kavita Sarin, MD, PhD, the study’s lead researcher.

Another important point: If you develop your first basal cell skin cancer at a young age, such as under 40, don’t wait until you develop even a second one to have this conversation with your doctor. These skin cancers are most common in people over age 50, but among the study participants, the average age of their first basal cell skin cancer diagnosis was age 44. The researchers are now studying how much of a factor age is in determining vulnerability to cancer.