Indoor Tanning and Melanoma Mutational Burden: Comparing the Data
Many people assume that because ultraviolet radiation drives genetic damage in skin cells, tumors that develop in individuals with a history of indoor tanning will automatically carry a higher volume of mutations than tumors in non-users. In 2025, investigators explored this exact comparison in a study published in JAMA Dermatology titled Melanoma Tumor Mutational Burden and Indoor Tanning Exposure. By measuring tumor mutational burden—the overall density of genetic mutations identified within tumor tissue—the researchers evaluated whether patients who used tanning beds developed melanomas with elevated mutation counts. Examining how mutational levels compare between tanning bed users and non-users offers key insights into tumor biology, treatment response markers, and skin health.
What Is Tumor Mutational Burden and Why Does It Matter?
Cutaneous melanoma generally demonstrates a higher tumor mutational burden relative to other cancer types because of ultraviolet-induced mutagenesis. When ultraviolet radiation penetrates skin cells, it causes direct DNA alterations that accumulate over time. In advanced melanoma, tumor mutational burden serves as an important prognostic marker. Clinical findings show that a higher mutational burden is associated with improved survival and a greater clinical response to immune checkpoint inhibition, an important category of cancer immunotherapy.
Because indoor tanning devices emit concentrated ultraviolet radiation, researchers set out to compare patients with documented indoor tanning exposure against those without it to see if tanning bed use drove higher mutation numbers.
Comparing Indoor Tanning Users vs. Non-Users: Study Design
To evaluate this question, investigators designed a retrospective cohort study conducted at Dana-Farber Cancer Institute, a tertiary-care cancer treatment center located in Boston, Massachusetts. The research analyzed medical records from patients treated between 2013 and 2022.
The study cohort included:
- A total of 617 patients diagnosed with cutaneous melanoma.
- Individuals for whom both next-generation genomic sequencing data and indoor tanning exposure histories were available in medical records.
- A group with a median age at diagnosis of 61 years.
- A demographic distribution including 337 male patients, representing 62.9% of the cohort.
Researchers collected details on indoor tanning exposure history, tumor characteristics, patient demographics, and dermatologic history through retrospective chart review. They then applied inverse probability of treatment weighted, multivariable modeling to isolate the relationship between tanning bed exposure and mutational counts while adjusting for confounding characteristics.
The Comparison: Indoor Tanning Exposure vs. No Exposure
When the authors completed their multivariable comparison, the findings departed from what many might expect from ultraviolet-driven cancers. After adjusting for demographic, dermatologic, and tumor characteristics, the analysis showed no association between indoor tanning exposure and melanoma tumor mutational burden.
The statistical comparison between the two groups showed:
- Patients with indoor tanning exposure: log2 mutational burden estimate of 4.07 (standard error of 0.44).
- Patients without indoor tanning exposure: log2 mutational burden estimate of 3.97 (standard error of 0.45).
- A P value of .39, indicating that this difference was not statistically significant.
As documented in the JAMA Dermatology study, while indoor tanning is known to increase the risk of developing melanoma, it was not meaningfully associated with higher mutational burden in this cohort. For broader background on tanning device hazards, review the tanning beds and UV risk evidence.
What Actually Corresponded With Higher Mutation Counts?
Although tanning bed history did not distinguish high-mutation tumors from low-mutation tumors, several other patient and tumor characteristics showed statistically significant associations with mutational burden:
- Older age at diagnosis: Older age at diagnosis showed a statistically significant association with higher mutational burden.
- Prior nonmelanoma skin cancer: Patients with a personal history of nonmelanoma skin cancer had significantly higher mutational burden compared to those without such history. (Read more about nonmelanoma skin cancer and melanoma characteristics).
- Head and neck tumor location: Tumors located on the head and neck exhibited significantly higher mutational burden relative to primary melanomas on other body sites.
- History of abnormal nevi: Conversely, patients with a documented history of abnormal nevi had statistically significantly lower average mutational burden (log2 estimate of 3.89, standard error 0.44) compared to patients without abnormal nevi (log2 estimate of 4.15, standard error 0.44), with a P value of .01.
These findings suggest that cumulative lifetime sun exposure on chronically exposed areas such as the head and neck, as well as advancing age, plays a more noticeable role in raising overall mutational levels than documented tanning bed use alone.
Study Limitations and Clinical Perspective
It is essential to view these results within the limits of the research. This was a single retrospective cohort study conducted at one specialized cancer center between 2013 and 2022. Retrospective medical record reviews depend on self-reported exposure histories, which may not capture exact tanning bed session frequency, machine power, or exposure duration.
Most importantly, the absence of an association with mutational burden does not suggest that indoor tanning is harmless. Indoor tanning remains a proven environmental cause of skin malignancies. Similarly, unregulated tanning products such as melanotan I and melanotan II bought online are unapproved and carry significant health hazards. Anyone with questions about atypical moles, skin damage, or UV exposure should consult a qualified doctor or dermatologist.
Sources
Published October 28, 2026. Sources are linked in the text. See our Medical Disclaimer.