Related Experiment Video
Updated: Jun 18, 2026
Spatial and Temporal Control of Murine Melanoma Initiation from Mutant Melanocyte Stem Cells
Published on: June 7, 2019
Reduced ultraviolet irradiation delays subsequent squamous cell carcinomas in hairless mice
Katrine Togsverd-Bo1, Catharina M Lerche, Thomas Poulsen
1Department of Dermatology, Bispebjerg Hospital, Copenhagen University Hospital, Copenhagen, Denmark. katrinetogsverd@hotmail.com
Background:
Ultraviolet (UV) radiation induces non-melanoma skin cancer (NMSC), and UV prophylaxis is essential to prevent skin cancer. It is unclear whether patients diagnosed with squamous cell carcinomas (SCC) may benefit from reduced UV exposures in terms of delaying the development of new tumors. The objective was to evaluate the significance of discontinued or reduced UV exposure for the development of subsequent skin tumors.
Methods:
Seven groups of mice (n = 175) were irradiated with UV doses of 2 and 4 standard erythema doses (SED) that were continued, reduced or discontinued at the time of appearance of the first skin tumor.
Results:
The development of new tumors was delayed, corresponding to the degree of reductions in UV dose in an inversely linear manner. Discontinuation of UV doses delayed the median times to the second tumor by 24 days (2 SED, P = 0.0549) and 33.5 days (4 SED, P < 0.0001), and when reduced to 1 SED, the median delays were 18 days (2 SED, P = 0.0469) and 33 days (4 SED, P < 0.0001). The median delay to the third tumor was after UV reduction 47 days (4 SED, P < 0.0001) and 35 days (2 SED, P = 0.151), and after UV discontinuation 49 days (4 SED, P < 0.0001) and 44 days (2 SED, P = 0.111).
Conclusion:
This suggests that patients with SCC may benefit from reduced UV exposure.
Insights
Reducing or stopping ultraviolet (UV) radiation exposure can delay the development of new skin tumors in mice with squamous cell carcinoma (SCC). This finding suggests UV protection is crucial for patients diagnosed with SCC.
Area of Science:
- Dermatology
- Oncology
- Photobiology
Background:
- Ultraviolet (UV) radiation is a known carcinogen, primarily causing non-melanoma skin cancer (NMSC).
- UV prophylaxis is a critical preventive measure against skin cancer development.
- The benefit of reduced UV exposure for patients previously diagnosed with squamous cell carcinoma (SCC) remains under investigation.
Purpose of the Study:
- To investigate the impact of reduced or discontinued UV exposure on the development of subsequent skin tumors in a preclinical model.
- To determine if limiting UV radiation can delay tumor recurrence or the onset of new skin cancers.
Main Methods:
- Seven groups of mice (n=175) were subjected to UV irradiation at 2 and 4 standard erythema doses (SED).
- UV exposure levels were either continued, reduced, or completely discontinued following the appearance of the first skin tumor.
- The median time to the development of second and third tumors was recorded for each experimental group.
Main Results:
- A dose-dependent delay in new tumor development was observed, correlating inversely with the reduction in UV dose.
- Discontinuing UV exposure significantly delayed the median time to the second tumor by 24-33.5 days (p<0.0001 at 4 SED).
- Reducing UV exposure to 1 SED also significantly delayed the median time to the second tumor by 18-33 days (p<0.0001 at 4 SED).
Conclusions:
- Reduced or discontinued UV exposure significantly delays the development of subsequent skin tumors.
- These findings support the recommendation for UV protection in patients diagnosed with squamous cell carcinoma (SCC).
- Further research into UV prophylaxis strategies for skin cancer patients is warranted.
