Mutation burden of narrowband ultraviolet B phototherapy (NB-UVB) in human skin - relevance to NB-UVB lifetime exposures and skin cancer surveillance

Q: What was the objective of the study on NB-UVB and human skin?

The study aimed to determine the mutation burden in human skin after a course of NB-UVB and to use these data to estimate when skin cancer surveillance should begin based on lifetime NB-UVB exposures.

Q: How were mutations measured in the participants?

Biopsies of normal skin were collected before and after a course of NB-UVB from psoriasis patients, and epidermal DNA was sequenced using NanoSeq to identify mutational signatures and quantify mutation burden.

Q: What did the researchers find about mutation burden after NB-UVB?

NB-UVB increased mutations in skin, with a median increase of 0.55 substitutions per Mb in infrequently sun-exposed buttock skin and 0.89 substitutions per Mb in frequently sun-exposed forearm skin.

Q: How did the study estimate NB-UVB exposure thresholds for skin cancer surveillance?

Mutation burden changes were modeled relative to minimal erythema dose (MED) and compared with average mutation burden in keratinocyte skin cancers to estimate total lifetime exposures. For patients with MED equal to 2 standard erythemal doses, surveillance should be offered at 422, 165, and 58 NB-UVB exposures for low, typical, and high sun exposure levels, respectively.

Sep 23, 2026

Uploaded by Aran

Ultraviolet radiation is used to treat psoriasis and other skin diseases, yet it can induce DNA mutations that may drive skin cancer development. Epidemiological evidence on cancer incidence after narrowband ultraviolet B (NB-UVB) therapy remains limited, and the mutagenicity of NB-UVB is clinically important for risk assessment. This study quantified mutation burden in human skin before and after NB-UVB using biopsies from psoriasis patients, applied mutational signature analysis, and modeled lifetime exposure thresholds for initiating skin cancer surveillance.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages11

Reading Time28 min

AccessFree to download

Abstract

Background

Objectives

Methods

Results

Conclusions

Br J Dermatol 2025; 193:718–728 [https://doi.org/10.1093/bjd/ljaf173](https://doi.org/10.1093/bjd/ljaf173) Advance access publication date: 3 May 2025 Translational Research Mutation burden of narrowband ultraviolet Bphototherapy (NB-UVB) in human skin: relevance to NB-UVB lifetime exposures and skin cancer surveillance Joanna C Fowler,1 Roshan K Sood,1 George Coltart,2,3 Chester Lai,2,3,4 Noeline Nadarajah,2 John W Holloway,5,6 Matthew J J Rose-Zerilli,6,7 Brian Diffey,8 Philip H Jones1,9 and Eugene Healy2,3 1Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK 2 Dermatopharmacology, University of Southampton, Southampton General Hospital, Southampton, UK 3 Dermatology, University Hospital Southampton NHS Foundation Trust, Southampton, UK 4 Department of Medicine and Therapeutics, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China 5 Human Development and Health, University of Southampton, Southampton General Hospital, Southampton, UK 6 Institute for Life Sciences, University of Southampton, Southampton, UK 7 Cancer Sciences, University of Southampton, Southampton General Hospital, Southampton, UK 8Translational and Clinical Research Institute (Dermatology), Newcastle University, Newcastle upon Tyne, UK 9 Department of Oncology, University of Cambridge, Hutchison Research Centre, Cambridge, UK Correspondence: Eugene Healy. Email: [ehealy@soton.ac.uk](ehealy@soton.ac.uk) [P.H.J. and E.H. are joint senior authors.](P.H.J. and E.H. are joint senior authors.) Linked Article: Paragh and Huss Br J Dermatol 2025; 193:589–590 . Abstract Background Ultraviolet radiation (UVR) is used as treatment for psoriasis and other skin diseases, but UVR can induce DNA mutations that may lead to skin cancer development. While skin cancers have been documented in patients treated with phototherapy, a limited number of epidemiological studies have examined the incidence of skin cancer in people receiving narrowband ultraviolet B (NB-UVB) treatment. Information on the mutagenicity of NB-UVB would help inform about the potential skin cancer risks of this treatment. Objectives To determine the mutation burden in human skin resulting from a NB-UVB treatment course and to use this data to estimate the total number of NB-UVB exposures whereupon skin cancer surveillance should begin . Methods Biopsies of normal skin were obtained before and after a course of NB-UVB from 16 patients with psoriasis . Epidermal DNA was sequenced using nanorate sequencing (NanoSeq) to determine the mutational signatures and mutation burden from NB-UVB. Results The NB-UVB treatment course increased the number of mutations in skin . Median increase in mutation burden was 0.55 substitutions per Mb in infrequently sun-exposed (buttock; n = 14) skin and 0.89 substitutions per Mb in frequently sun-exposed (forearm; n = 10) skin ( P< 0. 001) . Change in mutation burden due to NB-UVB ranged from 1.16- to 10. 50-fold in buttock skin and from 0.93- to 2. 33-fold in forearm skin . This increase was mainly attributable to UVR exposure-linked mutational signatures, SBS7a and SBS7b, with some evidence that mutational burden was related to the genetic background of the individual. Modelling the change in mutation burden from NB-UVB relative to minimal erythema dose (MED) in comparison with average mutation burden in keratinocyte skin cancers allowed estimation of total lifetime exposures at which patients are likely to require skin cancer surveillance; for patients with a MED equal to 2 standard erythemal doses (SEDs), skin cancer surveillance should be offered at 422, 165 and 58 NB-UVB exposures for those receiving low, typical and high levels of sun exposure, respectively. Conclusions A treatment course of NB-UVB causes UVR-induced mutations in the healthy skin of patients with psoriasis . Relating mutation burden to MED and sun behaviour habits allows estimation of when to begin skin cancer survei

FAQs

What was the objective of the study on NB-UVB and human skin?

The study aimed to determine the mutation burden in human skin after a course of NB-UVB and to use these data to estimate when skin cancer surveillance should begin based on lifetime NB-UVB exposures.

How were mutations measured in the participants?

Biopsies of normal skin were collected before and after a course of NB-UVB from psoriasis patients, and epidermal DNA was sequenced using NanoSeq to identify mutational signatures and quantify mutation burden.

What did the researchers find about mutation burden after NB-UVB?

NB-UVB increased mutations in skin, with a median increase of 0.55 substitutions per Mb in infrequently sun-exposed buttock skin and 0.89 substitutions per Mb in frequently sun-exposed forearm skin.

How did the study estimate NB-UVB exposure thresholds for skin cancer surveillance?

Mutation burden changes were modeled relative to minimal erythema dose (MED) and compared with average mutation burden in keratinocyte skin cancers to estimate total lifetime exposures. For patients with MED equal to 2 standard erythemal doses, surveillance should be offered at 422, 165, and 58 NB-UVB exposures for low, typical, and high sun exposure levels, respectively.

Sep 23, 2026

Uploaded by Aran