Ultraviolet Light Breaks Cell DNA in Skin Cancer Patients
Number of chromosomal breaks increased after exposure in sensitive patients
TUESDAY, Dec. 20 (HealthDay News) -- Sensitivity to ultraviolet B (UVB) radiation is associated with non-melanoma skin cancers but not with malignant melanoma, according to a study in the Dec. 21 issue of the Journal of the National Cancer Institute. The cells of sensitive patients display a higher number of chromosomal breaks after UVB exposure than controls.
Qingyi Wei, M.D., Ph.D., of the University of Texas M.D. Anderson Cancer Center in Houston, and colleagues collected lymphocytes from 231 patients with non-melanoma skin cancer, including basal and squamous cell carcinomas; 238 patients with cutaneous malignant melanoma; and 329 cancer-free control patients. The researchers determined the number of chromatid breaks per cell 24 hours after exposure to UVB radiation.
Non-melanoma skin cancer patients had a significantly higher number of chromatid breaks than controls, with a mean of 0.35-0.36 breaks per cell compared with 0.28 breaks per cell in controls. However, control patients with numbers of breaks above the median had a greater than twofold risk of developing basal or squamous cell carcinomas. The number of chromatid breaks in cutaneous malignant melanoma patients was not significantly different from controls (0.30 breaks per cell), according to the study.
"UVB-induced mutagen sensitivity may play a role in susceptibility to non-melanoma skin cancer, but not to cutaneous malignant melanoma," Wei and colleagues conclude.