Characterising UV transmission property of red hair using microspectrophotometer

Melanoma is one of the most severe types of skin cancer. Although it is generally believed that ultraviolet radiation (UVR) is the main environmental causative risk factor in the induction of melanoma, the cells of origin and mechanisms of melanoma remain unclear. Recent studies show that the melanocyte stem cells in the hair follicles could be the cells of origin of melanoma upon exposure to ultraviolet radiation. Red hair is usually considered as one of the risk factors for melanoma. Therefore, it is of interest to investigate the UV transmission characteristics of hairs from red-hair individuals. In this article, the measurement techniques using a micro-spectrophotometer for studying the transmission characteristics of human hair are demonstrated. Several hair samples from a red-haired adult are studied. The results show that non-medullated red hair has relatively superior transmission properties to the medullated red hair in the UV wavelength range. It has also been found that light blond hair has a noticeably lower attenuation coefficient in the ultraviolet-A (UVA) wavelength range than the light yellow and red hair from the same red-haired individual. Our findings support the hypothesis that the colorless hair may transmit sufficient UV photons to harm the melanocyte stem cells in the hair follicles, ultimately resulting in melanoma.