32329 Assessing the utility of Fontana-Masson and MART-1 stains in evaluating skin pigmentary changes induced by ultraviolet radiation and visible light

Abstract

One of the observed effects of ultraviolet radiation (UVR) and visible light (VL) on melanocompetent skin is increased pigmentation, also known as skin darkening or tanning. Many methods are used to measure skin pigment, including the Fontana-Masson stain (FMS) and MART-1 immunostain, which histologically highlight melanin and melanocyte density, respectively. While these approaches may be adequate in assessing baseline skin pigment among individuals of different races and phototypes, detecting the skin darkening induced by UVR and VL within the same individual is a challenge, especially in darker skin phototypes. We conducted a literature search and analyzed 16 articles comparing skin pigmentation changes induced by VL and UVR to their corresponding FMS and MART-1 results. Notably, significant skin darkening could be detected by diffuse reflectance spectroscopy after irradiation in skin phototypes III-VI, but FMS and MART-1 were unable to significantly differentiate these changes and reliably enumerate them within the same studies. Outcome measurements of FMS and MART-1 may be affected by several factors across studies, such as varying spectrums of radiation, radiation doses, skin phototypes, and subjectivity of the rater. Our results indicate that objective instrumental assessments, such as spectroscopy, are likely superior to FMS and MART-1 for measuring skin pigmentary changes induced by UVR and VL. Further research is recommended to investigate the value in performing FMS and MART-1 stains in future studies evaluating skin tanning from UVR and VL.