Huang Xiyong, Protheroe Michael D, Al-Jumaily Ahmed M, Chalmers Andrew N, Paul Sharad P, Fu Xiang
J Opt Soc Am A Opt Image Sci Vis. 2019 Apr 1;36(4):628-635. doi: 10.1364/JOSAA.36.000628.
The incidence of melanoma in children is extremely rare. However, there is convincing evidence supporting a higher risk of developing melanoma in individuals who have experienced excessive sun exposure during their childhood. A possible explanation for this phenomenon is that prior to puberty, the melanocyte stem cells in the bulge region of hair follicles are much shallower in the dermis, resulting in their increased vulnerability to sun exposure. To validate this hypothesis, a Monte Carlo simulation of light transport is applied to quantify the dose of solar UV power absorbed in the stem-cell layers at different depths in both child and adult skins. The simulated results suggest that the stem cells in vellus hair follicles would absorb over 250 times higher UV photons than those in the terminal hair follicles. Due to the thinner epidermis in child skin, the stem cells in vellus hair follicles absorb about 1.9 and 3.2 times greater ultraviolet A and ultraviolet B, respectively, than those in adult skin. These findings provide a possible explanation to why children are particularly vulnerable to sun exposure.
儿童黑色素瘤的发病率极为罕见。然而，有确凿证据表明，童年时期过度暴露于阳光下的个体患黑色素瘤的风险更高。对此现象的一种可能解释是，在青春期之前，毛囊隆突区的黑素细胞干细胞在真皮中的位置较浅，导致它们更容易受到阳光照射的影响。为了验证这一假设，应用光传输的蒙特卡罗模拟来量化儿童和成人皮肤不同深度的干细胞层中吸收的太阳紫外线能量剂量。模拟结果表明，毳毛毛囊中的干细胞吸收的紫外线光子比终毛毛囊中的干细胞多250倍以上。由于儿童皮肤的表皮较薄，毳毛毛囊中的干细胞吸收的紫外线A和紫外线B分别比成人皮肤中的干细胞多约1.9倍和3.2倍。这些发现为儿童为何特别容易受到阳光照射提供了一种可能的解释。
