Department Molecular Cellbiology, Dermatology Center Buxtehude, Klinikum Buxtehude, Buxtehude, Germany.
Prog Biophys Mol Biol. 2011 Dec;107(3):386-8. doi: 10.1016/j.pbiomolbio.2011.08.011. Epub 2011 Sep 3.
There is indicative epidemiological evidence that exposures of children younger than about 10 years are linked with an increased risk of the development of malignant melanoma as well as non-melanocytic skin cancers later in life. However, an important area of uncertainty relates to lack of knowledge of the sun-sensitivity of children's skin both absolutely and relative to that of adult's skin. For example the thickness of children's skin is very similar to that of adults but due to the nature of the anatomical structure of children's skin, there are indications of children's skin being adversely exposed on the top of the papilla before a significant exposure manifests itself as visible damage to the skin (for example erythema). This might also affect the induction of heavily UV-damaged cells persisting in the basal layer of the epidermis after UV-exposure which are supposed to be keratinocytic epidermal stem cells and may characterize an initiation step of non-melanoncytic skin cancer. For malignant melanoma the number of nevi received in dependence of UV-exposure in childhood is a clear risk factor. Recent data show that the bulge region of hair follicles hosting melanocytic stem cells are located deeper (more protected) in the skin in adults (terminal hair) as compared to pre-pubertal children (vellus hair). This may be an explanation for enhanced risk of malignant melanoma due to UV-exposure in pre-pubertal childhood.
有迹象表明，10 岁以下儿童的暴露与恶性黑色素瘤以及成年后非黑素细胞皮肤癌的风险增加有关。然而，一个重要的不确定领域是缺乏儿童皮肤对阳光的敏感性的知识，无论是绝对的还是相对于成人皮肤的敏感性。例如，儿童皮肤的厚度与成人非常相似，但由于儿童皮肤的解剖结构性质，有迹象表明，在皮肤明显受损（如红斑）之前，儿童皮肤的表皮乳头顶部就已经受到不利的暴露。这也可能影响到紫外线损伤严重的细胞的诱导，这些细胞在紫外线暴露后持续存在于表皮的基底层，这些细胞被认为是角朊细胞表皮干细胞，可能是非黑素细胞皮肤癌的起始步骤。对于恶性黑色素瘤，儿童时期接受的痣的数量是一个明确的危险因素。最近的数据表明，毛乳头区域的滤泡含有黑素细胞干细胞，在成年人（终毛）中比青春期前的儿童（绒毛）更深（更受保护）。这可能是青春期前儿童因紫外线暴露而导致恶性黑色素瘤风险增加的原因。
