Background. Langerhans cells (LCs) are professional Dendritic Cells (DCs) involved in immunoregulatory functions. At the skin level, LCs are immature. In response to tissue injuries, they migrate to regional Lymph Nodes (LNs), reaching a full maturation state. Then, they become effective antigen-presenting cells (APCs) that induce anti-cancer responses. Notably, melanoma patients present several DC alterations in the Sentinel Lymph Node (SLN), where primary antitumoral immunity is generated. LCs are the most represented DCs subset in melanoma SLNs and are expected to play a key role in the anti-melanoma response. With this paper, we aim to review the current knowledge and future perspectives regarding LCs and melanoma. Methods. A systematic review was carried out according to the PRISMA statement using the PubMed (MEDLINE) library from January 2004 to January 2024, searching for original studies discussing LC in melanoma. Results. The final synthesis included 15 articles. Several papers revealed significant LCs–melanoma interactions. Conclusions. Melanoma immune escape mechanisms include SLN LC alterations, favoring LN metastasis arrival/homing and melanoma proliferation. The SLN LCs of melanoma patients are defective but not irreversibly, and their function may be restored by appropriate stimuli. Thus, LCs represent a promising target for future immunotherapeutic strategies and cancer vaccines.
背景。朗格汉斯细胞（LCs）是参与免疫调节功能的专业树突状细胞（DCs）。在皮肤层面，LCs处于未成熟状态。当组织受损时，它们会迁移至区域淋巴结（LNs），达到完全成熟状态。随后，它们成为有效的抗原呈递细胞（APCs），能够诱导抗癌反应。值得注意的是，黑色素瘤患者在前哨淋巴结（SLN）中存在多种DCs异常，而SLN是产生原发性抗肿瘤免疫的关键部位。LCs是黑色素瘤SLN中最具代表性的DCs亚群，预计在抗黑色素瘤反应中发挥关键作用。本文旨在综述当前关于LCs与黑色素瘤的研究进展及未来展望。方法。根据PRISMA声明，在PubMed（MEDLINE）数据库中检索2004年1月至2024年1月期间讨论黑色素瘤中LCs的原创研究，进行系统性综述。结果。最终纳入15篇文献进行综合分析。多篇研究揭示了LCs与黑色素瘤之间存在显著相互作用。结论。黑色素瘤的免疫逃逸机制包括SLN中LCs的功能改变，这种改变有利于淋巴结转移的定植与黑色素瘤增殖。黑色素瘤患者的SLN LCs功能存在缺陷，但并非不可逆转，通过适当刺激可能恢复其功能。因此，LCs有望成为未来免疫治疗策略和癌症疫苗的重要靶点。
Langerhans Cells in Sentinel Lymph Nodes from Melanoma Patients
肿瘤(癌症)患者之家