基因突变引起的遗传性表皮溶解性大疱病（RDEB）患者中，表皮鳞状细胞癌（SCC）是导致患者死亡的主要原因。然而，患者从首次诊断到存活时间存在差异，有些肿瘤扩散特别快，而其他肿瘤可能局限于多年。由于治疗选择有限，迫切需要进一步深入研究RDEB肿瘤的病理机制，以阐明其临床异质性，并促进治疗方法的开发并支持临床决策。 本研究旨在调查RDEB肿瘤在分子和表型水平上的侵袭性差异，特别关注上皮向间质（EMT）转化状态和miR-200b作为调节因子。通过对RDEB-SCC角质形成细胞系的性质进行表征，包括细胞形态分类、免疫荧光、流式细胞术、合成逆转录聚合酶链反应（sqRT-PCR）和免疫印迹等分析EMT标记物的表达。测定RDEB-SCC细胞的迁移能力，并利用RDEB-SCC细胞的培养基处理内皮细胞进行血管生成实验。此外，我们挖掘之前生成的microRNA（miRNA）谱分析数据，以确定具有潜在治疗意义的候选基因，并进行短暂miRNA转染实验，研究候选基因逆转EMT特征的能力。 我们观察到RDEB-SCC细胞株之间的EMT状态存在高度变异，这与两个可用患者活检标本的原位分析和相应的临床疾病进程相一致。此外，我们发现miR-200b-3p在RDEB-SCC中下调，其失调程度与各个肿瘤株的EMT特征显著相关。将miR-200b-3p重新引入具有明显EMT特征的RDEB-SCC细胞系中，可以显著增加上皮特征，包括细胞形态、EMT标记物的表达、迁移和血管生成潜力。 总而言之，RDEB-SCC存在不同的EMT状态，miR-200b的水平表明RDEB-SCC在EMT途径上的进展程度。此外，miR-200b的重新引入明显减少了间质特征。 ©2023年作者。由牛津大学出版社代表英国皮肤科医师协会出版。

Cutaneous squamous cell carcinomas (SCC) are the leading cause of death in patients suffering from recessive dystrophic epidermolysis bullosa (RDEB). However, the survival time from first diagnosis differs among patients, and some tumours spread particularly fast, while others may remain localised over years. As treatment options are limited, there is an urgent need to provide further insights into the pathomechanisms elucidating the clinical heterogeneity of RDEB tumours to foster therapy development and support clinical decision-making.Investigate differences in RDEB tumours of diverging aggressiveness at the molecular and phenotypic level, with a particular focus on epithelial to mesenchymal (EMT) transition states and thus miR-200b as a regulator.Primary RDEB-SCC keratinocyte lines were characterised with respect to their EMT state. For this purpose, cell morphology was classified, and the expression of EMT markers was analysed using immunofluorescence, flow cytometry, sqRT-PCR, and western blotting. The motility of RDEB-SCC cells was determined and conditioned medium of RDEB-SCC cells was used to treat endothelial cells in an angiogenesis assay. In addition, we mined previously generated microRNA (miRNA) profiling data to identify a candidate with potential therapeutic relevance and performed transient miRNA transfection studies to investigate the candidate's ability to reverse EMT characteristics.We observed a high variability in the EMT state among the RDEB-SCC cell lines, which correlated with in situ analysis of two available patient biopsies and respective clinical disease course. Furthermore, we identified miR-200b-3p to be downregulated in RDEB-SCCs, with the extent of deregulation significantly correlating with EMT features of the various tumour lines. miR-200b-3p was reintroduced into RDEB-SCC cell lines with pronounced EMT features, resulting in a significant increase in epithelial characteristics, including cell morphology, EMT marker expression, migration and angiogenic potential.In summary, RDEB-SCCs exist in different EMT states and the level of miR-200b is indicative of how far an RDEB-SCC has gone down the EMT path. Moreover, reintroduction of miR-200b significantly reduced mesenchymal features.© The Author(s) 2023. Published by Oxford University Press on behalf of British Association of Dermatologists.