Keloid-specific gene expression profiling for accurate diagnostic and therapeutic applications.

Scars are a heterogeneous disease including normotrophic scars, hypertrophic scars, and keloids. Of these lesions, keloids are a distinct subtype from any other type of scar because clinically, it causes pain, itching, or tenderness, causing life discomfort and characteristically irreversible. Therefore, for accurate diagnosis and treatment of keloids, it is essential to identify keloid-specific genes. However, in previous studies, keloids were compared with controls such as scar-free normal skin. In these studies, general scar-related genes were likely to be chosen rather than keloid-specific genes. In this study, we acquired transcriptomic profiles of normotrophic scars, hypertrophic scars, and keloids from formalin-fixed paraffin-embedded human skin samples using high-throughput RNA-sequencing techniques. We compared the transcriptome profile of keloids with those of other scar lesions to select for highly accurate keloid-specific genes and pathways. The results revealed that genes related with several biological processes such as sensory/visual perception are upregulated strongly in keloids, whereas genes related with activation of immune response were downregulated remarkably in keloids. Furthermore, the biological process of extracellular matrix organization was highlighted in both hypertrophic scars and keloids. In conclusion, our study provides insight into the pathogenesis of keloids distinct from other scar lesions as well as potential keloid-specific biomarkers. RNA-seq of normotrophic scar, hypertrophic scar, keloid.