Abstract

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. Clinically, it causes pain, itching, or tenderness, causing life discomfort and characteristically irreversible.

Despite various treatment modalities, restoring keloids to normal tissues is difficult, and frequent recurrences have been reported. Therefore, it is essential to identify keloid-specific genes for accurate diagnosis and treatment of keloids. In an effort to find out keloid-specific genes, several studies compared keloids with scar-free normal skin, which leading general scar-related genes to be chosen rather than keloid-specific genes. To select for highly accurate keloid-specific genes and pathways, we compared the transcriptome profile of keloids with those of normotrophic scars and hypertrophic scars, which acquired from formalin-fixed paraffin-embedded human skin samples using high-throughput RNA-sequencing techniques. Differential expression analyses and over-representation analyses revealed that genes related to nervous system process were upregulated in keloids, whereas genes related with immune responses were downregulated in keloids. Additionally, the extracellular matrix related processes were highlighted in both hypertrophic scars and keloids. Finally, we highlight potential keloid-specific biomarkers and expression changes that can be employed for future therapeutics of keloids.

Keywords: Normotrophic scar; Hypertrophic scar; Keloid; RNA sequencing; Scar management