Site-Specific Biomarkers in Keloid Disease Differentiate Keloid Scars From Normal Skin, DFSP, and Fibrosarcoma: Insights From Cell and Tissue Analysis

This preliminary study explores the feasibility of identifying novel site-specific biomarkers in keloid disease to enhance understanding of its pathobiology. Keloid scars are clinically and morphologically heterogeneous, showing variable response to therapy. They also differ at the cellular and molecular levels between their actively growing margins and their dormant centers. In addition, keloids behave differently to other fibrous skin tumors, including DSFP and FS. Thus, we performed a high-throughput RNA sequencing and gene/protein analysis on keloid tissue, primary keloid fibroblasts, and keloid-derived immortalized fibroblast cell lines from different sites of the keloid tissue (Extralesional, Peripheral, Middle, and Top). These were compared with normal skin, DFSP, and FS. We identified MTCO1P12 as a common gene transcript exhibiting significantly high expression across all three keloid sites (Peripheral, Middle, and Top), FS, and DFSP compared to the extralesional keloid. Furthermore, three site-specific biomarkers were identified. SLITRK1 was uniquely expressed in the peripheral keloid tissue site and its corresponding fibroblasts. FOXS1 was localized to the middle keloid tissue site and its corresponding fibroblasts. KCNJ6 was exclusively expressed in the top keloid tissue site and its corresponding fibroblasts. It was not found in FS and DFSP. In conclusion, for the first time, we identified and validated three novel site-specific biomarkers within keloid, two of which (SLITRK1 and FOXS1) overlap with more aggressive tumors, while KCNJ6 is unique to keloids. In conclusion, for the first time, we identified and validated three novel site-specific biomarkers in keloids, two of which (SLITRK1 and FOXS1) overlap with more aggressive tumors, while KCNJ6 is unique to keloids. These findings demonstrate the feasibility of identifying spatially distinct molecular signatures in keloids, providing a foundation for future research into targeted therapies.