The fibroblast heterogeneity across keloid, normal and tumor samples from single-cell resolution.

Keloids are defined as a benign dermal fibroproliferative disorder, with excessive fibroblast proliferation, and excessive overproduction of collagen. Although the heterogeneity during keloid development has been extensively studied, the heterogeneity across different skin states is still unclear. So, a global comparison across skin states is needed. In this study, we collected samples from 5 states of skin, including melanoma, cutaneous squamous cell carcinoma, keloid skin, scar skin, and healthy control samples. The heterogeneity of cell types and subtypes was analyzed and compared across 5 states, and we observed significant differences among them. Our results showed a cancer-like fibroblast, which is not in normal samples, may play an important role in antigen processing and presentation. We also noticed that the mesenchymal fibroblast increased in keloid samples, which highly expressed POSTN. And POSTN may participate in epithelial-mesenchymal transition and collagen overexpression to promote keloid growth. These findings help to understand the alteration among different skin states and provide potential genetic basis for keloid therapies.