Apart from endothelial cells, fibroblasts were found to be a complex composition in SSc skin, which could be initially divided into two large subtypes, SFRP2+ and FMO1+, and five small subtypes were labeled by CRABP1, COL11A1, C2orf40, SFRP4, and PRG4, respectively [76]. This evidence concerns the gene SFRP4 and systemic sclerosis.