SPARC and systemic sclerosis: Overexpressed SPARC increases the production of type I and III collagen in keloid fibroblasts [36], whereas its knockdown reduces type I collagen mRNA and protein levels in dermal fibroblasts and other cell types [10,12,40,41,42], and decreases type II and III collagen expression in keloids and dermal fibroblasts from patients with systemic sclerosis [11,36].