We also found numerous genes that are involved in the regulation of synthesis or in the degradation of collagen and other extracellular matrix components to be differentially expressed in normal and SSc fibroblasts and modulated in response to PKC-δ inhibition, confirming the previous suggestions that PKC-δ plays an important role in the pathogenesis of tissue fibrosis in SSc and other fibrosing disorders [13]. This evidence concerns the gene PRKCD and systemic sclerosis.