Figures 4A, 4B, 4C, 4D and 4E, and Figures 5A, 5B, 5C, 5D and 5E show the root-locus plot of SPARC, TIMP3, COL3A1, CTGF, and COL1A2 with silica as the input in the normal and SSc fibroblasts, respectively. This evidence concerns the gene SPARC and systemic sclerosis.