In fact, a reduced expression of stromal cell-derived factor 1 (SDF1), an angiogenic factor also known as CXC motif chemokine 12 (CXCL12), and its receptor CXCR4 has been found in later stages of disease skin biopsy samples from SSc patients, while they were upregulated in the skin of patients with early SSc, playing probably a role in the inadequate angiogenic response [44]. This evidence concerns the gene CXCL12 and systemic sclerosis.