A variety of differences have been identified between breast carcinoma-associated stroma and its paired normal mammary stroma, primarily resulting in increased expression of cytokines (EGF, HGF PDGF, TLL-12, SSP-1, POSTN, CXCL-12, and CXCL14), extracellular matrix (ECM) molecules (FBN1, FB2M, SPARC, ADRA2A and ADM) and proteases (MMP-1, MMP-2, MMP-13) [10]–[16]. The gene discussed is CXCL12; the disease is breast carcinoma.