To focus on cytokines and growth factors specifically produced by ASCs (EGF, FGF, HGF, SDF, IL6, IL8, IL10) or epithelial breast cancer cells (EGF, FGF, HGF) known to be relevant in tumorigenesis, we carried out Q-PCR analyses both on ASCs or primary breast cancer cells, before and after co-culture. This evidence concerns the gene IL6 and breast cancer.