In our previous study, we showed that STAT3 phosphorylation was induced by fibronectin (FN, an extracellular matrix glycoprotein) and CD44 (breast cancer stem cell marker which contributes to cell attachment, growth, migration, differentiation, and oncogenic transformation) in vitro using MDA-MB-468 and BT20 [28, 29]. This evidence concerns the gene CD44 and breast cancer.