In addition, we investigated the association of YKL-40 with other two potential biomarkers GATA-binding protein 3 (GATA3) and E-cadherin in breast cancer, both of which correlate with ductal differentiation and a favourable prognosis of breast cancer (Bertucci et al, 2000; Graff et al, 2000; Garcia-Closas et al, 2007; Kouros-Mehr et al, 2008a). This evidence concerns the gene GATA3 and breast cancer.