In two studies in which the scoring method was used for the immunohistochemical staining (Chui et al, 1996; Ko et al, 2003), the immunoreactive score (IRS) of the c-kit expression of benign tumours was lower than that of normal breast tissue and the IRS of the breast cancer was significantly lower than that of the benign tumours. This evidence concerns the gene KIT and breast carcinoma.