By detecting the ratio of GFAP-positive cells to total number of cells, it was demonstrated that 1 nmol/l ATRA (35.33%), 10 nmol/l ATRA (49.50%) and 100 nmol/l ATRA (70.17%) exhibited a significantly more potent ability to promote differentiation compared with that of the BC group (25.83%; P=0.08, P<0.001 and P<0.001, respectively) (Fig. 2). This evidence concerns the gene GFAP and breast cancer.