To test whether Lin28A affects AR expression in ER-/Her2+ breast cancer cells, Lin28A siRNA#2(Lin28A siRNA#2 could obviously decrease the expression of Lin28A compared with Lin28A siRNA#1 and Lin28A siRNA#3) were transfected into MDA-MB-453, plasmid overexpressed Lin28A(Lin28A) were transfected into SK-BR-3 cells, and the expression level of AR mRNA and c-myc mRNA was analyzed by qRT-PCR. This evidence concerns the gene ESR1 and breast cancer.