RT-qPCR and western blotting identified that the expression of stem cell markers sry-box transcription factor 2 (SOX2), pou class 5 homeobox 1 (OCT4), myc proto-oncogene, bhlh transcription factor (c-MYC), and nanog homeobox (NANOG) were upregulated by MTA1 overexpression or MTA3 knockdown in breast cancer cells. The gene discussed is SOX2; the disease is breast cancer.