In keeping with previous studies that mithramycin A, a Sp1 inhibitor, markedly reduced basal survivin levels in colorectal cancer (Hsu et al., 2012) and breast cancer (Chuang et al., 2017) cells, we noted that mithramycin A also caused survivin reduction in FaDu cells (unpublished data). This evidence concerns the gene SP1 and breast cancer.