KLF4 and breast cancer: To investigate the involvement of A2BR in the regulation of BCSCs in primary breast cancer, we analyzed the correlation of A2BR expression with a 20-gene BCSC signature 35, and with the OSNK signature that composed of the expression of pluripotency factors OCT4, SOX2, NANOG, and KLF4, from human TNBC samples in TCGA database, and found that A2BR expression was strongly correlated with the BCSC signature (Figure 8D) and the OSNK signature (Figure 8E).