In particular, the basal subtype shows the lowest median expression of ARHGEF12, SFRP4 and TGFBR2, as compared to normal tissue, luminal A, B, Her2 amplified, or normal subtypes of breast cancer as shown in Supplementary Figure 47 in Supplementary Note 11, and this association is retained when cases are restricted to wildtype expression of ARHGEF12, SFRP4, and TGFBR2. This evidence concerns the gene SFRP4 and breast cancer.