Similarly, no differences in Rad21 expression were seen within the intrinsic breast cancer subtypes (luminal, 17 (42%) of 41; basal, 14 (44%) of 32; HER2, two (50%) of four; and null, one (20%) of five; P = 0.768) (Additional file 2 Table S2b). This evidence concerns the gene RAD21 and breast cancer.