As depicted in Figure 4a, Spearman correlation of the intergene RNA expression relations revealed a strong positive association between the two luminal cancer markers KRT20 and ERBB2 (Spearman rho 0.6811, p < 0.0001) and inverse relation between the luminal KRT20 and basal KRT5 marker (Spearman rho −0.3588, p = 0.0249) as expected. Here, ERBB2 is linked to cancer.