ERBB2 and breast cancer: Regarding the association of SLC7A8 CN and mRNA with the intrinsic (PAM50) subtypes, SLC7A8 CN gain was mainly observed in luminal B tumours (P < 0.001, Supplementary Table 2), whereas high mRNA expression was observed primarily in luminal A and B tumours and to lesser extent in HER2+BC (P < 0.001, Fig. 1f).