While SLC7A5 mRNA expression was not predictive of BCSS in any specific molecular class (Fig. 4b-e), high expression of SLC7A5 protein was only predictive of shorter BCSS in ER+ high proliferation (p = 0.007, Fig. 5d) and HER2+ tumours (p = 0.03, Fig. 5f). This evidence concerns the gene ERBB2 and neoplasm.