To expand the potential clinical relevance of these associations, we next monitored TTK expression in a cohort of TNBC and HER2+ PDX models20 and observed markedly upregulated TTK expression in both breast cancer subtypes (Figure 2e), an event that was also significantly correlated with c-Abl expression in a p53-dependent manner (Figure 2f). Here, ERBB2 is linked to breast cancer.