We next performed immunohistochemical analysis in breast cancer tissues taken prior to treatment (Supplementary Table 4) to examine the expression levels of Cyclin E (encoded by CCNE1) and c-Myc (encoded by MYC), two oncogenes that are frequently amplified in TNBC, and have been associated with replication stress in experimental models24–27 (Fig. 2b). Here, CCNE1 is linked to breast cancer.