MYC and breast cancer: 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).