While there was no significant difference in survival time between patients with breast cancer expressing a high level of Cdc6 and those expressing a low level of Cdc6 in ER-negative patients (Wilcoxon-Gehan test, p = 0.420; Fig. 4D), a high level of Cdc6 expression was significantly associated with a shorter survival time in breast cancer patients with ER positive breast cancer (Wilconxon-Gehan test, p = 0.004; Fig. 4E). This evidence concerns the gene ESR1 and breast cancer.