WEE1 and breast cancer: Overexpression of WEE1 has been reported in several malignant tumors such as hepatocellular carcinoma [21], breast cancer [22], glioblastoma [23], malignant melanoma [24] and colorectal cancer [25], while inhibition of WEE1, via small molecule inhibitors, has been shown to be a promising clinical approach in the treatment of cancer [17–20, 26–29].