The tyrosine kinase receptor TIE2, which induces dormancy in hematopoietic stem cells, also induces cell cycle arrest in breast cancer cells through CDK inhibitors CDKN1A (p21Waf1) and CDKN1B (p27Kip1) in vitro, decreases osteolytic metastases and response to antimetabolites in mice, and is associated with delayed time to metastasis in breast cancer patients [171]. Here, CDKN1A is linked to breast cancer.