LIFR and breast cancer: Further studies revealed that restoration of LIFR expression in highly malignant tumor cells inhibits metastasis by triggering the Hippo signaling pathway kinase cascade, which leads to phosphorylation, cytoplasmic retention, and functional inactivation of the transcriptional co-activator YAP; in contrast, loss of LIFR in non-metastatic breast cancer cells induces migration, invasion, and metastatic colonization of breast cancer cells through activation of YAP (30).