To investigate the molecular mechanism of GHR in breast cancer, this study evaluated the biological functions of GHR in breast cancer in vitro and in vivo, and explored the association between GHR and the B‐Raf proto‐oncogene, serine/threonine kinase (BRAF)/Mitogen‐activated protein kinase kinase (MEK)/Extracellular regulated protein kinases (ERK) signaling pathway. This evidence concerns the gene MARK2 and breast cancer.