MARK4 and neoplasm: We showed that miR‐515‐5p and MARK4 levels are significantly down‐regulated/up‐regulated in metastatic breast cancer tissues compared to primary tumour tissues, respectively, demonstrating the clinical relevance of our findings and indicating in the future that perhaps a miR‐515‐5p‐based therapy as possible treatment to prevent the migration of cancer cells from the primary tumour.