In one of the current papers in this issue, G. Rahmathulla et al. summarized the principal molecular and genetic mechanisms that underlie the development of brain metastasis (BrM) from aspects of migration-related events and molecules such as epithelial mesenchymal transition, interaction with tumor stroma, e-cadherin catenin complex, integrins, matrix metalloproteinases, urokinase-type plasminogen activator, CAI1, and tumor colonization. This evidence concerns the gene PLAU and neoplasm.