Blood brain barrier (BBB) dysfunction is a hallmark of many Central Nervous System (CNS) disorders. Secondary metastatic cancer of CNS lies on the lack of selective permeability and the consequent trafficking of immune cells through the BBB. At present, research has not yet developed a strategy to prevent this access. It has recently been discovered that Calnexin (Canx) cytoplasmic tail and Fatty Acid Binding Protein 5 (FABP5) interact forming a complex which it is suggested to be responsible for T-cell passage into the CNS. However, there are many issues concerning the mapping of the interaction and its mechanism that have not been explored yet.