Exportin 5 (XPO5) is a member of the importin β family of proteins and functions in tRNA export in a sequence dependent fashion. More recently, it has been shown to export pre-miRNA by a RanGTPase-driven process from the nucleus to the cytoplasm, where pre-miRNA processing occurs to produce mature miRNAs. Study of the miRNA biosynthesis pathway is essential in understanding the process of oncogenesis as global downregulation of miRNAs and the resulting alterations in the expression of tumor suppressor and oncogenic proteins is a common phenotype of cancers cells . Research studies have shown disruption of exportin 5 functions in many types of cancers including breast and lung, where pre-miRNA accumulates in the nucleus and miRNA maturation is impaired.