KIF5B is a kinesin protein involved in organelle, macromolecule and RNA transport as well as intracellular movement. KIF5B function is co-opted in some cancers; in triple negative breast cancer (TNBC), it has high expression and drives epithelial mesenchymal plasticity, promoting tumor cell stem-ness, migration and TGF-Beta-mediated invasion. In lung cancers, a KIF5B-RET fusion has been detected at a rate of around 1.4%, and when present has high rates of expression in cancer versus absence in normal tissue. This fusion functions as an oncogene that regulates cell growth and differentiation through the PI3K-Akt and RAS-Raf-MAPK pathways. In immunohistochemistry of normal tissue, KIF5B has cytoplasmic positivity in all tissues throughout the body. References: The UniProt Consortium. Nucleic Acids Res. 47: D506-515 (2019); Nucleic Acids Res. 2016 Jan 4;44(D1):D733-45, PMID:26553804; EBioMedicine. Volume 45, July 2019, Pages 92-107, DOI: 10.1016/j.ebiom.2019.06.009; Onco Targets Ther. 2019; 12: 4533–4542, PMID: 31289444