RET (Rearranged During Transfection) protein is activated as a receptor tyrosine kinase by interacting with GDNF (Glial Cell Line Derived Neuotrophic Factor), such interaction activates signaling pathways including PI3K-Akt signaling pathway and MAPK signaling pathway. It has been reported that a certain type of mutation in RET, known as ‘rearrangement’, fuse the RET gene with other nearby genes, resulting in a RET protein that contains parts of other proteins which makes it hyperactive oncogene and correlates with development of thyroid gland cancer and lung cancer.