To review recent studies on the research advance of RET( Rearranged during transfection) on-cogene in thyroid cancer,breast cancer,and lung cancer.The literatures on the structure of RET gene and coding product,cell signal transduction,relationship among thyroid cancer,breast cancer,and lung cancer are reviewed. RET gene encoding tyrosine kinase receptor,involving in cell signal transduction,rearrangement of RET gene is frequently seen in thyroid cancer,which is reported more and more in breast cancer,and lung cancer.Rearrange-ment of RET gene is closely correlated with the occurrence and progress of thyroid cancer,breast cancer,and lung cancer.Taking together,these findings suggest that RET present an attractive therapeutic target for the treatment of certain cancer subsets.