ETV6 (i.e. translocation-Ets-leukemia virus) protein is a transcription factor that in humans is encoded by the ETV6 (previously known as TEL) gene. The ETV6 protein regulates the development and growth of diverse cell types, particularly those of hematological tissues. However, its gene, ETV6 frequently suffers various mutations that lead to an array of potentially lethal cancers, i.e., ETV6 is a clinically significant proto-oncogene in that it can fuse with other genes to drive the development and/or progression of certain cancers. However, ETV6 is also an anti-oncogene or tumor suppressor gene in that mutations in it that encode for a truncated and therefore inactive protein are also associated with certain types of cancers.