Whole-Exome Sequencing (WES) on 117 samples of TETs and paired normal tissue has identified four recurrently mutated genes: general transcription factor II-I (GTF2I), HRAS, TP53, and NRAS. Clonality analyses revealed that the mutations in all four genes probably occurred at the onset or in the very early stages of tumor development. The gene discussed is GTF2I; the disease is neoplasm.