In conclusion, even if with the limits of a small number of mice carrying the homozygous null mutation of Patz1 (due to the embryonic lethality) and the lack of a systematic study on the metastatic behavior, the results presented here provide compelling evidence that impairment of PATZ1 expression promote the occurrence and aggressiveness of thyroid tumors in RET/PTC1TG mice, and per se may also be an initial event in thyroid carcinogenesis. This evidence concerns the gene RET and thyroid tumor.