A similar confusion arises when the solid-type papillary carcinoma occurring in RET/PTC 3 transgenic mice is considered as an equivalent of the solid PTC variant found in radiation-induced thyroid cancer of children harbouring an RET/PTC3 rearrangement (Powell et al, 1998; Thomas et al, 1999). This evidence concerns the gene NCOA4 and papillary carcinoma.