By using a conditional mouse model of BRAFV600E-inducible thyroid cancer [19] crossed with FOXE1 heterozygous knockout mice, we recently demonstrated that FOXE1 gene dosage affects cancer histology, proliferation and differentiation [20], thus showing for the first time a cause–effect relationship between FOXE1 and the thyroid cancer phenotype. This evidence concerns the gene FOXE1 and thyroid cancer.