The detection of these alterations in FAs may support a stepwiseadenoma to carcinoma sequence, or indicate the presence of “carcinoma in situ.” However, the PAX8/PPARγ rearrangement in itself may not besufficient for the development of a malignant phenotype: additional genetic orepigenetic events may be required to enable the full phenotypic expression offollicular thyroid carcinoma. The gene discussed is PPARG; the disease is in situ carcinoma.