 The RET/PTC1 oncogene, a rearranged form of the RET proto-oncogene, has been reported to be associated with human papillary thyroid carcinomas.     ///    "Our study showed that RET/PTC1 not only increased proliferation of thyrocytes, it also altered morphogenesis and differentiation. "    ///    These findings provide a model for the role of RET/PTC1 in the formation of abnormal follicles with reduced iodide uptake ability observed in human papillary thyroid carcinoma..     ///    We have shown that targeted expression of RET/PTC1 in the thyroid gland leads to the development of thyroid carcinomas in transgenic mice with histologic and cytologic similarities to human papillary thyroid carcinoma.     ///    Early cellular abnormalities induced by RET/PTC1 oncogene in thyroid-targeted transgenic mice..     ///    "To further investigate how RET/PTC1 expression contributes to the pathogenesis of papillary thyroid tumor, the time of tumor onset and the early phenotypic consequences of RET/PTC1 expression in thyrocytes were determined. "