RET/PTC expression has been demonstrated to inhibit transcription of thyroid-specific genes.     ///    "Acute expression of RET/PTC3 or RET/PTC3(Y541F), but not PTC2/PDZ, inhibited TSH-induced Tg and NIS expression, suggesting that activation of Shc-Ras, but not PLCgamma, is required for RET/PTC-induced dedifferentiation. "    ///    "In conclusion, activation of the Ras/Raf/MEK/MAPK pathway through Shc mediates RET/PTC-induced thyroid cell dedifferentiation. "    ///    "Acute expression of RET/PTC(Y541F) appropriately interacted with Shc, an intermediate in the activation of the Ras pathway, but failed to activate PLCgamma. "    ///    RET/PTC-induced dedifferentiation of thyroid cells is mediated through Y1062 signaling through SHC-RAS-MAP kinase..     ///    This suggests that inhibition of this pathway may promote redifferentiation in poorly differentiated thyroid carcinomas with constitutive activation of either Ras or RET/PTC.. 