目的：研究Ｐ５３和Ｐ２１ｒａｓ蛋白在甲状腺癌中的表达及与甲状腺癌的分化与转移的关系。方法：对已确诊的５５例甲状腺癌组织，采用ＬＳＡＢ免疫组织化学方法标记Ｐ５３、Ｐ２１ｒａｓ蛋白。结果：Ｐ５３、Ｐ２１ｒａｓ蛋白在未分化甲状腺癌的阳性表达率分别为６３６％和９０９％；在分化型甲状腺癌的阳性表达率分别为１５９１％和６８１８％；有淋巴结转移的甲状腺癌的阳性表达率分别为６３６４％和７７２７％。Ｐ５３蛋白在未分化型甲状腺癌和发生淋巴结转移的甲状腺癌组织中的阳性表达率均为６３６％，显著高于分化型和无淋巴结转移的甲状腺癌Ｐ＜００１。而Ｐ２１ｒａｓ蛋白在分化型甲状腺癌中的阳性表达率为６８１８％，明显高于其在未分化癌的表达率（Ｐ＜００１）。结论：Ｐ５３、Ｐ２１ｒａｓ蛋白的阳性表达率可作为甲状腺癌分化程度的评估指标，而Ｐ５３和Ｐ２１ｒａｓ的高阳性表达率可反映甲状腺癌发生淋巴结转移的可能性。 Objective: To study the expression of P53 and P21ras protein in thyroid carcinoma and its relationship with the differentiation and metastasis of thyroid carcinoma. Methods: Fifty-five cases of thyroid carcinoma were confirmed by immunohistochemical staining with LSAB P53, P21ras protein. Results: The positive rates of P53 and P21ras in undifferentiated thyroid cancer were 636% and 909%, respectively. The positive rates of P53 and P21ras in differentiated thyroid carcinoma were 1591% and 6818% respectively. There were lymph node The positive rates of metastatic thyroid cancer were 6364% and 7727% respectively. P53 protein in undifferentiated thyroid cancer and lymph node metastasis of thyroid cancer were 63.6% positive expression was significantly higher than differentiated and no lymph node metastasis of thyroid cancer P <0  01. The positive rate of P21ras protein in differentiated thyroid cancer was 68.18%, which was significantly higher than that in undifferentiated carcinoma (P <001). Conclusion: The positive expression rate of P53 and P21ras proteins can be used as an index to evaluate the differentiation degree of thyroid carcinoma. The positive expression rates of P53 and P21ras may reflect the possibility of lymph node metastasis in thyroid carcinoma.