目的　用免疫组织化学定量方法观察在上皮癌变过程中 Ｃｍｙｃ 的表达及意义。方法　标本取自病人颊粘膜，包括白斑（ Ｏ Ｌ Ｋ） 、慢性炎症（ Ｉ Ｆ） 、鳞状细胞癌（ Ｓ Ｃ Ｃ） 。采用免疫组化（ Ａ Ｂ Ｃ） 法，一抗为 Ｃｍｙｃ 单抗。用网格测试法对ｍｙｃ阳性反应细胞计数，可得出上皮ｍｙｃ 的阳性指数。结果　显示ｍｙｃ 在口腔上皮癌过程中有较高的表达，从 Ｉ Ｆ、 Ｏ Ｌ Ｋ 到 Ｓ Ｃ Ｃ 组，有逐渐增大的趋势。结论　 Ｃｍｙｃ 其表达程度主要与肿瘤细胞的分化关系密切，是判断细胞分化程度的一个参考指标。 Objective To observe the expression and significance of Cmyc in epithelial carcinogenesis by quantitative immunohistochemistry. Methods Specimens were collected from the buccal mucosa of the patient, including O L K, I F, and SCC. Using immunohistochemistry (A B C) method, the first antibody C  myc monoclonal antibody. Counting myc-positive cells with the grid test gives a positive index for epithelial myc. The results showed that myc in oral squamous cell carcinoma has a higher expression, from I F, O L K to S C C group, there is a gradual increase in the trend. Conclusion The expression level of C-myc is closely related to the differentiation of tumor cells and is a reference index for judging the degree of cell differentiation.