应用免疫组织化学染色ＡＢＣ法检测２９例头颈部癌及其癌旁组织中ｒａｓ基因产物Ｐ＿２１蛋白的表达，检测结果表明，头颈鳞癌阳性率为７５．８％，而癌旁组织阳性率为１７．３％，阳性表达主要分布于分化差的细胞表面，提示ｒａｓ癌基因产物Ｐ＿２１蛋白检测可作为头颈部鳞癌的诊断的标记物，尤其对癌旁组织的监测，可作为癌变和疾病预后的客观指标 Immunohistochemical staining ABC method was used to detect the expression of ras gene product P_21 protein in 29 cases of head and neck cancer and adjacent tissues. The results showed that the positive rate of head and neck squamous cell carcinoma was 75.8%, and the positive rate of adjacent tissues was positive. 17.3%, positive expression was mainly distributed on the surface of poorly differentiated cells, suggesting that the detection of ras oncogene product P_21 protein can be used as a marker for the diagnosis of head and neck squamous cell carcinoma, especially for the monitoring of adjacent tissues and can be used as cancerous disease and disease. Objective indicators of prognosis