P53、c-erbB - 2、Rb和PCNA的表达在胃癌起源中的意义

目的：检测针对胃癌基因蛋白产物（p63、c-erbB-2和Rb)和核增殖抗原（PCNA）的抗体，以间接了解不同基因蛋白产物的变化在胃癌起源过程中所处的不同阶段。方法：对15例正常黏膜，16例轻度肠化生、15例中度肠化生、13例重度肠化生和14例胃癌组织标本连续切片同步进行免疫组化ABC法染色。结果：4种蛋白产物过度表达均主要见于胃癌组织。p53基因蛋白产物的阳性率除重度肠化生组外非胃癌各组与胃癌组之间差别均有统计学意义（P＜0．05）。c-erbB-2基因蛋白产物的阳性率在非胃癌各组与胃癌组之间均有显著差别（P＜0．01）。PCNA免疫组化标记指数值在非胃癌各组与胃癌组之间差别显著（P＜0．05）。Rb基因蛋白产物的表达在非胃癌各组和胃癌组织间无明显差别（P＞0．05）。结论：p53蛋白可在胃癌的早期诊断中起作用，其改变在胃癌发生的早期即居于肠化生阶段的癌前变化过程中。c-erbB-2蛋白可用作胃癌肿瘤诊断的标记物，其改变在胃癌的起源过程中属一晚期变化，居于癌前变化的肠化生阶段之后。PCNA的变化在胃癌的起源过程中属一晚期改变，发生在胃癌前变化的肠化生阶段以后。Rb基因在胃癌起源中作用有限。

Expresssions of p53, c- erbB- 2, Rb and PCNA in Gastric Carcinogenesis

Objective: We analyze the expression of various proteins (p53, c - erbB -2 and Rb) and proliferating cell nuclear antigen (PCNA) in gastric carcinoma in order to investigate the molecular mechanism of gastric carcinogenesis. Methods: With antibodies directed against the proteins, we examine simultaneously the immunoreactivities with immunohistochemical staining ABC in 15 normal mucosa, 16 mild, 15 moderate and 13 severe intestinal metaplasia tissues and 14 gastric carcinoma tissues. Results: The overexpression of 4 proteins are mostly found in gastric carcinoma tissues. The difference of the positive rates of p53 gene is significant between gastric carcinoma and non - carcinoma tissues except severe intestinal metaplasia tissues (P<0.05). The significant difference of the positive rates (P<0.01) of c- erbB - 2 gene exists between gastric carcinoma tissues and non - carcinoma tissues. The proliferative activity expressed by mean PCNA labeling percent is 47.26% for gastric carcinoma tissues, a value significantly higher than non - carcinoma tissues (P<0.05). The difference of the expression of Rb gene encoded proteins (pRB) isn't obviously among all 5 groups (P>0.05). Conclusion: P53 protein can be used in early clinical diagnosis. Early in gastric carcinogenesis, its change occurs at intestinal metaplasia stage. C -erbB -2 oncoprotein can be used as a label in clinical diagnosis for gastric carcinoma. Being a later change in gastric carcinogenesis, its change occurs after intestinal metaplasia of all pre - carcinoma stages. In later gastric carcinogenesis, the change of PCNA occurs after intestinal metaplasia stage. Rb does not play a crucial role in the oncogenesis of gastric carcinomas.