目的　系统观察窦内皮细胞 (SEC)及其基膜中Ⅳ型胶原 (CoⅣ )及层黏素 (LM )在人慢性肝病和肝细胞癌 (HCC)的病理形态学改变 ,并探讨其临床病理意义。方法　对 30例人HCC及相应癌旁组织 ,10例肝硬化 ,5例轻度慢性肝炎和 4例正常肝组织进行了CD34、CoⅣ和LM的免疫组化检测 ,行半定量计数 ,系统地观察SEC及基膜成份在正常、慢性肝病和肝癌中的形态和数量的改变 ,并结合肝癌的临床病理资料进行分析。结果　正常肝窦无CD34及LM的表达 ,CoⅣ沿窦壁呈断续弱阳性表达 ,慢性肝病时可有少量CD34及LM弱阳性 ,肝硬化时CoⅣ阳性增强 ,沿窦壁呈均匀的连续线状阳性。HCC时窦壁呈弥漫的CD34阳性 ,同时CoⅣ及LM的阳性表达明显增强 ,在低分化癌及有门静脉癌栓的癌组织中基膜表达有所减少 ,易见断裂及缺失。LM、CoⅣ ,尤其是CD34的表达在癌组织与非癌性肝组织的表达差异有显著性。临床病理资料分析显示 ,瘤径 <2cm者CD34表达显著低于瘤径 >5cm者 ,CoⅣ的表达在HCC低分化组明显减少 ,有门静脉癌栓组CoⅣ和LM表达均有减少。结论　CD34是鉴别肝癌组织与非癌性肝组织的可靠指标。肝癌中基膜的断裂、缺失及减少可能参与癌细胞的转移机制 Objective To observe the pathomorphological changes of human chronic liver disease and hepatocellular carcinoma (HCC) in sinusoidal endothelial cells (SEC) and its basement membranes, and to explore its clinicopathological significance. . Methods Immunohistochemical detection of CD34, Co IV and LM were performed in 30 cases of human HCC and corresponding paracancerous tissues, 10 cases of cirrhosis, 5 cases of mild chronic hepatitis and 4 cases of normal liver tissue. Semi-quantitative counting was performed systematically. Changes in the morphology and number of SEC and basement membrane components in normal, chronic liver disease, and liver cancer, combined with the clinicopathological data of liver cancer were analyzed. Results Normal hepatic sinuses showed no expression of CD34 and LM. CoIV was intermittently expressed weakly along the sinus wall. In chronic liver disease, a small amount of CD34 and LM were weakly positive. CoIV was positive in liver cirrhosis and evenly continuous along the sinus wall. Positive. The sinus wall was diffusely positive for CD34 at the time of HCC, and the positive expression of CoMV and LM was significantly increased. The expression of basal lamina was decreased in poorly differentiated carcinoma and portal vein tumor thrombus, and it was easy to see rupture and absence. The expression of LM, CoIV, especially CD34, was significantly different between cancer tissues and non-cancerous liver tissues. Analysis of clinicopathological data showed that CD34 expression was significantly lower in tumor diameters <2cm than in those with tumor diameter >5cm. CoIV expression was significantly reduced in the HCC poorly differentiated group, and CoIV and LM expression was decreased in portal vein tumor thrombosis groups. Conclusion CD34 is a reliable indicator to identify hepatocellular carcinoma and non-cancerous liver tissue. The disruption, deletion and reduction of basement membrane in HCC may be involved in the metastasis mechanism of cancer cells