胃癌细胞表面α2,3唾液酸糖链结构的检测及意义

Detection of Linked Sialic Acid Residues in Human Gastric Adenocarcinoma and Its Significance

目的:检测胃癌组织中能与植物凝集素MAL(Maackia amurensis leukoagglutinin)特异性识别的糖蛋白末端糖链结构α2,3唾液酸残基,探讨这种糖链结构与胃癌患者临床病理学特征之间的关系。方法:采用凝集素组织化学染色法,检测55例胃腺癌组织及40例大肠癌组织(20例结肠癌,20例直肠癌)石蜡标本切片中α2,3唾液酸残基结构,通过对比分析,探讨这种糖链结构在胃癌细胞表面出现的特异性及其意义。通过计算MAL结合阳性率(MI),采用半定量法评价这种糖链结构与胃癌患者临床病理学特征之间的关系。结果:55例胃癌组织均呈现MAL阳性染色,尽管其显色位置及MI有所不同。在胃癌组织中,MAL仅在胃癌区域内有显色,而在癌旁相对正常组织内无显色。且MI与胃癌的侵袭深度显著相关,在T3、T4阶段明显高于T1、T2阶段(P=0.0024)。此外,α2,3唾液酸残基表达量与胃癌的分化程度相关,在低分化的胃癌组织中显著高于高、中分化的胃癌组织(P=0.0323)。另外,α2,3唾液酸残基结构与胃癌患者的年龄及性别无关。而在大肠癌组织中,MAL在癌组织及癌旁相对正常组织内均有显色,正常肠粘膜的吸收细胞及杯状细胞也呈现MAL着色。结论:胃癌细胞表面存在MAL特异性识别与结合的糖蛋白糖链结构α2,3唾液酸残基;这种糖链结构可能是一种有价值的胃癌病理学指标。

Objective： To examine the terminal carbohydrate structure a 2, 3-1inked sialic acid residues of glycoprotein in human gastric adenocarcinoma using plant lectin Maackia amurensis leukoagglutinin （MAL） and to estimate the relationship between 0 2, 3-1inked sialic acid residues and clinicopathological characteristics in patients with gastric adenocarcinoma. Methods： a 2, 3-1inked sialic acid residues in tissue samples of 55 cases of gastric adenocarcinoma and 40 cases of colorectal carcinoma （20 cases of colon carcinoma and 20 cases of rectal carcinoma） were evaluated using MAL histochemical staining. The relationship between a 2, 3-linked sialic acid residues and clinicopathological characteristics in patients with gastric adenocarcinoma was determined by calculating the percentage of MAL-positive tumor cells with respect to the MAL-staining index （MI）. Results： All 55 of the gastric adenocarcinoma samples displayed positive staining with MAL. MAL-positive staining was only detected in the regions of gastric cancer and was not found in adjacent normal regions. MAL staining was significantly associated with depth of invasion and differentiation of gastric tumors. The expression of α 2, 3-linked sialic acid residues was higher in T3 and T4 stages than in T, and T2 stages （P= 0.0024） and was higher in poorly differentiated cancers than in well or moderately differentiated cancers （P= 0.0323）. The intensity of a 2, 3-1inked sialic acid residues was not correlated with age or gender. In contrast, both colorectal carcinoma regions and normal colorectal mucosa regions showed MAL-positive staining. In areas of normal mucosa, positive staining was Iqcated on the cell surface of absorptive enterocytes, mucus of goblet cells, and submucosal regions. Conclusion： Alterations of sialylation detected by MAL exist in human gastric adenocarcinoma. High levels of α 2, 3-linked sialic acid residues seem to be closely associated with unfavorable behaviors of human gastric adenocarcinoma, α 2, 3-linked sialic acid residues might be a useful pathological index for diagnosis and prognosis of human gastric adenocarcinoma.