肿瘤相关抗原LEA的表达及其在病理诊断中的意义

背景与目的：目前,大肠癌诊断的肿瘤标志物如CEA（carcinoembryonic antigen)等,对大肠癌患者的特异性不强,用于早期诊断价值不高,研究表明LEA（large external antigen)对大肠癌组织有极好的特异性,本研究应用抗LEA单抗ND－1和抗CEA单抗对大肠癌组织的对比,探讨LEA在大肠癌中的表达及其临床病理诊断意义。方法：采用免疫组织化学S－P法检测170例大肠癌组织和100例大肠非癌组织（41例大肠腺瘤,32例癌旁粘膜,27例正常粘膜）LEA与CEA的表达,结果：LEA在高、中、低分化腺癌组织中表达阳性率分别为100％,83．1％和51．8％,而CEA分别为93．8％,92．3％,和70．4％,LEA大肠腺瘤,癌旁粘膜和正常粘膜中表达阳性率分别为75．6％,53．1％和14．8％,而CEA分别为82．9％,62．5％和40．7％,LEA对高分化腺癌表现出更高的选择性（P＜0．01）,CEA单抗对高、中、低分化腺癌选择性相似（P＞0．05）,与CEA相比,LEA在非癌组织中表达的阳性率较低（P＜0．05）,LEA与CEA的表达除在正常为膜外均有显著的相关性,LEA与CEA在组织学上诊断大肠癌的灵敏度分别为84．1％和88．8％,而特异度分别为48％和35％,结论：LEA可能是一种与细胞分化,侵袭能力相关的肿瘤抗原,LEA可用于大肠癌恶性程度判断的参考指标,是具有临床实用价值的肿瘤生物标记物。

Expression of tumor-associated antigen LEA and its significance for pathological diagnosis

Background &Objective:Tumor marker,such as carcinoembryonic antigen (CEA),has low specificity in colorectal carcinoma diagnosis with lower value in early diagnosis of colorectal carcinoma. The previous studies showed that large external antigen (LEA) had high specificity for colorectal carcinoma tissue . This study was designed to evaluate the expression of colorectal carcinoma associated antigen LEA in colorectal carcinoma and its significance for pathological diagnosis through the comparison of a new monoclonal antibody(ND 1) and anti CEA monoclonal antibody in colorectal carcinoma tissue. Methods: Expression of LEA in 170 colorectal cancer specimens, 41 colorectal adenomas, 32 surrounding non cancerous large intestine tissues,and 27 normal mucosa specimens were detected with immunohistochemistry S P method. Results: In the well, moderately,and poorly differentiated colorectal cancer,the positive rate of LEA was 100%,83.1%, and 51.8%,respectively;CEA was 93.8%,92.3%, and 70.4%,respectively. In adenoma, surrounding non cancerous mucosa, and normal mucosa, the positive rate of LEA was 75.6%, 53.1%,and 14.8%, while CEA was 82.9%, 62.5%, and 40.7%,respectively.The expression of LEA exhibited higher selectivity in well differentiated adenocarcinoma (P< 0.01). CEA had similar selectivity in well, moderately,and poorly differentiated adenocarcinoma(P< 0.05). Compared with CEA,the expression of LEA had lower positive rate in non cancerous tissue(P< 0.05). The expression of LEA and CEA showed significant correlation except in normal mucosa. In histological diagnosis of colorectal cancer the sensitivity of LEA and CEA were 84.1%and 88.8%,respectively,the specificity were 48%and 35%,respectively. Conclusions:LEA may be a tumor antigen that is related to cell differentiation and invasiveness. LEA can be used as a reference to the judgement of the malignancy degree of colorectal carcinoma. So it is a biological tumor marker with clinic value.