胃癌及癌前期病变粘膜芳香基酰胺酶同工酶的表达意义

Expression of arylamidase isoenzyme in gastric carcinoma and precancerous lesions

目的探讨胃癌及癌前期病变粘膜芳香基酰胺酶（ＡＡＤ）同工酶的表达规律，寻找癌前期病变及早期癌的标志物．方法采用本室建立的圆盘等电聚焦电泳（ＣＩＥＦ）分离１２２例各种胃病粘膜（胃癌４１例，浅表性胃炎４８例，萎缩性胃炎３０例，胃溃疡８例，其中伴肠化１９例，异型增生８例）中ＡＡＤ同工酶．以６０ｇ／Ｌ丙烯酰胺作支持递质，ｐＨ３５～５０和ｐＨ３５～１００两种载体两性电解质建立ｐＨ梯度，加匀浆液５０μｌ，阴极及阳极电极液分别用０２ｍｏｌ／ＬＮａＯＨ和０５ｍｏｌ／ＬＨ３ＰＯ４，恒压电泳（１０℃）１８ｈ后以亮氨酰β萘胺作为基质呈色．结果ＡＡＤ分为８条区带，从阳极到阴极依次命名为ＡＡＤⅠ～ＡＡＤⅧ，其中ＡＡＤⅣ主要见于胃癌（９０２％），不完全大肠型肠化（８６７％）和异型增生（７５０％）；而不伴有肠化或异型增生的良性胃病和正常胃中则未发现．ＡＡＤⅣ的阳性率与胃癌病理类型、细胞分化程度及临床分期无相关，且ＡＡＤⅣ等电点和胎盘型ＡＡＤ等电点相当．结论ＡＡＤⅣ是一种癌胚蛋白，即胃癌组织特异性同工酶，是癌前期病变及早期癌的标志物．

AIM To study the expression of arylamidase (AAD) isoenzyme in gastric carcinoma and precancerous lesions and to seek a marker for precancerous lesions and early gastric carcinoma. METHODS Using cylindrical isoelectric focusing (CIEF) electrophoresis designed by our laboratory, gastric mucosa arylamidase in 122 cases was studied. Acrylamide of 60g/L was used as supporting media, pH gradient was set up by pH 3 5-5 0 and 3 5-10 0 ampholytes, then added with 50μl homogenate solution, and 0 2mol/L NaOH and 0 5mol/L H 3PO 4 were used as solutions of the negative and the positive poles. After electrophoresis for 18h, leucyl β naphamide served as the substance for coloration. RESULTS Gastric mucosa AAD was separated into eight isoforms by CIEF, which were named AADⅠ AADⅧ from anode to cathode. AADⅣ was mainly present in gastric carcinoma (90 2%), incomplete large bowel type metaplasia (86 7%) and dysplasia (75 0%), but was not present in benign gastropathies without intestinal metaplasia and dysplasia and in normal gastric mucosa. There was no correlation among AAD Ⅳ, pathological type, cell classification and clinical staging in gastric carcinoma. AAD Ⅳ was the same as placental type AAD in isoelectric point. CONCLUSION AAD Ⅳ is a carcinofetal protein and a specific isoenzyme of gastric carcinoma, and can be regarded as a marker for precancerous lesions and early gastric carcinoma.