Analysis of the expression of cell cycle regulating genes in gastrointestinal tumors

细胞周期调控基因的表达。免疫组化和Western blotting分析正常粘膜、增生、腺瘤、腺瘤中癌和晚期结直肠癌中的阳性调节因子：G1细胞周期蛋白（cyclin D、E）、细胞周期蛋白依赖激酶（CDK2、4），阴性调节因子：CDK抑制剂（CDK4I/pI6）、RB。在正常粘膜中，每种蛋白仅在腺体底部的少数细胞中检测到。在增生性粘膜中，从腺体底部开始的上部细胞中大量检测到cyclin D和E的表达。在腺瘤中，经常检测到这些蛋白的过表达。cyclin D: 55/66 (83%), cyclin E: 42/50（84%）。在腺瘤癌中，我们注意到CDK2、p16和RB以及细胞周期蛋白D、E的过表达，例如。， cyclin D: 8/8 (100%), cyclin E: 13/13 (100%), CDK2: 10/12 (83%), p16: 10/14 (71%), RB: 10/12（83%）。最后，在晚期癌症中，所有的蛋白质都过度表达，例如。cyclin D: 2…More 6/45 (58%), cyclin E: 41/45 (91%), CDK2: 34/45 (76%), CDK4: 39/45 (87%), p16: 59/60 (98%), RB: 34/45 （76%）Western blotting定量分析进一步证实，这些蛋白在结肠癌中的表达比正常粘膜高几倍。此外，与正常粘膜相比，RB过磷酸化（失活）形式的比率高出1.46倍。相邻切片免疫组化对比分析发现，过表达RB的癌细胞也过表达cyclin E/CDK2，过表达CDK4的癌细胞也过表达p16。综上所述，在基于腺瘤-癌序列的多阶段结肠癌发生过程中，cyclin D和E在增生或腺瘤阶段过表达，CDK2和CDK4I/p16在腺瘤癌阶段过表达，CDK4在晚期癌阶段过表达。因此，我们认为细胞周期调节因子如G1周期蛋白、CDKs和CDK抑制剂的表达深入参与结肠癌的发生。并且，cyclin E/CDK2的过表达被认为参与RB蛋白的过度磷酸化。少

The expression of cell cycle regurating genes, eg., positive regulators : G1 cyclins (cyclin D,E), cyclin dependent kinases (CDK2,4), negative regulators : CDK inhibitor (CDK4I/pI6), RB,in normal mucosa, hyperplasia, adenoma, carcinoma in adenoma and advanced carcinoma of colorectum was analyzed by immunohistochemistry and Western blottings. In normal mucosa, each protein was detected only in a few cells of bottom parts of the gland. In hyperplastic mucosa, the expression of cyclin D and E was detected in large number of cells of upper parts from the bottom of the gland. In adenomas, the overexpression of these proteins are frequently detected, eg., cyclin D : 55/66 (83%), cyclin E : 42/50 (84%). In carcinoma in adenoma, the overexpression of CDK2, p16 and RB,as well as cyclin D,E,was noted, eg., cyclin D : 8/8 (100%), cyclin E : 13/13 (100%), CDK2 : 10/12 (83%), p16 : 10/14 (71%), RB : 10/12 (83%). Finally, in advanced carcinomas, all the proteins were overexpressed, eg., cyclin D : 2 … More 6/45 (58%), cyclin E : 41/45 (91%), CDK2 : 34/45 (76%), CDK4 : 39/45 (87%), p16 : 59/60 (98%), RB : 34/45 (76%). The quantitative analysis by Western blottings further confirmed a few times higher expression of these proteins in colon carcinomas compared to normal mucosa. Also, the rate of hyperphosphorylated (inactivated) form of RB was shown to be 1.46 times higher compared to normal mucosa. The comparative analysis using immunohistochemistry on the adjacent sections revealed that the cancer cells overexpressing RB also overexpressed cyclin E/CDK2 and those overexpressing CDK4 also expressed p16. In summary, during the multistep colon carcinogenesis based on adenoma-carcinoma sequence, cyclin D and E are overexpressed from the stage of hyperplasia or adenoma, CDK2 and CDK4I/p16 are overexpressed from the stage of carcinoma in adenoma, and CDK4 is overexpressed at the stage of advanced carcinoma. Thus, it was suggested that the expression of cell cycle regulators such as G1 cyclins, CDKs and CDK inhibitors are deeply involved in colon carcinogenesis. And, the overexpression of cyclin E/CDK2 was thought to be involved in hyperphosphorylation of RB protein. Less