应用双重原位杂交研究myc,ras癌基因在人肝细胞癌中的表达特征

目的： 建立非同位素双重原位杂交技术,以便在单细胞水平时显示两种不同的癌基因杂交信号,验证“癌变多步骤”学说。结论：肿瘤的性涉及多种癌原激活,激活是有次序性的,首先是ｒａｓ的“启动”激活,至于具体哪一种ｒａｓ似乎无关紧要,而ｍｙｃ的激活应是癌变过程较晚期的重要步骤。该观点似可部分修正“癌变多步骤”学说,即修正有关“癌基因激活的次序似乎并不重要的”论断,

Expressions of myc and ras gene in human hepatocellular carcinoma by applying the double in situ hybridization

Objective:To establish a method of non-isotope double in situ hybridization in order to detect the expression of two kinds of oncogenes at a single cell level simultaneously,and confirm the hypothesis of "model of stepwise carcinogenesis".Methods:The method of non-isotope doulbe in situ hybridization was established with the digoxigenin(Dig) and biotint(Bio) labeled probes.The expression of two members of oncogenes of the myc and/or ras gene families(myc and N-ras,myc and K-ras,myc and H-ras ,N-ras and K-ras, N-ras and H-ras,K-ras and H-ras) was further studied with the method in 10 cases of Chinese Hepatocellular Carcinomas(HCC).Results:Co-expression of two kinds of oncogenes was detected only in a few cases,reflected by co-showing two different hybridization signals,i. e.,co-showing of Dig-myc and Bio-H-ras,Dig-myc and Eio-N-ras , Dig-myc and Bio-K-ras was observed in 2 cases , 2 cases and one case ,respectively. The common characteristics were that positive cells of myc distributed diffusely, while positive cells of ras distributed sporadically or locally among the positive cells of myc,and only a few cells exibited co-showing of two oncogenes at a single cell level. There were only 2 cases representing co-showing of two oncogenes in ras gene family (Dig-N-ras and Bio-H-ras , Dig-N-ras and Bio-Kras,respectively).The two kinds of positive cells of different ras gene represented mixed local andsporadical distribution.and co-showing of two signals was found in a few cells at a single cell level. Conclusion: There are multiple oncogenes involving in tumorigenesis by their ordered activation. The activation of the ras gene family plays a role in promotion,while the activation of myc is an important event in late stage of tumorigenesis.