Li H C
Cancer Institute, Chinese Academy of Medical Sciences, Beijing.
Zhonghua Zhong Liu Za Zhi. 1990 May;12(3):161-4.
Retinoblastoma gene (Rb) is a tumor suppressor gene. In 21 esophageal cancer and 43 pericancerous non-tumor samples obtained from patients who had undergone surgery for esophageal cancer in Linxian County, a high incidence area of esophageal cancer, Rb gene was studied. DNAs were extracted from the above esophageal tissues, then were separately digested with Hind III, EcoRI, BamHI, PstI, MspI, HpaII and subjected to Southern analysis. The Southern blots were sequentially probed with two fragments of Rb cDAN clone: 0.9 kb and 3.8 kb. Of 43 adjacent non-tumor tissues examined, 15 were found to have structural anomaly (34.9%). Seven of 21 esophageal cancers also showed structural anomaly (33.3%). In order to study the cause of Rb gene deletion, esophageal carcinoma of human fetal origin induced by N-methyl-N-benzylnitrosamine (NMBzA) in nude mice were similarly examined and found to be deleted of Rb gene. Thus, deletional inactivation of Rb gene may play an important role in the pathogenesis of esophageal cancer in this high-risk area. N-nitrosamine may play a causative role in deletion of Rb gene. The above data for the first time demonstrate structural anomaly of Rb gene in esophageal cancer and confirm that chemical carcinogens, such as N-nitrosamines, can delete the antioncogene.
视网膜母细胞瘤基因（Rb）是一种肿瘤抑制基因。在食管癌高发区林县，从接受过食管癌手术的患者身上获取了21份食管癌组织样本和43份癌旁非肿瘤组织样本，对Rb基因进行了研究。从上述食管组织中提取DNA，然后分别用Hind III、EcoRI、BamHI、PstI、MspI、HpaII进行酶切，并进行Southern分析。Southern杂交膜依次用Rb cDNA克隆的两个片段：0.9 kb和3.8 kb进行探针杂交。在检查的43份相邻非肿瘤组织中，发现15份存在结构异常（34.9%）。21份食管癌组织中有7份也显示出结构异常（33.3%）。为了研究Rb基因缺失的原因，对用N-甲基-N-苄基亚硝胺（NMBzA）诱导的人胎儿源性食管癌裸鼠模型进行了类似检查，发现存在Rb基因缺失。因此，Rb基因的缺失失活可能在这个高危地区食管癌的发病机制中起重要作用。N-亚硝胺可能在Rb基因缺失中起致病作用。上述数据首次证明了食管癌中Rb基因的结构异常，并证实了化学致癌物如N-亚硝胺可导致抗癌基因缺失。
