Identification of a Chromosome Carrying a Putative Tumor Suppressor gene in Human Choriocarcinoma by Microcell-Mediated Chromosome Transfer.

完全葡萄胎的形成有两种主要机制；A)一个单倍体精子使一个空卵子受精，然后进行复制；b)两个单倍体精子使一个卵子受精。人们普遍认为，在所有形式的怀孕中，与绒毛膜癌相关的痣的风险是迄今为止最高的。鼹鼠隐性突变的纯合子表达被认为与这种恶性肿瘤的倾向有关。一些肿瘤抑制基因的改变和癌基因的激活被认为是绒毛膜癌发生的必要条件。痣中显示的遗传特征表明，前者的改变对于探索向恶性肿瘤的多步骤转化尤为重要。因此，来自正常细胞的单个染色体通过微细胞融合被引入绒毛膜癌细胞。微细胞杂交种的致瘤性评价表明，7号染色体携带一种推测的绒毛膜癌肿瘤抑制基因。基因印记或隐性突变可能是导致这种基因失活的原因。能够与痣的高恶性倾向相对应。现在，可以产生正常的7号染色体特有的cDNA表达自由。利用正常绒毛和CCI绒毛膜癌mRNA探针进行集落杂交，并进行自杀选择克隆，可以克隆绒毛膜癌的抑癌基因。

There are two main mechanisms of origin for complete hydatidiform mole ; a) fertilization of an empty egg by a haploid sperm followed by duplication and b) fertilization of such an egg by two haploid spermatozoa. It is widely accepted that of all forms of pregnancy that had to choriocarcinoma the risk associated with moles is by far the highest. Homozygous expression of a recessive mutation of moles has been assumed to associate with this propensity to malignancies.Alterations of several tumor suppressor genes together with activation of oncogenes are assumed to be necessary for choriocarcinogenesis. Genetic characteristics shown in the moles suggest that the former alterations are especially important to explore the multistep conversions to malignancies. Thus, individual chromosomes derived from normal cells were introduced into choriocarcinoma cells via microcell fusion. Evaluation of tumorigenicity in microcell hybrids suggested that chromosome #7 carried a putative tumor suppressor gene for choriocarcinoma. The gene imprinting or recessive mutation mmy be responsible for the inactivation of such a gene. Being able to correspond with the high propensity to malignancy of moles. Now, the cDNA expression liberaties specific to the normal #7 chromosome could be produced. Colony hybridization using mRNA probes obtained from normal villi and CCI choriarcinoma in addition to suicide selection cloning the revertant will be able to clone the tumor suppressor genes of choriocarcinoma.