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将单纯疱疹病毒胸苷激酶基因（ＨＳＶ－ｔｋ）导入恶性肿瘤细胞，随后可应用药物丙氧鸟苷（ｇａｎｃｉｃｌｏｖｉｒ， ＧＣＶ）选择性杀死肿瘤细胞．构建了含胸苷激酶与潮霉素磷酸转移酶（ｈｐｈ）融和基因（ＨｙｔＫ）的真核表达载体ＬＸｐｓｐ－ＨｙｔＫ．以脂质体（ｌｉｐｏｆｅｃｔｉｎ）为介导，将这种质粒与仅含潮霉素Ｂ基因的质粒ＬＸＳＨ 分别转染胃癌细胞系ＢＧＣ－８２３，用６０ Ｕ／ｍ ｌ潮霉素Ｂ进行筛选，得到了可稳定传代的阳性克隆，分别命名为ＢＧＣ－ＨｙｔＫ 和ＢＧＣ－Ｈｙ．三种细胞的生长曲线无明显差别．用不同浓度的ＧＣＶ 分别作用于ＢＧＣ－ＨｙｔＫ， ＢＧＣ－Ｈｙ 及ＢＧＣ－８２３，０．０２～２００ μｇ／ｍ ｌ 的ＧＣＶ 对ＢＧＣ－ＨｙｔＫ 细胞有明显的杀伤作用（ＩＣ５０＝ ０．０２ μｇ／ｍ ｌ），而对另外两种细胞几乎无毒性作用（ＩＣ５０＞ ２００μｇ／ｍ ｌ）．２０ μｇ／ｍ ｌＧＣＶ 作用９６ ｈ 后，仅存在２０％ 的ＢＧＣ－ＨｙｔＫ 就可使周围的大部分ＨＳＶ－ｔｋ－ 的肿瘤细胞死亡，说明存在较显著的“旁观者效应”
Herpes simplex virus thymidine kinase gene (HSV-tk) was introduced into malignant cells, and then the drug ganciclovir (GCV) was used to selectively kill tumor cells. An eukaryotic expression vector LXpsp-HytK containing thymidine kinase and hygromycin phosphotransferase (hph) fusion gene (HytK) was constructed. Using lipofectin as a mediator, this plasmid was transfected into the gastric cancer cell line BGC-823 with the plasmid LXSH containing only the hygromycin B gene and screened with 60 U/ml hygromycin B. Positive clones that can be stably passaged are named BGC-HytK and BGC-Hy. There was no significant difference in the growth curves of the three cells. Different concentrations of GCV were applied to BGC-HytK, BGC-Hy and BGC-823, respectively, and GCV of 0.02-200 μg/ml had significant killing effect on BGC-HytK cells (IC50= 0.02 μg/m). l), with almost no toxic effects on the other two cells (IC50> 200 μg/ml). After 20 μg/ml GCV for 96 h, the presence of only 20% of BGC-HytK killed most of the surrounding HSV-tk-tumor tumor cells, suggesting a significant “bystander effect”.