用新建立的抗白喉毒素突变型检测系统研究维生素A及其四种衍生物在化学诱变作用中的遗传学效应,并与姊妹染色单体互换频率指标进行比较,结果表明A类维生素具有抑制由间接诱变剂诱发的抗白喉毒素突变型频率和姊妹染色单体互换频率的作用.因此,A类维生素的抗肿瘤特性可能并不仅局限于其作用在肿瘤形成的第二步,也可作用在肿瘤形成的第一步(启动阶段). The genetic effects of vitamin A and its four derivatives in chemical mutagenesis were studied using the newly established detection system for diphtheria toxin mutants and compared with sister chromatid exchange frequency markers. The results showed that vitamin A has Inhibition of the diphtheria-toxin-mutant frequency induced by indirect mutagens and the role of sister chromatid exchange frequencies. Therefore, the anti-tumor properties of class A vitamins may not be limited to their role in the second step of tumor formation, but also Can act on the first step of tumor formation (initiation stage).