首次选取ＮＩＨ３Ｔ３细胞，对比检测外源性和致癌、促癌剂使细胞发生转化的能力。结果表明，单独作用组较正常对照组和启动剂量Ｂ（ａ）Ｐ单独作用组之转化率提高了近３倍；当与启动剂量Ｂ（ａ）Ｐ协同作用时，转化率较上述两组分别提高了约１１倍和１０倍；而用ＳＯＤ和ＣＡＴ清除胞外时，转化率下降了８２％。以上结果提示外源性可作为完全致癌剂尤其是促癌剂起作用，ＳＯＤ和ＣＡＴ对的转化有抑制作用。 For the first time, NIH3T3 cells were selected for comparative detection of the ability of exogenous and carcinogenic, cancer-promoting agents to transform cells. The results showed that the conversion rate of the single-acting group was nearly 3 times higher than that of the normal control group and the starter dose B(a)P alone group; when compared with the starter dose B(a)P, the conversion rate was higher than that of the above two groups. Increased about 11-fold and 10-fold; while using SOD and CAT to remove extracellular, the conversion rate decreased by 82%. The above results suggest that exogenous can act as a complete carcinogen, especially a carcinogen, and inhibit the conversion of SOD and CAT.