Tumor-initiating activity of quinoline and methylated quinolines on the skin of SENCAR mice.

Quinoline and all 7 positional isomers of methylquinoline were assayed for tumor-initiating activity on the skin of SENCAR female mice with promotion by tetradecanoyl phorbol acetate. The total initiation dose of either quinoline or the isomeric methylquinolines was 7.5 mg per mouse. Quinoline induced tumors in 53% of the mice (0.73 tumors per animal). While 2-, 3-, 5- and 7-methylquinoline did not exhibit significant tumorigenic activity in this assay, 4-methylquinoline induced tumors in 45% of the mice (0.90 tumors per animal). 8-Methylquinoline induced tumors in 45% of the mice (0.66 tumors per animal).