Methylating and ethylating carcinogens have different requirements for poly(ADP-ribose) synthesis during malignant transformation.

Transformation of mouse C3H 10T1/2 cells by various alkylating carcinogens can be modulated by inhibiting poly(ADP-ribose) synthesis with a low concentration of 3-amino-benzamide, which induces no additional toxicity or reported side effects. Transformation by methylating agents was decreased by 3-aminobenzamide, whereas transformation by ethylating agents was increased. These results confirm earlier work on transformation by methylating agents, X-rays and u.v. light. Transformation by ethylating agents, however, appears to proceed by a different mechanism.