Methyl groups or additional aromatic groups donate tumour promoting activity.

Abstract

There are many examples in chemical carcinogenesis in which the introduction of methyl groups or aromatic rings increased the potency of polycyclic hydrocarbons and aromatic amines. Examination of the data in the light of the multistage process of carcinogenesis indicates that these groups convert initiators into complete carcinogens. As complete carcinogens have both initiating and promoting action, the added groups may be considered to have donated tumour promoting activity to the molecule. Such groups were once called auxocarcinogens.1