The Carcinogenicities of Fluoro Derivatives of 10-Methyl-1,2-benzanthracene II. Substitution of the K Region and the 3′-, 6-, and 7-Positions

Abstract

Substitution of fluorine in the 4 position of the K region of 10-methyl-1,2-benzanthracene had little effect on the carcinogenic activity of this hydrocarbon toward mouse skin and the subcutaneous tissues of rats and mice. These results are in great contrast to our previously reported data on the lack of carcinogenic activity in the same tests of the 3-fluoro derivative which contains the fluorine substituent on the other carbon atom of the K region. Each of the 3′-, 6-, and 7-fluoro derivatives of 10-methyl-1,2-benzanthracene had considerable carcinogenic activity in two or more of the four tests employed, and therefore these positions do not appear to be directly involved in the carcinogenic activity of this hydrocarbon. 1,2-Benzanthracene and its 3-fluoro derivative exhibited little or no activity in these tests. 4′-Fluoro-1,2-benzanthracene had considerable carcinogenic activity toward the subcutaneous tissue of rats. The role of the K region in carcinogenesis by the polycyclic aromatic hydrocarbons has been reviewed. Where adequate tests have been made, the 3-substituted compounds have generally had little or no activity, whereas the 4-substituted compounds are, in some cases, relatively active. These data and the carcinogenic activities of some sulfur isosters which do not appear to contain a K region (Waravdekar and Ranadive; Tilak) clearly indicate the need for further studies in this area.