[Activation of the Ha-ras oncogene in tumors induced in mice by transplacental exposure to 7,12-dimethylbenz(a)anthracene].

A study of tumors induced in mice by transplacental exposure to 7,12-dimethylbenz(a)anthracene (DMBA) alone or in combination with postnatal tissue-specific promotion showed skin and liver tumor development to be associated with cellular Ha-ras oncogene activation in a large percentage of cases. As shown by Xba I RFLP, oncogene activation was caused by T for A substitution at the second position of codon 61. The said mutation was traced in DMBA-induced tumors of the liver alone but not in spontaneous hepatomas. The results of the study showed the role of oncogene activation in cancer development to be tissue-specific.