Long-term effects of flavone acetic acid on the growth of a rat tumour.

A rat tumour (MC7 sarcoma), growing subcutaneously, has been shown to be sensitive to a single application of flavone acetic acid. Thirteen rats were still alive after 50 days and 8 of these were tumour free, as compared with control rats which survived for 15.7 +/- 2.53 days. The 8 tumour free animals were rechallenged with MC7 sarcoma 40 weeks later, without further FAA treatment. The tumour grew initially but in all cases the animals became tumour free within 24 days. After a further 30 days they were rechallenged with D23 hepatoma which grew as effectively as in the controls.