Free radical increases in cancer: evidence that there is not a real increase.

The controversial finding of an increase in free radicals with the development of cancer was restudied with Walker 256 carcinosarcoma cells. It was confirmed that such an increase appears to occur, but it was also demonstrated that it is not a real increase. With growth of the tumor, the electron spin resonance lines for lyophilized samples became narrower, resulting in an increase in peak-to-peak height measurements, but there was no change in the total number of spins. The signals for lyophilized tumor samples were different from those for the same samples before lyophilization. Changes in line shape indicated that lyophilization. Changes in line shape indicated that lyophilized tumor samples contain a different mixture of radicals than lyophilized samples of normal tissue.