Tumor growth can often induce signs of oxidative stress in host organism. To assess the situation as for melanoma, the oxidative stress markers (specific malondialdehyde-thiobarbituric acid complexes: MDA-TBA; and less specific thiobarbituric acid reactive substances: TBARS) were measured in sera, liver and tumors of B16- and Cloudman S91- bearing mice and compared to those of control animals. The MDA-TBA levels (unlike TBARS) in the sera and liver of melanoma-bearing mice were significantly lower compared to controls. In addition, a significantly higher concentration of vitamin E was found in the blood and liver of both melanoma models compared to controls. Contrary to expectation, it appears that melanoma-bearing mice are able to suppress the level of lipid peroxidation. The free radical balance in melanoma-bearing hosts is unique and differs from other tumor types. This should be taken into consideration when designing a human melanoma therapy.
Free radical balance; Lipid peroxidation; Melanoma; Oxidative stress; Vitamin E