The cell cytosol superoxide dismutase (SODase) content of 46 human tumors was investigated. The extraction procedure of McCord and Fridovich was used with the epinephrine assay of Misra and Fridovich (J. Biol. Chem., 247: 3170–3175, 1975). The purpose of the study was to determine whether SODase could be reliably assayed from small, biopsy-sized pieces of tumor (0.5 to 1.0 g). In most cases it was possible to examined larger masses of tumor, which served as a control of the methodology. In this preliminary study SODase values, calculated from a standard curve derived from purified bovine blood SODase with a specific activity of 2584 units/mg, ranged from as little as 0.23 to as much as 160.5 units/g of tumor. These findings suggested that the procedures used might be feasible on a routine basis to determine the SODase content of tumors and its possible relationship to the radiation sensitivity of the tumors.
Supported in part by the Albert Soiland Cancer Foundation and by the S. K. Wellman Foundation.