ABSTRACT
Erythrocyte Cu/Zn superoxide dismutase [SOD] plays an important role in protecting cells from injury due to oxidative stress hence the role of SOD in cancer has been suggested [Oberley et al, 1979].The present study was done aiming to assess erythrocyte Cu/Zn SOD activity in some gastro-intestinal malignancies. These included 55 patients classified into hepatocellular carcinoma group [HCC; n= 25], and early colorectal cancer group [early CRC; n = 30], and in addition a group of 10 apparently healthy adults [control group] of matched age and sex was selected. Erythrocyte Cu/Zn SOD activity was determined by spectrophotometric method. The results revealed significant decrease of SOD activity in HCC before surgery as compared to their respective values in control group. Surgery induced insignificant increase of erythrocyte SOD activity in these patients. In early CRC group, LDH,CEA and erythrocyte Cu/Zn SOD levels was significantly increased in comparison to control group; however the levels of these parameters were decreased to normal range after surgical resection. In conclusion, SOD activity varies according to the cell type malignancies but in all of them reflect response of tumor to therapy