EXPRESSION OF CUZN-SUPEROXIDE AND MN-SUPEROXIDE DISMUTASE IN HUMAN COLORECTAL NEOPLASMS

Decreased intracellular SOD protein levels and activity have been rela ted with malignancy in the past. To investigate their relevance in the carcinogenetic process in the colon, we determined quantitatively CuZ n-SOD and Mn-SOD levels and total SOD activity by histochemical means in human normal colorectal mucosa, adenomas, and carcinomas. Protein l evels and activity were significantly decreased in carcinomas. CuZn-SO D protein levels, but not Mn-SOD levels or total SOD activity were rel ated with differentiation grade and to a lesser extent with Dukes stag e. Moderately differentiated carcinomas and Dukes stage A carcinomas s howed lowest levels. Some carcinomas expressed elevated levels of CuZn -SOD and this was an indication of poor survival. It is concluded that decreased SOD expression is not a prognostic marker and seems to be a secondary phenomenon rather than directly linked with the carcinogene tic process. (C) 1997 Elsevier Science Inc.