Expression of antioxidant enzymes in human prostatic adenocarcinoma

Antioxidant enzymes (AEs), which catalyze the conversion of reactive oxygen species (ROS) to water, include catalase (CAT), manganese-containing superoxide dismutase (MnSOD), and copper and zinc-containing superoxide dismutase (CuZnSOD). Previous work has indicated that MnSOD, CAT, and CuZnSOD levels are nearly always low in cancer cells.

Formalin-fixed, paraffin-embedded tissue from 31 radical prostatectomy specimens was immunohistochemically stained with polyclonal antibodies to CAT, MnSOD, and CuZnSOD.

Malignant glands are typically stained with less intensity than benign/ hyperplastic glands. Marked heterogeneity of staining intensity was seen in the malignant glands for each of the three enzymes. A similar, though less marked, spectrum of heterogeneity of staining intensity was observed in the benign/hyperplastic epithelium contained in the specimens. No statistically significant correlation was found between intensity of staining for any of the three antioxidant enzymes and Gleason score, tumor stage, or preoperative prostate-specific antigen (PSA).

Cellular levels of CAT, MnSOD, and CuZnSOD in prostatic adenocarcinoma reveal that many tumors appear to have decreased levels of expression. The finding that malignant prostate epithelium may have lowered expression of AEs suggests that further study of the role of AEs in malignant transformation in the prostate is warranted.