Superoxide dismutase (SOD1) and Lactate dehydrogenase (LDH) activities in breast cancer tissue
The antioxidant enzyme superoxide dismutase (SOD) activity was found to be higher in the tumor as compared to its surrounding (Fig-1a, SOD1). In essence, lactate dehydrogenase (LDH) is an enzyme necessary for the conversion of sugar into cellular energy. An elevated total serum SOD level is a predictor of tissue damage and inflammation (29). Another study has shown loss of LDH-B expression as an early and frequent event in human breast cancer (30). In our current study, we found the loss of LDH 3, 4 and 5 in breast cancer as compared to the surrounding whereas LDH 2 seems to be equally expressed both in the surrounding and the tumor. LDH has 2 subunits, subunit A and subunit B in different proportion in each type of LDH. In this study, we found that the expression of Subunit A is reduced or almost lacking in breast tumor. Therefore, the less is the expression of LDH 3, 4 and 5 in tumor tissue (Fig-1a).