Regulatory role of p53 in cancer metabolism via SCO2 and TIGAR in human breast cancer.

Cancer cells show a higher rate of anaerobic respiration than normal cells. The exact mechanisms for this higher glycolysis rate in cancer cells remain to be elucidated. The results of recent studies have indicated that p53, the most commonly mutated tumor suppressor gene, may have important functions in the regulation of energy-generating metabolic pathways that switch from oxidative phosphorylation to glycolysis via the synthesis of cytochrome c oxidase 2 (SCO2), p53-transactivated TP53-induced glycolysis (TIGAR), and apoptosis regulator. We evaluated the expression of p53, SCO2, TIGAR, and COX in 113 cases of invasive breast cancer using immunohistochemistry. A high expression of p53, SCO2, TIGAR, and COX was noted in 27.5% (31 cases), 84.1% (95 cases), 74.3% (84 cases), and 73.4% (83 cases) of the breast tumors, respectively. A high p53 expression was significantly associated with low expression levels of SCO2 (P = .008), COX (P < .0001), and TIGAR (P = .007). On the survival analysis, the low SCO2-expressing breast cancer patients showed a significantly poorer prognosis than that of the high SCO2-expressing breast cancer patients (P = .0078). These results suggest that p53 can modulate the metabolic pathways via the proteins SCO2 and TIGAR in human breast cancer.