Many key oncogenic signaling pathways converge to adapt to tumor cell metabolism . Hence, alterations in cellular metabolism should be considered a crucial hallmark of cancer. Cancer cells acquire alterations during carbohydrate, protein, lipid, and nucleic acid metabolism. The best characterized metabolic phenotype that was observed in tumor cells is the Warburg effect. Warburg demonstrated that cancer cells metabolized more glucose than normal cells, with enhanced aerobic glycolysis and pyruvate production [22, 23]. Furthermore, glutaminolysis is enhanced in cancer cells to supplement tricarboxylic acid cycle metabolites . ALT, which catalyzes the conversion of pyruvate and glutamate to alanine and α-ketoglutarate , functions in both glycolysis and glutaminolysis. Therefore, compared with serum AST levels, serum ALT level decreases (increased AST/ALT ratio) could be a manifestation of enhanced metabolism and consumed ALT in aggressive cancer cells; Conde et al.  supported this speculation. In vitro experiments with a bladder cancer cell line revealed decreased ALT levels in more invasive cells compared with less invasive cells. Furthermore, more invasive bladder cancer cells consumed glucose and pyruvate to a greater extent.