The results suggested that tadalafil capacity of anti-tumor partially depended on pde5 (Figure 8D) and its effect on amino acid metabolism also depended on pde5, which was presented by the downregulation of the expression of GPT, GGT5, and TAT in tadalafil treatment with pde5 knockdown groups (Figure 8E). The gene discussed is GPT; the disease is neoplasm.