Another important and interesting finding is that, in parallel with the upregulated HO-1 expression in CRC, the circulation levels of CO (measured as COHb) that is majorly derived from HO-1 catalyzed heme metabolism significantly increased in CRC patients (Figure 4), the circulation levels were also consistent with HO-1 expression in different clinicopathological conditions as shown in Table 2 and Figure 3. The gene discussed is HMOX1; the disease is colorectal carcinoma.