Circulation CO levels as evaluated as carboxyhemoglobin (COHb) in CRC patients. Circulation CO levels in CRC patients were analyzed by an ABL800 FLEX blood gas analyzer, and the values were compared between CRC and non-tumor normal patients (a), as well as between different clinicopathological characteristics of CRC as described in Figure 3
(b, c, d). Values are means ± SD; *P < 0.05, ***P < 0.001 between each compared groups (student’s t-test). See text for details.