KRAS and colorectal carcinoma: With reference to stage I-IV CRC patients, the odds ratio (OR) of paired CTCs and tumor tissues was 0.87 (95% CI; 0.60, 1.26) for KRAS codon12+13 mutation, 0.77 (95% CI; 0.51, 1.14) for KRAS codon12 mutation, and 1.32 (95% CI; 0.53, 3.29) for KRAS codon13 mutation (see Figure 2).