MUC1 and colorectal carcinoma: For the 6 studies estimating the correlation between MUC1 expression and CRC distant metastasis, the combination of ORs in fixed effect meta-analysis suggested that distant metastasis of CRC was more likely to occur when MUC1 expression was positive (OR = 2.22, 95% CI = 1.23–4.00, χ2 = 7.92, P = 0.160, I2 = 36.9%), as was shown in Fig 3A.