The sub-group analysis by antibody used demonstrated a positive correlation between MUC1 expression and CRC distant metastasis in the 2 studies using KL-6 (OR = 5.29, 95% CI = 1.64–17.01), whereas the correlation was indeterminate in studies using HMFC-7, ICR2 and Ma695 (Fig 3B). This evidence concerns the gene MUC1 and colorectal carcinoma.