CEACAM1 and neoplasm: The expression of CEACAM1 was lower in ccRCC tissues than in adjacent normal tissues, and its expression level was negatively correlated with tumor size status (P < 0.001), metastasis status (P = 0.009), pathological stage (P = 0.002), gender (P < 0.001), histological grade (P < 0.001), and primary therapy outcome (P = 0.045) of ccRCC.