To explore the expression characteristic of serum melanoma cell adhesion molecule (MCAM) in patients with hepatocellular carcinoma (HCC), evaluate the clinical significance of candidate MCAM in thediagnosis of HCC.

Eighty-three HCC patients and eighty-five healthy individuals at Shanghai Ruijin Hospital and Shanghai Tenth People’s Hospital from November 2013 to February 2015 were considered eligible for this study. Serum MCAM and cluster of differentiation (CD)₁₆₆ were examined using enzyme-linked immunosorben assay(ELISA). Analysis the relationship between MCAM and those seven indexes including alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), γ-glutamyl transpeptidase (γ-GT), total bileacid (TBA), total protein (TP) and alpha fetal protein (AFP) by using spearman. Meanwhile, to evaluate the specificity and sensitivity of MCAM in the diagnosisof HCC through the receiver-operating characteristics curve.

Serum MCAM, serum CD₁₆₆, AFP of healthy individuals were (2 776.7±25.8) ng/L, (222.6±74.9) ng/L, (21.7±9.6) μg/L and those of patients with HCC were (20 453.3±110.2) ng/L, (5 702.0±99.0) ng/L, (275.7±83.4) μg/L. A positivecorrelation was found between serum MCAM and CD₁₆₆(r=0.875, P<0.001). Besides, a positivecorrelation was also found between serum MCAM and AFP(r=0.858, P<0.001). In patients with HCC, the data of γ-GT, TBA, ALP, ALT, AST and TP were collected as follows: (120.8±10.0) IU/L, (123.6±24.8) μmol/L, (158.2±15.4) IU/L, (69.3±8.3) IU/L, (135.7±12.8) IU/L, (67.3±8.7) μg/L. Serum MCAM was also positively correlated with CD₁₆₆, ALT, AST, ALP, γ-GT TBA(r of 0875, 0.407, 0.831, 0.456, 0.670, 0.685, P<0.001). The areaunder the receiver operating characteristic curve for serum-MCAM was 0.940, for the differentiation of HCC patients from healthy individualswith a cut-off of 2 397.6 μg/L, sensitivity 90.4% (152/168), specificity 94.1%(158/168). AUC-ROC also indicated that the combination of MCAM and CD₁₆₆ with AFP(0.984, 95%CI 0.969-1.000), sensitivity 98.8% (160/168), specificity 94.1% (158/168) to diagnose HCC was only slightly better than AFP (0.931, 95%CI 0.887-0.974), sensitivity 89.2% (150/168), specificity 94.1% (158/168) or MCAM (0.940(95% CI 0.900-0.981), sensitivity 90.4% (152/168), specificity 94.1% (158/168) alone or the combination of MCAM and CD₁₆₆ (0.976, 95% CI 0.955-0.998), sensitivity 97.6% (164/168), specificity 92.9% (156/168).

Serum MCAM is a novel diagnostic tumor marker for HCC. With high sensitivity and specificity, MCAM could have a good diagnostic efficiency as a novel hepatocellular carcinoma tumor marker in the near future. But this still need to expand the sample size to further verification. The single examination of AFP, MCAM or the combination of MCAM with CD₁₆₆ are all hetpful for diagnosis of HCC in clinical application.