The efficacy of biliary and serum macrophage inhibitory cytokine-1 for diagnosing biliary tract cancer

The serum macrophage inhibitory cytokine-1 (MIC-1) levels are elevated in some inflammatory conditions and cancers. We thus compared the levels of biliary and serum MIC-1 and conventional tumour markers between 23 biliary tract cancer (BTC) patients (malignant group) and 29 benign biliary disease patients (benign group) and found that all markers were significantly elevated in the malignant group. The levels of two markers were higher in early BTC (Stage I/II, n = 15) than in the benign group: biliary MIC-1 [12 (0–2153) vs. 678 (0–4429) pg/ml, P < 0.01] and serum CA19–9 [13 (2–15,682) vs. 45.1 (2–10,478) U/ml, P = 0.02]. A receiver operating characteristic curve analysis revealed that the area under the curve for biliary MIC-1 was greater than that for serum CA19-9 (0.77 vs. 0.73). The cut-off value for biliary MIC-1 in diagnosing early BTC was 581.6 pg/ml, and this value yielded a sensitivity, specificity and accuracy of 71.4%, 82.8%, and 79.1%, respectively. The sensitivity of biliary MIC-1 for diagnosing early BTC was superior to that of biliary cytology (71.4% vs. 8.33%, P < 0.01), and the combination of serum MIC-1 with CA19-9 (cut-off value = 4021.2 pg/ml, 42.4 U/ml) was useful for screening BTC (sensitivity = 82.6%, specificity = 72.4%). In conclusion, biliary MIC-1 can effectively diagnose early BTC.