Serum Angiopoietin-Like Protein 4: A Potential Prognostic Biomarker for Prediction of Vascular Invasion and Lymph Node Metastasis in Cholangiocarcinoma Patients.

Cholangiocarcinoma (CCA) is a tumor arising from cholangiocytes lining the bile ducts. Vascular invasion and lymph node metastasis are important prognostic factors for disease staging as well as clinical therapeutic decisions for CCA patients. In the present study, we applied CCA sera proteomic analysis to identify a potential biomarker for prognosis of CCA patients. Then, using bioinformatics tools, we identified angiopoietin-like protein 4 (ANGPTL4) which expressed highest signal intensity among candidate proteins in proteomic analysis of CCA sera. Expression of ANGPTL4 in CCA tissues was determined using immunohistochemistry. The results showed that ANGPTL4 was stained at higher level in CCA cells when compared with normal cholangiocytes. The high expression of ANGPTL4 was associated with lymph node metastasis and advanced tumor stage (p = 0.013 and p = 0.031, respectively). Furthermore, serum ANGPTL4 levels in CCA and healthy control (HC) were analyzed using a dot blot assay. And it was found that ANGPTL4 level was significantly higher in CCA than HC group (p < 0.0001). ROC curve analysis revealed that serum ANGPTL4 level was effectively distinguished CCA from healthy patients (cutoff = 0.2697 arbitrary unit (AU), 80.0% sensitivity, 72.7% specificity, AUC = 0.825, p < 0.0001). Serum ANGPTL4 level was associated with vascular invasion and lymph node metastasis (p = 0.0004 and p = 0.006), so that it differentiated CCA with vascular invasion from CCA without vascular invasion (cutoff = 0.5526 AU, 64.9% sensitivity, 92.9% specificity, AUC = 0.751, p = 0.006) and it corresponded to CCA with/without lymph node metastasis (cutoff = 0.5399 AU, 71.4% sensitivity, 70.8% specificity, AUC = 0.691, p = 0.01) by ROC analysis. Serum ANGPTL4 levels showed superior predictive efficiency compared with CA 19-9 and CEA for vascular invasion and lymph node metastasis. In addition, serum ANGPTL4 level was an independent predictive indicator by multivariate regression analysis. In conclusion, serum ANGPTL4 could be a novel prognostic biomarker for prediction of vascular invasion and lymph node metastasis of CCA patients.

Serum Cystatin C as a Potential Marker for Glomerular Filtration Rate in Patients with Cholangiocarcinoma.

Background: Cholangiocarcinoma (CCA) is the second most common primary hepatobiliary cancer. These patients have meager prognosis and short-term survival. Precise assessment of glomerular filtration rate is a fundamental aspect of clinical care in cancer patients. Cystatin C has been proposed to be superior to creatinine, a well-known marker of renal function. This study aimed to evaluate cystatin C as a marker of GFR calculation in CCA patients. Materials and Methods: One hundred thirty serum samples from CCA patients and 32 from controls were included in this study. Serum cystatin C was measured using immunoturbidity assay. Estimated glomerular filtration rate was calculated by three equations established by chronic kidney disease epidemiology collaboration (based on creatinine and/or cystatin C). Results: Serum cystatin C in CCA patients was higher than that of controls (p=0.0002). Cystatin C was positively correlated with BUN in CCA group (p=0.019). eGFR based on cystatin C and based on both cystatin C and creatinine in CCA was low with significantly different from those of control (p<0.001). Although there was no difference in eGFR using three equations in control, creatinine based eGFR was high with significantly different from eGFR based on cystatin C and on both creatinine and cystatin C in CCA (P=0.000). Proportion in each eGFR stage by three equations showed a high sensitivity with significantly different in CCA (p<0.05). Conclusion: There was a high sensitivity of cys C with significant difference between creatinine and/or cystatin C based eGFR in CCA patients. It should be taken into consideration of mild changes in eGFR by cystatin C which is important in managing drug dosage for CCA patients.