Bile level of cytokeratin 7 as a diagnostic marker for cholangiocarcinoma: a case-control study in Egyptian patients

Cholangiocarcinoma (CCA) is an aggressive malignancy with a poor prognosis of less than 20% five-year survival rate. Early diagnosis is typically challenging due to asymptomatic characteristics at the earliest stages of the disease. This study aims to assess the potential utility of cytokeratin 7 (CK7) as a CCA diagnostic biomarker in bile. In total, 100 participants were included in this case-control study. Moreover, Group I had 30 CCA patients with malignant obstruction, and Group II had 20 patients with malignant biliary obstruction other than CCA formed. Group III included 20 patients with benign biliary obstruction, and 30 individuals undergoing cholecystectomy with no evidence of biliary obstruction made up the control group (Group IV). Bile samples were collected during endoscopic retrograde cholangiopancreatography or cholecystectomy for the control group. The CK7 levels in bile samples were measured using the enzyme-linked immunosorbent assay.

Results

The bile level of CK7 was significantly higher in cholangiocarcinoma patients (1555.4 ± 302.7 pg/mL) than those of the patients with malignancies other than CCA (581.9 ± 227.5 pg/mL), patients with benign obstruction (439.5 ± 255.7 pg/mL), and the control group (53 ± 26.4 pg/mL) (p value < 0.001). Furthermore, CK7 was significantly higher in CCA patients than in those with other malignancies (p value < 0.001). Patients with CCA with hilar lesions had the highest values compared to those with distal lesions. ROC curve analysis revealed that bile CK7 at a cut point of >1030 pg/mL yielded an area under a curve of 1 (95% CI: 1.000–1.000) in differentiating CCA from other groups.

Conclusion

The bile level of CK7 demonstrates outstanding performance that could help in diagnosing CCA.