High cellular prion protein expression in cholangiocarcinoma: A marker for early postoperative recurrence and unfavorable prognosis.

Background: The cellular prion protein (PrP^C), traditionally associated with neurodegenerative disorders, plays an important role in cancer progression and metastasis by inhibiting apoptosis.

Aim: To investigate the influence of PrP^C expression in cholangiocarcinoma (CCA) on patient outcomes following surgical resection.

Methods: Patients who underwent curative surgical resection for either intrahepatic or hilar CCA were enrolled in this retrospective study. Based on the immunohistochemical staining results of the surgical specimens, patients were categorized into two groups: The low PrP^C group (negative or 1+) and the high PrP^C group (2+ or 3+). Survival analyses, including overall survival and recurrence-free survival, were conducted using the Kaplan-Meier method and compared using the log-rank test.

Results: In total, seventy-six patients diagnosed with CCA (39 with intrahepatic and 37 with hilar CCA) underwent curative hepatectomy from January 2011 to November 2021. Among these patients, 38 (50%) demonstrated high PrP^C expression, whereas the remaining 38 (50%) showed low expression of PrP^C. During a median follow-up period of 31.2 months (range: 1 to 137 months), the high PrP^C group had a significantly shorter median overall survival than the low PrP^C group (40.4 months vs 137.9 months, respectively; P = 0.041). Moreover, the high PrP^C group had a significantly shorter median recurrence-free survival than the low PrP^C group (13.3 months vs 23.8 months, respectively; P = 0.026).

Conclusion: PrP^C expression is significantly associated with early recurrence and decreased survival period in CCA patients following surgical resection. Thus, PrP^C may be used as a prognostic factor in treatment planning.