High Prevalence of Cannabinoid Receptor 1 Expression in Thai Patients with Cholangiocarcinoma and Its Prognostic
Teerapat Ungtrakul1,2, Chitiarpa Amatawet2, Thaniya Sricharunrat1,2
1Princess Srisavangavadhana Faculty of Medicine, Chulabhorn Royal Academy, Bangkok, Thailand.
Objective:
Cholangiocarcinoma (CCA) is highly prevalent in Thailand and remains associated with poor outcomes. Emerging evidence suggests that dysregulation of the endocannabinoid system may be involved in CCA pathogenesis and prognosis. This study aimed to evaluate the prevalence of cannabinoid receptor 1 (CB1) expression and its association with clinicopathological features and survival outcomes in Thai patients with CCA.
Methods:
We retrospectively reviewed patients with histologically confirmed CCA treated at a tertiary cancer center in Thailand between January 2014 and December 2018. CB1 expression in tumor tissues was assessed by immunohistochemistry and semi-quantitatively scored according to staining intensity and extent.
Results:
Tumor specimens from 51 patients (median age 59 years; 41% female) were analyzed. Most patients had intrahepatic CCA (80%), and 47% presented with advanced-stage disease (stages III-IV). High CB1 expression was observed in 46 of 51 cases (90%). Patients with high CB1 expression more frequently had advanced-stage disease. During a median follow-up of 27.8 months, 34 patients died. The median overall survival (OS) was 18.5 months (95% CI, 6.1-36.5). There was no statistically significant difference in OS between patients with high and low CB1 expression (median OS 18.5 vs. 23.0 months, respectively; p = 0.68).
Conclusion:
High CB1 expression is highly prevalent in Thai patients with CCA. While no significant associations with clinicopathological features or survival were found in this small cohort, the widespread overexpression of CB1 supports its potential biological and therapeutic relevance in CCA and warrants further investigation in larger studies.
