Research study · Asian Pacific Journal of Cancer Prevention · 2026
High Prevalence of Cannabinoid Receptor 1 Expression in Thai Patients with Cholangiocarcinoma and Its Prognostic Implications
Verified on PubMed Oxford CEBM Level 2B: Clinical Cohort Study
A 2026 study in Asian Pacific Journal of Cancer Prevention tested cb1 cannabinoid receptor in cholangiocarcinoma. It made no clear difference to how long patients lived. This study shows that a receptor linked to the body's cannabis-like system is found in almost all of these bile duct tumors, which makes it worth studying further.
In plain language
Study overview
This study looked at tumor samples from 51 Thai patients with a cancer of the bile ducts, the tubes that carry digestive fluid from the liver. The researchers checked how much of a receptor called CB1, which the body's natural cannabis-like system uses, was present in each tumor. They then compared those levels with how sick patients were and how long they lived.
Findings
It made no clear difference to how long patients lived. Nearly all of the tumors had a lot of this receptor, but patients with more or less of it lived about the same length of time.
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The deeper readScientific analysis
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.
The paper
Citation
Ungtrakul T, Amatawet C, Sricharunrat T High Prevalence of Cannabinoid Receptor 1 Expression in Thai Patients with Cholangiocarcinoma and Its Prognostic Implications. Asian Pacific Journal of Cancer Prevention (2026). PubMed 42808403 · DOI
Limitations the authors noted
Small sample size (n = 51) with extreme imbalance between groups (46 high vs 5 low CB1), making the study underpowered for comparative analyses. Retrospective, single-center design limits generalizability. No power calculation; cutoff for high expression was chosen a priori but the scoring threshold leaves very few low-expression cases. CNRIP1 methylation and other epigenetic mechanisms were not evaluated. Cannabinoid exposure was not consistently documented, precluding assessment of cannabinoid therapy effects. Survival and stage data incomplete (stage unknown in 18%; grade unknown in 41%).
In practice
Why this matters
This study shows that a receptor linked to the body's cannabis-like system is found in almost all of these bile duct tumors, which makes it worth studying further. It does not show that the receptor affects how long people live, and it does not tell us whether cannabis or cannabis-like substances help these cancers, since patients' cannabis use was not recorded. The study was small, looked backward at old records, and came from one hospital, so the answers for other patients, other doses or other forms of cannabis remain open.
Frequently asked questions
Clinical Questions & Answers
What were the primary clinical findings regarding Cb1 cannabinoid receptor and Bile duct neoplasms?
It made no clear difference to how long patients lived. Nearly all of the tumors had a lot of this receptor, but patients with more or less of it lived about the same length of time.
What study limitations or clinical safeguards should patients keep in mind?
Small sample size (n = 51) with extreme imbalance between groups (46 high vs 5 low CB1), making the study underpowered for comparative analyses. Retrospective, single-center design limits generalizability. No power calculation; cutoff for high expression was chosen a priori but the scoring...
Browse related research
Condition: Bile duct neoplasms Condition: Cholangiocarcinoma Topic: Cb1 cannabinoid receptor Topic: Tumor biomarkers
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Reviewed by Dr. Caplan on November 3, 2026.
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