What is the prevalence of CLDN18.2 expression in patients with pancreatic ductal adenocarcinoma?
CLDN18.2 is a protein found on the surface of some cancer cells, making it a target for newer antibody drugs like zolbetuximab. In pancreatic ductal adenocarcinoma (PDAC), knowing how often CLDN18.2 is expressed helps determine how many patients might benefit from these targeted therapies. A large meta-analysis reports that about half of PDAC tumors express CLDN18.2, but the exact number depends on how expression is measured and which antibody is used 6. Real-world studies show that roughly 27% of patients have the high-level expression required for current clinical trials 10.
What the research says
A 2025 systematic review and meta-analysis of 16 studies including 2,025 PDAC patients found that the pooled prevalence of CLDN18.2 expression was 51.60% (95% CI: 40.93–62.19) 6. However, there was substantial variation between studies (I² = 95.4%), meaning the true rate can differ depending on the lab methods used. The type of antibody clone used for testing significantly affected the results 6. Importantly, CLDN18.2 expression was highly specific to cancer tissue compared to normal pancreas (odds ratio 102.40) 6, meaning it is rarely found in healthy cells.
A real-world study of 337 PDAC patients found that 83.1% had some degree of CLDN18.2 staining, but only 26.7% (95% CI: 22.3%–31.7%) met the stricter criteria used in clinical trials for gastroesophageal cancer (moderate or strong staining in at least 75% of tumor cells) 10. This study also showed that CLDN18.2-positive tumors tended to be lower grade and had lower tumor marker levels 10. Another study of 95 PDAC patients reported high CLDN18.2 expression (H-score ≥200) in 21.1% of cases, and this was linked to better survival after surgery 9.
Expression levels can also change with tumor differentiation: poorly differentiated tumors tend to have lower CLDN18.2 expression 6. Most patients (76.5%) show agreement in CLDN18.2 status between their primary tumor and metastases 10, suggesting that testing a single biopsy may be sufficient for treatment decisions.
What to ask your doctor
- Should I have my tumor tested for CLDN18.2 expression, and if so, which antibody and scoring method will be used?
- What does my CLDN18.2 result mean for my treatment options, including eligibility for clinical trials targeting this protein?
- If my tumor is CLDN18.2-positive, are there any targeted therapies or trials available for pancreatic cancer?
- How does my CLDN18.2 status relate to other factors like tumor grade or stage?
- Would testing a metastatic site be needed, or is the primary tumor result sufficient?
This question is drawn from common patient questions about this topic and answered using cited medical research. We do not provide individualized advice.