In G/GEJ tumors, CLDN18.2 status is determined by the percentage of tumor cells stained with moderate-to-strong membranous stain intensity.1
- Tissue slides with tumor cells present can demonstrate varying levels of CLDN18 membranous staining intensity, ranging from no staining to strong staining (0 to 3+)
- Two recently published phase III studies defined CLDN18.2 positivity as ≥75% of tumor cells demonstrating moderate-to-strong membranous staining3,4
- Account for tumor necrosis during interpretation
Matched H&E and IHC stain of gastric tumor necrosis (10x magnification)
How to Interpret CLDN18.2
Josef H. Rüschoff, MD
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References: 1. Pellino A, Brignola S, Riello E, et al. Association of CLDN18 protein expression with clinicopathological features and prognosis in advanced gastric and gastroesophageal junction adenocarcinomas. J Pers Med (Epub) 10-26-2021. 2. Rohde C, Yamaguchi R, Mukhina S, et al. Comparison of Claudin 18.2 expression in primary tumors and lymph node metastases in Japanese patients with gastric adenocarcinoma. Jpn J Clin Oncol 2019;49(9):870-6. 3. Shitara K, Lordick F, Bang YJ, et al. Lancet 2023;401(10389):1655-68. Errata in: Lancet 2023;402(10398):290; Lancet 2024;403(10421):30. 4. Shah MA, Shitara K, Ajani JA, et al. Nat Med 2023;29(8):2133-41.