The VENTANA Claudin 18 (43-14A) RxDx Assay is an FDA-approved qualitative immunohistochemical assay using a mouse monoclonal anti-Claudin 18 antibody intended for use in the assessment of Claudin 18 protein in formalin-fixed, paraffin-embedded (FFPE) gastric cancer tissue on a VENTANA BenchMark ULTRA instrument. Claudin 18 is indicated as an aid in identifying patients with Gastric Adenocarinoma including Gastroesophageal Junction (GEJ). Tumors that have Claudin 18 expression in ≥75% of tumor cells staining at 2+ and/or 3+ intensity may be eligible for treatment with VYLOY® (zolbetuximab).
Claudin 18 is expressed as two isoforms: CLDN18.1 and CLDN18.2*. While CLDN18.1 is predominantly expressed in normal and neoplastic lung tissue, CLDN18.2 is only expressed in differentiated epithelial cells of the gastric mucosa. CLDN 18.2 has been associated with various cellular functions that lead to tumor progression and metastasis, making it an attractive therapeutic target.
*The primary antibody used in the VENTANA CLDN18 (43-14A) RxDx Assay targets the conserved C-terminal region of the CLDN18 proteins, and therefore cannot distinguish CLDN18.1 from CLDN18.2
- A formalin-fixed, paraffin-embedded (FFPE) tissue block is preferred specimen type
or - One (1) unbaked, unstained slide for H&E staining (required) and two to three (2-3) positively charged unstained slides (all cut at 4-5 microns) for each test/antibody ordered
Block and slide identifiers should be clearly written and match exactly with the specimen ID and specimen labeling as noted on the requisition.
For evaluation, tissue submitted must have ≥50 viable tumor cells present.
Use refrigerated cold pack for transport. Make sure cold pack is not in direct contact with specimen.
Global: 48 hours, Tech-Only (stain only): 24 hours
- VENTANA Claudin 18 (43-14A) RxDx Assay. Package insert. Roche; 2024.