Synonyms
CLDN18, Claudin 18.2, CLDN 18.2, Claudin 18.1, CLDN 18.1
Special Instructions
Note: This test number is used for tracking oncology IHC specimens to the laboratory. Bill codes will be added when testing is complete, based on the processes performed in the laboratory.
Expected Turnaround Time
3 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Specimen Requirements
Specimen
Formalin fixed paraffin-embedded (FFPE) tissue block or slides
Volume
One paraffin block or five air-dried unstained slides sectioned at 4-5 microns, no more than 45 days in age
Minimum Volume
At least three unstained slides sectioned at 4-5 microns
Container
Paraffin block or unstained positive charged slides
Collection
Collect specimen on paraffin block or unstained slides sectioned off no more than 45 days in age.
The recommended fixative is 10% neutral buffered formalin for 24 hours with a range from six to 48 hours fixation time. Slides should be cut at 3-5 micron thickness and mounted onto positively charged slides. It is recommended that slides are stained shortly after slide preparation, as antigenicity of cut tissue sections may diminish.
Causes for Rejection
Tumor types other than gastric/gastro-esophageal adenocarcinoma; improper fixation; freezing; thawing; washing; heating; sectioning or contamination with other tissue; slides sectioned greater than 45 days prior to test request
Test Details
Use
This assay is indicated as an aid in identifying patients with gastric or gastro-esophageal junction (GEJ) adenocarcinoma who may be eligible for treatment with VYLOY™ (zolbetuximab) in accordance with the approved therapeutic product labeling.
Limitations
Decalcification and improper fixation may negatively affect results.
Methodology
Immunohistochemistry
References
Shitara K, Lordick F, Bang YJ, et al. Zobetuzimab plus mFOLFOX6 in patients with claudin-18 isoform 2 positive, HER2-negative, untreated, locally advanced unresectable or metastatic gastric or gastro-oesophageal junction adenocarcinoma (SPOTLIGHT): a multicentre, radomised, double-blind, phase 3 trial. Lancet. 2023 May 20;401(10389):1655-1668. PubMed 37068504
VENTANA CLDN18 (43-14A) RxDXAssay [package insert]. Ventana Medical Systems, Inc. Tucson, AZ; 2024.
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