Claudin 18 IHC

TEST: 452390
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CPT: 88360
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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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