CLDN 18.2

Reporting test results

Review best practices for accurate and consistent reporting of CLDN18.2 expression and positivity.

Reporting test results
Reporting test results
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Accurate reporting of CLDN18.2 expression requires assessment of both membranous staining intensity and the percentage of tumour cells stained1

In addition to membranous stain intensity and percentage of tumour cells stained, it is recommended that the biomarker report also include:

  • Type of testing method and antibody used, including companion diagnostic vs laboratory-developed test, antibody clone, and IHC stainer used
  • A description of the status of the sample, such as “positive,” “negative,” or “inconclusive,” including how positivity was defined
  • Type of specimen (biopsy vs surgical) and site of the sampling (primary vs metastatic disease, and if metastatic, define the site)
  • Sample adequacy, and if inadequate, state the cause
  • Any relevant notes or observations regarding the sample or results

How to Report CLDN18.2

Kristina A. Matkowskyj, MD, PhD

The current standard for CLDN18.2-positivity, based on IHC assessment in two recently published global Phase 3 studies, is ≥75% of tumour cells demonstrating moderate-to-strong (2+/3+) membranous CLDN18 staining.1-3

CLDN18.2 reporting template

Developed by a committee of experts, this template can help you generate reporting and integrate CLDN18.2 reporting into your current protocols.

Using the CLDN18.2 Reporting Template

Kristina A. Matkowskyj, MD, PhD

Consistent, integrated reporting of biomarkers can inform clinical decision-making and may improve patient care4

Integrated biomarker reporting

  • Helps inform the multidisciplinary team’s clinical approach based on biomarker test results
  • Can be used as a tool to help pathologists educate the multidisciplinary team

Pathologists drive consistent, integrated reporting, helping their multidisciplinary teams optimize treatment plans.

Gain more in-depth knowledge on our resources page

CLDN18.2=claudin 18 isoform. HCP=healthcare professional. IHC=immunohistochemistry.

References:

  • 1.Fassan M, Kuwata T, Matkowskyj KA, et al. Claudin-18.2 immunohistochemical evaluation in gastric and gastroesophageal junction adenocarcinomas to direct targeted therapy: a practical approach. Mod Pathol. 2024;37(11):100589.
  • 2.Shitara K, Xu RH, Ajani JA, et al. Global prevalence of claudin 18 isoform 2 in tumours of patients with locally advanced unresectable or metastatic gastric or gastroesophageal junction adenocarcinoma. Gastric Cancer. 2024;27(5):1058-1068. 
  • 3.Shah MA, Shitara K, Ajani JA, et al. Zolbetuximab plus CAPOX in CLDN18.2-positive gastric or gastroesophageal junction adenocarcinoma: the randomized, phase 3 GLOW trial. Nat Med. 2023;29(8):2133-2141.
  • 4.Warner JL, Jain SK, Levy MA. Integrating cancer genomic data into electronic health records. Genome Med. 2016;8(1):113. 10-26-2016.