FGFR2b Logo

This content is intended for pathologists
FGFR2b protein overexpression can be detected by IHC, similar to other gastric/GEJ cancer biomarkers1

Protein overexpression is determined by evaluating both membrane stain intensity and the percentage of tumor cells stained2

Positive FGFR2b overexpression

Tumor cells exhibiting moderate (2+) to strong (3+) membranous staining3-5

H&E-stained tissue sample of gastric adenocarcinoma
H&E of gastric adenocarcinoma2
Immunohistochemistry of gastric adenocarcinoma with strong (3+) membranous staining using anti-c-kit antibody
IHC of gastric adenocarcinoma exhibiting strong (3+) membranous stain intensity2

Evaluation of positive FGFR2b protein overexpression2,4

Any tumor cells with moderate (2+) to strong (3+) membranous staining, including any of the following:

  • Basal-lateral
  • Partial or complete circumferential
  • Basal only
  • Apical only
A red circle with two wires, symbolizing the membrane localization of FGFR2b protein overexpression in tumor cells

FGFR2b protein overexpression is scored only in the membrane of tumor cells1

Negative FGFR2b overexpression

alt="(0) no staining FGFR2b protein overexpression evaluation by IHC
FGFR2b in gastric adenocarcinoma with no (0) staining2
alt="(1+) weak staining FGFR2b protein overexpression evaluation by IHC
FGFR2b in gastric adenocarcinoma with predominantly weak (1+) staining2

Evaluation of negative FGFR2b protein overexpression2

No tumor cells with moderate to strong membranous staining OR tumor cells only exhibiting:

  • Negative to weak membranous staining and/or
  • Cytoplasmic-only staining at any intensity
Roche Diagnostics has created the VENTANA® FGFR2b (FPR2-D) Mouse Monoclonal Antibody assay (Class 1), for research use only, that recognizes FGFR2b via IHC6,7
Consider both stain intensity and percentage of tumor cells in test results5
SEE HOW FGFR2b IHC IS INTERPRETED

FGFR2b, fibroblast growth factor receptor 2, isoform IIIb; GEJ, gastroesophageal junction; H&E, hematoxylin and eosin; IHC, immunohistochemistry.

References: 1. Rha SY, et al. JCO Precis Oncol. 2025;9:e2400710. 2. Data on File, Amgen; 2024. 3. Ahn S, et al. Mod Pathol. 2016;29:1095-1103. 4. Wainberg ZA, et al. Lancet Oncol. 2022;23:1430-1440. 5. Wainberg ZA, et al. Gastric Cancer. 2024;27:558-570. 6. Roche Diagnostics. https://elabdoc-prod.roche.com/eLD/api/downloads/65a1283e-a4f6-ee11-2591-005056a71a5d?countryIsoCode=XG. Accessed May 15, 2025. 7. FDA.gov. https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfRL/rl.cfm?lid=516262&lpcd=NJT. Accessed May 15, 2025.

References: 1. FPO 2. FPO 3. FPO