GRB7 is an oncogenic driver and potential therapeutic target in oesophageal adenocarcinoma

J Pathol. 2020 Nov;252(3):317-329. doi: 10.1002/path.5528. Epub 2020 Sep 15.


Efficacious therapeutic approaches are urgently needed to improve outcomes in patients with oesophageal adenocarcinoma (OAC). However, oncogenic drivers amenable to targeted therapy are limited and their functional characterisation is essential. Among few targeted therapies available, anti-human epidermal growth factor receptor 2 (HER2) therapy showed only modest benefit for patients with OAC. Herein, we investigated the potential oncogenic role of growth factor receptor bound protein 7 (GRB7), which is reported to be co-amplified with HER2 (ERBB2) in OAC. GRB7 was highly expressed in 15% of OAC tumours, not all of which could be explained by co-amplification with HER2, and was associated with a trend for poorer overall survival. Knockdown of GRB7 decreased proliferation and clonogenic survival, and induced apoptosis. Reverse phase protein array (RPPA) analyses revealed a role for PI3K, mammalian target of rapamycin (mTOR), MAPK, and receptor tyrosine kinase signalling in the oncogenic action of GRB7. Furthermore, the GRB7 and HER2 high-expressing OAC cell line Eso26 showed reduced cell proliferation upon GRB7 knockdown but was insensitive to HER2 inhibition by trastuzumab. Consistent with this, GRB7 knockdown in vivo with an inducible shRNA significantly inhibited tumour growth in cell line xenografts. HER2 expression did not predict sensitivity to trastuzumab, with Eso26 xenografts remaining refractory to trastuzumab treatment. Taken together, our study provides strong evidence for an oncogenic role for GRB7 in OAC and suggests that targeting GRB7 may be a potential therapeutic strategy for this cancer. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Keywords: GRB7; HER2/ERBB2; oesophageal adenocarcinoma (OAC); oncogene; receptor tyrosine kinase; reverse phase protein array (RPPA); targeted therapy; trastuzumab.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / drug therapy
  • Adenocarcinoma / metabolism*
  • Adenocarcinoma / mortality
  • Adenocarcinoma / pathology
  • Animals
  • Antineoplastic Agents, Immunological / therapeutic use
  • Biomarkers, Tumor / metabolism*
  • Blotting, Western
  • Cell Line, Tumor
  • Esophageal Neoplasms / drug therapy
  • Esophageal Neoplasms / metabolism*
  • Esophageal Neoplasms / mortality
  • Esophageal Neoplasms / pathology
  • Female
  • GRB7 Adaptor Protein / metabolism*
  • Gene Knockdown Techniques
  • Humans
  • Immunohistochemistry
  • Mice
  • Mice, Inbred NOD
  • Mice, SCID
  • Neoplasm Transplantation
  • Prognosis
  • Receptor, ErbB-2 / metabolism
  • Survival Analysis
  • Trastuzumab / therapeutic use


  • Antineoplastic Agents, Immunological
  • Biomarkers, Tumor
  • GRB7 protein, human
  • GRB7 Adaptor Protein
  • ERBB2 protein, human
  • Receptor, ErbB-2
  • Trastuzumab

Supplementary concepts

  • Adenocarcinoma Of Esophagus