RNA expression profiles of HER2-positive advanced gastric or gastroesophageal junction cancer and healthy gastric mucosa control FFPE samples. RNA expression profiles of HER2-positive advanced gastric or gastroesophageal junction cancer and healthy gastric mucosa control FFPE samples

A subgroup of patients with HER2-positive metastatic gastric and gastroesophageal junction cancers shows long-term response under trastuzumab maintenance monotherapy. Obviously, HER2 status alone is not able to identify these patients. We performed this study to identify potential new prognostic biomarkers for this long-term responding patient group. Tumor samples of 18 patients with HER2-positive metastatic gastric and gastroesophageal junction cancer who underwent trastuzumab treatment were retrospectively collected from multiple centers. Patients were divided into long-term responding (n=6) or fast-progression group (n=12) according to progression-free survival (PFS≥12 months vs PFS=12, group 1) or fast progressing group (PFS<12, group 2) according to progression-free survival.