Clinical outcomes were assessed for patients with HER2+ advanced esophagogastric cancer who received first-line trastuzumab....Of 194 patients with tumors documented as clinically HER2+, 82 with HER2+ concordant tumors and 60 with HER2+ discordant tumors had a documented first-line therapy regimen containing trastuzumab….Among these patients, HER2+ concordant versus HER2+ discordant results between CGP and traditional HER2 tests were associated with significantly longer TTD (3.22 vs 0.95 months; aHR: 0.63; 95% CI: 0.43–0.90) and significantly longer OS (13.04 vs 7.52 months; aHR: 0.51; 95% CI: 0.33–0.79) (Figure 1 & Table 3)....When stratified by ERBB2 CN, ERBB2 CN ≥25 versus <25 (median) was also associated with significantly longer TTD (4.86 vs 1.64 months; aHR: 0.56; 95% CI: 0.35–0.88) and OS (17.51 vs 8.77 months; aHR: 0.52: 95% CI: 0.30–0.91) (Figure 2 & Table 4).