ERBB2 and neoplasm: Although in terms of BCSS, elevated HER2 ECD levels were significant in all 2,862 patients (log-rank P < 0.001) and in subgroups with any tumor size, with any LN status, with positive hormone-receptor status, and with positive tissue HER2 status, adjusted hazard ratios (HRs) calculated for each subgroup revealed none to be independently significant, except in a subgroup with positive tissue HER2 status [log-rank P < 0.001, adjusted HR = 2.6, 95% confidence interval (CI) = 1.2–5.3; Figure 5E].