GPD1 expression levels among the HER2-E subtype (HER2-enriched) tumours were correlated with a more favourable prognosis compared to the other four subtypes based on Sorlie's [20] (p = 0.0051, HR = 0.75, 95% CI = 0.61–0.92, NP = 595) and Hu's [21] (p = 0.0386, HR = 0.79, 95% CI = 0.64–0.99, NP = 485) classifications (Supplementary Table 6). The gene discussed is ERBB2; the disease is neoplasm.