Although there was no remarkable difference in OS among the luminal A, luminal B, HER2-positive, basal-like, and ER-positive subtypes of BC (Figure S1), high ZSCAN18 mRNA expression was correlated with better OS for the subtypes ER-negative (HR = 0.68; 95% CI = 0.48–0.96, p = 0.029, < 0.05), HER2-negative (HR = 0.67; 95% CI = 0.53–0.85, p = 0.001, < 0.01) lymph node-positive (HR = 0.58; 95% CI = 0.39–0.88, p = 0.0092, < 0.01), and lymph node-negative (HR = 0.64; 95% CI = 0.45–0.93, p = 0.018, < 0.05) (Figures 3E–H). The gene discussed is ESR1; the disease is breast cancer.