ERBB2 and breast cancer: The subgroup analysis showed that an elevated SII was associated with poor OS of patients with triple-negative breast cancer (TNBC; HR = 2.82, 95% CI 2.22–3.59, p < 0.001), patients with breast cancer that was positive for human epidermal growth factor receptor-2 (HR = 1.71, 95% CI 1.23–2.39, p = 0.002), and patients with mixed molecular stratification (HR = 1.33, 95% CI 1.09–1.63, p = 0.005; Table 2).