SLPI and breast cancer: SLPI is downregulated in breast cancer than in normal tissues [29]; Results reveal that SCGB3A1 promoter methylation is notably elevated in the tumor group and correlated significantly with various clinicopathologic features in breast cancer [30]; Low expression of KRT15 is significantly linked to a poor prognosis in patients with BRCA, suggesting that KRT15 may play a crucial role in the progression of breast invasive carcinoma [31].