Gli1 is a potential cancer stem cell marker and predicts poor prognosis in ductal breast carcinoma

Glioma-associated oncogene homolog 1 (Gli1) maintains the cancer stem cell-like characteristics in various tumors. However, its expression in cancer stem cells (CSC) in ductal breast carcinoma has not been well studied. We aimed to characterize Gli1 as a potential CSC marker and investigate its clinical significance in ductal breast carcinoma. Immunohistochemical staining was used to study the relationship of Gli1 to clinicopathologic features, cell cycle regulation-related genes, and CSC markers. Gli1 was expressed to a greater extent in ductal breast carcinoma than in normal breast tissues (P = .002). Its expression was significantly correlated with tumor grade (P = .044), pT stage (P = .017), and molecular subtype (P = .008). Expression was associated, not only with the expression of HIF-1α (P < .001), but also with greater microvessel density (MVD; P = .012). Kaplan-Meier survival analysis revealed that Gli1 was significantly associated with lower overall survival (OS; P = .02). Univariate Cox regression analysis confirmed that Gli1 was a poor prognostic factor for OS (P = .037) and was associated with the expression of the cell cycle-related genes cyclin D1 (P = .011), p21 (P = .009), and pAkt-Thr308 (P = .038). Moreover, Gli1 expression correlated significantly with the expression of two CSC markers, Sox2 (P = .01) and LSD1 (P = .01). Gli1 could be a stem cell marker and an indicator of poor prognosis in patients with ductal breast carcinoma.