Objective:To explore the cooperation and clinical significance of HIF-1α,ALDH1 and Hedgehog signaling pathway in the activation of cancer stem cell(CSC) in triple negative breast cancer(TNBC).Methods: ALDH1+(Aldehyde dehydrogenase1)breast cancer stem cells and ALDH1-breast cancer cells were selected from MDA-MB-231 cells by magnetic activated cell sorting system(MACS),qRT-PCR method was employed to analyze the expression differences of HIF-1α and Hedgehog signaling molecules Sonic hedgehog(SHH),patched1(PTCH1),Smoothened(SMO) and Glioma-associated oncogene homoglog1(GLI1) in ALDH1+ breast cancer stem cells and ALDH1-breast cancer cells.Immunohistochemical method was applied to study the expressions of HIF-1α and ALDH1 and the relationships among HIF-1α,ALDH1 and Hedgehog signaling molecules in TNBC.Results: The expressions of HIF-1α mRNA,SMO mRNA and GLI1 mRNA in ALDH1+ breast cancer stem cell were higher than those in ALDH1-breast cancer cell(P all<0.05).The positive expression rates of HIF-1α were 90.0% and 70.0%,and the positive rates of ALDH1 were 93.3 % and 66.7 % in TNBC and non-TNBC,respectively(P all<0.05).Spearman rank correlation analysis showed that the expression of HIF-1α was positively related with that of ALDH1 in TNBC(r=0.53,P<0.01).HIF-1α expression was correlated with lymph node metastasis and TNM stage(P all<0.05),ALDH1 expression was correlated with histological grade and TNM stage(P all<0.05).In addition,the expression of HIF-1α was positively related with that of Hedgehog signaling molecules SHH(r=0.584,P<0.01),SMO(r=0.467,P<0.01) and GLI1(r=0.439,P<0.05),the expression of ALDH1 was positively related with that of SHH(r=0.426,P<0.05) and GLI1(r=0.394,P<0.05).Conclusion: HIF-1α and Hedgehog signaling pathway were activated in ALDH1+ breast cancer stem cell.HIF-1α,ALDH1 and Hedgehog molecules may cooperate with each other to activate breast CSC to promote the malignant progression of TNBC.