Expressions and clinical significances of aldehyde dehydrogenase 1 and transforming growth factor-β2 in triple negative breast cancer

Abstract

Objective To investigate the expressions and clinical significances of breast cancer stem cell markers such as aldehyde dehydrogenase 1 (ALDH1) and transforming growth factor-β2 (TGF-β2) in patients with triple negative breast cancer. Methods Samples of 60 triple negative breast cancer tissues were investigated for the expressions of ALDH1 and TGF-β2 proteins by immunohistochemical staining. The correlation analysis, disease-free survival analysis and overall survival analysis were performed. Results The positive expressions of ALDH1 protein and TGF-β2 protein in the 60 breast cancer primary lesions were 23 cases (38.33%) and 38 cases (63.33%) respectively. The expression of ALDH1 protein was not correlated with tumor size (χ2=0.307, P=0.580), histological grade (χ2=4.244, P=0.120), clinical stage (χ2=0.982, P=0.612) or lymph node metastasis (χ2=1.111, P=0.292). The expression of TGF-β2 protein was not correlated with histological grade (χ2=4.651, P=0.098), lymph node metastasis (χ2=3.513, P=0.061), clinical stage (χ2=1.310, P=0.519) or tumor size (χ2=0.629, P=0.428). The disease-free survival time [(38.43±3.86) months vs. (53.38±2.58) months] and the overall survival time [(42.00±3.11) months vs. (53.84±2.19) months] of ALDH1-positive patients were significantly shorter than those of ALDH1-negative patients, and the differences were statistically significant (χ2=8.490, P=0.004; χ2=11.270, P=0.001). The disease-free survival time [(42.81±3.32) months vs. (54.72±2.50) months] and the overall survival time [(44.74±2.68) months vs. (57.18±1.55) months] of TGF-β2 positive patients were significantly shorter than those of TGF-β2-negative patients, and the differences were statistically significant (χ2=4.300, P=0.038; χ2=8.900, P=0.003). The expression of ALDH1 protein was positively correlated with the expression of TGF-β2 protein (r=0.360, P=0.005). Conclusion The ALDH1 phenotype is an indepen-dent predictor of poor prognosis. The activation of TGF-β2 signaling pathway may be involved in the regulation of triple-negative breast cancer stem cells. Key words: Breast neoplasms; Neoplastic stem cells; Transforming growth factor beta 2; Aldehyde dehydrogenase 1