Original Article
Potential protective effect of ALDH-1 stromal expression against early recurrence of operable breast cancers
Abstract
Background: The emerging cancer stem cell (CSC)model proposes that the stem cell niche plays a major role in the risk ofcancer recurrence. Enzymatic activity of aldehydes, including aldehydedehydrogenase 1 (ALDH-1), has been used as a marker of normal and malignantbreast stem cells (BSCs). However, the clinical implications of the expressionof stem cell markers in the stroma have not yet been investigated.
Methods: To determine the relationships of ALDH-1expression, the currently reliable BSCs marker, with clinical characteristicsand survival, we used immunohistochemical staining of tissue microarrays from180 stroma and epithelial cancer tissues in patients diagnosed with operableearly breast cancer (stage 0–III).
Results: ALDH-1 expression was observed in93.4% of the stromal cells and in 37.2% of the epithelial cells, and theexpression levels between the two cell types were significantly correlated(P=0.001). The stromal expression of ALDH-1 was not correlated with any clinicalfactors, whereas epithelial expression was significantly correlated with anegative estrogen-receptor status (P<0.001), high proliferation based onKi-67 expression (P<0.001), and younger age (P=0.04). After 27.8 months of followup, negative stromal expression of ALDH-1 was significantly correlated withshorter overall survival (positive, 56.9±3.0 months vs. negative,30.5±3.0 months; P=0.01).
Conclusions: Stromal ALDH-1 expression was notdirectly correlated with known clinical factors, but its expression may play aprotective role against early recurrence. Further observation and large-scalestudies are needed to validate the clinical implications of ALDH-1 in breastcancer.
Methods: To determine the relationships of ALDH-1expression, the currently reliable BSCs marker, with clinical characteristicsand survival, we used immunohistochemical staining of tissue microarrays from180 stroma and epithelial cancer tissues in patients diagnosed with operableearly breast cancer (stage 0–III).
Results: ALDH-1 expression was observed in93.4% of the stromal cells and in 37.2% of the epithelial cells, and theexpression levels between the two cell types were significantly correlated(P=0.001). The stromal expression of ALDH-1 was not correlated with any clinicalfactors, whereas epithelial expression was significantly correlated with anegative estrogen-receptor status (P<0.001), high proliferation based onKi-67 expression (P<0.001), and younger age (P=0.04). After 27.8 months of followup, negative stromal expression of ALDH-1 was significantly correlated withshorter overall survival (positive, 56.9±3.0 months vs. negative,30.5±3.0 months; P=0.01).
Conclusions: Stromal ALDH-1 expression was notdirectly correlated with known clinical factors, but its expression may play aprotective role against early recurrence. Further observation and large-scalestudies are needed to validate the clinical implications of ALDH-1 in breastcancer.
