Purpose: It is widely accepted that aldehyde dehydrogenase (ALDH) activity is a signature of breast cancer stem cells, and high activity has been reported to be associated with poor clinical outcome. The aim of this study was to assess the expression of members of the ALDH family of isozymes in breast cancer tissues and to evaluate the implications of the results.
Methods: We analyzed paraffin-embedded tumor tissue from 160 patients with breast cancer. Immunohistochemistry (IHC) staining was performed on the slides using antibodies against different ALDH family members. We collated the IHC results with patient clinical characteristics and determined their prognostic value. In addition, we analyzed normal, hyperplastic, and carcinomatous tissues in situ to check their ALDH distributions.
Results: All the tested ALDH members were detected in the various tissue types, but at different levels. Only ALDH 1A3 was found to be significantly associated with distant metastasis (p=0.001), disease-free survival (p<0.001), and overall survival (p<0.001).
Conclusion: The level of ALDH 1A3 in breast cancer tissue is a predictive marker of a poor clinical outcome.
Keywords: Breast neoplasms; Metastasis; Neoplastic stem cells; Prognosis.