ASSOCIATION OF CANCER STEM CELLS IDENTIFIED BY ALDH1 AND CD44 EXPRESSION WITH BREAST CANCER SUBTYPES IN WEST ALGERIAN PATIENTS

Breast cancer represents the most common malignancy and leading cause of death among women worldwide and particularly in Algeria. Some breast cancer subtypes are of poor prognosis causing drug resistance that has become the major cause of treatment failure. The cancer stem cell (CSC) hypothesis has important clinical implications for cancer therapeutics because of the proposed role of CSCs in chemoresistance. Putative breast cancer stem cells might express surface markers such as aldehyde dehydrogenase 1 (ALDH1) and Cluster of differentiation 44 (CD44) proteins. The aim of this study was to explore the expression of these proteins in breast cancers from an Algerian population and their associations with the clinicopathological characteristics and breast cancer subtypes.

Methods: Clinical information was obtained by reviewing preoperative and postoperative medical records for 4 years, then 46 paraffin-embedded breast carcinoma samples were analyzed by immunohistochemical methods. Finally, statistical analyses were to evaluate associations between CD44 and ALDH1 expressions and various clinicopathological parameters including breast cancer subgroups

Results: In total, 9 tumors (21%) expressed ALDH1, whereas 11 (28%) expressed CD44 protein. Expression of ALDH1 was associated with high young age (P =0.05), Progesterone receptor positivity (P = 0.014) and triple negative breast cancer (P=0.045). On the other hand, CD44 expression was associated with SBR grade II (P = 0.057), HER2 subtype (P = 0.001) and the triple negaive subtype (P = 0.049).

Conclusion: CD44+ and ALDH1+ phenotypes seem to identify CSC with distinct levels of differentiation. It seems that the biomarkers that identify breast CSC within the breast cancer subtypes need to be better explored, because it is pivotal to translate the CSC concept to clinical practice. In the future, the recognition of reliable markers to distinguish the CSC pool in each molecular subtype will be decisive for the development of specific target therapies.