The prognostic significance of breast cancer stem cells in patients with metastatic breast cancer.

e12565 Background: Breast cancer ranks as the first malignancy affecting females.There is increasing evidence that this cancer is originated in and maintained by a small population of undifferentiated cells with self-renewal and proliferation capacities that called breast cancer stem cells (BCSCs). Methods: This study was conducted on 60 patients with metastatic breast cancer, presented to outpatient clinics in Oncology Center, Mansoura University from December 2010 till November 2014. All patients received treatment according to protocols and guidelines. The presence of breast cancer Stem cells was evaluated by immunohistochemistry expression of CD44 and CD24 to assess its possible prognostic and predictive values via correlation with overall survival, tumor response and different clinico-pathological features of the patients. The expression patterns were analyzed according to the clinico-pathologic prognostic parameters as well as overall survival. Results: Median age was 50 (31-70) years. Twenty six patients (43.3%) were premenopausal and 34 patients (56.7%) were postmenopausal. This study classified the breast tumor tissues into four subgroups according to CD44 and CD24 expression patterns (CD44+ CD24- group that carry stem cell property were 41.7% and the remaining three groups ( CD44- CD24-, CD44+ CD24+ , CD44- CD24+) were 58.3%. 64% of tumors with CD44+ CD24- BCSCs were IDC histology, 84% of cases belongs to this group were grade 3, 88% were stage III on presentation, 56% were luminal subtype, 68% of them developed both bone and visceral metastasis. Our study showed that presence of BCSCs (CD44+ CD24-) carry significantly shorter OS (19 vs. 44 months) compared to other three groups. Also, a multivariate analysis, showed that presence of BCSCs (CD44+ CD24-) was significant independent prognostic factor for poor overall survival. Conclusions: This study is a prospective trial testing the concept of detecting breast cancer stem cells in tumor tissue biopsies, according to CD44 & CD24 expression status. As such, it has demonstrated both the feasibility of this approach and its implication as a future prognostic marker, and has paved the way for future research in this field.