الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Breast cancer ranks as the first malignancy affecting females, contributing 29% of all female cancers diagnosed each year. It affects 1 in every 14 women during their life time. It is second only to lung cancer as a cause of cancer death in females; almost one of every three women will die of the disease. However, progress in screening programs, understanding of cancer biology, and the development of new treatments, have reduced the likelihood of dying from breast cancer. Despite this progress and the availability of adjuvant therapies that have significantly reduced recurrence, breast cancer recurrence still occurs in a substantial proportion of women after treatment and death rates remain unacceptably high. Somatic stem cells are responsible for tissue homeostasis in the adult and have limited plasticity. They are responsible for tissue renewal and repair and can become activated in response to environmental signals such as hormones. Somatic stem cells are part of a hierarchy of cells in the tissue, including the slowly proliferating somatic stem cell, the more differentiated and proliferating transit-amplifying cell progeny, and the several lines of differentiated cells.
This study conducted on 60 patients with Breast cancer stage IV, presented to outpatient clinics Oncology Center, Mansoura University. All patients received treatment ranges from (surgery,
chemotherapy, radiotherapy, hormonal treatment or combination of two or more lines) according to protocols and guidelines.
This study prospectively identified tumorigenic breast cancer cells showing stem cell properties as CD44+/CD24-, to determine the prevalence and clinical implication of CD44 and CD24 expression
patterns in breast cancer, using immunohistochemical staining procedures in clinical practice. The expression patterns were analyzed according to the clinicopathologic prognostic parameters, such as
hormone receptors, Her2/neu status, grade of tumors and stage on presentation as well as overall survival.
Our study classified the breast tumor tissues obtained from the studied cases into four subgroups according to CD44 and CD24 expression patterns (CD44+ CD24- group that carry stem cell property were 41.7% of studied samples and the remaining three groups ( CD44- CD24-, CD44+ CD24+ , CD44- CD24+) were 58.3% .
The study showed that 64% of tumors with CD44+ CD24- BCSCs were IDC histology, 84% of cases belongs to this group were grade 3 and the relation was significant, 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) when compared to other three groups. Also, a multivariate analysis, showed that presence of BCSCs was significant independent prognostic factor for poor overall survival.
Conclusion: The role of BCSCs in the genesis, progression, clinical behavior and metastasis of breast cancer is becoming increasingly clear.
Further prospective studies with large numbers of patients are warranted to confirm the role of CD44 and CD24 as a prognostic factor, since there is
no established prognostic marker based on CSCs detection in breast cancer. CD44 and CD24 may possibly play a role as tumor marker in tailored management for breast cancer.
Key words: Breast Cancer Stem Cells - Metastatic Breast Cancer.