A- Isolation and characterization of BCSCs from European patients (4 months ,UK).
    Freshly frozen tumour cells from 5 pathologically matched French patients will be obtained from Cancer Research Center of Lyon, INSERM U1052,Lyon,France, in collaboration with Dr David Cox.BCSCs will be isolated in the European Cancer Stem Cell Research Institute, University of Cardiff, UK(in collaboration with Dr Mathew Smalley).For this purpose, cells will be sorted based on their expression to CD44 , CD24 and ALDH1 , using Fluorescent Activated Cell Sorter(FACS). Isolated cells will be then functionally charaterized using in-vitro mammosphere, and drug resistance assays. For each sample, the cell population which exhibit BCSCs features will be identified.
B- Isolation and characterization of BCSCs from Egyptian patients (4 months ,UK).
   Tumour specimens (pathologically matched to the French cohort) will be collected from benha Teaching Hospital and processed to get single cell populations (as described in Veneziani et al.,2007). BCSCs will be isolated and characterized (as described above) in the center of excellence in cancer research (Tanta) in collaboration with Prof.Dr.Mohamed Labib Salem.
C- Identification of genes responsible for BCSCs drug resistance in Egyptian population (2 months ,Egypt).
All isolated cells from A and B will be treated with routinely used drugs in Egypt (Doxorubcin and Cyclophasmid).Real Time PCR arrays (Lonza) will be designed to test the expression of 48 genes before and after treatment . Genes which show difference in their expressions (in response to drug treatment), in the Egyptian samples compared to the European samples, will be determined.