Breast cancer stem cells: A novel therapy for breast cancer.

Abstract

e13030 Background: Simple BRCA screening is insufficient for ‘event-free survival’ as breast cancer is clinically and pathologically an extremely heterogeneous disease. Targeting Breast Cancer Stem Cells (BCSCs) present in bone marrow and breast tissues is a lucrative alternative. Identification of BCSCs is salient aspect of our research. Invasive and mesenchymal property of BCSCs with CD44+/CD24low/ALDH1+ phenotype has made them a promising target for eliminating metastatic capacity of primary tumors. We hypothesize that ability to therapeutically attack stem cell hinges upon identifying unique targets like cell surface markers and this will decide development of specific target therapies. Methods: A total of 10 early chemo-naive patients with biopsy proven triple-negative metastatic breast cancer in the age group of 18-36 yr.s (mean age 28 yr.s) were selected randomly and tested for CD44/CD24 cell surface markers following immunosorting using magnetic cell sorter and immunophenotyping by flowcytometric analysis. Isolated BCSCs were cultured for in vitro drug sensitivity towards platinum, anthracycline and docetaxel. Correlation was drawn between cell differentiation, % of stem cells and drug response. Accordingly chemotherapy was designed for a particular patient. % of BCSCs in pre- and post-chemotherapeutic condition was further compared. Results: We have detected BCSCs in 90% of cases. Among positive samples, 89% patients showed platinum sensitivity and rest were found to be anthracycline sensitive. No sensitivity to docetaxel was observed. In lieu of this, cisplatin was applied in vivo and % of BCSCs came down to 6.58% from initial 11.16% (for a representative case). Conclusions: Thus primary aim to target BCSCs at the onset of tumors in breast cancer patients to control metastasis and relapse of disease was somewhat obtained. We further plan to correlate ratio of selected markers present in patients in pre- and post-chemotherapeutic condition with time to recurrence, mortality, morbidity and progression-free survival. Finally, if no BCSCs prevail after chemotherapy, then patients would be kept under observation and if traces are found, we would proceed to targeted therapy trial like PARP inhibitor or autologous stem cell replacement.