O13: TUMOUR STROMAL CELLS - A CULPRIT IN BREAST CANCER RECURRENCE AFTER NEOADJUVANT CHEMOTHERAPY

Abstract Introduction The goal of neoadjuvant chemothepaeutics(NACs) and surgical excision breast cancer is to control ultimately eliminate the malignant tumour. Despite advances in treatment, a subset patients will develop disease recurrence. Tumour stromal cells(TSCs) are non-cancerous cells that support malignancy within tumour microenvironment(TME). In particular, TSCs can suppress host immune response It unclear if NACs affect survival of–or alter immunosuppressive functions this correlates with recurrance or chemoresistance? Method Associated Normal Stromal Cells(TANs) were isolated from tissue harvested at surgery. Clonogenic assays performed following exposure increasing doses Paclitaxel (range 0-1000nM), Cyclophosphamide 0-3μM) Doxorubicin (0-100nM). co-cultured CD4+ CD8+ T-cells determine effect chemotherapeutics on their ability T-cell proliferation. Result TSCs(n=5) less susceptible cytotoxic effects chemotherapy compared TANs 21%(p-0.0001), 21%(p-0.001) 15%(p-0.026) more colonies across all Paclitaxel, respectively. Chemo naïve suppressed T-Cell proliferation by 44% 20.5% respectively(p-0.001, p-0.042). Interestingly, Paclitaxel-treated further 11.1%(p-0.047) 35.6%(p-0.017). Additionally, Cyclophosphamide-treated enhanced suppression 25.6%(p-0.029). Conclusion Our data indicate enhance function - potentially creating an inert TME vivo. Future studies explore correlation between NAC activities patient tumours/blood Take-home message After chemotherapy, highly may contribute