O1-11-4 - Sox2 in Inflammatory Breast Cancer: Did We Eventually Have an Answer?

Abstract

Background: inflammatory breast cancer (IBC) is the most aggressive type of breast cancer and continuous research to identify its nature is of utmost importance.Patients and methods: This is a retrospective case control study including all eligible cases of advanced IBC compared to a control group of stage comparable locally advanced breast cancer (LABC) cases presenting to the National Cancer Institute (NCI), Cairo University in the period between November 2007 and February 2011. SOX2, as a stem cell marker, was assessed in both arms by quantitative RT-PCR. All patients received standard FEC10. Assessment of clinical response (CR) was done after 4 cycles. Primary endpoints were 1-assessment of SOX2 expression in IBC and LABC. 2-Assessment of correlation between SOX2 expression and CR in both arms. Secondary endpoints were assessment of correlation between SOX2 expression and PFS & OS in both arms.Results: 30 cases of IBC and 19 cases of LABC were included with a median follow up period of 31.3 months.SOX2 was highly expressed in IBC compared to LABC (p-values: 0.03). SOX2 expression was significantly correlated with clinical response in IBC where 100% of the SOX2 –ve cases had good overall clinical response (Complete and partial remission) compared to 64.7% of the SOX2 +ve cases (P-value: 0.042). SOX2 expression was significantly correlated with PFS in IBC where 1 and 2 year PFS were 72.7% and 45.5% in SOX2 negative versus 36.8% and 5.3% in SOX2 positive (p-value = 0.045). SOX2 expression showed a trend towards significant correlation with OS in IBC where 1 and 2 year OS were 100% and 90.4% in SOX2 negative versus 95.2% and 73.7% in SOX2 positive (p-value = 0.087).Conclusion: SOX2 expression, as a Stem cell marker, is significantly expressed in IBC and is well correlated with clinical outcome.Key words: SOX2 – stem cell phenotype- Inflammatory breast cancer