The SOX2 Status of Disseminated Tumor Cells in Breast Cancer Patients Treated With Neoadjuvant Chemotherapy.

Abstract

Detection of disseminated tumor cells (DTCs) after systemic treatment predicts poor prognosis in breast cancer patients. The aim of our study was to assess the expression of stem-cell marker SOX2 on DTCs and in the primary tumor of patients treated with neoadjuvant chemotherapy (NAT). In 170 DTC-positive patients after NAT an additional slide of bone marrow aspirate was stained by double immunofluorescence to detect SOX2-positive DTCs. The SOX2 status of the primary tumor was assessed using the same antibody. The SOX2-status of DTCs was determined in 62 patients and 20 of those (32%) had SOX2 positive DTCs. The SOX2 status of DTCs was not associated with any of the clinicopathological factors. A total of 36% of the patients with a SOX2-negative tumor showed SOX2-positive persistent DTCs. SOX2-positive DTCs can be detected in breast cancer patients after NAT, even in patients with SOX2-negative primary tumors. This suggests that these populations may have evolved independently of each other.