1097 Background: The cancer stem cell theory that was established for hematopoietic neoplasms has significantly changed the concept of cancer therapy. Aldehyde dehydrogenase 1 (ALDH1)-positive cells show stem-like or progenitor ability, and have been considered as a clinically important diagnostic and therapeutic target in breast cancer patients. However, responsiveness of ALDH1-positive cells to chemotherapy in primary and metastatic lesions remains unclear, along with relationships to prognosis in patients with breast cancer. This study evaluated responsiveness to chemotherapy in the ALDH1-positive cells for primary and metastatic lesions and relationships to prognosis in patients with node-positive breast cancer. Methods: We evaluated 115 breast cancer patients with cytologically confirmed lymph node metastases who had undergone surgery after neoadjuvant chemotherapy (NAC). Using ALDH1 immunohistochemistry of core needle biopsy for the primary tumor and cytology samples for axillary lymph nodes before NAC and pathological samples of each after NAC, we evaluated the clinical significance of ALDH1-positive cell status in primary and metastatic lesions before and after NAC. Results: Presence of ALDH1-positive cancer cells, not ALDH1-negative cancer cells, in primary and metastatic lesions after NAC was associated with worse prognosis. In multivariate analysis, only ALDH1-positive cells in metastatic lesions after NAC correlated with overall survival. Responsiveness of ALDH1-positive cells to chemotherapy differed between primary and metastatic lesions, and ALDH1-positive cells in metastatic lesions after NAC might clinically precede those in the primary lesion. Conclusions: Responsiveness of the ALDH1-positive cells to chemotherapy in primary and metastatic lesions, and the prognostic significance, were clarified in breast cancer patients. ALDH1-positive status might offer a surrogate marker as a new concept in patients with node-positive breast cancer.
Differentially expressed genes between primary cancer and paired lymph node metastases predict clinical outcome of node-positive breast cancer patients
