Putative Biomarkers of Response to Treatment in Breast Cancer Patients: A Pilot Assay

Identifying tumor biomarkers associated with clinical behavior in breast cancer patients may allow higher accuracy in the selection of treatment. Different types of cells were determined in the primary tumors of stage I, II, and III of breast cancer patients, who were assigned to one of the two groups: (1) disease-free or (2) relapsed/progressed, at 5 years after primary treatment. We studied 32 tumor samples. CD4⁺ lymphocytes and CD44⁺CD24^-/low cells (cancer stem cells) showed a significant association with clinical outcome at 5 years of primary treatment, while CD8⁺, Foxp3⁺, CD34⁺, and myeloid-derived suppressor cells did not show any association. Coincident with the results of individual analysis, we identified CD4⁺ cells and CD44⁺CD24^-/low cells as good predictors of long-term clinical outcome in a logistic regression.