Stem cell markers: A guide to neoadjuvant therapy in breast carcinomas.

Abstract

This study aims to investigate potential associations between the stem cell population and the degree of tumor regression in breast carcinomas treated with neoadjuvant therapy. The study included 92 patients with breast carcinoma who received neoadjuvant therapy. Tumor regression was defined based on Miller and Payne grading system. Patients with grade 1 or 2 regression on a 5-point scale were included in group 1 (n = 37), grade 3 regression in group 2 (n = 32), and grade 4 or 5 regression in group 3 (n = 23). Immunohistochemical staining was performed on paraffin block sections of every case using CD44, CD24, CD29, CD133, ID4, and ALDH1 antibodies to detect stem cells. IBM Statistical Package for the Social Sciences (SPSS), version 23.0 (IBM Corp., Armonk, NY, USA) software was used for statistical analyses, and a P value less than 0.05 was considered statistically significant. Histologically high-grade tumors are more common in the near-complete/complete response group (P = 0.004). HER2-positive tumors were more common in the complete/near-complete response group (P = 0.054). Tumor cells positive for stem cell markers CD44 and CD24 were more common in the poor response group (P = 0.027 and P = 0.001, respectively). CD29 expression was reduced in the posttreatment residual tumor tissue in the near-complete/complete response group. High CD44 and CD24 expression may be a predictor of poor response/nonresponse to neoadjuvant therapy in breast carcinomas. In recent years, stem cells have been defined as the main cell population responsible for resistance to anticancer therapies.