Epithelial-Mesenchymal Transition in Tumor Cells and Activated Intra-Tumor Immunity Respectively Are Correlated With Prognosis and Chemo-Sensitivity in Breast Cancer Patients With a Non-pathological Response to Neoadjuvant Chemotherapy

To clarify whether changes in biological features of breast tumor cells and intra-tumor immunity after neoadjuvant chemotherapy (NAC) may correlate with pathological responses and prognosis in breast cancer patients treated with NAC, we investigated various biomarkers using both pre- and post-NAC tumor samples. The study subjects were 24 primary breast cancer patients, who were treated with NAC at the Department of Breast and Thyroid Surgery, Kawasaki Medical School Hospital between 2010 and 2011. All of them had a non-pathological complete response (pCR) to NAC and their pre- and post-NAC tumor samples were available for biomarker assays. Ki67 labeling index, apoptosis, factors related to cancer stem cells and epithelial-mesenchymal transition, tumor infiltrating lymphocytes (TILs), and expression levels of CD-8, CD-4, FoxP3, PD-L1, and PD-1 were studied using the paired samples. Biological characteristics of residual tumors such as nuclear grade (NG) and vascular invasion (v) were also investigated. The median age was 53 years-old and 14 patients had stage III tumors, while 10 had stage II tumors. A higher expression level of CD8, CD4, or PD-1 in pre-NAC samples and of CD8, CD4 or PD-L1 in post-NAC samples was significantly correlated with a better pathological response to NAC. Positivity of ZEB1, vimentin, and v or NG 3 in post-NAC samples was significantly correlated with either worse disease-free survival (DFS) or worse overall survival (OS) by univariate analyses. Multivariate analyses for DFS and OS revealed that positivity for v and vimentin expression in residual tumors were independent prognostic factors in this study. These findings indicate that activated intra-tumor immune microenvironments may play significant roles in pathological responses to NAC, and that the up-regulation of vimentin and v-positivity in residual tumors may be pivotal prognostic factors in non-pCR cases to NAC.