Significance of Tumor-Infiltrating Lymphocytes and the Expression of Topoisomerase IIα in the Prediction of the Clinical Outcome of Patients with Triple-Negative Breast Cancer after Taxane-Anthracycline-Based Neoadjuvant Chemotherapy

<b><i>Purpose:</i></b> The aim of this study was to determine factors able to predict chemotherapeutic responses and clinical outcomes in patients with triple-negative breast cancer (TNBC) after neoadjuvant chemotherapy (NAC). <b><i>Methods:</i></b> Fifty-two TNBC patients on taxane-anthracycline-based NAC were included. The expression of Ki67, topoisomerase IIα (TOPOIIα), and p53, as well as the presence of CD4+ tumor-infiltrating lymphocytes (TILs) and CD8+ TILs were evaluated in biopsy specimens by immunohistochemistry. The expression of Ki67, TOPOIIα, and p53, as well as CD4 and CD8 in TILs was calculated according to the pathological response to NAC, disease-free survival (DFS), and overall survival (OS). <b><i>Results:</i></b> Fourteen (26.9%) TNBC patients demonstrated a pathological complete response (pCR). According to univariate analyses, significant factors associated with pCR were high infiltration of CD4+ TILs (<i>p = </i>0.004), high infiltration of CD8+ TILs (<i>p = </i>0.010), and high expression of topoisomerase IIα (TOPOIIα) (<i>p = </i>0.006). CD4+ TILs and TOPOIIα were significantly positively correlated with CD8+ TILs. Multivariate analyses indicated that TOPOIIα was an independent predictor of pCR. Although TNBC patients with high infiltration of CD4+ TILs, CD8+ TILs, or with high expression of TOPOIIα exhibited a significantly good 5-year DFS, only TNBC patients with a high infiltration of CD8+ TILs exhibited significantly positive 5-year OS probabilities. <b><i>Conclusion:</i></b> Our study demonstrated that CD4+ TILs and TOPOIIα in pretreated cancer tissues were significantly correlated with CD8+ TILs. CD4+ TILs, CD8+ TILs, and TOPOIIα expression were predictors of pCR and 5-year DFS of TNBC patients who were treated with NAC, and TOPOIIα was an independent predictor of pCR. CD8+ TILs were a key factor in the prediction of good 5-year OS rates of TNBC patients after taxane-anthracycline-based NAC.