e12620 Background: Preoperative neutrophil-lymphocyte ratio (NLR) have been suggested to be correlated with the prognosis of patients with breast cancer (BC). However, the results still remain controversial. The goal of our study was to evaluate the predictive and prognostic value of NLR in early stage triple negative and HER2-pos breast cancer patients undergoing NAC. Methods: 96 female patients (pts) with histologically proven breast cancer (51 TNBC, and 45 HER2 pos) were analysed in this retrospective analysis. The NLR before the initiation of NAC was documented. Histopathological response in surgically removed specimens was evaluated using the Residual Cancer Burden (RCB) Calculator (by MD Anderson Cancer Center). The pCR was defined as no invasive tumor in primary tumor bed and lymph nodes. The NLR variable was analyzed as both continuous and categorical. The impact on pCR and RCB was tested using Mann-Whitney, Kruskal-Willis or the Chi-2 test, respectively. Results: Only 4 categories of NAC were used: in TNBC 4 x ACdd followed by 12 x PCL (38 pts) or 4 x ACdd followed by 12 x PCL+ carboplatin AUC 1.0-2 (13 pts), in HER2-pos 39 pts received 6 x TCH (docetaxel + tratuzumab + carboplatin AUC 6) and 6 pts 4 x ACdd followed by 12 x PCL iv + 4 x trastuzumab. In 27 pts (53%) with TNBC and 24 pts (53%) with HER2-pos breast cancer pCR was obtained after NAC. RCB distribution was: 0-53.1%, 1-22%, 2-17.6%, 3-7.3%. No association with NLR and pCR could be observed (p > 0.26). No association with NLR and RCB could be observed (p > 0.18). Conclusions: In our retrospective analysis we could not demonstrate predictive or prognostic value of NLR in the cohort of early stage triple negative and HER2-positive breast cancer patients treated with NAC. Further studies are planned in a group of patients with Luminal B, HER2 – negative breast cancer, who received NAC.