Aim: Determination of cut-off value for Ki67 index, it’s corelation in luminal breast carcinoma with patient’s age, tumor size, histological grade (HG), and expression of estrogen (ER) and progesterone (PR). Introduction: Breast cancer is a heterogeneous disease characterized by different morphology, immunohistochemical profile, clinical course and response to applied therapy. Ki67 proliferative index is one of the prognostic and predictive factors, whose methodological determination and analysis are still unstandardized. Material and Methods: Retrospectively, we analysed 120 pathohistological reports of patients who were treated in the period 01.01.2009. until 31.12.2011. at the Oncology Institute of Vojvodina, and to whom immunohistochemistry was proven luminal breast cancer (positive ER and PR, negative HER2), without axillary lymph node metastases. Results: The average patient’s age was 57.42±10.17 years; average tumor size 17.98±6.97mm; recurrence was registered in 8 (6.7%) patients with average recurrence time of 49±20.23 months. “Cut off” Ki67 value of prognostic significance for period without recurrence is 20.75%. For correlation testing χ2 and Kendal τ-b tests were used. It’s shown unsignificant relationship between Ki67 and patient’s age (p=0.401 and p=0.293), as well as the strength of expression ER (p=1.00, p=0.957) and PR (p=0.273, p=0.189). Significant correlation is present for Ki67 with size (p=0.035, p=0.20) and tumor’s HG (p=0.041, p=0.20). Conclusion: Breast carcinoma is heterogeneous disease, so it’s difficult to predict its course and outcome using standard histopathological factors and biomarkers. For prognostic-predictive purposes, it’s necessary to include additional biomarkers, where Ki67 stands out above all, whose high value correlates with factors of bad prognosis.

Aim: The aim of our study was to evaluate status of estrogen and progesteron hormone receptors (ER and PR), and HER2 receptors in diagnostic core biopsy specimens, compared to surgical resection specimens of the same patients after NAC regimens all including trastuzumab. Introduction: Neoadjuvant chemotherapy (NAC) is associated with phenotypic alteration in breast carcinoma, especially with the change of molecular phenotype through the modulation of hormone and HER2 receptors expression. Material and Methods: The study included 35 patients with HER2-amplified locally advanced breast carcinoma that were treated with NAC regimens that included trastuzumab, and which had receptors status determined on pre-NAC core biopsy, and on surgical specimen after the completion of the therapy. Results: Pathological complete response (pCR) was observed in 4 cases (11.4%), while partial response to therapy was noted in 31 cases (88.6%). Invasive breast carcinoma of no special type (NST) was the most common histological type in 27 cases (87.1%), while the most common histological grade (HG) was HG3 in 27 cases (87.1%). There were no noted changes in histological type or grade of the carcinoma. The rates of ER and PR receptors positivity on diagnostic core biopsy compared to post-NAC surgical resection specimens were 61.29% to 67.74% and 48.39% to 64,52%, respectively. HER2 receptors status changed from positive to negative in 2 cases (6,45%). Conclusion: Changes in status of the receptors in breast carcinoma after NAC is significant due to implications in tailored therapy approach, and subsequent modification of adjuvant therapy regimens.