Breast cancer is a heterogeneous group of different histological subtypes, which are based on various molecular and genetic factors. All patients are given radiotherapy after breast-conserving surgery, which is actually considered unnecessary in two-thirds of these patients. Therefore, the fact that which patients should be administered radiotherapy has gained great importance. In this respect, known clinical and histopathological prognostic factors can not be sufficient to predict local control. Today, genetic and biotechnological advances caused significant progresses in molecular oncology, which is reflected in clinical oncology. In this article, molecular and genetic predictive factors that could be effective in the local control of breast cancer have been focused on, and a review of studies data conducted on the predictive value of the factors such as molecular classification, multigene tests, radiation resistance, DNA repair capacity, signaling pathways, cancer stem cells, and inhibition of CYP2D6 on local control was presented.

Keywords: breast cancer, signal pathways, genetic, molecular structures, neoplastik stem cells, hypoxia, CYP2D6