Breast cancer is the most frequently diagnosed cancer and leading cause of cancer-related death among females worldwide. In this article, we investigate the applicability of densely connected convolutional neural networks to the problems of histology image classification and whole slide image segmentation in the area of computer-aided diagnoses for breast cancer. To this end, we study various approaches for transfer learning and apply them to the data set from the 2018 grand challenge on breast cancer histology images (BACH).Keywords: digital pathology, breast cancer, deep learning 1. mitotic activity as a measure of cellular proliferation, 2. nuclear pleomorphism, i.e. how different the tumor cells are in comparison to normal cells, and 3. glandular and tubular differentiation, i.e. how well the tumor resembles normal structures.Current developments in the area of digital pathology are driven by the observation that genetic and phenotypic intra-tumor heterogeneity have a direct impact on both diagnosis and disease management [18] as well as the availability of effective machine learning techniques, such as deep convolutional neural networks. Particularly the segmentation of WSIs, i.e. the second part of the BACH challenge, plays an increasingly important role as it facilitates not only a standardized assessment of resection margins, but also novel scoring approaches, such as the ImmunoScore [11], and a better understanding of tumor heterogeneity and micro-environment, e.g. via phenotype-guided genetic readouts.