Breast cancer is the most frequently diagnosed cancer type and the second-leading cause of cancer-related deaths among women worldwide. The causes of breast cancer are not yet fully known, although a number of risk factors have been identified. Tumor biomarker is a term used to describe potential markers of cancer development and progression. As we explore these biomarkers further, we must try to understand the underlying mechanisms of tumor development, as we move along the path to discovery of novel therapies that will increase our ability to offer personalized patient care in the future. With the migration of advanced high throughput technologies, such as Next Generation Sequencing from clinical practice, biomarker research and discovery are poised to explode once again. Translation of novel biomarkers into clinical practice and diagnostic laboratories is coupled with regulatory and administrative requirements that must be met, while collaboration between research institutions, industry, and the private sector drives further advancements in the field of breast cancer biomarker discovery and application.

The aim of this special issue is to provide new findings regarding molecular pathways and biomarkers that could improve the diagnosis and the prognostic classification of breast cancers, their application in the clinical setting, and their potential utility in personalized patient therapy.

Potential topics include but are not limited to the following:

• Next-generation sequencing of breast cancer
• Biomarkers in breast cancer prognosis
• Biomarkers in breast cancer diagnosis
• Pathogenesis of breast carcinoma
• Breast cancer epigenomics