Molecular Pathology and Diagnostics of Breast Cancer

Proper treatment of breast cancer often depends on timely and accurate diagnosis. Due to the heterogeneic nature of breast cancer, it is important to continually develop diagnostic methods and tools that strive to provide consistent and reliable results for optimal patient specific care. Early microscopic observations of tumor sections have revealed that specific morphological structures of the mammary gland, such as luminal or basal layers, are often mimicked by cancer cells. This has resulted in a hypothesis that hyperplastic cells originate from their respective anatomical sites. Newer findings now suggest breast cancer arises from mammary stem or progenitor cells, which then differentiate into various lineages by molecular mechanisms not yet fully understood. Subtypes of breast cancers are reliably labeled aggressive, including triple negative and hereditary breast cancers. Molecular diagnosis is currently available through various platforms, including: MammaPrint®, Veridex®, Theros®, and Oncotype DX®, which have improved the resolution of diagnosis. Significant advancements in a variety of scientific disciplines in basic research, integration of next-generation sequencing technologies, and innovative computational and mathematical methods in integration of diverse data types on a large scale will likely translate into clinical applications such as breast cancer diagnosis.