Breast carcinoma: Is molecular evaluation a necessary part of current pathological analysis?

Breast cancer is the most common women cancer and is the second leading cause of cancer-related mortality in women. While the last two decades revolutionized breast cancer treatment with the development and use of therapies targeting steroid receptors and HER2/neu, there are limits to the risk estimation provided by traditional clinicopathologic parameters and IHC. Therefore, there is continued potential for inaccurate risk stratification of breast cancer patients which may lead to over- or under-treatment. In this review, we discuss the latest developments in the area of breast cancer research which have lead to better understanding of the breast cancer mechanisms, provided more accurate risk stratification, and identified potential new treatment targets. Specifically, we review the new dualistic model of breast carcinogenesis, which can inform pathologic diagnosis and tumor grading; we also discuss the intrinsic molecular classification of breast cancer and its impact on diagnosis and treatment; lastly, we compare the most common commercial molecular prognostic and predictive assays, with their respective strengths and weaknesses, and their clinical utility.