The 2019 World Health Organization classification of tumours of the breast

Abstract

The newly published World Health Organization (WHO) Classification of Tumours of the breast features significant changes compared to earlier editions. In this review, we outline the major changes in this important reference source for those diagnosing tumours, or engaged in cancer research, and describe the significant changes. For breast cancer, the overview acknowledges the treatment-relevant subtypes of invasive carcinoma (based on ER and HER2 status) and new data is added to support the differences in pathogenesis, treatment response and prognosis of these clinically relevant groupings. The WHO Classification of Tumours is increasingly evidence-based, with a clear update cycle, improved ..