A critical review why assessment of steroid hormone receptors in breast cancer should be quantitative.

Steroid receptors have been around in the field of breast cancer for decades now. Still, controversy remains on how best to report steroid receptors. In this review, we will convince the reader why benefits outweigh pitfalls, when reporting steroid receptors in a quantitative rather than qualitative way. Summarizing decades of research in this field, we will explore the evidence why quantitative reporting is superior in all settings (neoadjuvant, adjuvant and metastatic settings). Furthermore, we will also summarize different staining methods, definitions and pitfalls that have shown to be important points of discussion in earlier debates. Although the molecular unraveling of breast cancer in the past decade has revolutionized the way we think about breast cancer, we should not easily abandon the classical pathological variables such as steroid receptors in favor of molecular tools.