Comparison of risk assessment in 1652 early ER positive, HER2 negative breast cancer in a real-world data set: classical pathological parameters vs. 12-gene molecular assay (EndoPredict).

Background: Risk assessment on the molecular level is important in predictive pathology to determine the risk of metastatic disease for ERpos, HER2neg breast cancer. The gene expression test EndoPredict (EP) was trained and validated for prediction of a 10-year risk of distant recurrence to support therapy decisions regarding endocrine therapy alone or in combination with chemotherapy. The EP test provides the 12-gene Molecular Score (MS) and the EPclin-Score (EPclin), which combines the molecular score with tumor size and nodal status.

PIK3CA mutations are associated with lower rates of pathologic complete response to anti-human epidermal growth factor receptor 2 (her2) therapy in primary HER2-overexpressing breast cancer.

Purpose: Phosphatidylinositol 3-kinase (PI3K)/AKT pathway aberrations are common in breast cancer, with mutations in PIK3CA being the most common. This study investigated the association between PIK3CA genotype and pathologic complete response (pCR) rates in human epidermal growth factor receptor 2 (HER2)-positive breast cancer treated with either dual or single anti-HER2 treatment in addition to neoadjuvant chemotherapy.

Patients And Methods: PIK3CA mutations in 504 tumor samples from participants in the neoadjuvant GeparQuattro, GeparQuinto, and GeparSixto studies were evaluated.