Thymosin beta 15A (TMSB15A) is a predictor of chemotherapy response in triple-negative breast cancer

Background: Biomarkers predictive of pathological complete response (pCR) to neoadjuvant chemotherapy (NACT) of breast cancer are urgently needed. Methods: Using a training/validation approach for detection of predictive biomarkers in HER2-negative breast cancer, pre-therapeutic core biopsies from four independent cohorts were investigated: Gene array data were analysed in fresh frozen samples of two cohorts (n=86 and n=55). Quantitative reverse transcription polymerase chain reaction (qRT–PCR) was performed in formalin-fixed, paraffin-embedded (FFPE) samples from two neoadjuvant phase III trials (GeparTrio, n=212, and GeparQuattro, n=383). Results: A strong predictive capacity of thymosin beta 15 (TMSB15A) gene expression was evident in both fresh frozen cohorts (P