Fig. 1From: Molecular signature of response to preoperative radiotherapy in locally advanced breast cancera Infographic summarizing treatment protocol and sample collection of locally advanced breast cancer patients treated at the Institute of Oncology and Radiology of Serbia between 1997 and 2000 (IORS-LABC cohort). The IORS-LABC cohort included 134 patients who had initial biopsy taken before any treatment, followed by radiotherapy and radical mastectomy. Exceeding tumour material was formalin-fixed and paraffin embedded (FFPE) and stored at room temperature. b Flowchart representing the study outline for sample processing, quality control, data analysis and biomarker validation. FFPE samples were review by a pathologist to select those with > 70% of tumour material, retaining 118 pre-RT biopsy tumour samples (a) and 21 post-RT tumour samples (b). These samples were split into discovery (NA = 22 pre-RT and NB = 21 post-RT) and validation (NA = 96) subsets. After quality control of extracted RNA only 23 samples from the discovery subset were selected for microarray hybridization (NA = 18 and NB = 5), of which only 14 (NA = 11 and NB = 3) passed data quality control. Out of 96 pre-RT samples designated for validation, only 60 had passed RNA quality control and were used for qRT-PCR. Of those, 42 samples passed data quality control and were retained for the downstream analysisBack to article page