Overview of the study design and patient flow. FFPE tissue samples of 870 FL specimens were subjected to NanoString-based GE measurements. Following quality control and normalization, 680 of 870 tumor samples (78%) remained and were subsequently analyzed to develop a prognostic model in advanced-stage FL (n = 556; separated into training and validation cohorts) or to investigate for the differential GE of localized-stage FL (n = 110) and advanced-stage FL.