ROR1 and Richter syndrome: ROR1 expression was more frequently observed in primary refractory DLBCL (7/11, 83%), Richter ́s syndrome (9/10, 90%) and transformed follicular lymphoma (9/11, 82%) than in relapsed (8/22, 36%) and non-relapsed DLBCL patients (10/30, 33%) (p < 0.001) (Figure 1e).