IGLL5 and classic Hodgkin lymphoma: The most frequently mutated genes in pre-treatment plasma samples were SOCS1 in 52% of cHL patients, followed by KMT2D (36%), TNFAIP3 (31%), IGLL5 (26%), GNA13 (24%), CREBBP (21%), ARID1A, CSF2RB, STAT6 (19%), B2M, BCL7A (17%) and NOTCH2 (14%) (Fig. 1).