IGHM and Hodgkins lymphoma: In non-relapsed pediatric HL, the more abundant spots were identified as five unique proteins: isoform 2 preproprotein of complement C4-A (C4-A), complement C4-B (C4B), fibrinogen γ chain (FGG), inter-α-trypsin inhibitor heavy chain H2 (ITIH2), and immunoglobulin heavy chain constant region mu (IGHM).