As loss of both HLA class I and II expression constitutes a recurrent driver in aggressive B-cell lymphoma pathogenesis and TCR-mediated anti-tumor activity requires an intact HLA apparatus, we were intrigued to observe a substantial subgroup of patients harboring an immunohistochemical loss of B2M and/or HLA-DR which did however not impact clonality measures (Figure 1A–E) [26,27]. Here, B2M is linked to B-cell non-Hodgkin lymphoma.