B2M and diffuse large B-cell lymphoma: The majority of CD58 alterations lead to the expression of a truncated, nonfunctional protein.159 While CD58 expression is normally high in GC B cells compared to naive B cells, surface protein expression is lost in DLBCL cases featuring CD58 alterations.159 Furthermore, CD58 expression levels modulate the cytolytic capacity of NK cells in vitro.159 The frequent combined loss of both CD58 and B2M in DLBCL may therefore enable lymphoma B cells to escape recognition by the two arms of antitumor immunity, ie, CD8+ T cells and NK cells (Figure 5).