FGL2 and neoplasm: Further elucidating the detrimental impact of FcγRIIB+CD8+ T cell death, linear regression showed that the frequency of FcγRIIB+CD8+ T cells was negatively associated with tumor size in WT HSC–reconstituted mice (R2 = 0.58, P = 0.0101; Supplemental Figure 4A) but not in Fgl2–/– HSC–reconstituted mice (Supplemental Figure 4B).