Figure 2.

B lymphocyte infiltration and its positive prognostic value in TNBC. A, TIL-B quantification by IHC within normal breasts and TNBC (N = 15 each, Bart's IHC cohort), and by GEx (normal breast) vs. TNBC (N = 10 vs. 131, KCL GEx cohort); non-TNBC vs. TNBC (N = 515 vs. 123, TCGA GEx cohort); TNBC subtypes [mesenchymal (M), luminal androgen receptor (LAR), basal-like 1 and 2 (BL1 and 2), and immunomodulatory (IM; N = 122, KCL GEx cohort]. The Mann–Whitney test was used for statistical significance. B, TNBC TIL-B correlation with TIL-T by IHC (r = 0.72, Bart's IHC cohort) and by GEx (r = 0.73, KCL GEx cohort). Linear regression analysis was used to calculate correlation coefficients (r) and P values. C, B lymphocyte metagene NanoString GEx data comparing B lymphocytes in primary tumors with metastatic sites (N = 31 vs. 17; NanoString cohort). D, High (above median) TIL-B densities by IHC were associated with better overall survival in TNBC (N = 15; Bart's IHC cohort), and in the basal-like subtype by high CD20 GEx (N = 241; KM plotter cohort; log rank test used to assess statistical significance). E, Kaplan–Meier survival curves display DMFS for naïve B cells, plasma cells, and memory B cells in TNBC (KCL GEx cohort) using CIBERSORT (20). Data were divided into four groups based on B lymphocyte subset and TIL levels stratified by semiquantitative TIL classification. Statistical significance was assessed using univariate Cox proportional hazards regression models. F, Representative IHC/IF images (Bart's IHC cohort) depicting nucleated cells (DAPI), epithelial cells (PanCK), B lymphocytes (CD20), and T lymphocytes (CD3) within TNBC TIL-B^low and TIL-B^high lesions. Scale bar, 50 μm. G, Representative TNBC (TIL-B^high) images highlighting numerous lymphoid aggregates (within white dash lines) consisting of B lymphocytes assembled adjacent to a T lymphocyte zone. Brown dash lines indicate carcinoma edge. Scale bar, 2 mm. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001.