(A–D) Representative BPH mixed nodule (no. 9a) showing (A) H&E-stained transverse cross section through prostate (urethra center), with red square marking transition zone location of BPH nodule. (B) Magnified view with nodule border (and microdissected region) demarcated by red-dashed line. Blue square indicates further magnified region shown for immunohistochemistry (brown staining) of (C) CD20 (B cells) and (D) CD3 (T cells). Scale bars: 1 cm (A) and 1 mm (B–D). (E–H) Stacked bar graphs depict cumulative frequency of top 10 clonotypes for (E) BCR clonotypes across BPH nodules; and (F–H) TCR clonotypes across (F) BPH nodules (color-coded by nodule type), (G) normal prostate (peripheral zone, PZ), and (H) age-matched blood samples. Samples ordered by cumulative top 10 clonotype frequencies. (I–N) Scatter plots comparing (I–J) BCR versus TCR (I) top clonotype (frequencies), (J) top 10 clonotypes (cumulative frequencies), and (K) Shannon diversity index. Data are presented as mean ± 1 SD. ***P < 0.001 by 2-sided Student’s t test. NS, not significant. (L–N) Scatter plots comparing TCR (L) top clonotype (frequencies), (M) top 10 clonotypes (cumulative frequencies), and (N) Shannon diversity index among stroma-rich nodules, epithelial nodules, normal prostate (PZ), and blood. Data are presented as mean ± 1 SD. **P < 0.01, ***P < 0.001 by 1-way ANOVA with Tukey’s multiple-comparison test.