Intra-tumoral B-cell density compared to and extra-tumoral B cell density in each D'Amico risk group. Box plots representing the B-cell density inside the delineated tumor region (intra-tumoral) and outside the tumor regions (extra-tumoral) in radical prostatectomy speciments. B cell density was defined as: the area of CD20 positive staining (mm2)/ total area analyzed ie. intra-or extra-tumoral prostatectomy tissue region in each section. The B cell densities in the intra-tumoral regions were compared to the extra-tumoral regions in each of the D'Amico risk groups: low (n = 10), intermediate (n = 9), and high (n = 15) and in the group of patients with known prostate cancer recurrence (n = 26). The median B cell density is shown as the horizontal line in each box plot. Asterisk over recurrence group indicates outlier.