Characterization of the intra-prostatic immune cell infiltration in androgen-deprived prostate cancer patients

Our goal was to study the hormonal regulation of immune cell infiltration in prostate cancer patients treated by androgen deprivation therapy (ADT) using an optimized computer-assistance quantification approach.The relative density of immune cell subtypes (CD3(+), CD8(+), CD20(+), CD56(+), CD68(+) and Foxp3(+)) was analyzed by immunohistochemistry in archived prostate specimens from control patients (radical prostatectomy only, n=40) and ADT-treated patients (ADT prior to radical prostatectomy, n=35) using an image analysis software and a whole-slide scanner.ADT-treated patients had significantly increased relative density of CD3(+) (p<0.001) and CD8(+) T lymphocytes (p<0.001) as well as CD68(+) macrophages (p<0.001). Elevated abundance of CD56(+) Natural Killer (NK) cells was associated with a lower risk of prostate cancer progression (p=0.044), while a high density of CD68(+) macrophages was related to an increased risk of biochemical recurrence (p=0.011).Our results demonstrate that the infiltration of specific immune cell subtypes is modulated by ADT. Furthermore our data confirm that NK cells have a protective role against tumor progression while macrophages seem to favor the development of advanced prostate cancer.