TNF and benign prostatic hyperplasia: In another study, it was used for to investigate the association of the expression of tumor necrosis factor-α (TNF-α) with asymptomatic inflammatory prostatitis National Institutes of Health (NIH) category IV and prostatic calculi, in patients with obstructive benign prostatic hyperplasia (BPH) treated by transurethral electroresection of the prostate (TURP) (30).