OBJECTIVES To ascertain the role and prognostic value of antigen-presenting molecules and chemokines in the prophylactic effect of intravesical bacille Calmette-Guerin (BCG) in tumor recurrence. We compared its gene expression in urothelium biopsy and tumor specimens from patients who had undergone BCG immunotherapy. METHODS Patients with nonmuscle-invasive bladder cancer were divided into 3 groups, according to the cancer recurrence status: group 1, primary cancer without recurrence for a minimal period of 12 months, group 2, primary cancer with Subsequent recurrence; and group 3, recurrent cancer at study entry. From each patient, cancerous bladder tissue and biopsy specimens of the urothelium (before and 3 months after transurethral resection of the bladder) were collected. The RNA levels of the antigen-presenting molecules CD1a, CD1b, CD1c, CD1d, CD1e, and major histocompatability complex-I, class I (MHC-I) and the chemokines macrophage inflammatory protein-la, monocyte chemoattractant protein-1 and -2, interferon-inducible protein 10 kD (IP10), and monokine induced by gamma-interferon (MIG) were evaluated using real-time polymerase chain reaction on all samples. RESULTS Generally, BCG treatment increased the Urothelium expression of antigen-presenting molecules and chemokines. However, the differences for CD1a (P = .005), CD1b (P < .000), CD1c (P = .03), CD1e (P =.007), MHC-I (P < .000), MIG (P < .0001), and IP10 (P < .0001) were significantly superior in the BCG-treated Urothelium of group I compared with the other groups. Tumor tissue from group 1 also had increased expression of MHC-I (P = .04) and contrasted with tumor tissue from group 3 with decreased expression of CD1c (P = .007) and CDle (P = .02). CONCLUSIONS Patients without recurrence had greater increased urothelium expression of antigen-presenting molecules and chemokines after BCG treatment. These parameters might, therefore, Serve to predict and monitor the efficacy of BCG immunotherapy. UROLOGY 74:944-950, 2009. (C) 2009 Elsevier Inc.