Adenovirus-mediated tissue-targeted expression of a caspase-9-based artificial death switch for the treatment of prostate cancer.

Clinical experience with suicide gene therapy for prostate cancer using first-generation approaches has provided a basis for developing improved strategies. Given the low proliferation rate exhibited by prostate cancer, one improvement would be to develop suicide genes that effectively kill both dividing and nondividing cells. A second improvement would be to restrict cytotoxicity to prostate cancer cells, limiting injury of nondiseased tissue. Here we describe a novel approach to achieving both goals based on: (a) the use of a small, but potent, prostate-specific composite promoter, ARR(2)PB, based on the rat probasin gene; and (b) the use of a powerful artificial death switch, called inducible caspase-9 (iCaspase-9). ARR(2)PB includes two copies of the androgen response region (ARR), each containing two androgen receptor (AR)-binding sites, placed upstream of the probasin promoter elements necessary for basal transcription. Because iCaspase-9 contains two binding sites for the dimeric ligand, AP20187, administration of chemical inducers of dimerization leads to aggregation and caspase activation, followed by rapid apoptosis in both dividing and nondividing cells. Using both reagents, we constructed two novel adenoviruses (ADVs), ADV.ARR(2)PB-iCasp9 expressing iCaspase-9 and control ADV.ARR(2)PB-EGFP expressing enhanced green fluorescent protein (EGFP). We demonstrate that tissue specificity is not sacrificed in an ADV backbone because the marker protein, EGFP, is expressed in R1881-stimulated ADV.ARR(2)PB-EGFP-transduced LNCaP cells but not in AR(-) PC-3, 293, HuH-7, U-87, and MCF-7 cells. Similarly, Pro-iCaspase-9 is expressed in ADV.ARR(2)PB-iCasp9-infected LNCaP cells after R1881 administration and is activated after AP20187 administration. In vitro experiments revealed rapid and efficient iCaspase-9-induced apoptosis of LNCaP cells in both an R1881- and AP20187-dependent manner. Only 28, 8, and 0.5% survival of LNCaP cells was seen at multiplicities of infection of 2, 10, and 25, respectively. Furthermore, at a multiplicity of infection of 10, extraordinary sensitivity to AP20187 was seen (IC(50), approximately 3 pM). In vivo experiments showed that ADV.ARR(2)PB-iCasp9 induced apoptosis in LNCaP but not in HuH-7 xenograft tumors in an AP20187-dependent manner. Furthermore, a simple i.p. injection of AP20187 dramatically suppressed LNCaP tumor growth in nude mice and led to a significantly increased host survival. This study demonstrates the feasibility of using tissue-specific expression of cell cycle-independent iCaspases as a nonmutagenic alternative modality for prostate cancer suicide gene therapy.

Adenovirus-mediated transfer of inducible caspases: a novel "death switch" gene therapeutic approach to prostate cancer.

In patients with localized prostate cancer, radical prostatectomy and radiation therapy, although effective in controlling localized disease, are often associated with significant side effects attributable to injury of adjacent tissues. Moreover, patients with metastatic disease eventually fail systemic hormonal or chemotherapy because of the development of progressive, refractory disease. In this study, we evaluated the safety and efficacy of a novel suicide gene therapy that could potentially spare normal tissue while bypassing molecular mechanisms of apoptosis resistance by using chemically inducible effector caspases to trigger apoptosis in prostate cancer cells. Initially, we compared the ability of a panel of inducible Fas signaling intermediates to kill human and murine prostate cancer cell lines. On the basis of the superior killing by downstream caspase-1 and caspase-3, replication-deficient adenoviral vectors expressing conditional caspase-1 (Ad-G/iCasp1) or caspase-3 (Ad-G/iCasp3), regulated by nontoxic, lipid-permeable, chemical inducers of dimerization (CID), were constructed. Upon vector transduction followed by CID administration, aggregation and activation of these recombinant caspases occur, leading to rapid apoptosis. In vitro, both human (LNCaP and PC-3) and murine (TRAMP-C2 and TRAMP-C2G) prostate cancer cell lines were efficiently transduced and killed in a CID-dependent fashion. In vivo, direct injection of Ad-G/iCasp1 into s.c. TRAMP-C2 tumors caused focal but extensive apoptosis without evidence for a bystander effect at the maximal viral dose (i.e., 2.5 x 10(10) viral particles/25 microl) in host animals that also received CID compared with control animals. Treatment with Ad-G/iCasp1 plus CID resulted in a transient, yet significant, reduction both in tumor growth and volume compared with tumors treated with vector but not CID (P < 0.035) or vector-diluent plus CID (P < 0.022), both of which grew more rapidly. These results demonstrate that CID-regulated, caspase-based suicide gene therapy is safe and can inhibit the growth of experimental prostate cancer in vitro and in vivo through potent induction of apoptosis, providing a rationale for further development.

Detection of metastatic prostate cancer using a splice variant-specific reverse transcriptase-polymerase chain reaction assay for human glandular kallikrein.

We developed a highly sensitive splice variant-specific reverse transcriptase-PCR (RT-PCR) assay for human glandular kallikrein (hK2) mRNA and tested its ability to detect metastatic disease in men with clinically localized prostate cancer. An RT-PCR assay using primers spanning intron IV and including a significant portion of the 3' untranslated region of the hKLK2 gene, with maximum nonhomology to both hK1 and hK3, was developed. The limit of detection of the assay was five copies of hK2 cDNA and one LNCaP cell in 10(9) lymphoblasts. RT-PCR-hK2 was performed on preoperative peripheral blood specimens from 228 consecutive radical prostatectomy patients as well as 7 metastatic prostate cancer patients and 14 healthy men without prostate cancer. This new RT-PCR-hK2 assay amplifies two distinct fragments. The larger fragment (hK2-U) is approximately 680 bp in length and corresponds to the amplified product of a previously reported splice variant in the splice donor site of intron IV in the hKLK2 gene. The smaller fragment (hK2-L) is approximately 643 bp in length and corresponds to the amplified product of the native hK2 mRNA. Whereas the RT-PCR-hK2-L assay was positive in 71% of our patients with metastatic prostate cancer, 14% of healthy control men also tested positive. By univariate (P = 0.028) and multivariate (P = 0.0269) analysis, which controlled for preoperative PSA, clinical stage, and biopsy Gleason score, RT-PCR-hK2-L status added prognostic information to the prediction of lymph node-positive disease. We have developed a new RT-PCR assay which demonstrates a high sensitivity for detecting hK2 mRNA. Preoperative RT-PCR-hK2-L status helps predict pathological lymph node positivity in patients with clinically localized prostate cancer.

A precursor form of prostate-specific antigen is more highly elevated in prostate cancer compared with benign transition zone prostate tissue.

Prostate-specific antigen (PSA) is a widely used serum marker for prostate cancer (PCa), but in the critical diagnostic range of 4-10 ng/ml it has limited specificity for distinguishing early PCa from benign prostatic hyperplasia (BPH). PSA in serum is comprised of a variety of both "free" and "complexed" forms that have been used to improve the specificity of PSA for prostate cancer detection. We previously reported that pro PSA (pPSA), the zymogen or precursor form of PSA, is a component of free PSA in the serum of PCa patients. In the current study, we examined prostate tissues to understand the origin and specificity of pPSA. PSA was immuno-affinity purified from matched sets of prostate tissues including peripheral zone cancer (PZ-C); peripheral zone noncancer; and benign tissue from the transition zone (TZ), the primary site of BPH within the prostate. We found that pPSA is differentially elevated in PZ-C, but is largely undetectable in TZ. N-terminal sequencing revealed that the pPSA was comprised primarily of [-2]pPSA and minor levels of [-4]pPSA, containing pro leader peptides of 2 and 4 amino acids, respectively. The median value of pPSA was 3% in PZ-C and 0% (undetectable) in TZ (P < 0.0026). No pPSA was detected in 13 of 18 transition zone specimens (72%), but only 2 of the 18 matched cancer specimens (11%) contained no measurable pPSA. These results demonstrate that pPSA is more highly correlated with prostate cancer than with BPH. The pPSA in serum may represent a more cancer-specific form of PSA that could help distinguish prostate cancer from BPH.

Prediction of response to salvage radiation therapy in patients with prostate cancer recurrence after radical prostatectomy.

PURPOSE: To identify factors predictive of local recurrence as defined by a complete response to salvage radiation therapy in patients whose disease recurs after radical prostatectomy. PATIENTS AND METHODS: Ninety-five patients with recurrence after radical prostatectomy who were evaluated by prostatic fossa biopsies, and a subset of 49 of these patients treated with radiation for control of presumed or biopsy-proven local recurrence, were studied. RESULTS: Biopsies were positive in 40 (42%) of the 95 biopsied patients. Multivariate analysis revealed that prebiopsy prostate-specific antigen (PSA) level, postrecurrence PSA doubling time, and positive digital rectal examination (DRE) of the prostatic fossa were all statistically significant predictors of a positive biopsy. For the 49 patients subsequently treated with salvage radiation therapy, the overall actuarial 3- and 5-year PSA relapse-free probabilities were 43% and 24%, respectively. Univariate analysis showed no differences in the PSA relapse-free probabilities associated with any pathologic features of the radical prostatectomy specimen, biopsy confirmation of local recurrence, or DRE of the prostatic fossa. In multivariate analysis, controlling for all other variables, preradiation PSA and postrecurrence PSA doubling time measured before radiation were the only statistically significant predictors of outcome. CONCLUSION: DRE of the prostatic fossa, prebiopsy PSA, and postrecurrence PSA doubling time predict which patients will have biopsy-proven local recurrence. However, response to salvage radiation therapy is associated with postrecurrence PSA doubling time and with preradiation PSA level only. DRE of the prostatic fossa and biopsy confirmation of local recurrence are not associated with salvage radiation outcome.

Preoperative plasma levels of transforming growth factor beta(1) (TGF-beta(1)) strongly predict progression in patients undergoing radical prostatectomy.

PURPOSE: Elevated local and circulating levels of transforming growth factor beta(1) (TGF-beta(1)) have been associated with prostate cancer invasion and metastasis. We tested the hypothesis that preoperative plasma TGF-beta(1) levels would independently predict cancer stage and prognosis in patients who undergo radical prostatectomy. PATIENTS AND METHODS: The study group consisted of 120 consecutive patients who underwent radical prostatectomy for clinically localized prostate cancer (median follow-up, 53.8 months). Preoperative plasma levels of TGF-beta(1) were measured and correlated with pathologic parameters and clinical outcomes. TGF-beta(1) levels also were measured in 44 healthy men without cancer, in 19 men with prostate cancer metastatic to regional lymph nodes, and in 10 men with prostate cancer metastatic to bone. RESULTS: Plasma TGF-beta(1) levels in patients with lymph node metastases (14.2 +/- 2.6 ng/mL) and bone metastases (15.5 +/- 2.4 ng/mL) were higher than those in radical prostatectomy patients (5.2 +/- 1.3 ng/mL) and healthy subjects (4.5 +/- 1.2 ng/mL) (P <.001). In a preoperative analysis, preoperative plasma TGF-beta(1) level and biopsy Gleason sum both were predictors of organ-confined disease (P =.006 and P =.006, respectively) and PSA progression (P <.001 and P =.021, respectively). In a postoperative multivariate analysis, preoperative plasma TGF-beta(1) level, pathologic Gleason sum, and surgical margin status were predictors of PSA progression (P =.020,P =.020, and P =.022, respectively). In patients who progressed, preoperative plasma TGF-beta(1) levels were higher in those with presumed distant compared with local-only failure (P =.019). CONCLUSION: Plasma TGF-beta(1) levels are markedly elevated in men with prostate cancer metastatic to regional lymph nodes and bone. In men without clinical or pathologic evidence of metastases, the preoperative plasma TGF-beta(1) level is a strong predictor of biochemical progression after surgery, presumably because of an association with occult metastatic disease present at the time of radical prostatectomy.

Association of p53 mutations with metastatic prostate cancer.

In prostate cancer, mutation of the p53 tumor suppressor gene has been associated with locally advanced disease and hormone-resistant disease that is predominantly localized to bone. However, little is known regarding the status of the p53 gene in metastatic prostate cancer that has not been treated with hormonal manipulation. We evaluated formalin-fixed, paraffin-embedded malignant tissues from 86 patients with various stages of prostate cancer, including pathologically confined, locally advanced, and metastatic disease, to detect abnormal p53 nuclear protein accumulation using immunohistochemistry. No abnormal p53 immunostaining was detected in 18 patients with prostate cancer confined to the gland. Two tumors from 21 patients with locally advanced disease (extracapsular extension and/or seminal vesicle invasion) had abnormal nuclear p53 accumulation, and a mutation in exon 7 of the p53 gene was detected in tumor DNA from one patient using single-strand conformation polymorphism-direct sequencing analysis. Of the remaining 47 patients studied in whom tissues from the prostate gland and a metastatic site (44 lymph node, 2 bone, and 1 lung) were available, only 3 had received hormonal therapy prior to obtaining metastatic tissue. In four patients both primary and metastatic tumors demonstrated accumulation of p53 protein, whereas seven additional patients exhibited p53 accumulation only at the metastatic site. In three patients the metastatic tumors harbored missense single-base substitutions in exon 5, as detected using single-strand conformation polymorphism-direct sequencing. These results indicate that p53 abnormalities are associated with lymph node metastases derived from prostate cancer patients that had not undergone hormonal therapy.

Primary human prostate cancer cells harboring p53 mutations are clonally expanded in metastases.

Recent studies suggest a role for p53 in prostate cancer progression. Although p53 mutations in primary prostate cancer tissues are relatively infrequent, they occur at significant levels in metastatic disease. Here we describe a novel approach to the molecular analysis of p53 in paired specimens of primary and metastatic prostate cancer that results in quantitative estimates of the extent of clonal expansion. In 20 pairs with 1 or both specimens p53 immunopositive and in 6 pairs with both specimens immunonegative, the frequency of mutations was estimated by microdissection of the cancer from fixed and sectioned tissues, isolation of the DNA followed by PCR amplification of p53 genomic fragments, and cloning of the PCR products into plasmid vectors. At least 90 clones/tissue specimen were screened for mutations by single-strand conformational polymorphism analysis. DNA from abnormally migrating single-strand conformational polymorphism samples was sequenced to confirm mutations. Missense mutations in exon 5, 7, or 8 were detected in 9 of 20 immunopositive pairs and in 1 of 6 immunonegative pairs. A marked heterogeneity of mutations in primary prostate cancer was apparent. The frequency of p53 mutations was greater in the metastases than in the primary tumors. In three immunopositive pairs, the same p53 mutation was demonstrated at a low frequency in the primary tumor but was demonstrated at a greater frequency in the metastasis, indicating relatively limited clonal expansion of cells harboring specific p53 mutations in the primary tumor, yet significant clonal growth at metastatic sites as determined by this novel method.

Robust prostate-specific expression for targeted gene therapy based on the human kallikrein 2 promoter.

Tissue-specific transcriptional regulatory elements can increase the safety of gene therapy vectors. Unlike prostate-specific antigen (PSA/hK3), whose expression displays an inverse correlation with prostate cancer grade and stage, human glandular kallikrein 2 (hK2) is upregulated in higher grade and stage disease. Therefore, our goal was to develop a strong and prostate-specific hK2-based promoter for targeted gene therapy. We identified the minimum "full-strength" hK2 enhancer and built transcriptional regulatory elements composed of multiple tandem copies of this 1.2-kb enhancer, fused to the hK2 minimal promoter. Relative to the weak induction of the minimal hK2 promoter by androgen analog (R1881) in androgen receptor (AR)-positive LNCaP cells, transcriptional activity was increased by 25-, 44-, 81-, and 114-fold when one to four enhancers were spliced to the hK2 promoter, respectively. In contrast, the enhancer/promoter elements were inactive in the AR(-) prostate cancer line PC-3 and in a panel of nonprostate lines, including 293, U87, MCF-7, HuH-7, and HeLa cells. Furthermore, we generated a recombinant adenovirus, ADV.hK2-E3/P-EGFP, expressing enhanced green fluorescent protein (EGFP) under the control of the hK2 triplicate enhancer/promoter, and compared its properties with ADV.CMV-EGFP expressing EGFP under the control of the cytomegalovirus (CMV) enhancer/promoter. Unlike the CMV promoter, the hK2-E3/P promoter was at least 100-fold inducible by R1881 in the adenoviral backbone. Compared with in situ injection of subcutaneous LNCaP tumors with ADV.CMV-EGFP, which led to detectable EGFP expression in tumor, liver, and brain tissue, ADV.hK2-E3/P-EGFP injection led to robust but tumor-restricted EGFP expression. These results suggest that the hk2 multienhancer/promoter should be a powerful novel reagent for safer targeted gene therapy of prostate cancer.

Mesenchymal-epithelial interactions and transforming growth factor-beta 1 expression during normal and abnormal prostatic growth.

Mesenchymal-epithelial interactions are associated with growth and morphogenesis of the prostate. We have detected three isoforms of transforming growth factor beta (TGF-beta) in the developing mouse prostate that may mediate some of these interactions. Separation of the fetal urogenital sinus (UGS) tissue into mesenchymal and epithelial components indicated that mRNA expression of TGF-beta 1, 2, and 3 was more abundant in the mesenchyme compared to the epithelium. Immunohistochemical analysis revealed accumulation of TGF-beta 1 in the mesenchyme surrounding ductules in the UGS and neonatal prostate. Further analysis of TGF-beta 1 localization in surgically removed adult human prostate tissues revealed more intense staining associated with regions of abnormal growth compared to normally appearing tissue. The percent of the total stained area with extracellular accumulation of TGF-beta 1 was 59% in prostate cancer, 26% in benign prostatic hyperplasia (BPH), and 8.6% in normal tissue. In additional immunohistochemical studies we observed that intracellular TGF-beta 1 was predominantly associated with the epithelial cells in prostate cancer (epithelial cells = 33.5% of the total stained area, stromal cells = 13.3%, and unstained = 53.2%), whereas in BPH intracellular TGF-beta 1 was predominantly associated with stromal cells (stromal cells = 32.2% of the total stained area, epithelial cells = 12.3%, and unstained = 55.5%). Although additional experimental and clinical studies are needed to better understand the relationships between TGF-beta 1 and abnormal prostatic growth, our observations thus far suggest a role for TGF-beta 1 in the development of benign and malignant growth abnormalities in the prostate. One approach to establishing the pathobiological significance of TGF-beta 1 accumulation in the prostate is by introducing and overexpressing the TGF-beta 1 cDNA in prostate tissue using the mouse prostate reconstitution model system. We discuss applicability of transgenic animal and organ reconstitution models for experimental studies concerning TGF-beta-induced prostate growth abnormalities.

Cavermap-assisted sural nerve interposition graft during radical prostatectomy.

Wide excision of the neurovascular bundle and interposition nerve grafting of the cavernous nerves when there is suspected extracapsular extension at the posterolateral prostatic margin are logical applications of improved understanding of pelvic neuroanatomy. Although the indications for neurovascular bundle excision will remain controversial for the foreseeable future, evidence suggests that neurovascular bundle excision improves cancer control in some patients. The ability to predict extracapsular extension reliably at the neurovascular bundle would be a powerful addition to the urologist's armamentarium. The authors have shown, as proof of principle in bilaterally resected neurovascular bundle at the time of RRP, that sural nerve grafting can restore erectile function. The authors' data also support a role for sural nerve grafting in unilateral neurovascular bundle excision. Although the side effects of sural nerve harvest are minor, the ability to predict preoperatively which patients will benefit from such grafts would reduce the number of failures. The success of the authors' interposition nerve-grafting project has resulted, in part, from the use of a multidisciplinary team approach that includes experienced oncologic surgeons and a plastic surgeon with extensive microsurgical and nerve-grafting experience. The technique for sural nerve grafting described herein gives urologists an additional tool to improve patients' quality of life without compromising the chances of success in treating prostate cancer.

Treatment options for upper tract transitional-cell carcinoma.

Nephroureterectomy with a bladder cuff remains the gold standard of treatment of transitional-cell carcinoma of the upper urinary tract. The natural history of the disease, specifically its multifocal nature and its propensity for local recurrence, argues for an aggressive treatment approach. Good clinical results using renal-sparing treatment of low-grade ureteral tumors reveal the feasibility of renal-sparing approaches in limited circumstances. It is likely that, with increasing use of renal-sparing therapy by endoscopic means, topical chemotherapeutic agents will take on an analogous role in the treatment of superficial disease and their role on the treatment of bladder cancer.

Testosterone therapy in hypogonadal men and potential prostate cancer risk: a systematic review.

This paper provides a systematic review of the literature about prostate cancer risk associated with testosterone therapy for hypogonadism. A comprehensive search of MEDLINE, EMBASE and other resources was conducted to identify articles that highlight occurrences of prostate cancer in men receiving testosterone therapy for hypogonadism treatment. Articles that met study inclusion criteria were assessed for causality between testosterone treatment and prostate cancer, increased prostate-specific antigen or abnormal digital rectal examination findings. Of 197 articles relating to testosterone therapy, 44 met inclusion criteria: 11 placebo-controlled, randomized studies; 29 non-placebo-controlled studies of men with no prostate cancer history; and 4 studies of hypogonadal men with history of prostate cancer. Of studies that met inclusion criteria, none demonstrated that testosterone therapy for hypogonadism increased prostate cancer risk or increased Gleason grade of cancer detected in treated vs untreated men. Testosterone therapy did not have a consistent effect on prostate-specific antigen levels.

Treatment of congenital penile curvature with penile torsion: a new twist.

Congenital penile curvature secondary to asymmetry of corpora cavernosal length is an uncommon cause of penile deformity. Although the deformity generally is not severe enough to preclude sexual intercourse it can be a source of great concern to the patient and may cause him to avoid all sexual contact. The Nesbit procedure is a simple, effective surgical technique to correct lateral or ventral curvature. Rarely penile deviation is accompanied by penile torsion. This unique problem requires a novel surgical approach to create a straight, nontwisted erection. We report 2 cases of congenital lateral penile curvature with accompanying penile torsion and describe a simple modification of the Nesbit procedure for surgical correction.

Dyspareunia: an unusual presentation of leiomyoma of the bladder.

Leiomyoma is a rare, benign tumor of the bladder. It frequently has an unusual presentation and its treatment options remain controversial. We describe a case of a leiomyoma of the bladder in a young female whose chief complaint was dyspareunia, and we review the management options.

Local recurrence after radical prostatectomy: correlation of US features with prostatic fossa biopsy findings.

PURPOSE: To evaluate the diagnostic accuracy of transrectal ultrasonography (US) in the detection of local recurrence following radical prostatectomy. MATERIALS AND METHODS: Ninety-nine patients with biochemical recurrence after radical prostatectomy were evaluated at transrectal US and prostatic fossa biopsy. Location of suspected recurrence at transrectal US and clinical features, such as prostate-specific antigen levels and digital rectal examination findings, were correlated with biopsy results. RESULTS: Forty-one (41%) of 99 cases of local recurrence were detected. The percentage of sites of lesions identified at transrectal US and corresponding positive biopsy rates were as follows: the urethrovesical anastomotic area, 56% and 61%; bladder neck, 26% and 54%; retrovesical space, 4% and 100%; and more than one site, 14% and 71%. By comparing transrectal US and digital rectal examination, the sensitivities were 76% and 44% (P =.007), while specificities were 67% and 91% (P =.004), respectively. An increased positive biopsy rate with increasing prostate-specific antigen levels was noted (P =.04). CONCLUSION: Transrectal US is more sensitive but less specific than digital rectal examination in the detection of local recurrence. Biopsy findings in more than half of the suspected lesions at the urethrovesical anastomotic area and bladder neck were positive. Lesions in the retrovesical space, although less frequently encountered, had a high likelihood of representing cancer recurrence.

Analysis of continent versus standard urinary diversion.

The seemingly high complication and re-operation rates associated with continent urinary diversion have led some to criticize its morbidity and question its role in reconstructive urological surgery. We therefore reviewed our experience with all patients undergoing either continent or standard urinary diversion performed by 3 urological surgeons during a specified 3-year period. In 73 consecutive patients (22 continent urinary diversion, 51 standard urinary diversion), no significant difference was demonstrated with respect to the number of post-operative in-hospital days, complication rate, re-operation rate and operative mortality rate between the 2 groups. While those undergoing continent diversion were on average younger and healthier than their counterparts receiving standard diversion, stratification of patients in each group according to age and a pre-operative "fitness" score showed no significant difference in operative mortality or major morbidity between comparable patients in each group. The mean post-operative length of hospital stay was, however, 3 days shorter for the youngest and fittest patients receiving standard versus continent urinary diversion.

Characteristics of normal prostate vascular anatomy as displayed by power Doppler.

BACKGROUND: To define the vascular anatomy of the normal prostate as depicted by power Doppler and to provide baseline data for evaluation of this modality in the diagnosis and management of prostatic disease. METHODS: The vascular anatomy of 40 subjects was studied. Power Doppler images were correlated with corresponding gray-scale images. Doppler spectral waveform measurements were obtained for the vessels identified. RESULTS: Separate branches of the capsular vessels were visualized clearly, distributed radially in the peripheral and central zones and converging toward the center of the gland. Urethral vessels were visualized in the transition zone coursing from bladder neck to verumontanum. The neurovascular bundles were identified posterolaterally along the length of the gland. No significant difference between the resistive indexes of the urethral and capsular vessels was identified (P = 0.595), although there was a significant difference between the resistive index of the neurovascular bundles and that the prostatic vessels (P < 0.001). CONCLUSIONS: The vascular anatomy of the normal prostate as displayed by power Doppler demonstrates a reproducible and symmetric flow pattern. Power Doppler is highly sensitive in depicting blood flow, the number, course, and continuity of vessels more readily than other imaging modalities, such as color Doppler. These data should allow comparison of the vascular anatomy of the normal prostate with that of the prostate with diseases such as prostate cancer and benign prostatic hyperplasia.

Diagnosis and management of incidental ureterocele during the treatment of clinically localized prostate cancer.

Two instances of simultaneous diagnosis of prostate cancer and ureterocele were recently identified. In one patient an ectopic ureterocele in a duplex system with an obstructed upper pole was unroofed at the time of radical prostatectomy. Surgical excision of the ureterocele wall provided decompression of the obstructed system. In a second patient, bilateral intravesical ureteroceles associated with normal renal units were left untreated. Complications were not associated with the untreated ureteroceles. On rare occasions a ureterocele may be discovered incidentally during the evaluation of patients with prostate cancer. When radical prostatectomy is planned, treatment of the ureteroceles should be determined by the ureterocele's size, anatomic configuration, and location and by the degree of obstruction of the affected renal unit. Surgical excision of the ureterocele at the time of radical prostatectomy may be the best approach for patients requiring treatment.

Horseshoe kidney is associated with an increased relative risk of primary renal carcinoid tumor.

PURPOSE: Carcinoid tumor is a rare neoplasm of the kidney with an unknown histogenesis. Of only 31 cases previously reported in the literature 4 arose within horseshoe kidneys. We report a case of primary carcinoid tumor arising within a horseshoe kidney and discuss the unique insight it provided into the pathogenesis of this tumor. MATERIALS AND METHODS: We reviewed in detail all 31 reported cases of renal carcinoid tumor and, using reported incidence rates of horseshoe kidney, we calculated the relative risk of renal carcinoid tumor arising within a horseshoe kidney. Immunohistochemical staining for neuroendocrine related markers was performed on tissue sections from the present carcinoid tumor, the adjacent kidney and 5 control samples of normal renal parenchyma. RESULTS: Of the reported tumors 15.6% occurred in horseshoe kidneys, yielding a calculated relative risk of 62. The present tumor was multifocal, arising from the wall of a cystic lesion and possibly representing a dilated calix within the isthmus. Intestinal epithelium lining the cyst cavity exhibited multifocal neuroendocrine cell hyperplasia with an immunohistochemical profile identical to that of the carcinoid tumor cells. CONCLUSIONS: The relative risk of renal carcinoid tumor developing in a horseshoe kidney is markedly greater than that for Wilms tumor or transitional cell carcinoma. The clinical course of renal carcinoid tumor arising within a horseshoe kidney appears to be more benign than that of the nonhorseshoe variant. Our observations support the hypothesis that renal carcinoid tumors may arise from neuroendocrine cells within foci of metaplastic or teratomatous epithelium within the kidney.