Intermediate-term survival of robot-assisted versus open radical cystectomy for muscle-invasive and high-risk non-muscle invasive bladder cancer in The Netherlands.

BACKGROUND: Radical cystectomy with pelvic lymph node dissection is the recommended treatment in non-metastatic muscle-invasive bladder cancer (MIBC). In randomised trials, robot-assisted radical cystectomy (RARC) showed non-inferior short-term oncological outcomes compared with open radical cystectomy (ORC). Data on intermediate and long-term oncological outcomes of RARC are limited. OBJECTIVE: To assess the intermediate-term overall survival (OS) and recurrence-free survival (RFS) of patients with MIBC and high-risk non-MIBC (NMIBC) who underwent ORC versus RARC in clinical practice. METHODS AND MATERIALS: A nationwide retrospective study in 19 Dutch hospitals including patients with MIBC and high-risk NMIBC treated by ORC (n = 1086) or RARC (n = 386) between January 1, 2012 and December 31, 2015. Primary and secondary outcome measures were median OS and RFS, respectively. Survival outcomes were estimated using Kaplan-Meier curves. A multivariable Cox regression model was developed to adjust for possible confounders and to assess prognostic factors for survival including clinical variables, clinical and pathological disease stage, neoadjuvant therapy and surgical margin status. RESULTS: The median follow-up was 5.1 years (95% confidence interval ([95%CI] 5.0-5.2). The median OS after ORC was 5.0 years (95%CI 4.3-5.6) versus 5.8 years after RARC (95%CI 5.1-6.5). The median RFS was 3.8 years (95%CI 3.1-4.5) after ORC versus 5.0 years after RARC (95%CI 3.9-6.0). After multivariable adjustment, the hazard ratio for OS was 1.00 (95%CI 0.84-1.20) and for RFS 1.08 (95%CI 0.91-1.27) of ORC versus RARC. Patients who underwent ORC were older, had higher preoperative serum creatinine levels and more advanced clinical and pathological disease stage. CONCLUSION: ORC and RARC resulted in similar intermediate-term OS and RFS in a cohort of almost 1500 MIBC and high-risk NMIBC.

Androgen deprivation of the PC-310 [correction of prohormone convertase-310] human prostate cancer model system induces neuroendocrine differentiation.

Neuroendocrine (NE) cells are androgen-independent cells and secrete growth-modulating neuropeptides via a regulated secretory pathway (RSP). We studied NE differentiation after androgen withdrawal in the androgen-dependent prostate cancer xenograft PC-310. Expression patterns of chromogranin A, secretogranin III, and prohormone convertase-1 were analyzed at both protein and mRNA level to mark the kinetics of NE differentiation both in vivo and in vitro. PC-310 tumor-bearing nude mice were killed at 0, 2, 5, 7, 14, and 21 days postcastration. PC-310C cultures initiated from collagenase-treated tumor tissue could be maintained up to four passages, and androgen-deprivation experiments were performed similarly. PC-310 tumor volumes decreased by 50% in 10 days postcastration. Proliferative activity and prostate-specific antigen (PSA) serum levels decreased to zero postcastration, whereas PSA levels in PC-310C culture media first decreased and subsequently increased after 5 days. In vivo, androgen receptor (AR) expression decreased initially but returned to control level from 5 days postcastration on. CgA, secretogranin III, and secretogranin V expression increased in vivo from 5 days postcastration on. Subsequently, prohormone convertase-1 and peptidyl alpha-amidating monooxygenase as well as the vascular endothelial growth factor were expressed from 7 days postcastration on, and, finally, growth factors such as gastrin-releasing peptide and serotonin were expressed in a small part of the NE cells 21 days postcastration. The PC-310 tumors did not show colocalization of the AR on the NE cells in the tumor residues after 21 days. As in the PC-310 xenograft, NE differentiation was induced and AR expression relapsed after prolonged androgen suppression in PC-310C. For PC-310C cells, this relapse was associated with the secretion of PSA. PC-310C is the first culture of human prostatic cancer cells having the NE phenotype. The PC-310 model system is a potential androgen-dependent model for studying the role of NE cells in the progression of clinical prostate cancer. Androgen deprivation of NE-differentiated prostate cancer may induce the formation of both NE- and AR-positive dormant tumor residues, capable of actively producing NE growth factors via a RSP, possibly leading to hormone refractory disease.

The prognostic value of CD44 isoforms in prostate cancer patients treated by radical prostatectomy.

CD44 forms a group of transmembranous glycoproteins formed by alternative splicing of a single mRNA. The expression of v6 exon-containing variants correlates with metastasis and poor prognosis in a number of malignancies. The distribution and prognostic value of CD44s, CD44v5, and CD44v6 were studied immunohistochemically in the radical prostatectomy specimens of 97 patients with prostate cancer and in 12 lymph node metastases. The mean follow-up period was 84 months. The percentage of CD44-immunoreactive cells was scored semiquantitatively. CD44 mRNA expression was studied in nine prostate cancer and eight benign prostatic hyperplasia (BPH) samples by reverse transcriptase-PCR. Benign prostatic glands almost always expressed CD44s, CD44v6, and, at a lower intensity, CD44v5. CD44 scores decreased from low- to high-grade prostatic intraepithelial neoplasia. CD44s, CD44v5, and CD44v6 were expressed in 86, 23, and 69% of the adenocarcinomas, respectively. Gleason sum score (GSS) and pT stage were correlated inversely with CD44s and CD44v6 scores. CD44 was not found in the lymph node metastatic tumor cells. At the mRNA level, 89% of the tumors and all BPH samples expressed CD44s. CD44v6-v10 mRNA was present in 44 and 75% of the tumors and BPH samples, respectively. Loss of CD44s and CD44v6 predicted an adverse prognosis at univariate analysis. The independent prognosticators identified by multivariate analysis were: GSS, pT stage, and CD44s for clinical progression; GSS and CD44s for prostate-specific antigen progression; and GSS for tumor-specific survival. Loss of CD44s expression in prostate adenocarcinoma predicts a poor prognosis, independent of stage and grade.

Expression and prognostic value of Wilms' tumor 1 and early growth response 1 proteins in nephroblastoma.

Wilms' tumor is one of the most common solid tumors of children. The protein product of the tumor-suppressor gene, Wilms' tumor 1 (WT-1), binds to the same DNA sequences as the protein product of the early growth response 1 (EGR-1) gene. There is experimental evidence that EGR-1 is involved in controlling cell growth. The expression of both genes in Wilms' tumor was studied by others, mainly at the mRNA level. The present study evaluates the prognostic value of WT-1 and EGR-1 in 61 Wilms' tumors of chemotherapeutically treated patients at the protein level, using an immunohistochemical approach. WT-1 was expressed in normal kidney tissues and in the blastemal and epithelial component of Wilms' tumor, whereas stromal tissue was negative. EGR-1 was expressed in normal kidney tissues and in the three main cell types of Wilms' tumor. In 59 and 56% of Wilms' tumor, the blastemal cells stained for WT-1 and EGR-1, respectively. The blastemal expression of WT-1 and EGR-1 and the epithelial expression of WT-1 were statistically significantly correlated with clinical stage. WT-1 immunoreactivity correlated with EGR-1 expression. Univariate analysis showed that blastemal WT-1 and EGR-1 expression were indicative for clinical progression and tumor-specific survival, whereas epithelial staining was of no prognostic value. Multivariate analysis showed that blastemal WT-1 expression is an independent prognostic marker for clinical progression other than stage. We conclude that a relationship exists between WT-1 and EGR-1 expression in clinical nephroblastomas. Blastemal WT-1 and EGR-1 expression is related to prognosis.

Dexverapamil to modulate vinblastine resistance in metastatic renal cell carcinoma.

Multidrug resistance (MDR) in a variety of human tumours such as renal cell carcinoma (RCC) is thought to be caused by expression of the MDR1 gene and may be reversed by applying modern chemosensitisers such as dexverapamil, which inhibit the MDR1 gene product P-glycoprotein. This preliminary report gives information on a clinical study complying with good clinical practice regulations in patients with advanced RCC. The final evaluation is pending. Vinblastine, if anything the most effective chemotherapeutic agent (5-day continuous regimen), was combined with oral dexverapamil (6 times per day) as a chemosensitiser and dexamethasone to increase dexverapamil tolerance. All patients had histologically proven RCC, which was metastatic and progressive at study entry. The statistical design featured a pre-study regimen of two cycles of vinblastine alone followed by evaluation. If no response was documented, with all patients thus serving as their own control, dexverapamil and dexamethasone were added for three cycles of combination therapy. Having obtained institutional permission from the ethical review committee, we enrolled patients of whom 25 qualified for the combined-treatment arm; 13 patients finished the study, 5 patients failed to complete all treatment cycles (1 because of treatment-related toxicity, 3 for personal reasons, not related to treatment, 1 for tumour-related reasons) and 7 patients were at too early a stage for evaluation. Altogether, 61% of all patients tolerated a dose of dexverapamil of at least 2400 mg/day with peak serum levels reaching, in some cases, approximately 8 microM (the sum of dexverapamil plus nordexverapamil levels). WHO grade 3 and 4 toxicities were mainly myelosuppression (5/18). The combination of 1.4 mg m-2 day-1 vinblastine plus dexverapamil was generally felt to be safe and well tolerated. One partial response and 7 stable diseases were noted in this heavily pretreated study population. Four-hourly administration of dexverapamil in combination with dexamethasone plus escalation to the individually tolerated doses have permitted increases in serum levels of dexverapamil.

[Prostate cancer screening benefit very low, even after 13 years]. / Opbrengst prostaatkankerscreening zeer laag, ook na 13 jaar.

The 13-year results of the European Randomised Study of Screening for Prostate Cancer (ERSPC) have recently been published. Authors presented a 'substantial' reduction in prostate cancer-specific mortality of 20%. However, absolute risk reduction is very small (0.11 per 1000 person years) and no effect was shown on all-cause mortality. Additionally, the number of unnecessary prostate cancer diagnoses and the number of diagnostic procedures for this small effect are considerable. We believe that the discussion on the introduction of a population-based screening programme for prostate cancer could be at an end. Prostate cancer detection should be limited to men with signs or symptoms of the disease. Prostate-specific antigen (PSA) testing in non-symptomatic men should be a patient's personal decision, after weighing the pros and cons of any subsequent procedures.

[Complications due to lack of knowledge of the urinary sphincter prosthesis]. / Complicaties door gebrekkige kennis van urinaire sfincterprothese.

BACKGROUND: The placement of an artificial urinary sphincter prosthesis is a recognised treatment for men with urinary incontinence that is caused by insufficient sphincter action, although it is rarely used. Physicians from specialties other than urology know little about the components and mechanism of action of this prosthesis, which can lead to severe complications. CASE DESCRIPTION: A 67-year-old patient with a history of radical prostatectomy came to the emergency department with abdominal pain after a colonoscopy. A few years prior, he had received an artificial urinary sphincter prosthesis because of urinary incontinence. An abdominal CT scan showed a cystic lesion, which was punctured under ultrasonic guidance. The patient was completely incontinent after the intervention. It appeared to have been the pressure balloon of the urinary sphincter prosthesis that was punctured. The pressure balloon was operatively replaced several weeks later. During this procedure, the pressure balloon was placed intravesically instead of in the retropubic space and a reoperation was necessary. CONCLUSION: To prevent complications, all physicians should know how medical implants function, including the ones that are rarely used. In addition, patients need to be well informed of their use.

The genetic make-up of renal cell tumors.

Recent developments in (molecular genetics have led to a better understanding of renal tumor biology. The current knowledge of the genetics of benign as well as malignant renal tumors is discussed briefly. This knowledge may, in the near future, be used to more accurately diagnose these tumors and also to optimalize individually based therapy.

The prognostic influence of neuroendocrine cells in prostate cancer: results of a long-term follow-up study with patients treated by radical prostatectomy.

The distribution of immunohistochemically defined neuroendocrine (NE) cells in benign, pre-cancerous and neoplastic prostatic tissues and the prognostic value of these cells in prostate cancer were studied in the radical prostatectomy specimens of 90 patients from whom complete long-term follow-up data were available. The tissue blocks containing all the different Gleason patterns observed in a particular tumor were selected and immunostained. Since chromogranin B stained only a few cells compared to chromogranin A (CgA), NE cells were only defined by their reactivity with CgA. A semi-quantificative CgA score was assessed for all distinct pathological areas. Cox's regression model was used to analyze the influence of final TNM classification (TNM, 1992), Gleason sum score (GSS), age and CgA score on the probability of progression and tumor-specific death. NE cells were demonstrated in all normal prostatic tissues and in most hyperplastic and intra-epithelial neoplastic lesions. CgA staining was seen in 78% of the tumors. CgA scores were not related with Gleason growth patterns, GSS or TNM classification and had no prognostic value. The independent prognostic variables in Cox's regression model were: GSS and pT stage for progression and GSS for tumor-specific survival. Theoretically, NE cells could influence tumor behavior and this discrepancy suggests the need for experimental studies to investigate the role of NE cells in the normal and neoplastic prostate.

Neuroendocrine cells in the normal, hyperplastic and neoplastic prostate.

Neuroendocrine cells can be demonstrated in normal, hyperplastic and neoplastic prostatic tissues. The products secreted by these cells can be used as tissue and/or serum markers but may also have biological effects. Neuroendocrine cells in prostate cancer most probably do not contain the androgen receptor and are therefore primarily androgen independent. Some of the neuropeptides secreted by the neuroendocrine cells may act as growth factor by activation of membrane receptors in an autocrine-paracrine fashion or by ligand-independent activation of the androgen receptor in neighboring non-neuroendocrine cells. Evidence is accumulating from experiments with tumor models that neuropeptides indeed can influence the growth of prostatic tumor cells. Future research on neuroendocrine differentiation may answer some questions concerning the biological behavior of clinical prostatic tumors.

The prognostic value of pretreatment expression of androgen receptor and bcl-2 in hormonally treated prostate cancer patients.

PURPOSE: We determined the prognostic value of oncoprotein bcl-2 and androgen receptor expression in pretreatment transurethral resection specimens of hormonally treated prostate cancer patients. MATERIALS AND METHODS: A total of 68 pretreatment transurethral resection specimens, 30 radical prostatectomy specimens and 21 palliative transurethral resection specimens with androgen independent prostate cancer was stained with a monoclonal antibody against bcl-2. Androgen receptor immunohistochemistry was performed on pretreatment transurethral resection specimens only. Results were scored semiquantitatively and were correlated with tumor stage and grade and with the occurrence of clinical progression or tumor related death. RESULTS: Bcl-2 expression by adenocarcinoma cells was found in 32, 17 and 24% of pretreatment transurethral resection, radical prostatectomy and palliative transurethral resection specimens, respectively. The bcl-2 scores did not correlate with tumor stage or grade. Androgen receptor was expressed in 88% of pretreatment transurethral resection specimens. Androgen receptor scores were marginally related to tumor grade, but not to tumor stage. A prognostic value of bcl-2 or androgen receptor in pretreatment transurethral resection specimens was not found. When a combined bcl-2/androgen receptor score was used, this parameter was an independent prognostic marker to predict clinical progression with Gleason grade and stage classification. Gleason grade was the only independent prognostic marker to predict tumor related death. CONCLUSIONS: The expression of bcl-2 and androgen receptor in pretreatment prostate cancer specimens is not related to the prognosis of hormonally treated prostate cancer. Bcl-2 expression is not increased in endocrine therapy resistant prostate cancer. Surprisingly, a combined bcl-2/androgen receptor score acts as an independent prognosticator for clinical progression.

Decreased expression of CD44 in metastatic prostate cancer.

Decreased expression of CD44 is an independent prognostic marker for surgically treated prostate cancer. To investigate immunohistochemically defined CD44 expression in primary and metastatic prostate cancer, 2 groups of patients undergoing radical prostatectomy for clinically localized prostate cancer were studied. (1) pN1 group: 23 patients, finally staged pN1, of whom the radical prostatectomy specimen and the lymph nodes were investigated to establish a correlation between CD44 expression in the concurrently resected primaries and metastases; (2) pN(0) group: 23 patients with pN(0) disease matched for pT stage and Gleason sum score with the pN(1) patients. Progression rates based on serum prostate-specific antigen (PSA) levels could be determined in 42 of these 46 patients. In addition, 28 distant metastases were studied. A CD44 score of < 10% was found in 22 of the 23 lymph node metastases (96%) and in 20 of the corresponding radical prostatectomies. In the pN(0) group this was observed in only 6 out of 23 specimens. In most of the distant metastases CD44 scores were < 10%. Patients with pN0 disease and > 10% CD44-positive tumor cells had a significantly better prognosis than the other patients who were not significantly different from each other. CD44 expression is thus strongly reduced in prostate cancer metastases as well as in the corresponding primary tumors. This reduction may be used to predict the N stage clinically, provided that CD44 scores can be determined reliably on preoperative biopsy specimens.

Value of tissue markers p27(kip1), MIB-1, and CD44s for the pre-operative prediction of tumour features in screen-detected prostate cancer.

The pre-operative prediction of prognostic tumour features in the radical prostatectomy specimen using routine clinicopathological variables remains limited. The present study evaluated the predictive value of the cell-cycle protein p27(kip1), the proliferation marker MIB-1, and the cell-adhesion protein CD44s, determined on the diagnostic needle biopsy of asymptomatic men screened for prostate cancer. Of 81 screen-detected prostate cancers, representative biopsy cores and matched radical prostatectomy specimens were immunohistochemically stained for these tissue markers. Conventional pre-operative and post-operative clinicopathological variables were assessed and cancers were divided according to a validated tumour classification model (potentially harmless, clinically significant). Low (<50%) p27(kip1) expression, high (> or = 10%) MIB-1 expression, and low (<25%) CD44s expression were considered adverse prognostic signs. Binary logistic regression analysis was performed to assess the most valuable predictors of clinically significant disease. An adverse prognostic immunostaining assessment on the biopsy was found in 10 (12.3%), 17 (21.0%), and 25 (30.9%) cases for p27(kip1), MIB-1, and CD44s, respectively. The concordance in tissue marker assessment between the biopsy specimen and matched radical prostatectomy specimens was low for all three. The positive predictive value (PPV) of p27(kip1) was 90.0%, remarkably higher than that of MIB-1 and CD44s (41.2% and 52.0%, respectively), indicating that a low radical prostatectomy p27(kip1) score is expected if the biopsy p27(kip1) score is low. Logistic regression analysis revealed that biopsy Gleason score (p<0.01) and p27(kip1) assessment (p<0.01) remained the only significant predictors of clinically significant disease. All cases with low p27(kip1) expression were found to have clinically significant disease after radical prostatectomy. The assessment of p27(kip1) in the biopsy specimen might thus assist in distinguishing between potentially aggressive and potentially non-aggressive disease in prostate cancer screening.

Determination of Ki-67 defined growth fraction by monoclonal antibody MIB-1 in formalin-fixed, paraffin-embedded prostatic cancer tissues.

The applicability of MIB-1, a monoclonal antibody directed against the Ki-67 antigen, was studied in the PC-82 and LNCaP prostatic tumor models at various levels of proliferative activity. Statistically significant correlations were found in LNCaP cultures between Ki-67 and MIB-1 scores (r = 0.84, P < 0.001), and in PC-82 tumors between MIB-1 scores and paraffin tissue Ki-67 (pKi-67) (r = 0.90, P < 0.001), frozen tissue (fKi-67) (r = 0.86, P < 0.001), and BrdU uptake (r = 0.70, P < 0.001), respectively. pKi-67 scores were double the fKi-67 scores, which may be due to methodological differences. MIB-1 scores exceeded both the fKi-67 and pKi-67 scores. The affinity of MIB-1 for the antigen is much higher than the affinity of Ki-67, which may explain the differences. MIB-1 is a promising means of evaluating the presence of only minute amounts of the Ki-67 antigen in paraffin-embedded human tumor material, especially in relatively slowly growing tumors.

Neuroendocrine differentiation in human prostatic tumor models.

Neuroendocrine (NE) cells can be identified in benign and malignant prostatic epithelia. Factors regulating their presence and their functions are poorly understood, mainly due to a lack of suitable experimental models. Fifteen in vitro and in vivo prostatic cancer tumor models, including a number of newly established in vivo models, were studied immunohistochemically for the presence of NE cells under different hormonal conditions. None of the in vitro models (PC-3, DU 145, LNCaP, and TSU) contained NE cells. Five of the seven xenograft models established at this laboratory contained NE cells. In three of these, NE cells were found only in the initial mouse passages. In the other two (PC-295 and PC-310), the NE phenotype was stable. NE features were confirmed by transmission electron microscopy and by Western analysis of chromogranin A expression. Immunohistochemical double-labeling experiments confirmed that NE cells in prostate cancer are post-mitotic (no Ki-67 expression) and do not express the androgen receptor. In the PC-295 and PC-310 models, short-term androgen withdrawal resulted in a rapidly increased number of NE cells. A time course experiment with PC-295-bearing mice strongly suggests that this increase occurred by induction of NE differentiation rather than by rapid proliferation and subsequent differentiation or selective persistence. In conclusion, these models are suitable to resolve fundamental questions with regard to the presence and functions of NE cells in human prostate cancer.

Androgen-independent growth is induced by neuropeptides in human prostate cancer cell lines.

BACKGROUND: Androgen-independent growth leads to progressive prostate cancer after androgen-ablation therapy. This may be caused by altered specificity of the androgen receptor (AR), by ligand-independent stimulation of the AR, or by paracrine growth modulation by neuropeptides secreted by neuroendocrine (NE) cells. METHODS: We established and characterized the androgen-independent FGC-DCC from the androgen-dependent LNCaP fast growing colony (FGC) cell line. The androgen-independent DU-145, FGC-DCC, and PC-3, and the androgen-dependent LNCaP and PC-346C cell lines were used to study growth modulation of gastrin-releasing peptide (GRP), calcitonin (CT), serotonin (5-HT), and vasoactive intestinal peptide (VIP) by (3)H-thymidine incorporation. Specificity of the growth-modulating effects was tested with the anti-GRP monoclonal antibody 2A11 and induction of cAMP by neuropeptides. RESULTS: Androgen-independent growth stimulation by neuropeptides was shown in DU-145 and PC-346C. 2A11 inhibited GRP-induced (3)H-thymidine incorporation in DU-145 and PC-346C and inhibited proliferation of the FGC-DCC and PC-3 cell lines. With some exceptions, cAMP induction paralleled growth stimulation. Dideoxyadenosine (DDA) inhibited the GRP-induced growth effect in DU-145 and PC-346C, whereas oxadiazoloquinoxaline-1-one (ODQ) had no effect on (3)H-thymidine incorporation. None of the neuropeptides stimulated growth of LNCaP, FGC-DCC, or PC-3. CONCLUSIONS: GRP-induced growth of DU-145 and PC-346C was specific and cAMP-mediated. Androgen-independent growth of FGC-DCC cells was mainly due to an induction of Bcl-2 expression and possibly through the activation of an autocrine and NE-like pathway, as has been shown also for the PC-3 cell line. Growth induction of non-NE cells by neuropeptides could be a possible role for NE cells in clinical prostate cancer.

Prognostic value of cell cycle proteins p27(kip1) and MIB-1, and the cell adhesion protein CD44s in surgically treated patients with prostate cancer.

PURPOSE: Molecular tissue markers may give the clinician additional information about patients with prostate cancer at risk for treatment failure after retropubic radical prostatectomy. We substantiate the prognostic value of 3 tissue markers, the cell cycle proteins p27(kip1) and MIB-1, and the cell adhesion protein CD44s, in addition to more conventional pathological prognosticators in an historical (before prostate specific antigen) cohort of patients with prostate cancer. MATERIALS AND METHODS: Representative tumor sections from 92 patients who underwent retropubic radical prostatectomy were immunohistochemically stained with antibodies against p27(kip1), MIB-1 (Ki-67) and CD44s, and assessed in a semiquantitative manner. Gleason score and pathological tumor stage were recorded. All variables were correlated with clinical progression and disease specific survival on univariate and multivariate analyses. RESULTS: On univariate analysis low (less than 50%) p27(kip1), high (10% or greater) MIB-1 and loss of CD44s expression were significantly associated with clinical outcome parameters, although MIB-1 did not reach statistical significance for disease specific survival. All 3 molecules were highly correlated with Gleason score and pathological tumor stage. Multivariate analysis showed that low p27kip1 was independent of grade and stage in predicting clinical recurrence (p <0.001) and disease specific survival (p = 0.045), while loss of CD44s was an additional independent prognostic factor for clinical recurrence (p = 0.02). CONCLUSIONS: Reduced p27(kip1) expression is an independent predictor of poor outcome in prostate cancer, while MIB-1 is not. Decreased expression of CD44s yields additional information in predicting clinical recurrence. These tissue markers may identify patients at risk for disease recurrence after retropubic radical prostatectomy who may benefit from adjuvant therapy.

Kinetics of neuroendocrine differentiation in an androgen-dependent human prostate xenograft model.

It was previously shown in the PC-295 xenograft that the number of chromogranin A (CgA)-positive neuroendocrine (NE) cells increased after androgen withdrawal. NE cells did not proliferate and differentiated from G0-phase-arrested cells. Here we further characterized NE differentiation, androgen receptor status, and apoptosis-associated Bcl-2 expression in the PC-295 model after androgen withdrawal to assess the origin of NE cells. PC-295 tumor volumes decreased by 50% in 4 days. Intraperitoneal bromodeoxyuridine (BrdU) incorporation and MIB-1 labeling decreased to 0%, and the apoptosis was maximal at day 4. Androgen receptor expression and prostate-specific antigen (PSA) serum levels decreased rapidly within 2 days. The number of NE cells increased 6-fold at day 4 and 30-fold at day 7. Five and ten percent of the CgA-positive cells were BrdU positive after continuous BrdU labeling for 2 and 4 days, respectively. However, no MIB-1 expression was observed in CgA-positive cells. NE cells expressed the regulated secretory pathway marker secretogranin III but were negative for androgen receptor and Bcl-2. Bcl-2 expression did increase in the non-NE tumor cells. In conclusion, androgen withdrawal leads to a rapid PC-295 tumor regression and a proliferation-independent induction of NE differentiation. The strictly androgen-independent NE cells that were still present after 21 days differentiated mainly from G0-phase-arrested cells.

The prognostic significance of apoptosis-associated proteins BCL-2, BAX and BCL-X in clinical nephroblastoma.

Apoptotic cell death represents an important mechanism for the precise regulation of cell numbers in normal tissues. Various apoptosis-associated regulatory proteins, such as Bcl-2, Bax and Bcl-X, may contribute to the rate of apoptosis in neoplasia. The present study was performed to evaluate the prognostic value of these molecules in a group of 61 Wilms' tumours of chemotherapeutically pre-treated patients using an immunohistochemical approach. Generally, Bcl-2, Bax and for Bcl-X(S/L) were expressed in the blastemal and epithelial components of Wilms' tumour. Immunoreactive blastema cells were found in 53%, 41% and 38% of tumours for Bcl-2, Bax and for Bcl-X(S/L), respectively. An increased expression of Bcl-2 was observed in the blastemal component of increasing pathological stages. In contrast, a gradual decline of Bax expression was observed in the blastemal component of tumours with increasing pathological stages. Also blastemal Bcl-X(S/L) expression decreased with stage. Univariate analysis showed that blastemal Bcl-2 expression and the Bcl-2/Bax ratio were indicative for clinical progression, whereas epithelial staining was of no prognostic value. Multivariate analysis showed that blastemal Bcl-2 expression is an independent prognostic marker for clinical progression besides stage. These findings demonstrate that alterations of the Bcl-2/Bax balance may influence the clinical outcome of Wilms' tumour patients by deregulation of programmed cell death.

Expression and prognostic value of epidermal growth factor receptor, transforming growth factor-alpha, and c-erb B-2 in nephroblastoma.

BACKGROUND: Wilms tumor is one of the most common solid tumors in children. A transforming growth factor-alpha (TGF-alpha)/epidermal growth factor receptor (EGF-R) autocrine loop plays an important role in tumor growth. Abnormal expression of TGF-alpha, EGF-R and c-erb B-2 has been demonstrated in several human malignancies. METHODS: The immunohistochemical expression of TGF-alpha, EGF-R, and c-erb B-2 was studied in paraffin material of 62 clinical Wilms tumors. Patients had a mean follow-up of 5.7 years. RESULTS: Generally, TGF-alpha, EGF-R, and c-erb B-2 were expressed in tissue of the normal kidney and at variable levels in the three cell types of Wilms tumor, i.e., blastemal, epithelial, and stromal cells. Immunoreactive blastema cells were found in 48%, 44%, and 34% of tumors for TGF-alpha, EGF-R, and c-erb B-2, respectively. It was found that TGF-alpha, EGF-R, and c-erb B-2 blastemal and epithelial expression gradually increased from T1 to T3. The blastemal expression of TGF-alpha was statistically significantly correlated with clinicopathologic stages. Both univariate and multivariate analysis showed that blastemal TGF-alpha expression was indicative for clinical progression, but neither blastemal TGF-alpha, nor EGF-R or c-erb B-2 expression correlated with patients survival. Epithelial staining was of no prognostic value. The simultaneous expression of TGF-alpha/EGF-R was indicative for clinical progression at univariate level. CONCLUSIONS: Increased expression of TGF-alpha in the blastemal part of Wilms tumor correlated with tumor classification and clinical progression. These findings suggest that significant expression of TGF-alpha and EGF-R may play a role in promoting transformation and/or proliferation of Wilms tumor, perhaps by an autocrine mechanism. Therefore, their expression may be of value in identifying patients at high risk of tumor recurrence.