Efficacy of carboplatin-taxane combinations in the management of castration-resistant prostate cancer: a pooled analysis of seven prospective clinical trials.

BACKGROUND: Docetaxel is associated with prolonged survival in castration-resistant prostate cancer (CRPC). Platinum compounds have modest but distinct single-agent activity. Carboplatin may have greatest potential for benefit when combined with taxanes. We investigated whether there is a subset of patients with CRPC for whom the efficacy of combination taxane-estramustine-carboplatin (TEC) chemotherapy may be greatest. PATIENTS AND METHODS: Individual patient data (n = 310) were obtained from seven trials using TEC chemotherapy. Prostate-specific antigen (PSA) response was defined as > or = 50% post-therapy decline from baseline. Overall survival was defined from baseline to death from any cause. Logistic and Cox regression were used to investigate heterogeneity in outcome to TEC by patient and disease characteristics. Predicted survival probabilities were calculated from the Halabi Cancer and Leukemia Group B (CALGB) nomogram. RESULTS: The pooled PSA response proportion was 69% [95% confidence interval (CI) 56% to 80%]. There was no evidence of differential PSA response by disease characteristics. Established prognostic factors were associated with survival. The pooled 12-month survival estimate of 79% (95% CI 71% to 84%) was higher than the median 59% 12-month nomogram-predicted survival. CONCLUSIONS: TEC chemotherapy has significant clinical activity in CRPC. A randomized, controlled trial evaluating the addition of carboplatin to taxane-based chemotherapy is needed to elucidate the value of carboplatin in CRPC.

Superoxide dismutase analog (Tempol: 4-hydroxy-2, 2, 6, 6-tetramethylpiperidine 1-oxyl) treatment restores erectile function in diabetes-induced impotence.

We hypothesized that the administration of the superoxide dismutase (SOD) mimetic Tempol (4-hydroxy-2, 2, 6, 6-tetramethylpiperidine 1-oxyl) may reverse diabetes-induced erectile dysfunction. To test this hypothesis, reactive oxygen species-related genes (SOD1, SOD2, GP x 1, CAT, NOS2, NOS3) were tested, erectile functional studies and immunohistochemical analysis were carried out in diabetic rats treated with or without Tempol. Thirty Sprague-Dawley (3-4 months old) rats were divided into three groups (n=10 each), 20 with diabetes (diabetic control and Tempol treatment) and 10 healthy controls. At 12 weeks after the induction of diabetes by streptozotocin and Tempol treatment, all groups underwent in vivo cavernous nerve stimulation. Rat crura were harvested and the expression of antioxidative defense enzymes were examined by semi-quantitative reverse transcriptase PCR (RT-PCR). To confirm the RT-PCR results, we carried out immunohistochemistry (IHC) for catalase (CAT) and iNOS (NOS2). Nitration of tyrosine groups in proteins was also examined by IHC. Mean intracavernous pressure in the diabetic group was significantly lower than in the healthy controls (P <0.001) and was reversed by Tempol treatment (P <0.0108). NOS2 protein expression was significantly increased in diabetic animals compared with healthy controls and Tempol restored NOS2 protein level. Nitrotyrosine was also higher in diabetic animals and although Tempol treatment decreased its formation, it remained higher than that found in healthy controls. This study suggests that Tempol treatment increased erectile function through modulating oxidative stress-related genes in diabetic rats. This is the first report about the relationship between diabetes-induced erectile dysfunction and oxidative stress, and antioxidative therapy using the superoxide dismutase mimetic, Tempol, to restore erectile function.

Knockdown of astrocyte-elevated gene-1 inhibits prostate cancer progression through upregulation of FOXO3a activity.

Astrocyte-elevated gene-1 (AEG-1) has been reported to be upregulated in several malignancies and play a critical role in Ha-ras-mediated oncogenesis through the phosphatidylinositol 3-kinase/AKT signaling pathway. However, the role of AEG-1 in prostate cancer (PC) has never been reported. We now show that AEG-1 is overexpressed in clinical PC tissue samples and cultured PC cells compared to benign prostatic hyperplasia tissue samples and normal prostate epithelial cells. Interestingly, AEG-1 knockdown induced cell apoptosis through upregulation of forkhead box (FOXO) 3a activity. This alteration of FOXO3a activity was dependent on reduction of AKT activity in LNCaP and PC-3 cells with high constitutive AKT activity, but not in DU145 cells with low constitutive AKT activity, although AEG-1 knockdown had no impact on phosphatase and tensin homolog expression in these cells. AEG-1 knockdown also attenuated the constitutive activity of the nuclear factor kappaB (NF-kappaB) and the activator protein 1 (AP-1) with a corresponding depletion in the expression of NF-kappaB and AP-1-regulated genes (interleukin (IL)-6, IL-8 and matrix metalloproteinase-9) and significantly decreased cell invasion properties of PC-3 and DU145 cells. Overall, our findings suggest that aberrant AEG-1 expression plays a dominant role as a positive auto-feedback activator of AKT and as a suppressor of FOXO3a in PC cells. AEG-1 may therefore represent a novel genetic biomarker to serve as an attractive molecular target for new anticancer agents to prevent PC cell progression and metastasis.

Transrectal colour Doppler ultrasonography for quantifying angiogenesis in prostate cancer.

OBJECTIVE: To assess the correlation between angiogenesis and Doppler signal intensity using transrectal colour Doppler ultrasonography (CDUS) in patients with prostate cancer. PATIENTS AND METHODS: The study comprised 56 patients who underwent radical prostatectomy and had untreated tumours with a volume of> 0.1 mL in the peripheral zone. CDUS images were recorded on videotape before surgery. The Doppler signal intensity in tumours was evaluated using the colour pixel intensity (PI). Microvessel density (MVD) and vascular endothelial growth factor (VEGF) immunoreactivity were determined in the prostatectomy specimens. Microvessels were identified by immunohistochemical staining of endothelial cells for CD31. RESULTS: The PI in the tumour correlated with MVD (P < 0.001) and increased with higher levels of VEGF immunoreactivity (P = 0.004). There was no correlation between Gleason score and MVD or PI in the tumour. CONCLUSION: Blood flow assessed by CDUS may reflect the state of angiogenesis in prostate cancer. CDUS may be a useful technique for predicting tumour progression or prognosis, and may be useful for monitoring the effects of anti-angiogenic agents in the future.

Modulation of heat-induced cell death in PC-3 prostate cancer cells by the antioxidant inhibitor diethyldithiocarbamate.

OBJECTIVE: To examine the relationships between the form of cell death (apoptosis or necrosis), reactive oxygen species (ROS) generation, superoxide dismutase (SOD) activity and the level of heat-shock protein 70 (hsp 70) expression after thermotherapy of PC-3 prostate cancer cells; also assessed were the tumoricidal effects of combined treatment with both heat and the antioxidant inhibitor diethyldithiocarbamate (DDC). MATERIALS AND METHODS: PC-3 cells were treated with thermotherapy at 42, 43 or 44 degrees C for 30, 60, 90 or 120 min. Cell proliferation, ROS generation, SOD activity and cellular hsp 70 level were determined using tetrazolium-based cytotoxicity, fluorescent dichlorofluorescein (DCF) and nitroblue tetrazolium assays, Western blot analysis and flow cytometry, respectively. The apoptotic and necrotic cells were determined by staining with propidium iodide and fluorescein isothiocyanate-labelled annexin V. These variable were also measured after combined treatment of PC-3 cells with 1 mmol/L DDC and thermotherapy at 43 or 44 degrees C for 60 min. RESULTS: Cell survival was significantly lower after heating cells at 43 degrees C for 60, 90 and 120 min and at 44 degrees C for all periods tested (P<0.05). At 43 degrees C apoptosis increased with the duration of heating and was similarly enhanced after heating at 44 degrees C for 30 min. Necrosis was not increased by heating at 42 or 43 degrees C, but was markedly enhanced after heating at 44 degrees C with both the duration of heating and with time after heating. Significant increases in DCF production were induced by heating at 43 degrees C for 60, 90 and 120 min (P<0.05) and at 44 degrees C at all times (P<0.010-0.005). There was a significant correlation between the level of ROS generation and necrosis (P<0.001) but no correlation between the ROS level and apoptosis. SOD activity increased in cells after heating at 43 degrees C, with significant differences among cells heated for 60, 90 and 120 min (P<0.05). After heating at 44 degrees C, SOD activity was maximal in cells heated for 30 min (P<0.005), by 30 min and then decreased with time after heating. There were significant increases in hsp 70 level in cells heated at 43 degrees C for 90 and 120 min (P<0.05) and at 44 degrees C for 30 and 60 min (P<0.05 and <0.025, respectively). Hsp 70 levels decreased after heating at 44 degrees C for 90 and 120 min. The combination of DDC and heating significantly increased ROS generation and the percentage of cell death, and decreased SOD activity (P<0.05). CONCLUSION: These findings show a qualitative change in the form of cell death induced by thermotherapy of PC-3 cells, which changed from apoptosis to necrosis according to the degree and duration of heating. Mild thermotherapy induced marginally low occurrence of apoptosis of PC-3 cells and DDC may represent a useful future strategy for the treatment of prostate carcinoma.

Alterations of beta- and gamma-catenin in N-butyl-N-(-4-hydroxybutyl)nitrosamine-induced murine bladder cancer.

Abnormal degradation of beta-catenin caused by alteration of the glycogen synthase kinase-3beta (GSK-3beta) consensus motif is an important step for carcinogenesis. We hypothesize that beta- and gamma-catenin may play an important role in the pathogenesis of bladder cancer. We tested this hypothesis through analysis of beta- and gamma-catenin in both murine and human bladder cancers. A murine bladder cancer model was prepared by use of N-butyl-N-(-4-hydroxybutyl)nitrosamine (BBN) in 6-week-old male B6D2F1 mice. After 4, 8, 12, 16, 20, 24, and 28 weeks of BBN treatment, bladder specimens were harvested and analyzed for both protein and gene expression for beta- and gamma-catenin. Mutational analysis of the NH(2)-terminal regulatory domains of beta- and gamma-catenin was performed in each specimen by PCR-single-strand conformational polymorphism (SSCP) analysis. Mutations were further confirmed by direct DNA sequencing with a dye terminator method. Human bladder cancer specimens with normal tissues, dysplasia, carcinoma in situ, and carcinoma of grades, 1, 2, and 3 were also analyzed for beta- and gamma-catenin expression. beta- and gamma-catenin were analyzed for mutations by SSCP and direct DNA sequencing. Intracellular accumulation of beta- and gamma-catenin was observed in 6 of 20 invasive carcinoma specimens. There was no intracellular accumulation of beta- and gamma-catenin in mucosal dysplasia, papillary or nodular dysplasia, and carcinoma in situ specimens. On an SSCP analysis for beta-catenin, abnormal bandshifts were detected in two invasive carcinomas with intracellular beta-catenin accumulation. Further sequencing revealed two mutations [AGT(S) to ATT(I) and TCT(S) to CCT(P)] within the consensus motif for GSK-3beta phosphorylation. On the other hand, SSCP analysis for gamma-catenin followed by sequencing revealed three mutations in two invasive carcinomas with intracellular accumulation of gamma-catenin. These three alterations affected the 3' downstream region outside the GSK-3beta phosphorylation site [ACC(T) to GCC(A), CTC(L) to ATC(I), and CTC(L) to ATG(M)]. In human bladder cancer, beta- and gamma-catenin expression was significantly weaker than in normal bladder. On SSCP analysis one abnormal bandshift was observed in high-grade human bladder cancer with intracellular beta-catenin accumulation. DNA sequencing revealed mutation TCT(S) to TGT(C). In summary, alterations in beta- and gamma-catenin are late events favoring tumor progression in mouse BBN-induced bladder cancer. Changes affecting the GSK-3beta phosphorylation site appear to be associated with activation of beta-catenin, but not with activation of gamma-catenin. In human blabber cancer, beta- and gamma-catenin expression is similar to the expression in the mouse model. The present study demonstrates that beta- and gamma-catenin may play an important role in bladder cancer progression.

Heat-induced cellular damage and tolerance in combination with adriamycin for the PC-3 prostate cancer cell line: relationships with cytotoxicity, reactive oxygen species and heat shock protein 70 expression.

OBJECTIVE: To analyze the relationships among the antitumor effect of chemothermotherapy, generation of reactive oxygen species (ROS), and expression of heat shock protein 70 (HSP-70) in the PC-3 prostate cancer cell line. MATERIALS AND METHODS: Changes in cell proliferation, cell cycle fractions, intracellular ROS accumulation and HSP-70 expression were examined after thermotherapy of PC-3 cells at 41, 42, 43 and 44 degrees C and/or simultaneous treatment with Adriamycin for 1 h, using the trypan blue dye exclusion method, flow cytometry, fluorescent 2', 7'-dichlorofluorescein (DCF) assay, and Western blot analysis. RESULTS: A significant decrease in the number of viable cells was observed with chemothermotherapy compared with thermotherapy at 42, 43, or 44 degrees C (p<0.05). DNA distribution histograms revealed cell accumulation in the S-G(2)/M phase after thermotherapy at 43 degrees C and after chemothermotherapy at 37, 41, 42 and 43 degrees C. After thermotherapy and chemothermotherapy at 44 degrees C, DNA histograms revealed no accumulation of cells with S-G(2)/M DNA content and cells exhibited a marked loss of viability. A significant increase in DCF production was observed with chemothermotherapy compared with thermotherapy at 42, 43 or 44 degrees C (p<0.05, p<0.01 and p<0.01, respectively). HSP-70 levels increased linearly with increasing temperature. HSP-70 levels after thermotherapy and chemothermotherapy increased with time and reached plateaus at 30 min, whereas the level after thermotherapy at 44 degrees C decreased at 60 min. CONCLUSIONS: In conclusion, one possible synergism in cytotoxic effects of chemothermotherapy and Adriamycin could be evaluated by the relationship between ROS accumulation and HSP-70 expression in the PC-3 prostate cancer cell line.

Clinical significance of mdm2 and p53 expression in bladder cancer. A comparison with cell proliferation and apoptosis.

BACKGROUND: Clinical significance of immunohistochemically detectable level of p53 protein has been reported, but with some limitation as a prognosticator of bladder cancer patients. Whether or not simultaneous evaluation of mdm2 and p53 expression in bladder cancer exceed the prognostic significance of conventional histological findings, cell proliferation markers and apoptotic parameters remains unclear. MATERIALS AND METHODS: The paraffin-embedded materials taken from 84 patients with transitional cell carcinoma of the bladder who were treated with total cystectomy were used in this study. Immunostainings of p53 protein, mdm2 protein and Ki67 antigen were performed using monoclonal antibodies (clone DO7, clone 1B10 and clone MIB1, respectively). In addition, the apoptotic cells were determined using a terminal deoxynucleotidyl transferase (TdT) mediated dUTP biotin nick end labeling (TUNEL) technique. The results were quantitatively evaluated using a CAS 200 Image Analyzer (Cell Analysis System, Elmhurst, Ill., USA) and were compared with histological findings and clinical course. RESULTS: The mean values of mdm2 expression, p53 immunoreactivity, Ki67 expression and apoptotic index were 19.2, 20.5, 22.4 and 0.96%, respectively. Histological grade and pT category were significantly positively correlated with 53 immunoreactivity (p < 0.05 and p < 0.05, respectively), Ki67 expression (p < 0.005 and p < 0.0001, respectively) and apoptotic index (p < 0.01 and p < 0.0001, respectively), while both were not correlated with mdm2 expression. Using univariate analysis, the prognostic relevance for both survival and disease progression was noted in histological grade, pT category, p53 expression, Ki67 index and apoptotic index, whereas it was not in mdm2 expression. However, when analyzing the simultaneous evaluation of mdm2 and p53 expression (mdm2-p53 category), the relationship of the mdm2-p53 category with Ki67 expression and apoptotic index showed a statistical significance and a borderline significance (p = 0.0085 and p = 0.0652, respectively). In addition, the patients with both mdm2(-) and p53(-) showed a significant better prognosis as compared with either counterpart of mdm2-p53 category (p < 0.05 for both). Multivariate analysis revealed only pT category and mdm2-p53 category as independent factors for both disease progression and survival. CONCLUSIONS: Clinical significance of simultaneous evaluation of mdm2 and p53 immunostaining proved to be superior over that of cell proliferation and/or apoptotic markers when elucidating the biological characteristics of bladder cancer.

Inverted papilloma of the urinary bladder in a girl.

We report a case of inverted papilloma of the urinary bladder in a 10-year-old girl. She was referred to us with intermittent asymptomatic gross hematuria. A polypoid, pedunculated mass, which had a thin and long stalk, approximately 6 x 20 mm in diameter, was observed by cystscopic examination at the right paratrigone. The lesion was resected endoscopically. Histological findings were compatible with the trabecular type of inverted papilloma. There have been only 3 cases reported of inverted papilloma in children, and no report has previously been published concerning a girl. Since the biological potential of pediatric inverted papilloma remains unclear, we believe that our patient should undergo periodic and detailed urological examinations.

Biallelic mutations of the Tsc2 gene in chemically induced rat renal cell carcinoma.

A number of cancer genes have been identified by the study of hereditary human cancers and shown to be involved in sporadic genesis of the same tumors. We have identified a germline mutation in the rat homologue of the human tuberous sclerosis (TSC2) predisposing gene in the Eker rat model. In this study, we searched for mutations of the Tsc2 gene in chemically induced non-Eker rat renal cell carcinomas (RCs). N-ethyl-N-hydroxyethylnitrosamine (EHEN)- and diethylnitrosamine (DEN)-induced non-Eker rat primary RCs were subjected to polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) analysis using specific primers covering all exons of the Tsc2 gene (41 coding exons and 1 non-coding exon). We simultaneously searched for mutations in the Vhl gene, a rat homologue of von Hippel-Lindau disease (VHL) gene, as well as the Tsc2 gene. Mutations in the Vhl gene were not detected in any rat RCs (0/8). In contrast, Tsc2 gene mutations were detected at a high frequency in EHEN-induced RCs (2/3) and DEN-induced RCs (3/5) (total 5/8) (p < 0.05). By a direct cloning approach utilizing PCR analysis in 2 applicable cases, we could demonstrate the presence of intragenic somatic mutations in both alleles of the Tsc2 gene. Our results suggest that Tsc2 gene inactivation plays an important role in EHEN- and DEN-induced RCs as well as in Eker rat RCs.

Comparison of chromosomal aberrations detected by fluorescence in situ hybridization with clinical parameters, DNA ploidy and Ki 67 expression in renal cell carcinoma.

To evaluate the significance of chromosomal aberrations in renal cell carcinoma, fluorescence in situ hybridization (FISH) was used to determine its prevalence and correlation with clinical parameters of malignancy. In addition, correlation of chromosomal aberration with Ki 67 expression was analysed. We performed FISH with chromosome-specific DNA probes, and the signal number of pericentromeric sequences on chromosomes 3, 7, 9 and 17 was detected within interphase nuclei in touch preparations from tumour specimen. The incidence of loss of chromosome 3 was significantly higher than those of chromosomes 7, 9 and 17 (P < 0.001, P = 0.03 and P < 0.001 respectively). Hyperdiploid aberration of chromosomes 3 and 17 was significantly correlated with tumour stage (P = 0.03, P = 0.02 respectively), whereas hyperdiploid aberration of chromosome 9 was associated with nuclear grade (P = 0.04). Disomy of chromosome 7 was correlated with venous involvement (P = 0.04). Ki 67 expression was significantly associated with hyperdiploid aberration of chromosome 17 (P = 0.01), but not with aberration of chromosome 3. There was a significant relationship between hyperdiploid aberration of chromosome 7 and Ki 67 expression (P = 0.01). In conclusions, gain of chromosome 17 may reflect tumour development, and aberration of chromosome 7 may affect metastatic potential of malignancy, whereas loss of chromosome 3 may be associated with early stage of tumour development in renal cell carcinoma.

Identification of a leader exon and a core promoter for the rat tuberous sclerosis 2 (Tsc2) gene and structural comparison with the human homolog.

Hereditary renal carcinoma in the Eker rat is an excellent example of predisposition to a specific cancer being transmitted as a dominant trait. Recently, we identified a germline mutation of the tuberous sclerosis 2 (Tsc2) gene in the Eker rat. In the present study, we analyzed the upstream region of the Tsc2 gene. A novel leader exon (exon 1a) in a CpG island was found, and core promoter activity was identified in a 242-bp region of this island. Exon 1a and the promoter region were conserved in the human TSC2 gene. In addition, a rat homolog of a gene found upstream of TSC2 in human has been identified, indicating that the genomic organization around Tsc2/TSC2 is conserved between the two species. Characterization of the 5' region of Tsc2 and TSC2 will facilitate studies of the regulation of the gene and its disregulation in tumorigenesis.

Somatic mutation of the tuberous sclerosis (Tsc2) tumor suppressor gene in chemically induced rat renal carcinoma cell.

PURPOSE: von Hippel-Lindau (VHL) gene mutations are detected in noninherited, sporadic human renal cell carcinomas (RCs) at a high frequency. We recently identified a germline mutation in the rat homologue of the human tuberous sclerosis (TSC2) predisposing RC gene in the Eker rat model, and in this study we searched for mutations of the Tsc2 gene in chemically induced non-Eker rat RCs. MATERIALS AND METHODS: Chemically [N-ethyl-N-hydroxyethylnitrosamine (EHEN)]-induced non-Eker rat RC lines (designated as BP13 and BP36B) were subjected to PCR-single strand conformation polymorphism (PCR-SSCP) analysis using specific primers covering entire exons of Tsc2 gene (41 coding exons and one non-coding exon). We simultaneously searched for mutations of Vhl gene, a rat homologue of von Hippel-Lindau disease gene (VHL) as well as Tsc2 gene. RESULTS: BP36B showed an abnormal mobility shift from the normal tissue of the same rat in exon 35 on analysis by PCR-SSCP. This mutation was confirmed by direct sequencing and found to be a T-to-C transition at the second position of codon 1470, resulting in an amino acid change from leucine to proline (missense mutation). CONCLUSIONS: This is the first demonstration of Tsc2 gene somatic mutation in non-Eker rat RCs. Our present findings call attention to further investigation of the role of Tsc2 gene mutations in rat renal carcinogenesis and possible Tsc2 gene mutations in human RCs, especially of the non-clear cell type, which are not related to the VHL gene.

Quantitative analysis of NM23 protein immunoreactivity in renal cell carcinoma using an image analyzer.

PURPOSE: nm23 is a candidate tumor suppressor gene. Whether or not tumor metastasis suppressive activity is present in renal cell carcinoma (RCC) was studied. MATERIALS AND METHODS: Immunohistochemical analysis of nm23 protein using an anti-human nm23 H1/H2 polyclonal antibody was performed in 67 RCCs and in the corresponding 67 normal proximal renal tubules (NTs). The quantity and intensity of nm23 protein immunoreactivity were evaluated using a computer-interfaced image analyzer, and the obtained results were compared with pathological findings and clinical outcome. RESULTS: The quantity and intensity of nm23 protein immunoreactivity were significantly higher in RCCs than those observed in NTs (p <0.0001, respectively). Both quantity and intensity of nm23 protein immunoreactivity held a tendency to increase along with histological grade (p = 0.094 and p = 0.089, respectively) and T category (p = 0.063 and p = 0.063, respectively). Similarly, the immunoreactivity had a tendency to be higher in RCCs with lymph node involvement than those tumors without involvement (p = 0.060 and p = 0.067, respectively). However, no significant difference in nm23 protein immunoreactivity was found between tumors with and without distant metastasis. Using a univariate analysis, a high nm23 protein immunoreactivity (quantity > or = 51.0% or intensity > or = 72.5%) significantly correlated with a poor clinical outcome (p = 0.0051 and p = 0.0013, respectively). Furthermore, a multivariate analysis adjusted to age, T, N and M categories, showed that a high intensity of nm23 protein immunoreactivity was significantly associated with a poor clinical outcome in patients with RCCs (p = 0.0192). CONCLUSIONS: Immunohistochemical analysis of nm23 protein intensity is an additional tool for analyzing the difference of biological features in RCCs. The potential role of the tumor metastasis suppressive activity of nm23 remains unclear in RCCs.

Intragenic Tsc2 somatic mutations as Knudson's second hit in spontaneous and chemically induced renal carcinomas in the Eker rat model.

We searched for the rat homologue of the human tuberous sclerosis (TSC2) gene mutations in loss of heterozygosity (LOH)-negative Eker rat renal carcinomas (RCs) by polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP) analysis using 45 primer sets covering all 41 coding exons and one leader exon including splicing donor/acceptor sites. We have identified intragenic somatic mutations in 7 of 21 spontaneous RCs, including one cell line (33%), and in 3 of 9 (33%) N-ethyl-N-nitrosourea (ENU)-induced LOH-negative RCs. Interestingly, five mutations in the spontaneous RCs were either deletion or duplication (5/7 = 71%). In contrast, all three in ENU-induced RCs were base substitutions (3/3 = 100%), as expected. Thus, a qualitative difference in the second hit might exist between spontaneous and ENU-induced mutations (e.g., deletion or duplication versus point mutation). By a direct cloning approach utilizing the restriction length difference caused by germline insertional mutation or reverse transcriptase-PCR analysis in two applicable cases, we could clearly show the presence of intragenic somatic mutations in the second copy (wild-type) of the Tsc2 gene. This is the first demonstration at the DNA sequence level of the validity of Knudson's two-hits hypothesis in the Tsc2 gene.

Clinical significance of immunohistochemically detectable p53 protein in renal cell carcinoma.

OBJECTIVE: To elucidate the clinical significance of p53 protein in renal cell carcinoma (RCC). MATERIALS AND METHODS: The p53 protein in the paraffin-embedded materials taken from 72 patients with RCCs was evaluated immunohistochemically and was compared with the histological findings, expression of proliferating cell nuclear antigen (PCNA), genetic instability as assessed by 2c deviation index (2cDI) and 5c exceeding rate (5cER) as well as clinical outcome. RESULTS: The p53 positivity was demonstrated only in a localized and/or focal area of the cancerous tissue. The positive rate of p53 protein was 40.3% in this study. The p53 protein significantly correlated with nuclear grade as well as PCNA expression (p < 0.001 and p < 0.01, respectively). Although there was a wide scatter of 2cDI and 5cER values between p53 positive and negative RCCs, the RCC with positive p53 exhibited significantly higher values in 2cDI as well as 5cER, as compared to that with negative p53 (p < 0.02 and p < 0.005, respectively). However, some of the RCCs with negative p53 showed relatively higher values in 2cDI and 5cER. Using univariate analysis, the prognostic relevance was noted in T, N, M categories, age and p53 positivity, while it was not in 2cDI, 5cER and PCNA expression. Multivariate analysis demonstrated that N category and p53 positivity were independently significant indicators in predicting survival. CONCLUSIONS: The presence of p53 protein might reflect the genetic instability already occurred. The p53 positivity reflecting a high cellular proliferation could afford an additional but useful information when predicting survival in patients with RCC.

Inverted papilloma of the urinary bladder: a case evaluated for malignant potential.

We report a case of inverted papilloma in the urinary bladder with special reference to its malignant potential. A 77-year-old male patient complaining of microhaematuria was subjected to cystoscopic examination, which showed a non-papillary pedunculated tumour at the postero-lateral wall, and was treated with transurethral resection. The histological findings of the specimen were compatible with inverted papilloma of the urinary bladder, except for the presence of low grade dysplastic changes in the tumour nuclei. We revealed the malignant potential of this tumour, analyzing and evaluating nuclear DNA content, proliferating cell nuclear antigen (PCNA) as well as p53 expression.