Cell surface antigens of human bladder tumors: definition of tumor subsets by monoclonal antibodies and correlation with growth characteristics

Normal human urothelium and tumors of urothelial origin were analyzed with a panel of seven mouse monoclonal antibodies that identify surface antigens of cultured bladder cancer cell lines. Three categories of antigens were defined on the basis of differential expression on normal urothelium versus bladder tumors. Om5 (a category 1 antigen) is a highly restricted, differentiation antigen detected in the normal urothelium of 50-60% individuals. No other normal cell type in Om5- or Om5+ individuals expresses Om5. The incidence of Om5 expression in superficial bladder tumors is significantly higher (88%) than in normal urothelium, whereas its expression in invasive or metastatic tumors is far lower (20%), suggesting Om5 gain/loss in bladder tumors. Paired biopsies of normal urothelium and bladder tumors from the same individuals have shown Om5 induction in the superficial bladder tumors of Om5- individuals and Om5 loss in invasive bladder cancers of Om5+ individuals. Category 2 antigens (T43, T138, T23) are not expressed by normal urothelium or most superficial bladder tumors but are detected on a high proportion of invasive or metastatic bladder tumors, indicating that category 2 antigens are associated with late stages of tumor progression. Category 3 antigens (T16, T87, J143) provide lineage markers for normal or neoplastic cells of urothelial origin, being found on normal urothelium and virtually all bladder tumors. Thus, differential expression of category 1 and 2 antigens divide bladder tumors into distinct subsets, and these subsets correlate with pathological and clinical features of the disease.     

Monoclonal antibody against a tumor-associated sialoglycoprotein of superficial papillary bladder tumors and cervical condylomas.

A mouse IgG1 monoclonal antibody (MAb), 19A211, defining a tumor-associated cell-surface antigen of superficial papillary bladder tumors, was generated by immunizing with fresh bladder tumor cells mice neonatally injected with normal human urothelial cells. The reactivity of the antibody with cell lines was examined by indirect immunofluorescence staining and was restricted to 3/14 bladder cancer lines and 3/31 cancer cell lines of non-bladder origin, including HeLa cervical cancer. No normal fibroblast, kidney cells, EBV-lymphocytes, erythrocytes or leukocytes expressed the antigen. Reactivity of MAb 19A211 was well preserved on tissue paraffin sections. Immunoperoxidase staining of normal adult or fetal tissues showed no reactivity except for a patchy or uniform staining of umbrella cells in 6/23 adult and 1/4 fetal urothelium samples. Positive and often heterogeneous staining was observed on 24/38 papillary superficial tumors (Ta) and 4/5 carcinoma in situ bladder lesions but on only 4/20 infiltrating tumors. It was also observed on 5/6 cervical condylomas and one bladder condyloma, but none of 6 penile or vulvar condylomas. All other tumors tested were negative. The antigenic determinant is present on a heterogeneous group of proteins with molecular weights ranging from 90 to 200 kDa. It is sensitive to periodate treatment and to neuraminidase but only partially sensitive to proteases. MAb 19A211 is different from other reported MAbs with similar reactivity to superficial bladder tumors and umbrella cells of normal urothelium. When tested in competition assays, several of these MAbs, but not 19A211, were found to react with Lewis X blood group determinant. Our results suggest that 19A211 may be useful for detection and stratification of bladder tumors.     

Activity of the human blood group ABO, Se, H, Le, and X gene-encoded glycosyltransferases in normal and malignant bladder urothelium

Immunohistochemistry has led to the finding of an expression of ABO-related blood group antigens in normal and malignant bladder urothelium which is different from that found on erythrocytes from the same individual. This includes a loss of blood group ABO expression in malignant urothelium, and the expression of Leb antigens in normal and malignant cells from individuals with Le(a+b-) and Le(a-b-) erythrocytes. To elucidate the mechanism of this blood group antigen expression in urothelium we have analyzed the activity of the specific glycosyltransferases encoded by the ABO, Se, H, Le, and X blood group genes in normal and malignant urothelium. Biopsies of normal urothelium were obtained from 22 individuals and biopsies of urothelial tumors from 20 individuals. The tissue donors were typed for ABO, Lewis, and secretor status on erythrocytes and saliva. The biopsies were disaggregated to single cell suspensions, and the activity of the individual glycosyltransferases was determined as pmol of labeled sugar incorporated by oligosaccharide acceptors per 100,000 cells. The A (alpha-3-N-acetyl-D-galactosaminyl) and B (alpha-3-D-galactosyl) gene-specified transferases showed no activity in malignant cells, whereas all other enzymes examined were expressed in both normal and malignant cells. Secretors and nonsecretors showed the same alpha-2-L-fucosyltransferase activity in both normal and malignant cells, whereas the alpha-3-L-fucosyltransferase was reduced (P less than 0.02) in malignant cells from Lewis positive individuals. The Lewis gene-encoded alpha-4-L-fucosyltransferase showed a similar activity in Lewis positive and negative individuals. These results indicate that the disappearance of A and B blood group antigens in bladder tumors and the expression of Leb antigens in normal and malignant cells from individuals with Le(a+b-) and Le(a-b-) erythrocytes are due to corresponding differences in glycosyltransferases. The results indicate that the ABO, H, Se, and Le genes are subjected to a tissue-dependent differential expression.     

Monoclonal antibodies raised against cell membrane components of human bladder tumor tissue recognizing subpopulations in normal urothelium

Monoclonal antibodies to human bladder carcinoma membrane antigens were produced by fusion of MOPC-21 NS/1 mouse myeloma cells with spleen cells from BALB/c mice immunized against a crude membrane extract from a metastatic bladder carcinoma. Hybrids were screened for antibody production in a solid-phase radioimmunoassay and selected for their reactivity with subpopulations of urothelial cells on normal bladder tissue sections. Three antibody groups were defined: Group I (4-72-2) was urothelium specific and stained the basal and intermediate cells in normal urothelium; group II (3-48-2, 48-1, and 3-50-3) showed reactivity with intermediate and superficial cells; group III (8-30-3, 77-1, 2-94-2, 3-71-1, and 94-3) was restricted to antigens on the luminal membrane of superficial cells. All antibodies recognized antigenic determinants in fixed paraffin-embedded material and within groups showed a range of staining patterns in other tissues. Studies on sections representing different stages of neoplastic progression showed disruption in the antibody-staining pattern in urothelium and, in all cases, a strong distinct staining of invasive tumor areas and metastatic secondary tumors. Biochemical analysis of the antigens defined at least three antigenic systems, two of which consisted of molecules having Mr of 250,000 and 300,000 as judged by Western blot analysis. Antigenic determinants recognized by some antibodies (3-48-2, 48-1, 3-50-3, 8-30-3, 77-1, and 3-71-1) were shown to be carbohydrate by reactivity with glycolipid fraction and suggest that antibodies within groups recognize different epitopes on the same molecule.     

CXCR4 expression reflects tumor progression and regulates motility of bladder cancer cells

Transitional cell carcinoma of the urinary bladder remains life threatening due to the high occurrence of metastases. Emerging evidence suggests that chemokines and their receptors play a critical role in tumor metastases. In our study, we performed a systematic analysis of the mRNA and protein expression levels of all 18 chemokine receptors in normal urothelium and bladder cancer. CXCR4 was the only chemokine receptor whose mRNA expression level was upregulated in bladder cancer cell lines as well as in invasive and locally advanced bladder cancer tissue samples (pT2-pT4). In contrast, superficial bladder tumors (pTa and pT1) displayed low CXCR4 expression levels and normal urothelial cells were negative for CXCR4. Immunohistochemistry of a bladder cancer tissue microarray (TMA) confirmed that a subgroup of invasive bladder cancers revealed a high CXCR4 protein expression, while superficial bladder tumors showed low immunoreactivity. To investigate the functional significance of CXCR4 expression, we performed migration and invasion assays. Exposure of CXCR4-positive bladder cancer cells to CXCL12 in a Boyden chamber type assay provoked a significant increase in migration as well as invasion across a Matrigel barrier. Enhanced migration and invasion were inhibited by a CXCR4-specific blocking antibody. In contrast, normal urothelial cells did not respond to CXCL12 and lacked chemotactic migration. In conclusion, bladder cancer cells express CXCR4 progressively with advanced tumorigenesis and this receptor interacts with CXCL12 to mediate tumor chemotaxis and invasion through connective tissue. These properties identify CXCR4 as a potential target for the attenuation of bladder cancer metastases.     

Antibody drug carrier for immunotherapy of superficial bladder cancer: ultrastructural studies.

Superficial bladder cancer represents a promising target for intravesical, antibody-guided therapy. The construction of an optimum antibody-cytotoxic drug conjugate depends mostly on the appropriate selection of a monoclonal antibody (mAb). We have used immunogold labeling and SEM to specifically map the distribution of antigens expressed on three bladder cancer cell lines and on the luminal surface of biopsies from human transitional cell carcinoma of various grades and from normal bladder mucosa. The 48-127 mAb, which recognizes a M(r) 54,000 surface glycoprotein (gp54), was found to be very promising as a potential drug carrier. This antibody reacts with the surface of cells from low- and high-grade tumors; it does not react with the normal urothelium. Labeling of normal bladder mucosa was observed, however, on microvillous intermediate urothelial cells occasionally exposed by small areas of desquamation. The 48-127 mAb could target drugs to all areas of transformed urothelium while avoiding drug delivery to the normal, undesquamated bladder mucosa. Kinetics of gp54/48-127/gold complexes were tested in vitro with T24 and RT4 human bladder carcinoma cell lines incubated in the presence of the 48-127 mAb directly conjugated with 17.7-nm gold particles. Internalization of the gp54/48-127/gold complex was readily demonstrated by transmission electron microscopy. These results suggest that the 48-127 mAb represents a valuable drug carrier for intravesical therapy, allowing specific tumor targeting and internalization of various cytotoxic agents.     

Human bladder cancer associated antigens: evaluation of antigenicity in TCC tissues of different grades and in normal urothelium

The expression of five antigens, associated with transitional cell carcinoma (TCC) of the urinary bladder on biopsies of tumors or normal urothelium, was studied by immunostaining with the corresponding monoclonal antibodies. Both tissue sections and single cell preparations were investigated with either indirect immunoperoxidase staining or immunofluorescence. All 5 antigens were expressed on the majority (70-90%) of sectioned tumor specimens from 44 TCC patients, and 4 of them were similarly expressed on single cell tumor preparations from 26 additional patients. However, in both types of preparation, the degree of expression of these antigens varied from scattered staining of less than 25% of the tumor cells to homogenous staining of all or almost all cells. This degree of expression varied individually for each of the antigens and was not related to the malignancy grade of the tumors. However, as most of the tumors were of grades II or III, no conclusions regarding the relationship of antigen expression to the aggressiveness of the tumors can be drawn. In any event, all tumors expressed at least one and mostly several of these antigens. Antigen expression on biopsies of normal bladder mucosa from TCC patients or on urothelial biopsies from patients with prostate hyperplasia was also observed on single cell specimens (34 patients) but not on sectioned material (9 patients). However, the frequency of positive specimens was much lower (4-20%). Moreover, the number of cells expressing one or, occasionally, several of the antigens in normal urothelium was small (usually less than 5%). Because of these marked differences in antigen expression between tumors and normal tissue, the results indicate that a combination of 3-5 of the antibodies used in this study may be suitable for diagnostic purposes.     

The epidermal growth factor receptor and the prognosis of bladder cancer

Epidermal growth factor is found in high concentrations in urine, and its receptor (EGFr) has been identified in certain bladder tumors. This study was performed to determine whether receptor positivity in the tumor was associated with a poor clinical outcome. One hundred one patients with newly diagnosed bladder cancer were studied prospectively by immunohistochemical staining for the EGFr. There were 76 men and 25 women, with a mean follow-up of 30 months; 49 had tumors invading muscle: 18 were pTl (tumor invading lamina propia) and 34 were pTa (tumor confined to urothelium). Strong staining for the EGFr was found in 48% of tumors and was associated with high stage (P less than 0.001). Death of bladder cancer (40 of 101) was associated independently with high stage (P less than 0.0001) and EGFr positivity (P less than 0.001). In patients with pTa and pTl tumors, EGFr positivity was associated with multiplicity (P less than 0.01), time to recurrence (P less than 0.03), and recurrence rate (P less than 0.004). Tumor progression was associated with EGFr positivity (P less than 0.0001) and multiplicity (P less than 0.05). EGFr were found on a significant proportion of bladder tumors: such tumors were more likely to result in death, recurrence, and progression.     

Enhanced expression of a tumor-cell-derived collagenase-stimulatory factor in urothelial carcinoma: Its usefulness as a tumor marker for bladder cancers

A mouse monoclonal antibody (MAb) E11F4, previously raised against the tumor-cell-derived collagenase-stimulatory factor (TCSF) from LX-1 human lung-carcinoma cells, has been used to define the expression and distribution of TCSF in human non-neoplastic urothelium and tumors of the urinary bladder. Immunohistochemically, TCSF was detected in 27/28 transitional-cell carcinomas (TCC) of the bladder, of which 23 were judged to be positive for TCSF according to objective criteria. Twenty-four of 28 non-neoplastic urothelium from 22 individuals were judged to be negative for TCSF by this criteria. However, TCSF immunostaining that was confined to the superficial umbrella cells was frequently observed in nonneoplastic urothelium. In bladder carcinomas, TCSF was in most cases demonstrated in the majority of cells, including at the invasion front. Its localization to the cell membrane was demonstrated by immunoelectron microscopy. The high level of expression of TCSF in bladder tumors, but not in non-neoplastic urothelium, was also demonstrated by immunoblotting of tissue extracts. Furthermore, E11F4 immunostaining identified tumor cells obtained from bladder washings or voided urine and detected more TCC cases than conventional cytology. Since TCSF immunostaining was positive even in low-grade TCC (immunohistochemically and immunocytochemically in 4/5 TCC grade I), the application of TCSF immunostaining to urine cytology appears promising as a valuable adjunct to conventional methods in the clinical evaluation of patients with TCC. © 1993 Wiley-Liss, Inc.     

膀胱尿路上皮癌组织中EGFL7蛋白的表达及微血管密度的意义

目的:研究膀胱尿路上皮癌组织中EGFL7蛋白的表达及微血管密度（microvessel density,MVD）,探讨EGFL7及MVD与膀胱尿路上皮癌生物学特征的内在联系。方法:应用免疫组化SP法,对63例膀胱尿路上皮癌组织及10例正常人膀胱组织中的EGFL7蛋白进行检测,同时应用八因子抗体对膀胱尿路上皮癌组织中微血管进行染色,结合Meta-Morph显微荧光图像分析系统测定并分析63例膀胱尿路上皮癌中微血管密度（MVD）及其与EGFL7和膀胱尿路上皮癌的病理分期、临床分级之间的关系。结果:EGFL7在正常膀胱组织均呈阴性表达,40例膀胱尿路上皮癌EGFL7蛋白表达阳性,阳性率为63%（P<0.05）。EGFL7蛋白的表达在膀胱尿路上皮癌不同肿瘤组织学分级、临床分期组间比较差异具有统计学意义(P<0.05)。MVD值在膀胱尿路上皮癌组织中不同病理分级、临床分期组间有显著性差异（P<0.05）。结论:EGFL7和MVD在膀胱尿路上皮癌组织中表达与肿瘤病理分级及临床分期密切相关,在膀胱尿路上皮癌浸润转移过程中起重要作用。     

Differential expression of cell cycle regulators in phenotypic variants of transgenically induced bladder tumors: implications for tumor behavior

Proteins controlling cell growth, differentiation, apoptosis, and oncogenic stress are often deregulated in tumor cells. However, whether such deregulations affect tumor behavior remains poorly understood in many tumor types. We recently showed that the urothelium-specific expression of activated H-ras and SV40 T antigen in transgenic mice produced two distinctive types of tumors strongly resembling the human superficial papillary tumors and carcinoma in situ of the bladder, respectively. Here we assessed the expression of a key set of cell cycle regulators in these mouse tumors and in a new transgenic line expressing a cyclin D1 oncogene in the urothelium. We found that urothelia of the wild-type and cyclin D1 transgenic mice exhibited a profile of cell cycle regulators found in quiescent (G(0)) cells, indicating that urothelium overexpressing the cyclin D1 (an 8-fold increase) is reminiscent of normal urothelium and remains slow-cycling. Low-grade superficial papillary tumors induced by activated H-ras had no detectable Rb family proteins (Rb, p107, and p130) and late cell cycle cyclins and kinases (cyclin A, E, and CDK1), but had increased level of p16, p53, and MDM2. These data suggest that the inactivation of the Rb pathway plays an important role in H-ras-induced superficial papillary tumors and that oncogenic H-ras can induce a compensatory activation of alternative tumor suppressor pathways. In contrast, carcinoma in situ of the bladder induced by SV40 T antigen had increased expression of cell cycle regulators mainly active in post-G(1) phases. The fact that phenotypically different bladder tumors exhibit different patterns of cell cycle regulators may explain why these tumors have different propensity to progress to invasive tumors. Our results indicate that the transgenic mouse models can be used not only for studying tumorigenesis but also for evaluating therapeutic strategies that target specific cell cycle regulators.     

Stage-associated overexpression of the ubiquitin-like protein, ISG15, in bladder cancer

Bladder cancer is among the most prevalent malignancies, and is characterised by frequent tumour recurrences and localised inflammation, which may promote tissue invasion and metastasis. Microarray analysis was used to compare gene expression in normal bladder urothelium with that in tumours at different stages of progression. The innate immune response gene, interferon-stimulated gene 15 kDa (ISG15, GIP2), was highly expressed at all stages of bladder cancer as compared to normal urothelium. Western blotting revealed a tumour-associated expression of ISG15 protein. ISG15 exhibited a stage-associated expression, with significantly (P<0.05) higher levels of ISG15 protein in muscle-invasive T2-T4 tumours, compared with normal urothelium. Although ISG15 is involved in the primary immune response, ISG15 expression did not correlate with bladder inflammation. However, immunohistochemical staining revealed expression of ISG15 protein in both cancer cells and stromal immune cells. Interestingly, a significant fraction of ISG15 protein was localised to the nuclei of tumour cells, whereas no nuclear ISG15 staining was observed in ISG15-positive stromal cells. Taken together, our findings identify ISG15 as a novel component of bladder cancer-associated gene expression.     

Cytochrome P450 isoenzyme mRNA expression pattern in human urinary bladder malignancies and normal urothelium

This study was designed to analyze the cytochrome P450 isoenzyme mRNA expression pattern of transitional cell carcinomas of the bladder (N = 19) and normal urothelium (N = 10). In addition, biopsies from normal urothelium (N = 32) taken at the time of transurethral resection of bladder cancer in eight patients from surrounding histologically normal urothelium also were characterized concerning their specific cytochrome P450 mRNA expression pattern. A total of 13 of 19 of the analyzed tumor specimens (68%) revealed expression of cytochrome P450 1B1. Cytochrome P450 4B1 and 1A1 mRNA expression were detected in 79% (15 of 19) and 53% (10 of 19) of the tumor specimens, with no correlation between tumor stage and grade of the neoplasm. Biopsies from macroscopically and histologically normal urothelium from tumor-invaded bladders also showed expression of cytochrome P450 1B1 in 75% (24 of 32), 4B1 in 62.5% (20 of 32), and 1A1 in 50% (16 of 32). Furthermore, a 75% homology concerning cytochrome P450 1B1 and 4B1 mRNA expression was observed between the bladder tumor and the biopsies from this bladder. The polymerase chain reaction analysis of normal urothelium from normal bladders that do not harbor a neoplasm revealed CYP450 mRNA expression for CYP450 1A1 in 6 of 10; 1B1 in 5 of 10; 4B1 in 6 of 10; 2D6 in 2 of 10; and 2E1 in 2 of 10. According to our data, CYP450 1B1 mRNA expression is not tumor-specific. The present findings are the first to compare CYP450 expression in bladder cancer with biopsies from the same tumor-bearing bladder, and they indicate that, from the enzymatic point of view, bladder cancer also is a panurothelial field disease present in even normal urothelium.     

An improved intravesical model using human bladder cancer cell lines to optimize gene and other therapies

Orthotopic implantation of human bladder cancer cells into immunodeficient mice is an important tool for studying the biology and effects of therapy. Nevertheless, the incidence of tumor implantation and growth by transurethral instillation of the human bladder cancer cells into murine bladders has been low or not reproducible. However, using a modified intravesical technique and the human bladder cancer cell lines, KU-7 and UM-UC-2, we have been able to obtain a high and reproducible incidence of superficial bladder tumors. Furthermore, intravesical administration of the LacZ adenovirus vector resulted in significant beta-galactosidase expression in these bladder tumors as well as the normal urothelium, which was associated with the removal of the glycosoaminoglycan layer. Because this modified technique produces a high incidence of superficial human tumor growth and allows the efficacy of gene transfer to be evaluated, it should be a useful model for the study of intravesical gene therapy for human bladder cancer.     

Histochemistry of NADH diaphorase and gamma-glutamyltranspeptidase in rat bladder tumors

To improve identification of preneoplastic bladder cancer cells,we have studied two enzyme histochemical changes in bladdertumors induced in male Fisher 344 rats by the carcinogen N-butyl-N-(4-hydroxybutyl)-nitrosamine.In early areas of focal nodular hyperplasia there was a dramaticincrease in staining for NADH:menadione oxidoreductase (diaphorase)activity. In nonfocal areas as well, there were many individualcells with intense staining, while the controls were of uniformmoderate staining. Large papillomas and carcinomas often showedheterogeneous staining. - Glutamyltranspeptidase (GGT) was absentfrom normal urothelium and from all tumors except the most advancedcarcinomas and large papillomas. In old, carcinogen-exposedanimals, GGT activity was seen in the luminal surface of tumorsand in the interlesion urothelium. In newborn rats and in ratswith regenerative hyperplasia following wounding of the urothelium,the diaphorase staining was less than that in the untreatedadult. Our findings suggest that increased diaphorase activitymay serve to identify early islands of carcinogen-induced, enzymaticallyaltered bladder cells, while GGT will not.     

ras induced lesions in a heterotopic mouse bladder

To determine the in vivo phenotype elicited in bladder epithelium following the expression of a ras oncogene we have introduced the HaSV ras transforming gene into transplants of normal urothelium. Stripped adult bladder mucosa incubated with HaSV, in the presence or absence of helper virus, was transplanted beneath the renal capsule of syngeneic animals and maintained for periods up to three months. Control implants, exposed to helper virus alone, formed heterotopic bladders lined by urothelium displaying focal areas of full differentiation when associated with underlying submucosal elements. Exposure of urothelium to HaSV resulted in increased proliferative potential of mucosal and submucosal elements with the appearance of a normal differentiated heterotopic bladder 10 days post-implantation. Implants left for 28 days presented a range of hyperplastic lesions (mild-severe) characterized from histological evaluation and antibody markers recognizing basal (D66) and superficial cell populations (H10) in normal bladder mucosa. Staining of mild hyperplastic lesions revealed an increased basal cell compartment and a loss of fully differentiated cells lining the lumen of the implanted bladder. In severe hyperplasia no superficial cells were observed but mucosal elements stained throughout with antibody D66. This phenotype was accompanied by an irregular laminin staining pattern associated with a disorganized basement membrane and increased blood vasculature. Similar experiments conducted with HaSV and helper virus resulted in the generation of mesenchymal lesions at 28 days with little surviving urothelium. The H-ras oncogenic protein can induce hyperplastic lesions in normal urothelium which were characteristic of preneoplastic changes identified in bladder carcinogenesis.     

Fluorescence confocal microscopy and image analysis of bladder cancer using 5-aminolevulinic acid

5-aminolevulinic acid mediated changes in tissue specific fluorescence were studied in bladder cancer. Bladders of normal patients and also patients diagnosed with cancer were instilled with 5-aminolevulinic acid and the resultant protoporphyrin IX mediated fluorescence intensity was imaged and quantified with confocal laser microscopy and fluorescence image analysis. Urothelial tumour cells were observed to fluoresce more intensely than normal urothelial cells. Submucosa and muscle tissues exhibited minimal fluorescence compared to urothelial cells of malignant origin and also normal urothelial cells. Degree of fluorescence intensity was in the order of malignant urothelium > normal urothelium > normal submucosa > normal muscles. Fluorescence intensity was also found to increase with duration of ALA instillation. Grade 3 malignant cells produced more fluorescence compared to grade 2 and grade 1. Similarly, T1 transitional cell carcinoma (TCC) showed increased fluorescence intensity than that of Ta TCC. Also, tumour blood vessels fluoresced more intensely compared to blood vessels found in normal bladder tissue. Tissue specific ALA mediated PpIX micro fluorescence can be used as a diagnostic technique for early detection of neoplasms and confocal laser microscopy and fluorescence image analysis are advantageous diagnostic tools for the photodynamic diagnosis of bladder neoplasms in vivo.     

CDC91L1 (PIG-U) mRNA expression in urothelial cell carcinomas

CDC91L1 (PIG-U) was recently discovered as a new oncogene in human bladder cancer and showed mRNA overexpression in 36% of primary bladder tumor tissues compared to normal urothelium. We further investigated CDC91L1 mRNA expression in 8 bladder cancer cell lines, 14 normal bladder tissues and 42 urothelial cell carcinomas by real-time quantitative PCR. The prognostic value of CDC91L1 mRNA expression was also investigated. Surprisingly, only one (2.4%) tumor tissue showed overexpression compared to normal urothelium. No significant relationship of CDC91L1 mRNA expression with increasing pathologic stage (p = 0.962) or grade (p = 0.557) was observed. Median normalized CDC91L1 mRNA expression values were 0.19 for superficial tumors (n = 21) and 0.18 for invasive tumors (n = 21). Grade I, grade II and grade III tumors had median normalized expression values of 0.26, 0.18 and 0.33, respectively. CDC91L1 mRNA expression level was not indicative of early tumor recurrence (log rank p = 0.1629), tumor progression (log rank p = 0.9307) or overall and disease-specific survival (log rank p = 0.9193 and 0.4710, respectively). Our results suggest, in contrast to those of Guo et al. (Nat Med 2004;10:374-81), that the oncogene CDC91L1 is not overexpressed at the mRNA level in urothelial cell carcinomas and cannot be used to predict the course of the disease.     

Lectin receptors in transitional cell tumors of the bladder

Binding sites for lectins of peanuts, soya-beans and concanavalin A were identified in the tissues of normal human urinary bladder and its transitional cell tumors (31 patients) using the lectin-peroxidase technique. No binding sites for any of the lectins were found in normal urothelium. Receptors for peanut and soya-bean lectins were observed on the plasma membranes of 20% of tumor cells in transitional cell papillomas. A diffuse distribution of those lectins in tumor cell cytoplasm was interpreted as a tendency to malignant transformation of tumor. There were no concanavalin A receptors in tumor cells.