Polymorphic expression of a human superficial bladder tumor antigen defined by mouse monoclonal antibodies

Urine biomarkers in bladder cancer - current status and future perspectives

Urine markers to detect bladder cancer have been the subject of research for decades. The idea that urine - being in continuous contact with tumour tissue - should provide a vector of tumour information remains an attractive concept. Research on this topic has resulted in a complex landscape of many different urine markers with varying degrees of clinical validation. These markers range from cell-based assays to proteins, transcriptomic markers and genomic signatures, with a clear trend towards multiplex assays. Unfortunately, the number of different urine markers and the efforts in research and development of clinical grade assays are not reflected in the use of these markers in clinical practice, which is currently limited. Numerous prospective trials are in progress with the aim of increasing the quality of evidence about urinary biomarkers in bladder cancer to achieve guideline implementation. The current research landscape suggests a division of testing approaches. Some efforts are directed towards addressing the limitations of current assays to improve the performance of urine markers for a straightforward detection of bladder cancer. Additionally, comprehensive genetic analyses are emerging based on advances in next-generation sequencing and are expected to substantially affect the potential application of urine markers in bladder cancer.

Turning antibodies off and on again using a covalently tethered blocking peptide

In their natural form, antibodies are always in an "on-state" and are capable of binding to their targets. This leads to undesirable interactions in a wide range of therapeutic, analytical, and synthetic applications. Modulating binding kinetics of antibodies to turn them from an "off-state" to an "on-state" with temporal and spatial control can address this. Here we demonstrate a method to modulate binding activity of antibodies in a predictable and reproducible way. We designed a blocking construct that uses both covalent and non-covalent interactions with the antibody. The construct consisted of a Protein L protein attached to a flexible linker ending in a blocking-peptide designed to interact with the antibody binding site. A mutant Protein L was developed to enable photo-triggered covalent crosslinking to the antibody at a specific location. The covalent bond anchored the linker and blocking peptide to the antibody light chain keeping the blocking peptide close to the antibody binding site. This effectively put the antibody into an "off-state". We demonstrate that protease-cleavable and photocleavable moieties in the tether enable controlled antibody activation to the "on-state" for anti-FLAG and cetuximab antibodies. Protein L can bind a range of antibodies used therapeutically and in research for wide applicability.

Comparative evaluation of ProEx C and ImmunoCyt/uCyt assays in atypical urine cytology

CONTEXT

Detection of urothelial carcinoma by urine cytology can be challenging. Recently, ProEx C has been studied as a marker to improve detection of urothelial carcinoma. ProEx C is an assay targeting expression of topoisomerase II-α and the minichromosome maintenance protein-2 and is used to assist in diagnoses of gynecologic specimens.

OBJECTIVE

To evaluate the utility of ProEx C and uCyt in atypical urine cytology.

DESIGN

Sixty-eight specimens with a diagnosis of atypical urine cytology, concurrent uCyt testing, and surgical biopsy follow-up were included. Slides were restained with ProEx C. ProEx C was recorded as positive when nuclear staining was seen in at least one morphologically atypical urothelial cell. The uCyt was scored as positive if at least one morphologically atypical urothelial cell showed positive fluorescence staining. Thirteen cases (19%) had benign histologic diagnoses, 18 (26%) had low-grade papillary urothelial carcinoma, and 37 (54%) had high-grade urothelial carcinoma.

RESULTS

The overall sensitivity was 85% for ProEx C, 85% for uCyt, and 93% for the combination of the 2 assays. The overall specificity was 69% for ProEx C, 31% for uCyt, and 23% for the combination of the 2 tests. In predicting high-grade urothelial carcinoma, sensitivity was 92% for ProEx C, 86% for uCyt, and 92% for both tests. In predicting low-grade papillary urothelial carcinoma, sensitivity was best with the combination of the 2 tests at 94%.

CONCLUSION

ProEx C has superior specificity to uCyt. The combination of the 2 tests yielded high sensitivity not only for high-grade urothelial carcinoma but also for low-grade papillary urothelial carcinoma.

Microbubble-mediated ultrasound therapy: a review of its potential in cancer treatment

The inherently toxic nature of chemotherapy drugs is essential for them to kill cancer cells but is also the source of the detrimental side effects experienced by patients. One strategy to reduce these side effects is to limit the healthy tissue exposure by encapsulating the drugs in a vehicle that demonstrates a very low leak rate in circulation while simultaneously having the potential for rapid release once inside the tumor. Designing a vehicle with these two opposing properties is the major challenge in the field of drug delivery. A triggering event is required to change the vehicle from its stable circulating state to its unstable release state. A unique mechanical actuation type trigger is possible by harnessing the size changes that occur when microbubbles interact with ultrasound. These mechanical actuations can burst liposomes and cell membranes alike allowing for rapid drug release and facilitating delivery into nearby cells. The tight focusing ability of the ultrasound to just a few cubic millimeters allows for precise control over the tissue location where the microbubbles destabilize the vehicles. This allows the ultrasound to highlight the tumor tissue and cause rapid drug release from any carrier present. Different vehicle designs have been demonstrated from carrying drug on just the surface of the microbubble itself to encapsulating the microbubble along with the drug within a liposome. In the future, nanoparticles may extend the circulation half-life of these ultrasound triggerable drug-delivery vehicles by acting as nucleation sites of ultrasound-induced mechanical actuation. In addition to the drug delivery capability, the microbubble size changes can also be used to create imaging contrast agents that could allow the internal chemical environment of a tumor to be studied to help improve the diagnosis and detection of cancer. The ability to attain truly tumor-specific release from circulating drug-delivery vehicles is an exciting future prospect to reduce chemotherapy side effects while increasing drug effectiveness.

Microbubble-mediated ultrasound therapy: a review of its potential in cancer treatment

The inherently toxic nature of chemotherapy drugs is essential for them to kill cancer cells but is also the source of the detrimental side effects experienced by patients. One strategy to reduce these side effects is to limit the healthy tissue exposure by encapsulating the drugs in a vehicle that demonstrates a very low leak rate in circulation while simultaneously having the potential for rapid release once inside the tumor. Designing a vehicle with these two opposing properties is the major challenge in the field of drug delivery. A triggering event is required to change the vehicle from its stable circulating state to its unstable release state. A unique mechanical actuation type trigger is possible by harnessing the size changes that occur when microbubbles interact with ultrasound. These mechanical actuations can burst liposomes and cell membranes alike allowing for rapid drug release and facilitating delivery into nearby cells. The tight focusing ability of the ultrasound to just a few cubic millimeters allows for precise control over the tissue location where the microbubbles destabilize the vehicles. This allows the ultrasound to highlight the tumor tissue and cause rapid drug release from any carrier present. Different vehicle designs have been demonstrated from carrying drug on just the surface of the microbubble itself to encapsulating the microbubble along with the drug within a liposome. In the future, nanoparticles may extend the circulation half-life of these ultrasound triggerable drug-delivery vehicles by acting as nucleation sites of ultrasound-induced mechanical actuation. In addition to the drug delivery capability, the microbubble size changes can also be used to create imaging contrast agents that could allow the internal chemical environment of a tumor to be studied to help improve the diagnosis and detection of cancer. The ability to attain truly tumor-specific release from circulating drug-delivery vehicles is an exciting future prospect to reduce chemotherapy side effects while increasing drug effectiveness.

Localized in vivo activation of a photoactivatable doxorubicin prodrug in deep tumor tissue

Sparing sensitive healthy tissue from chemotherapy exposure is a critical challenge in the treatment of cancer. The work described here demonstrates the localized in vivo photoactivation of a new chemotherapy prodrug of doxorubicin (DOX). The DOX prodrug (DOX-PCB) was 200 times less toxic than DOX and was designed to release pure DOX when exposed to 365 nm light. This wavelength was chosen because it had good tissue penetration through a 1 cm diameter tumor, but had very low skin penetration, due to melanin absorption, preventing uncontrolled activation from outside sources. The light was delivered specifically to the tumor tissue using a specialized fiber-optic LED system. Pharmacokinetic studies showed that DOX-PCB had an α circulation half-life of 10 min which was comparable to that of DOX at 20 min. DOX-PCB demonstrated resistance to metabolic cleavage ensuring that exposure to 365 nm light was the main mode of in vivo activation. Tissue extractions from tumors exposed to 365 nm light in vivo showed the presence of DOX-PCB as well as activated DOX. The exposed tumors had six times more DOX concentration than nearby unexposed control tumors. This in vivo proof of concept demonstrates the first preferential activation of a photocleavable prodrug in deep tumor tissue.

Ultrasound mediated localized drug delivery

Chemotherapy is one of the frontline treatments for cancer patients, but the toxic side effects limit its effectiveness and potential. The goal of drug delivery is to reduce these side effects by encapsulating the drugs in a carrier which prevents release and can circulate throughout the body causing minimal damage to the healthy tissue. Slow release carriers have been developed which reduce the exposure to healthy tissue but this slow release also limits the maximum levels of drug in the tumor and nonspecific accumulation in healthy tissue remains a major hurdle. The next advance is to design these carriers to produce a rapid burst release of drug, but only in response to a localized trigger. The trigger of choice is low intensity focused ultrasound. A new particle is described here which incorporates an ultrasound sensitive microbubble of perfluorocarbon gas within a protective liposome carrier along with the payload. It is shown that this design can accomplish the desired burst release when exposed to ultrasound focused to small spatial locations within tissue phantoms. The ability to trigger release could provide a second level of spatial and temporal control beyond biochemical targeting or passive accumulation, making these promising particles for further development.

[Tumor marker tests in bladder cancer]

The gold standard for detecting bladder cancer is cystoscopy which identifies nearly all papillary and sessile lesions. However, it is an invasive procedure causing some discomfort for patients. Urine cytology is the standard non-invasive marker with very high specificity, but unfavourable poor sensitivity for Ta, G1, and T1 bladder tumors. To improve early detection of bladder cancer as well as to monitor treatment response and tumor recurrence, bladder tumor markers are eligible. An ideal bladder cancer test would have the potential to replace or delay cystoscopy in the follow-up of bladder cancer patients. In recent years, the FDA approved non-invasive tumor marker tests ImmunoCyt / uCyt+, BTA TRAK, BTA stat, NMP22, NMP22 BladderChek, and UroVysion have been investigated. The tests demonstrated higher sensitivity for diagnosis of bladder cancer compared to urine cytology. Overall, the mean sensitivity and mean specificity was 64-80% and 71-95% and the mean positive and negative predictive values to detect malignancy were 49-84% and 79-95%, respectively. BTA TRAK, BTA stat, NMP22, and NMP22 BladderChek assays are limited by false-positive results in patients with benign urological diseases such as hematuria, urocystitis, renal calculi or urinary tract infections. Due to low specificity BTA TRAK, BTA stat, NMP22, and NMP22 BladderChek should not be used without first ruling out benign or malignant genitourinary disease other than bladder cancer. With the exception of UroVysion achieving 80% sensitivity and 94% specificity, none of these non-invasive tests revealed a high sensitivity and specificity at the same time, which is a main demand to be made on an ideal tumor marker. Insufficient sensitivity along with limited specificity does not allow replacing cystoscopy in diagnosis of bladder cancer or treatment decisions based on a positive test result.

Diagnostic Utility of the ImmunoCyt/uCyt+ Test in Bladder Cancer

Bladder cancer is a common malignancy in the United States. Although urine cytology is a useful adjunct in both diagnosis and follow-up and is highly sensitive for detecting high-grade tumors, it is limited by decreased sensitivity in detecting low-grade tumors, which constitute the majority of new diagnoses. Additional screening tests with high sensitivity and specificity for urothelial tumors of all grades are indicated to help improve the diagnostic ability of urine cytology as well as to reduce the need for frequent cystoscopies, especially in those with low-risk disease. Several assays have been developed, with the ImmunoCyt/uCyt+ test (DiagnoCure, Inc., Québec, Canada) being especially promising. Recent studies on the applicability and efficacy of ImmunoCyt/uCyt+ testing are reviewed, as are its sensitivity, specificity, and predictive value in the follow-up and screening of urothelial malignancies.

Development of new prostate specific monoclonal antibodies

BACKGROUND

Despite the need for new prostate-specific diagnostic and therapeutic targets, very few unique prostate (cancer) specific antigens have been characterized. Monoclonal antibody (mAb) technology is a powerful tool to identify specific antigenic markers, which could be potential targets for cancer diagnostics or therapy.

METHODS

Splenocytes from mice immunized with prostate cancer (PCa) homogenates of different origin were fused using standard techniques. Employing a differential high-throughput screening method followed by immediate screening in immunohistochemistry (IHC) a large number of hybridomas were screened for prostate (cancer) specificity.

RESULTS

From 25 successful fusions approximately 300 clones were identified excreting PCa-reactive antibodies. Subsequent immunohistochemical fine-specificity analysis reduced this number to 26. Eventually, after extensive fine-specificity analysis, the number of mAbs appearing to define prostate-specific antigenic structures that might serve as new diagnostic or therapeutic targets was reduced to three.

CONCLUSIONS

Using mAb technology combined with a high throughput screening method we have developed three mAbs (1.8, 2.26, and 3.10) directed against prostate associated antigens that might identify potential new therapeutic targets.

Identification of two genes differentially expressed upon different spatial configuration of the MGH-U3 human bladder cancer cells

By using mRNA differential display technology, we have compared gene expression in neoconfluent (actively proliferating) and 14-day confluent (non-proliferative) MGH-U3 cells. Two clones (6.17.6 and 10.9.2) displayed significantly increased expression in the 14-day confluent MGH-U3 cells, as confirmed by Northern blot analysis. Nucleotide sequence showed that clone 6.17.6 was part of the human insulin-like growth factor binding protein-5 (IGFBP-5) cDNA, while clone 10.9.2 was part of a human gene with unknown function (clone HSI12602). The differential IGFBP-5 expression in this model system was also evidenced by Western analysis. The possible anti-proliferative role of IGFBP-5 in this model system is briefly discussed.

Biomarker risk assessment and bladder cancer detection in a cohort exposed to benzidine

BACKGROUND

Cancer screening with highly sensitive, specific biomarkers that reflect molecular phenotypic alterations is an attractive strategy for cancer control. We examined whether biomarker profiles could be used for risk assessment and cancer detection in a cohort of Chinese workers occupationally exposed to benzidine and at risk for bladder cancer.

METHODS

The cohort consisted of 1788 exposed and 373 nonexposed workers, followed from 1991 through 1997. We assayed urothelial cells from voided urine samples for DNA ploidy (expressed as the 5C-exceeding rate [DNA 5CER]), the bladder tumor-associated antigen p300, and a cytoskeletal protein (G-actin). Workers were stratified into different risk groups (high, moderate, and low risk) at each examination based on a predefined biomarker profile. For workers who developed bladder cancer, tumor risk assessment was analyzed from samples collected 6-12 months before the cancer diagnosis. The associations between risk group and subsequent development of bladder cancer were analyzed by Cox proportional hazards regression analysis and logistic analysis, after adjustment. All statistical tests were two-sided.

RESULTS

Twenty-eight bladder cancers were diagnosed in exposed workers and two in nonexposed workers. For risk assessment, DNA 5CER had 87.5% sensitivity, 86.5% specificity, an odds ratio (OR) of 46.2 (95% confidence interval [CI] = 8.1 to 867.0), and a risk ratio (RR) of 16.2 (95% CI = 7.1 to 37.0); p300 had 50.0% sensitivity, 97.9% specificity, an OR of 40.0 (95% CI = 9.0 to 177.8), and an RR of 37.9 (95% CI = 16.8 to 85.3). The risk of developing bladder cancer was 19.6 (95% CI = 8.0 to 47.9) times higher in workers positive for either the DNA 5CER or p300 biomarkers than in workers negative for both biomarkers and 81.4 (95% CI = 33.3 to 199.3) times higher in workers positive for both biomarkers. G-actin was a poor marker of individual risk.

CONCLUSIONS

Occupationally exposed workers at risk for bladder cancer can be individually stratified, screened, monitored, and diagnosed based on predefined molecular biomarker profiles.

Monoclonal antibodies : generation and clinical use

Originally, the term "antibody" referred to an unknown entity in serum, which had the capacity to neutralize pathogenic bacteria. Ehrlich discovered that the socalled antibody had to be a discrete substance, and was the first to propose a theory on antibody formation (1). A few years later, he hypothesized that antibodies might be applied for selective treatment of cancer, provided that the antibody showed specificity for the tumor tissue (2 ). Later studies showed that antibodies could be produced against a wide variety of substances, including tumors.

Image analysis combined with visual cytology in the early detection of recurrent bladder carcinoma

BACKGROUND

Early detection of recurrent transitional cell carcinoma of the bladder (TCC) is important to permit early treatment, which produces maximal preservation of the bladder and maximum survival.

METHODS

This retrospective cohort study attempted to determine the period of time over which urinary DNA image analysis combined with visual cytology is useful in the early detection of recurrent TCC of the bladder. The authors believe this study is unique in that it measured the effectiveness of this test (image analysis plus visual cytology combined) at varying times before clinical diagnosis of recurrence was made. The cohort was comprised of 175 urologic patients from urologic practices across the U.S. Data, collected between January 1991 and February 1994, included cystoscopy, biopsy, DNA image analysis, and visual cytologic reports.

RESULTS

Sixty patients in the cohort were found to have active TCC whereas 115 patients had a history of, but no active, disease during the follow-up period. As expected, the sensitivity and specificity of DNA image analysis in combination with visual cytology, and DNA image analysis alone, were greatest when urinary samples were obtained close to the time of diagnosis. In general, the longer the interval from the combined tests to the time of diagnosis, the lower the sensitivity. The combined tests had predictive value up to 3 months prior to clinical diagnosis when any detectable cytologic abnormality was considered positive. At the optimal cutoff points as determined from receiver operating characteristic curves, sensitivity increased when DNA image analysis was supplemented with visual cytology.

CONCLUSIONS

The combination of DNA image analysis and visual cytology provides a better method for the early detection of recurrent TCC than DNA image analysis alone. This test potentially may be useful in providing information regarding bladder tumor recurrence up to 3 months prior to clinical evidence of disease.

Influence of spatial configuration on the expression of carcinoembryonic antigen and mucin antigens in human bladder cancer

CEA and cellular mucin antigens have been recognized as potential targets for specific immunotherapy and are frequently expressed in bladder cancer. We studied the coordinated expression of a bladder cancer-associated CEA glycoform and of the mucins MUC1, MUC2 and MAUB under various growth conditions in the MGH-U3 bladder-cancer cell line. CEA and MUC2 mRNAs and proteins were detected in nude mouse tumors and spheroids but not in monolayer cultures. Expression of MAUB and bladder-cancer CEA also was induced according to spatial configuration of cells. MUC1 was always expressed under various growth conditions, but its glycosylation was modulated: in spheroids and mostly in tumor cells, the SM3 protein epitope was unmasked and sialyl-Tn was induced. The kinetics of modulation of MAUB and bladder-cancer CEA were different. The epitope recognized by the monoclonal antibody (MAb) 19A211 was rapidly induced in the aggregation phase of spheroid formation and rapidly lost upon plating of tumor cells, suggesting a relationship with cell contact. By contrast, MAUB induction in spheroids was delayed to the compaction phase, when cell aggregates become resistant to disruption, and loss of expression upon tumor plating occurred slowly over several culture passages. No induction of these 2 antigens was observed in the presence of differentiation agents, endothelial cell products or interferon-gamma, but it occurred when MGH-U3 cells were cultured at high density on extracellular matrix. Our results suggest that CEA and mucin antigen expression in bladder cancer is modulated by the spatial configuration of cells.

Biochemical analysis of a bladder-cancer-associated mucin: structural features and epitope characterization

Three monoclonal antibodies (mAbs), M344, M300 and M75, were shown to define a unique tumour-associated antigen (TAA) of superficial bladder tumours. The antigenic determinants are expressed on a very-high-molecular-mass component and, in about 50% of the positive samples, one determinant is also detected on a 62 kDa molecular species, observed only under reducing conditions. The objectives of the present study were to characterize further this TAA by analysing (1) the biochemical nature of the epitopes recognized by the three mAbs, and (2) the biochemical and structural features of the molecule bearing them. The antigenicity was resistant to heat denaturation, trypsin and alpha-chymotrypsin treatments but highly sensitive to papain and Pronase digestion. NaIO4 oxidation decreased reactivity to mAbs M344 and M300 but enhanced reactivity to mAb M75. The three determinants were insensitive to beta-galactosidase and alpha-L-fucosidase but were sensitive to Vibrio cholerae neuraminidase. None of the three mAbs reacted with ovine, bovine or porcine submaxillary mucins. Deglycosylation with O-glycosidase or trifluoromethanesulphonic acid completely abolished the reactivity of the mAbs whereas N-glycosidase F deglycosylation had no appreciable effect. The presence on the molecule of cryptic Gal(beta(1-3))GalNAc as a major core disaccharide was demonstrated by a heterologous sandwich assay using mAb M75 and peanut agglutinin. Thiol reduction using beta-mercaptoethanol increased mobility of the high-molecular-mass component in polyacrylamide gels. We thus conclude that mAbs M344 and M300 react with sialylated carbohydrate epitopes, and mAb M75 reacts with a partially cryptic and periodate-resistant sialylated epitope expressed on a typical secreted high-molecular-mass oligomeric mucin which we named MAUB for mucin antigen of the urinary bladder.

MAUB is a new mucin antigen associated with bladder cancer

The M344 tumor-associated antigen, expressed in 70% of superficial bladder tumors, is a sialylated carbohydrate present on a high molecular mass thiol-reducible secreted mucin, which we named MAUB for mucin antigen of the urinary bladder. Herein we studied the relationship between MAUB and other known mucins in the MGH-U3 bladder cancer line where MAUB expression is modulated by culture conditions. Northern blots, immunoradiometric assays, and Western blots showed that only MUC1 and MUC2 are expressed in this MAUB-positive cell line. MUC1 differs from MAUB by its molecular mass and its non-oligomeric nature, while MUC2 has similar molecular mass and response to culture conditions. However, in double determinant immunoradiometric assays, MAUB and MUC2 did not cross-react. Moreover, confocal microscopy showed different subcellular localization of the two antigens. Treatment of MGH-U3 cells with MUC2 antisense oligodeoxynucleotides resulted in decreased expression of MUC2 and increased expression of MAUB, ruling out the possibility that monoclonal antibody M344 recognizes a different glycosylated form of MUC2. In addition, we identified a tumor specimen expressing MAUB but no MUC2 antigen or mRNA. Together, these results suggest that there is expression of at least three mucins in MGH-U3 cells and that MAUB is a cancer-associated mucin distinct from those identified so far.

Basic research

Basic research is currently investigating the molecular cascade associated with bladder cancer development. Many new findings are potential leads towards the improvement of the diagnosis and prognosis of this disease. Special care, however, should be taken in the design of protocols for clinical evaluation of the value of these markers. Some initial guidelines have been put forward in this report.

Prognostic value of epidermal growth factor-receptor, T138 and T43 expression in bladder cancer

Tumour-associated markers defined by monoclonal antibodies have proven useful to phenotype bladder tumours. In order to evaluate the prognostic value of such markers, we performed an immunohistochemical study on 57 transitional cell carcinomas (23 infiltrative and 34 superficial tumours) and ten healthy bladders using monoclonal antibodies against the external domain of the epidermal growth factor receptor (EGFR) and against the tumour-associated antigens T43, 19A211 and T138. Immunohistochemistry was performed on frozen sections using a two-step alkaline phosphatase method. The staining pattern obtained with each antibody was analysed according to the TNM classification, and results were analysed according to the subsequent clinical course. 19A211 preferentially stained superficial tumours, and T43, T138 and EGFR preferentially stained invasive tumours. Three monoclonal antibodies appeared to have prognostic value, since progression rate survival was significantly (log-rank test) associated with their expression of EGFR (P = 0.017), T138 (P = 0.0009) and T43 (P = 0.031). T138 expression was found to have an independent significant prognostic value using a stepwise logistic regression. T138 antibody may add significant information to classical pathological parameters.

Studies of monoclonal antibody BL2-10D1 as a marker for the detection of the urothelial origin of tumors

BACKGROUND

In previous studies, the authors demonstrated the value of the monoclonal antibody (MoAb) BL2-10D1 in identifying malignant transitional cells. In this study, the authors evaluate the possible diagnostic value of a murine MoAb, BL2-10D1, raised against human bladder cancer in the determination of the urothelial origin of metastases in a series of 29 patients with metastatic bladder or prostatic carcinoma.

METHODS

Using an immunoperoxidase method, BL2-10D1 and anti-prostate-specific antigen (anti-PSA) reactivity were studied, using histologic sections from 18 pelvic lymph nodes and 4 other anatomic sites invaded by transitional cell cancer, and from 7 pelvic lymph nodes containing prostatic cancer.

RESULTS

All lymph nodes containing metastases of transitional cell carcinoma were positive with BL2-10D1, whereas all metastases of prostatic cancer were negative; the four instances of distant urothelial metastases were positive with BL2-10D1 MoAb. Conversely, anti-PSA reacted only with prostatic metastases.

CONCLUSION

Thus, MoAb BL2-10D1 and anti-PSA complement each other in the separation of cancers of prostatic and urothelial origin, and the BL2-10D1 MoAb has potential usefulness in differentiating between urothelial carcinoma and prostate adenocarcinoma. In patients with bladder tumors of uncertain origin, BL2-10D1 may be helpful in confirming that a tumor is a transitional cell carcinoma.

Bladder cancer risk assessment with quantitative fluorescence image analysis of tumor markers in exfoliated bladder cells

BACKGROUND

The detection of potentially highly curable low-grade bladder cancers by noninvasive techniques remains an unsolved problem. Conventional cytology detects such tumors with 50% sensitivity, and addition of DNA measurements to cytology only improves sensitivity incrementally. Tumor-associated antigens potentially offer an additional diagnostic marker.

METHODS

In this study, the M344 antibody against a tumor-associated antigen expressed mainly by low-grade tumor cells was tested for its sensitivity and specificity, alone and in combination with DNA ploidy and cytology. Voided urine samples from 69 asymptomatic control subjects, urines and bladder washings from 59 patients with cancer, and 195 symptomatic control patients were collected. Cells were double-labeled with M344 monoclonal antibody and Hoechst. Each case was blinded, and the number of positive cells was scored by two independent observers.

RESULTS

High-grade and low-grade transitional cell carcinomas (TCC) were detected with equal efficiency (78%, P < 0.001 versus symptomatic control patients). Urine samples proved higher specificity in detecting cancers. Patients being monitored for recurrence, but without current detectable cancer, were intermediates between control subjects and patients with cancer, suggesting that this marker also responds to dysplasia or field disease. Patients with outlet obstruction did not significantly differ from patients with previous TCC (P = 0.95). When combined with DNA ploidy measurements and cytology, the sensitivity for low-grade and high-grade tumors was 88% and 95%, respectively.

CONCLUSIONS

The M344 antibody potentially could improve the specificity and sensitivity of detection of low-grade bladder tumors in symptomatic and asymptomatic patients as well as monitoring for recurrence, therapeutic response, and assessment of individual risk.

Alterations in phenotypic biochemical markers in bladder epithelium during tumorigenesis

Phenotypic biochemical markers of oncogenesis and differentiation were mapped in bladder biopsies to investigate changes that occur in bladder tumorigenesis and to identify markers for increased bladder cancer risk. Touch preparations from biopsy specimens from 30 patients were obtained from tumors, the adjacent bladder epithelium, and random distant bladder epithelium. Markers, including DNA ploidy, epidermal growth factor receptor (EGFR), and oncoproteins, were quantified in individual cells by using quantitative fluorescence image analysis. Cluster analysis revealed the markers fell into three independent groups: (i) G-actin and EGFR; (ii) ploidy, cytology, and p185 (HER-2/neu oncoprotein) (ERBB2); and (iii) p300, a low-grade tumor antigen. Each marker displayed a gradient of abnormality from distant field to adjacent field to tumor. Different patterns for each marker suggested a developmental sequence of bladder cancer oncogenesis; G-actin was altered in 58% of distant biopsies (vs. 0/6 normals, P < 0.001), ploidy and cytology were altered in < 20% of distant fields and approximately 80% of tumors, and the other markers were intermediate. Patterns of EGFR and p185 suggest low-and high-grade tracks diverge early (P < 0.05 by Mann-Whitney U test for EGFR and ANOVA for p185). In conclusion, this study shows that a sequence of phenotypic changes accompanies development and progression of bladder cancers. Biochemical alterations in cells of the bladder field are often detectable before abnormal pathology, and markers previously thought to be limited to tumors were found in the field. The hierarchy of expression may be useful in identifying high-risk patients, assessing completeness of response to therapy, and monitoring and predicting recurrence.

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 non-neoplastic 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.

Cell surface differentiation antigens of normal urothelium and bladder tumors

Bladder cancer ranks as the third most common malignancy among men and tenth among women. Superficial transitional cell carcinomas (stage Ta, Tis, and T1) account for approximately 70-80% of these tumors, while the remaining 20-30% are invasive (T2, T3, and T4). Approximately 70% of superficial tumors will have one or more recurrences, with 25% of these expressing a higher histologic grade and 10-15% subsequently developing invasive and/or metastatic disease. The detection and prediction of tumor recurrence and/or tumor progression is crucially important if timely and appropriate therapy is to be instituted. Conventional histopathologic evaluation usually provides definitive diagnosis upon which therapeutic planning is based. However, at present there are no more reliable morphologic indicator to identify which individuals will have recurrent disease or who will progress to invasive and/or metastatic cancer. Recent advances in tumor biology have identified markers that are good candidates for clinical applications in early tumor detection, as well as for the stratification of patients with like-appearing morphological lesions with different biological and clinical behavior. The ultimate goal is to develop predictive assays that would segregate patients with high probability of failures versus patients who would be cured by localized modes of therapy.

Immunopathologic analysis of human urinary bladder cancer. Characterization of two new antigens associated with low-grade superficial bladder tumors

The authors have further characterized the normal human tissue distribution and tumor expression of two highly restricted tumor-associated antigens, detected by mouse monoclonal antibodies M344 and 19A211, which are primarily expressed on low-grade superficial urinary bladder tumors. This study was conducted using immunohistochemical staining of frozen and deparaffinized sections of human normal and tumor tissues. The antigens are stable and well preserved on deparaffinized tissue sections. M344 antibody identifies a high-molecular-weight determinant on a cytosolic protein component of over 300,000 Mr. This antigen was not detected on any normal tissue analyzed, including 14 specimens of normal urothelium and 22 cases of cystitis; however, M344 was positive in 74.5% of Ta-T1 tumors and 11% of T3-T4 tumors. 19A211 antibody identifies a sialylated epitope on a cytoplasmic protein complex of 100,000 to 200,000 Mr. This antigen also was expressed preferentially on low-grade superficial bladder tumors (77% Ta-T1) and less frequently on deeply infiltrating tumors (10% T3-4). 19A211 was negative on all normal cells tested, with the exception of umbrella cells, in approximately 25% of the normal urothelium and cystitis specimens studied. Either one or both of these tumor-associated antigens are detected in approximately 80% of low-grade papillary superficial tumors and carcinoma in situ of the urinary bladder. The expression of these antigens on a subset of low-grade bladder tumors, known to progress in only about 10% of cases, suggests that phenotypic differences may reflect biologic potential. Beyond their possible biologic significance, antibodies M344 and 19A211 may provide clinically useful probes for early detection and stratification of urinary bladder tumors.

Alterations in antigen expression in superficial bladder cancer

Bladder cancer can be viewed as a prototype for carcinogen-induced neoplasia. This has been demonstrated experimentally in a variety of systems and in man through epidemiological studies of occupational exposure to putative carcinogens. The natural history of this neoplasm demonstrates recurrence in time and space, i.e., multifocal disease. This clinical scenario is precisely what would be expected if a target tissue, e.g., urothelium, was continuously exposed to a weak carcinogen. The detection of gross disease is clinically easy. However, the ability to intervene at early stages and monitor the success of this treatment requires the definition of early markers for bladder cancer. Integrins are a family of cell surface proteins, many of which function as receptors for extracellular matrix components. Normal epithelial cells express the integrin alpha 6 beta 4 in association with an anchoring structure known as the hemidesmosome. Urothelium expresses alpha 6 beta 4 on the basal layer of cells similar to the distribution seen on other epithelial surfaces. Even early stages of bladder cancer demonstrate an alteration in the expression of this integrin. Low-stage bladder tumors express alpha 6 beta 4 diffusely throughout the tumor as well as at the invading margin. Altered expression of alpha 6 beta 4 may be an early marker for bladder cancer which may contribute to an invasive phenotype. A second potential marker is detected by DD23, an IgG1 murine monoclonal antibody triggered by the immunization of a BALB/c mouse with a fresh human bladder tumor specimen. The antigen detected by DD23 is not present on normal urothelial specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Occupation, smoking, and the risk of high-grade invasive bladder cancer in Missouri

Numerous epidemiological studies have established that occupational exposures and smoking are the two major known risk factors for the development of bladder cancer. Using data from the Missouri Cancer Registry, we investigated the hypothesis that individuals with occupationally-related bladder cancer are more likely to have a more invasive form of the disease. Data were analyzed for 2,893 white males diagnosed with primary bladder cancer in Missouri between 1984 and 1988. Of the 1,415 cases whose occupational status was recorded, 236 (17%) were employed in high-risk occupations. Cases with high-grade disease were more likely to have been employed in a high-risk occupation, after adjustment for age and smoking (adjusted odds ratio [AOR] = 1.7, 95% confidence interval [CI] = 1.1-2.6). High-risk workers under 60 years of age were most at risk for developing high-grade bladder tumors (AOR = 2.3, 95% CI = 1.0-5.3). There was no overall association between high-risk occupation and late-stage disease (AOR = 1.1, 95% CI = 0.7-1.5), but it was present in the men younger than 60 years of age (AOR = 2.0, 95% CI = 1.0-3.8). No association was found between tobacco use and grade (AOR = 1.1, 95% CI = 0.8-1.5), but cases with late-stage disease were more likely to be smokers (AOR = 1.5, 95% CI = 1.1-1.9). When occupations were examined individually, motor vehicle operators, truck drivers, vehicle mechanics, other mechanics, and janitors were among those most likely to be diagnosed with high-grade or late-stage tumors. Although further studies are necessary to confirm these results, they suggest that surveillance and targeted screening of workers in high-risk occupations may result in a greater yield of early invasive cancers and possibly decrease the mortality associated with this disease.

Strategies of chemoprevention based on antigenic and molecular markers of early and premalignant lesions of the bladder

Using monoclonal antibodies, we have identified a series of tumor-associated antigens selectively expressed on tumor subtypes with distinct clinical behaviours. The mucinous antigen M344 and the gp200 surface antigen 19A211 are preferentially expressed on papillary superficial tumors and carcinoma in situ lesions of the bladder. The combination of these two antigenic markers in immunocytology and flow cytometry studies of exfoliated cells has improved the sensitivity of detection for bladder tumors. Moreover, the detection of M344- and 19A211-positive exfoliated cells from previously treated but currently tumor-free patients appears to be predictive of tumor recurrence on follow-up. These results, as well as results of bladder mapping studies in tumor patients, suggest that these antigenic changes occur in a premalignant stage and may provide tools to monitor the efficacy of chemopreventive measures. Other markers, such as the surface antigen T138 and the soluble molecules autocrine motility factor (AMF) and tumor collagenase stimulating factor (TCSF), are produced by primary or recurrent tumors with a higher metastatic potential. They may be useful in identifying high risk patients for distant failure. The highly restricted antigen 19A211 is also expressed on cervix condylomas and carcinoma. This observation led us to investigate a possible viral etiology of some bladder cancers. Using PCR techniques, we detected the presence of human papillomavirus (HPV) 16 DNA sequences in a significant proportion of bladder tumors. HPV positivity was inversely correlated with the presence of p53 mutations in exons 5-9 of the same tumors as measured by PCR-SSCP technique. This combination of markers may provide a basis for chemoprevention strategies targeted to distinct etiological events.

Comparison of 15 monoclonal antibodies against tumor-associated antigens of transitional cell carcinoma of the human bladder

Quantitative urinary immunocytology with our monoclonal antibody (mab) 486p 3/12 proved to be valuable for diagnostic use in bladder-cancer patients' urine, especially in the followup of patients with superficial bladder carcinoma. To evaluate the use of other monoclonal antibodies in bladder cancer, we compared 15 mabs directed against bladder-tumor-associated antigens from seven research groups in a broad panel of cellular and tissue specimens (bladder tumor, prostatic adenoma, and kidney stone). Quantitative evaluation was done in cytocentrifuged preparations and tissue specimens. None of the 15 mabs was bladder-tumor-specific. All 15 stained normal urothelium to some extent and six stained granulocytes. Each of the 15 seemed to identify a different cellular antigen, as can be clearly demonstrated by the staining pattern of different regions in the normal kidney. The sensitivity of quantitative urinary immunocytology in bladder-tumor patients can be improved by using a panel, rather than one mab in bladder-tumor patients, but specificity decreases simultaneously. A main reason for the poor specificity of quantitative urinary immunocytology with all 15 mabs is that false-positive results are obtained with all mabs in kidney-stone patients. Our quantitative urinary immunocytology method is a general tool for the diagnostic use of all mabs in bladder-tumor patients. Mabs that have a high sensitivity might be useful in the followup of patients with superficial bladder carcinoma. None of the 15 mabs (because of their poor specificity) seems to be helpful in quantitative urinary immunocytology for screening a population for bladder carcinoma.

Contemporary Management of Bladder Cancer: Identifying patients who are at risk

Bladder cancer is currently the fifth most common cancer in Western society, and its incidence appears to be increasing. Important advances have recently occurred in both diagnostic and therapeutic approaches to bladder neoplasms. Presentation is not unique, and physician awareness is important to identify patients who are at risk for bladder neoplasia and consequently require further investigation. A diagnostic approach and contemporary management are discussed.

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.

A useful monoclonal antibody (BL2-10D1) to identify tumor cells in urine cytology

The monoclonal antibody (MoAb) BL2-10D1 directed against a tumor-associated antigen of human bladder cancer was used to identify tumor cells obtained by bladder washing or voided urine. The reactivity of BL2-10D1 MoAb was detected by an immunoperoxidase method and evaluated in ten healthy donors and in a series of 65 patients. The 65 patients studied were divided into three groups: ten with nontumor bladder disease (group A); 36 with bladder carcinoma (group B); and 19 with a history of bladder neoplasia but no visible tumor at the time of cytologic sampling (group C). The results were compared with the standard cytologic diagnosis on Papanicolaou-stained preparations. Conventional cytologic study showed a high false-negative rate in low-grade tumors (transitional cell carcinomas [TCC] Grades 1 and 2, 1/4 and 4/17, respectively). All urine from patients with a histologically proved TCC Grade 1 were stained with BL2-10D1 MoAb. Cytologic findings from patients with TCC Grade 2 (17 cases) contained positive cells in 14 cases and failed to react in three cases. Furthermore, whereas urine from patients with TCC Grade 2 or 3 was not always stained with BL2-10D1 MoAb, all patients with dysplastic lesions (three cases) or carcinoma in situ (5 cases) showed a positive reactivity. Such results suggest that BL2-10D1 MoAb may be considered as a valuable adjunct to the classical methods of early detection and follow-up of bladder cancer. However, a larger scale study is needed for MoAb BL2-10D1 to be proposed as an aid to improve the diagnostic sensitivity of urine cytologic investigation in the follow-up of patients treated for recurring bladder cancer, and for the screening of workers exposed to potent bladder carcinogens.

Enhanced bladder cancer detection with the Lewis X antigen as a marker of neoplastic transformation

Recent evidence indicates that the Lewis X determinant is a tumor-associated antigen in the urothelium. Immunohistochemical analyses on frozen and deparaffinized, formalin-fixed tissue sections have demonstrated that the Lewis X antigen is not detected in normal adult urothelium except for occasional umbrella cells. However, papillomas and transitional cell carcinomas express this blood group-related antigen in more than 90% of the cases regardless of the grade or stage of the tumor, or the blood type or secretor status of the individual. To determine the presence of Lewis X antigen on exfoliated bladder epithelial cells we used an anti-Lewis X monoclonal antibody (P-12) and the avidin-biotin-peroxidase technique on 129 bladder barbotage specimens. Of 40 controls 34 were negative for Lewis X antigen, for a specificity of 85%. The 89 bladder tumor patients consisted of 14 with papilloma, 13 with flat carcinoma in situ, 49 with transitional cell carcinoma, and 13 with a positive cytology and negative biopsy results. Of these 89 patients 76 were considered positive for Lewis X antigen, for an over-all sensitivity 85.4%. The sensitivity for cytology alone was 61.2%. However, the combination of a positive cytology and/or positive Lewis X antigen result yielded a sensitivity of 93.2%. The data suggest that immunocytological detection of the Lewis X antigen on exfoliated bladder cells enhances the detection of urothelial tumor cells, particularly from low grade and low stage neoplasms.

Increase in murine monoclonal-antibody-defined urinary antigens in patients with bladder cancer and benign urogenital disease

Monoclonal antibodies (MAbs) were obtained from hybridoma clones established by cell fusion between P3X63Ag8.653 mouse myeloma cells and spleen cells of mice or rats hyperimmunized against human bladder cancer tissue or BC47 rat bladder cancer cells. RBS-31 and RBS-85 mouse MAbs and RBA-1 rat MAb were raised against BC47 cells and HBP-1 MAb was raised against human bladder cancer tissues. Urinary antigens detected by these MAbs were quantitatively assayed by means of ELISA using 50 microliters of 1:2 diluted urine samples. The cut-off value of the assay was set up as the mean + 4 X SD of the mean using data from the healthy individual urine samples. The reactivity of all healthy control urine samples were under the cut-off value (negative). By contrast, urine from bladder cancer patients reacted positively with the RBS-31 MAb at 72%, with the RBS-85 MAb at 63%, with the RBA-1 MAb at 51% and with the HBP-1 MAb at 35%. The urine samples from some patients with renal calculi, acute cystitis or complicated urinary tract infections showed only a weak reactivity with our MAbs. As for extra-bladder cancers, some patients with renal, renal pelvis, prostate or ureter cancer, but no patients with esophageal, gastric, colon or liver cancer or leukemia, had reactive urinary antigens.

Antigen common to several species, recognized by a rat monoclonal antibody raised against syngeneic rat bladder tumor

A rat monoclonal antibody (MAb) termed RS-II (Ig M) was obtained by syngeneic immunization with rat bladder tumor cells induced by N-butyl, N-hydroxybutylnitrosamine (BBN). Immunocytochemical analysis showed that RS-II is also reactive with mouse, dog and human bladder tumor-cell lines and some other human tumor-cell lines but not myeloma or leukemia cells. Immunohistochemical examination of paraffin-embedded tissues has shown that RS-II is reactive with mouse, rat, dog and human bladder tumors (5/5, 5/5, 1/1, 31/49) and some other tumors, but not with normal human urothelium or normal rat tissues. The antigen is expressed on the majority of low-grade or well-differentiated tumors, but less on advanced, invasive tumors. The immunofluorescence staining pattern of cultured cells was cytoplasmic and filamentous. Immunoblotting revealed that the antigen is a Mr 54,000 to Mr 56,000 protein which was extracted with difficulty from the cultured cells with Triton X-100. The antigen was also detected in the culture supernatant by means of ELISA. Our results suggest that the epitope is expressed on cytoskeletons common to a wide variety of mammalian cells at a certain stage of differentiation.