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

Clinical Significance of ErbB Receptor Family in Urothelial Carcinoma of the Bladder: A Systematic Review and Meta-Analysis

The prognostic importance of examining ErbB receptor family expression in human bladder cancer remains uncertain. Using published evidence, we examined the clinical value and the updated results of clinical trials targeting ErbB receptor family members. Twenty-seven articles from 65 references related to ErbB receptor expression assessment in bladder cancer were reviewed. The estimates included the association significance, hazard ratios, and 95% confidence intervals (CIs) from actuarial curves and survival analyses. A meta-analysis was done on those reports using univariate log-rank tests or a Cox-regression model. The methods of analysis and study subjects chosen varied widely among studies. The overall risks of disease progression for patients with EGFR or ErbB2 overexpression were 4.5 (95% CI: 2.5–8.4) and 1.1 (95% CI: 0.6–1.9), and the risks of mortality were 3.0 (95% CI: 1.6–5.9) and 1.1 (95% CI: 1.0–1.2), respectively. However, the significance of coexpression patterns of the ErbB receptor family remains controversial. None of six clinical trials yielded convincing results for blockading ErbB receptor signaling in urothelial carcinoma. The results of this analysis suggest that assessing co-expression patterns of the ErbB family may provide better prognostic information for bladder cancer patients.

Developing biomarkers for improved diagnosis and treatment outcome monitoring of bladder cancer

IMPORTANCE OF THE FIELD

A non-invasive marker for the follow-up and diagnosis of bladder cancer is highly needed. Several markers have been studied with regard to sensitivity and specificity in detecting bladder cancer. Comparison of studies is complicated by limited data on tumor characteristics and treatment details. Many studies do not differentiate between primary and recurrent tumors, nor is the performance of the studied marker assessed separately in superficial and invasive or high- versus low-grade tumors.

AREAS COVERED IN THIS REVIEW

The field of bladder cancer biomarker research from the past 15 years. WHAT THE READER GAIN: A summary of the current field of bladder biomarker research with concluding remarks on some specific challenges in developing biomarkers for improved diagnosis and monitoring the disease.

TAKE HOME MESSAGE

In general, the best new markers give higher sensitivity than urinary cytology, but specificity is usually lower. By using new markers, the intervals between follow-up cystoscopies can be increased and the detection of relapse can be improved. But to date no non-invasive biomarker has proven to be sensitive and specific enough available to replace cystoscopy, neither in the diagnosis nor in the follow-up of bladder cancer. However, new marker combinations and algorithms for risk assessment hold promise for the future.

A phase II trial of cisplatin (C), gemcitabine (G) and gefitinib for advanced urothelial tract carcinoma: results of Cancer and Leukemia Group B (CALGB) 90102

BACKGROUND

This phase II trial (Cancer and Leukemia Group B 90102) sought to determine the efficacy of cisplatin, standard infusion of gemcitabine and gefitinib in patients with advanced urothelial carcinoma.

PATIENTS AND METHODS

Eligible patients had previously untreated measurable disease, Eastern Cooperative Oncology Group (ECOG) performance status of zero to two and creatinine clearance >50 ml/min. Treatment consisted of cisplatin 70 mg/m(2) day 1 and gemcitabine 1000 mg/m(2) on days 1 and 8 given every 3 weeks concurrent with gefitinib 500 mg/day orally for six cycles. Maintenance gefitinib 500 mg/day was continued for responding or stable disease.

RESULTS

Fifty-four of 58 patients were assessable. Twelve patients (22%) had node-only disease, and 25 (46%) had an ECOG performance status of zero. There were 23 objective responses for an overall response rate of 42.6% [95% confidence interval (CI) 29.2% to 56.8%]. The median survival time was 15.1 months (95% CI 11.1-21.7 months) and the median time to progression was 7.4 months (95% CI 5.6-9.2 months).

CONCLUSIONS

The combination of cisplatin, gemcitabine and gefitinib is well tolerated and active in advanced transitional cell carcinoma. The addition of gefitinib does not appear to improve response rate or survival in comparison to historical controls of cisplatin and gemcitabine alone.

Molecular Pathology of the Genitourinary Tract: Prostate and Bladder

The knowledge of cellular mechanisms in tumors of the prostate and bladder has grown exponentially. Molecular technologies have led to the discovery of TMPRSS2 in prostate cancer and the molecular pathways distinguishing low- and high-grade urothelial neoplasms. UroVysion with fluorescence in situ hybridization is already commonplace as an adjunct to cytologic diagnosis of urothelial neoplasms. This trend portends the future in which classification and diagnosis of tumors of the prostate and bladder through morphologic analysis will be supplemented by molecular information correlating with prognosis and targeted therapy. This article outlines tumor molecular pathology of the prostate and bladder encompassing current genomic, epigenomic, and proteonomic findings.

Molecular targets and targeted therapies in bladder cancer management

Bladder cancer remains a significant health problem. Currently, conventional histopathologic evaluation criteria (tumor grade and stage) are limited in their ability to accurately predict tumor behavior. A significant number of patients with muscle-invasive or extravesical disease treated by radical cystectomy alone die of metastasis. Intense research efforts are being made to better identify and categorize tumors by their molecular alterations and biological characteristics. A majority of the aggressive, invasive bladder carcinomas have alterations in the p53 and retinoblastoma pathways that regulate the cell cycle by interacting with signal transduction pathways. Angiogenesis further contributes to the neoplastic growth by providing a constant supply of oxygen and nutrients. It is becoming apparent that the accumulation of genetic and molecular changes ultimately determines a tumor's phenotype and subsequent clinical behavior. We provide a contemporary outline of our current understanding of the molecular and genetic events associated with tumorigenesis and progression. We emphasize the ways by which molecular biology is likely to affect the development of future therapies that will be able to target molecular alterations in individual tumors based on their respective profiles. The current status of targeted therapies for bladder cancer is also presented as well as the ongoing clinical trials.

A phase II trial of cisplatin, fixed dose-rate gemcitabine and gefitinib for advanced urothelial tract carcinoma: results of the Cancer and Leukaemia Group B 90102

OBJECTIVE

To conduct a phase II trial to determine the efficacy of cisplatin, a fixed dose-rate infusion of gemcitabine and gefitinib (an orally active epidermal growth factor receptor tyrosine kinase inhibitor) in patients with advanced urothelial carcinoma.

PATIENTS AND METHODS

Eligible patients had previously untreated measurable disease, an Eastern Cooperative Oncology Group performance status of 0-2 and creatinine clearance of >50 mL/min. The treatment regimen consisted of cisplatin 70 mg/m(2) on day 1, gemcitabine 1000 mg/m(2) on day 1 and 8, administered at a fixed dose rate of 10 mg/m(2)/min, given every 3 weeks concurrent with gefitinib 500 mg/day orally for a maximum of six cycles. Maintenance gefitinib 500 mg/day was continued for responding or stable disease.

RESULTS

In all, 27 patients were accrued before the study was halted because the dose-limiting toxicity (DLT) exceeded pre-established stopping rules. The DLT events were two grade 5 (one infection, one cardiovascular accident) and three with grade 4 non-haematological toxicity. In 25 evaluable patients there were nine objective responses, for an overall response rate of 36% (95% confidence interval, CI, 18-57%). The median (95% CI) survival time was 11.1 (5.2-35.3) months.

CONCLUSION

The combination of cisplatin, fixed dose-rate gemcitabine and gefitinib is active in advanced TCC, although the relative contribution of gefitinib cannot be determined. However, this regimen was associated with excessive toxicity.

Molecular Pathways in Invasive Bladder Cancer: New Insights Into Mechanisms, Progression, and Target Identification

Papillary and invasive cancers of the urinary bladder appear to evolve and progress through distinct molecular pathways. Invasion in bladder cancer forebodes a graver prognosis, and these tumors are generally characterized by alterations in the p53 and retinoblastoma (RB) pathways that normally regulate the cell cycle by interacting with the Ras–mitogen activated protein kinase signal transduction pathway. Tumor angiogenesis further contributes to the neoplastic growth by providing a constant supply of oxygen and nutrients. Distinct epigenetic and genetic events characterize the interplay between the molecules involved in these pathways, thus affording their use as indicators of prognosis. Efforts are now underway to construct molecular panels comprising multiple markers that can serve as more robust predictors of outcome. While clinical trials for targeted chemotherapy for bladder cancer have commenced, novel genetic and pharmacologic agents that can target pathway-specific molecules are currently under development. The next generation of clinical management for urothelial carcinoma will witness the use of multimarker panels for prognostic prediction and combination therapy directed at novel molecular targets for treatment.

Epidermal growth factor receptor and proliferating cell nuclear antigen expression in urine ThinPrep specimens

OBJECTIVE

To evaluate proliferating cell nuclear antigen (PCNA) and epidermal growth factor receptor (EGFR) expression in urine ThinPrep (TP) specimens, to compare these findings with clinical and histological features and to determine whether these immunomarkers are predictive of clinical stage.

PATIENTS AND METHODS

The TP processed urine samples and the corresponding tissue sections from 42 patients with newly diagnosed bladder cancer (18 non-muscle invasive and 24 muscle invasive) were included in our study. Urine was collected for cytological evaluation before transurethral resection. Tumour grade and clinical stage were assessed from the transurethral resection specimens. The EGFR and PCNA expression was obtained by an automated immunostainer.

RESULTS

There was a remarkable concordance in the expression of both antibodies in TP smears and tissue sections. No significant association was detected for any of the immunomarkers examined with regard to tumour grade. The EGFR expression as well as grade of malignancy were significantly associated with stage of disease (P = 0.0001). PCNA was not found to be a significant predictor of stage (P = 0.210).

CONCLUSION

Our data suggest that the evaluation of grade of malignancy and EGFR immunopositivity can be considered as reliable predictors of disease stage in urine TP specimens.

Prognostic value of EGF receptor and tumor cell proliferation in bladder cancer: therapeutic implications

Changes in growth factor receptor expression may confer a growth advantage on tumour cells. Epidermal growth factor-receptor (EGF-R) has been associated with the genesis of bladder tumours. We sought a link between EGF-R expression and MIB-1 cell proliferation and examined their prognostic value in the progression of bladder cancer. Fresh frozen samples from 113 transitional cell carcinomas (TCC) of the bladder and 10 healthy bladders were studied by immunohistochemistry, using monoclonal antibodies for EGF-R expression and MIB-1 for cell proliferation. Qualitative and quantitative immunostaining were analyzed in relation to time to progression and compared with clinical and pathologic parameters for prognostic significance in univariate and multivariate analysis (stepwise logistic regression). EGF-R stained more intensively in invasive tumours. Median nuclear over-expression of MIB-1 was 28%. Progression free survival rate estimates (log rank test) were significantly lower in patients EGF-R positive and with MIB-1 score above 28% (P < 0.0001, P < 0.0001, respectively). Multivariate analysis indicated that MIB-1 immunostaining was the most significant independent variable and EGF-R expression had no additional prognostic value over clinical stage and grade and cell proliferation. The MIB-1 proliferation index is a stronger predictor of bladder tumour progression than is EGF-R over-expression. This marker yield significant prognostic information in addition to stage and grade and may be of value for the clinical management of superficial and invasive bladder carcinomas. The pattern of EGF-R immunostaining and its association with tumour progression makes it a candidate for antigrowth factor therapy.

Bladder Carcinoma in Situ in 2003: State of the Art

Carcinoma is situ (CIS) of the bladder is a high-grade non-invasive malignancy with a high tendency of progression and transitional cell carcinoma outside the bladder. The diagnosis is a combination of abnormal cytology and cystoscopy with biopsies. Although cytology has clear limitations in low-grade lesions, such as a low inter- and intra-observer reproducibility, high-grade lesions and CIS should be diagnosed with a high degree of sensitivity and specificity. Currently available urinary markers do not (yet) seem to match cytology. The cystoscopic diagnosis is more difficult, since flat lesions are often difficult to see. The application of fluorescence cystoscopy and resection clearly improves the detection of the number of CIS lesions per patient and also the number of patients with CIS. For treatment of CIS (maintenance) BCG remains the golden standard. BCG appears to be able to prevent or delay progression to muscle invasive disease. BCG refractory patients are at high risk for progression and cancer death, and cystectomy is the treatment of choice. Alternatives for BCG refractory CIS patients, like intravesical chemo-immunotherapy, new chemotherapeutic drugs or photo-dynamic therapy, remain highly experimental. Last but not least, the danger for CIS patients is failure to respond to therapy and a high subsequent chance of progression and cancer-specific death. Unfortunately, despite much research, this prediction is not yet possible with molecular markers in daily practice.

Overview of bladder cancer trials in the Cancer and Leukemia Group B

The Cancer and Leukemia Group B (CALGB) Genitourinary Committee has developed a broad range of clinical trials across most stages of bladder cancer. Recurrence rates of superficial bladder cancer after transurethral resection range from 50-70%. Although adjuvant bacillus Calmette-Guerin reduces the risk of disease recurrence or progression, only 30% of patients have long-term disease-free survival. Because the development of novel secondline agents is needed, the CALGB is evaluating the utility of intravesicle gemcitabine as well as an oral proapoptotic agent (CP-461). In patients with locally advanced disease with an increased risk of disease recurrence after cystectomy, a randomized trial of conventional chemotherapy versus sequential dose-dense therapy is under development. The gemcitabine/cisplatin combination has become a commonly used regimen for the treatment of advanced transitional cell carcinoma (TCC). The CALGB is undertaking a Phase II study that incorporates a fixed dose rate gemcitabine infusion in this regimen, together with a selective epidermal growth factor receptor tyrosine kinase inhibitor, Iressa (Astra Zeneca, Wilmington, DE). In patients with renal insufficiency, a regimen of carboplatin, gemcitabine, and Iressa is planned. Novel agents, including arsenic trioxide and trastuzumab (Herceptin; Genentech, Inc., South San Francisco, CA), are being evaluated as secondline therapy in patients with advanced TCC who have disease progression after frontline therapy.

Molecular aspects of bladder cancer III. Prognostic markers of bladder cancer

The current pathological and clinical parameters provide important prognostic information, yet still have limited ability to predict the true malignant potential of most bladder tumors. In the last years, investigation of the basic mechanisms involved in carcinogenesis and tumor progression by molecular biology has provided a host of markers which are of potential diagnostic or prognostic value for bladder carcinoma. These markers may serve as tools for early and accurate prediction of tumor recurrence, progression and development of metastases and for prediction of response to therapy. The precise prediction of tumor biological behavior would facilitate treatment selection for patients who may benefit from radical surgical treatment or adjuvant therapy. We provide a current, comprehensive review of the literature on bladder tumor markers with a special emphasis on their prognostic potential. The literature suggests that currently no single marker is able to accurately predict the clinical course of bladder tumors and thus would serve as a reliable prognosticator. A combination of prognostic markers could predict which superficial tumors need an aggressive form of therapy and which invasive tumors require adjuvant therapy. Altogether, the most promising markers are, at this point, Ki-67 and p53 expression as well as matrixmetalloproteinase complex and angiogenesis.

Establishment of two new human bladder carcinoma cell lines, CAL 29 and CAL 185. Comparative study of cell scattering and epithelial to mesenchyme transition induced by growth factors

We describe here two new human urothelial carcinoma cell lines, CAL 29 and CAL 185, established from two patients with high-grade tumours and which display very different properties in vitro. We have shown that CAL 29 cells were tumorigenic in mice and expressed characteristic features of both cell scattering and transition from epithelial to mesenchymal phenotype (EMT) after triggering by the EGF receptor ligands, TGFalpha and EGF. At the opposite, the CAL 185 cells were not tumorigenic in mice and neither scattered nor expressed vimentin intermediary filaments in the presence of growth factors. We further demonstrated that CAL 29 cell scattering was reversible after growth factor removal and that both scattering and EMT were markedly impaired after treatment with MEK, Src and PI3-kinase inhibitors suggesting that these kinases might be important components of the cellular responses to EGF and TGF-alpha leading to scattering and EMT. These agents could help to understand the intracellular pathways involved in invasiveness and to find new targets for limiting metastasis. In conclusion, these two new cell lines could be good models to dissect the molecular mechanisms involved in invasion and metastasis development in human bladder cancer.

A prospective pilot evaluation of urinary and immunohistochemical markers as predictors of clinical stage of urothelial carcinoma of the bladder

OBJECTIVE

To determine, in patients newly diagnosed with bladder cancer, whether p53, epidermal growth factor receptor (EGFR), microvessel density (MVD), urinary bladder tumour antigen (BTA TRAKtrade mark, Bion Diagnostic Sciences, Redmond, WA) and cytology were predictive of clinical stage, evaluated as a function of the clinical stage obtained at transurethral resection of the bladder tumour with and without the addition of clinical grade, a known strong predictor of clinical stage.

PATIENTS AND METHODS

Between December 1997 and September 1998, 22 men and seven women with a cystoscopic diagnosis of urothelial bladder carcinoma were prospectively enrolled in the study. Urine was collected for cytological and BTA TRAK evaluation before transurethral resection. Tumour grade and clinical stage were obtained from the transurethral resection specimen. MVD was evaluated by computerized calculations of 'optimal MVD' (OMVD) and 'area-weighted MVD' (AWMVD) while p53 and EGFR information was obtained by manual immunohistochemical techniques; 21 patients had sufficient tissue for all immunohistochemical assessments and comprised the study group. Univariate and multivariate comparisons were carried out to determine the contribution of each variable to the prediction of clinical stage.

RESULTS

Although there was a trend, cytological analysis and p53 and MVD immunoreactivity did not significantly correlate with clinical stage, while tumour grade, BTA TRAK and EGFR immunoreactivity did. In a univariate analysis, tumour grade and BTA TRAK were related to clinical stage. In a multivariate analysis, grade was the single best predictor of clinical stage. This analysis also showed that the addition of BTA TRAK and MVD information to grade incrementally improved the predictive ability of grade.

CONCLUSIONS

This pilot study suggests that BTA TRAK and MVD contribute incremental information to tumour grade in predicting the clinical stage of urothelial carcinomas of the bladder; grade remains the most important predictor. These results suggest that further work with BTA TRAK and MVD in more patients and on biopsy material obtained during clinic cystoscopy is warranted for the future development of less invasive methods of identifying patients with invasive bladder cancer.

Mutation of cell cycle regulators and their impact on superficial bladder cancer

Early cytogenetic studies in bladder cancer identify regions of chromosomal gain or loss that can be candidate loci for oncogenes and tumor suppressor genes. Oncogenes with potential prognostic significance identified in bladder cancer the RAS family, epidermal growth factor receptor, ERBB-2, MDM2, and cyclin D1. The TP53 gene has been the most thoroughly characterized tumor suppressor gene in bladder cancer, with correlation of TP53 alterations with type of carcinogenic exposure, tumor stage and grade, as well as prognosis. Studies evaluating alterations of the retinoblastoma pathway have identified the retinoblastoma gene, RB, p161NK4A/CDKN2, and E2F-1 as tumor suppressor genes with potential prognostic significance in patients with bladder cancer. Better understanding of the genetic mechanisms underlying bladder tumor development and progression will allow better prevention, diagnosis, and treatment strategies.

[Prognostic factors of infiltrating bladder tumors]

In France, invasive bladder cancer is the most frequent urologic malignancy after prostate carcinoma. The standard treatment of bladder cancer is radical cystectomy. New therapeutic approaches such as chemoradiation combination for a conservative procedure, neoadjuvant or adjuvant chemotherapy are still in development. In this prospect, a rigorous selection of patients is needed. This selection is based on prognostic criteria which could be divided into four groups: 1) the volume of the tumour including the tumour infiltration depth, the nodal status, the presence or not of hydronephrosis and the residual tumour burden after transuretral resection; 2) the histologic aspects including histologic grading, the presence or not of an epidermoid metaplasia, of in situ carcinoma or of thrombi; 3) the expression of circulating tumour cell biological markers; 4) the biologic characteristics of the tumour such as ploidy, presence of cytogenetic abnormalities, expression of Ki67, expression of oncogenes or tumour suppressor genes, expression of telomerase, expression of tumour antigens or growth factor receptors. This paper reviews the prognostic value of these different parameters.

Levels of TGF-alpha and EGFR protein in head and neck squamous cell carcinoma and patient survival

BACKGROUND

The most accurate predictor of disease recurrence in patients treated for head and neck squamous cell carcinoma is, at present, the extent of regional lymph node metastasis. Since elevated levels of epidermal growth factor receptor (EGFR) and of its ligand, transforming growth factor-alpha (TGF-alpha), have been detected in primary tumors of patients with head and neck squamous cell carcinoma, we determined whether tumor levels of these proteins were of prognostic importance.

METHODS

Monoclonal antibodies specific for EGFR and TGF-alpha were used for immunohistochemical detection of each protein in tissue sections of primary tumors from 91 patients who were treated by surgical resection. Levels of immunoreactive EGFR and TGF-alpha were quantified by use of a computerized image analysis system and were normalized to appropriate standards. The logrank test and proportional hazards regression analysis were used to calculate the probability that EGFR and TGF-alpha levels were associated with disease-free survival (i.e., no recurrence of cancer) and cause-specific survival (i.e., patients do not die of their disease). All P values were two-sided.

RESULTS

When tumor levels of EGFR or TGF-alpha were analyzed as continuous variables, disease-free survival and cause-specific survival were reduced among patients with higher levels of EGFR (both P = .0001) or TGF-alpha (both P = .0001). In a multivariate analysis, tumor site, tumor level of EGFR, and tumor level of TGF-alpha were statistically significant predictors of disease-free survival; in a similar analysis, regional lymph node stage and tumor levels of EGFR and of TGF-alpha were significant predictors of cause-specific survival.

CONCLUSION

Quantitation of EGFR and TGF-alpha protein levels in primary head and neck squamous cell carcinomas may be useful in identifying subgroups of patients at high risk of tumor recurrence and in guiding therapy.

Heparin-binding EGF-like growth factor is an autocrine growth factor for human urothelial cells and is synthesized by epithelial and smooth muscle cells in the human bladder

The epidermal growth factor receptor (HER1) has been implicated in regenerative growth and proliferative diseases of the human bladder epithelium (urothelium), however a cognate HER1 ligand that can act as a growth factor for normal human urothelial cells (HUC) has not been identified. Here we show that heparin-binding EGF-like growth factor (HB-EGF), an activating HER1 ligand, is an autocrine regulator of HUC growth. This conclusion is based on demonstration of HB-EGF synthesis and secretion by primary culture HUC, identification of HER1 as an activatable HB-EGF receptor on HUC surfaces, stimulation of HUC clonal growth by HB-EGF, inhibition of HB-EGF-stimulated growth by heparin and of log-phase growth by CRM 197, a specific inhibitor of HB-EGF/HER1 interaction, and identification of human urothelium as a site of HB-EGF precursor (proHB-EGF) synthesis in vivo. ProHB-EGF expression was also detected in the vascular and detrusor smooth muscle of the human bladder. These data suggest a physiologic role for HB-EGF in the regulation of urothelial proliferation and regeneration subsequent to mucosal injury. Expression of proHB-EGF is also a feature of differentiated vascular and detrusor smooth muscle in the bladder. Because proHB-EGF is known to be the high affinity diphtheria toxin (DT) receptor in human cells, synthesis of the HB-EGF precursor by human urothelium also suggests the possibility of using the DT-binding sites of proHB-EGF as an in vivo target for the intraluminal treatment of urothelial diseases.

Clinical correlates of bombesin-like peptide receptor subtype expression in human lung cancer cells

The importance of the expression of the autocrine growth system for bombesin-like peptides (BLPS) to the biological behavior of human lung cancer has not been determined. Three BLP receptor subtypes have been identified in human lung and lung cancer cells: gastrin-releasing peptide (GRP) receptor, neuromedin B (NMB) receptor, and bombesin receptor subtype 3 (BRS-3). The goals of this study were: (1) to determine BLP receptor subtype expression by human lung cancer cell lines by RT/PCR; (2) to evaluate possible clinical correlates of characteristics of the patients from whom the cell lines were derived with patterns of BLP receptor expression. Degenerate PCR primers were designed to amplify all known BLP receptors and yielded products from 19/20 small cell lung carcinoma (SCLC) and 12/13 non-small cell lung carcinoma (NSCLC) cell lines. GRP receptor was the most commonly expressed BLP receptor subtype, being detected in 17/20 SCLC and 11/13 NSCLC. Eleven of 20 SCLC expressed NMB receptors, and 5/20 expressed BRS-3, compared with 4/13 and 1/13, respectively, in NSCLC cell lines. Evaluation of the clinical data of the patients from whom the cell lines were derived revealed expected age, sex, smoking history and survival based on histology and stage. Patients from whom cell lines expressed GRP receptor experienced a better survival than those whose cell lines did not (367 +/- 274 days vs. 211 +/- 114 days), but the results were not statistically significant. RT/PCR analysis is a feasible, sensitive and specific means of determining BLP receptor expression in lung cancer cells and may yield prognostic information in patient tissue.