Detection of increased amounts of the extracellular domain of the c-erbB-2 oncoprotein in serum during pulmonary carcinogenesis in humans

Soluble Human Epidermal Growth Factor Receptor 2 (sHER2) as a Potential Risk Assessment, Screening, and Diagnostic Biomarker of Lung Adenocarcinoma

Lung cancer is the leading cause of cancer-related death in the United States. Here, we evaluated the potential clinical utility of soluble human epidermal growth factor receptor 2 (sHER2) for the risk assessment, screening, and diagnosis of non-small cell lung cancer (NSCLC) using an unmatched case-control study design. Serum sHER2 concentrations were measured by immunoassay in 244 primary NSCLC cases and 218 healthy controls. Wilcoxon rank-sum tests, logistic regression models, and receiver operating characteristic plots were used to assess whether sHER2 is associated with lung cancer. Median serum sHER2 concentrations are higher in patients with adenocarcinoma than squamous cell carcinoma regardless of gender, and sHER2 is a weak, independent biomarker of adenocarcinoma, but not of squamous cell carcinoma, adjusted for age and gender. The age-adjusted relative risk (odds) of adenocarcinoma is 3.95 (95% CI: 1.22, 12.81) and 7.93 (95% CI: 2.26, 27.82) greater for women and men with high sHER2 concentrations (≥6.60 ng/mL) vs. low sHER2 concentrations (≤1.85 ng/mL), respectively. When adjusted for each other, sHER2, age, and gender discern healthy controls from patients with primary adenocarcinomas of the lung with 85.9% accuracy. We conclude that even though serum sHER2 is not a strong, stand-alone discriminatory biomarker of adenocarcinoma, sHER2 may be a useful, independent covariate in multivariate risk assessment, screening, and diagnostic models of lung cancer.

Dysregulation of the immune system caused by silica and asbestos

Silica and asbestos cause pneumoconioses known as silicosis and asbestosis, respectively, that are each characterized by progressive pulmonary fibrosis. While local effects of inhaled silica particles alter the function of alveolar macrophages and sequential cellular and molecular biological events, general systemic immunological effects may also evolve. One well-known health outcome associated with silica exposure/silicosis is an increase in the incidence of autoimmune disorders. In addition, while exposure to silica--in the crystalline form--has also been seen to be associated with the development of lung cancers, it remains unclear as to whether or not silicosis is a necessary condition for the elevation of silica-associated lung cancer risks. Since asbestos is a mineral silicate, it would be expected to also possess generalized immunotoxicological effects similar to those associated with silica particles. However, asbestos-exposed patients are far better known than silicotic patients for development of malignant diseases such as lung cancer and mesothelioma, and less so for the development of autoimmune disorders. With both asbestos and crystalline silica, one important dysregulatory outcome that needs to be considered is an alteration in tumor immunity that allows for silica- or asbestos- (or asbestos-associated agent)-induced tumors to survive and thrive in situ. In this review, the immunotoxicological effects of both silica and asbestos are presented and contrasted in terms of their abilities to induce immune system dysregulation that then are manifest by the onset of autoimmunity or by alterations in host-tumor immunity.

Liquid-based fluorescence in situ hybridization assay for detection of ERBB2 gene amplification in patients with breast cancer

BACKGROUND

Current reference methods for evaluating gene amplification and expression of ERBB2 (also known as HER-2)--cell-based fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC)--are subjective and influenced by methods of tissue preparation and fixation. We developed and evaluated a novel, quantitative liquid-based FISH (L-FISH) assay that uses flow cytometry to detect ERBB2 gene amplification in breast cancer patients.

METHODS

DNA was extracted from serum or tissue, biotinylated, hybridized to differentially labeled probes for ERBB2 and a chromosome 17-specific single-copy sequence (17-SSC), and immobilized to streptavidin-coated microspheres. The ERBB2/17-SSC signal ratio measured by flow cytometry was used to evaluate ERBB2 amplification. We used L-FISH to test 122 stored formalin-fixed, paraffin-embedded (FFPE) tissue samples and 22 serum samples from randomly selected breast cancer patients; results were compared with those obtained with conventional FISH and IHC.

RESULTS

The inter- and intraassay imprecisions were 3.7%-18.9% for FFPE tissue and 2.8%-6.3% for serum. Overall, L-FISH analyses of FFPE tissues demonstrated 84.4% concordance with results obtained with conventional FISH (P < 0.001) and 78.8% concordance with IHC results (P < 0.001). L-FISH analyses of serum samples showed 91% concordance with tissue-based IHC/FISH results (P = 0.038).

CONCLUSIONS

Our data indicate that this PCR-free L-FISH method can be used to evaluate ERBB2 amplification in both cell-containing (paraffin-embedded tissue) and cell-free (serum) samples. This approach provides more objective results and is amenable to automation and quantitative measurement.

Serum EGF-receptor and HER-2 extracellular domains and prognosis of non-small-cell lung cancer

This retrospective study aimed at evaluating the prognostic impact of high serum levels of either the HER-2 extracellular domain (ECD) or the epidermal growth factor receptor (EGFR) ECD measured using two specific ELISAs in 221 patients with non-small-cell lung cancer (NSCLC) receiving conventional therapy and 41 nonmalignant pulmonary diseases patients. It was not possible to discriminate between lung cancer and benign lung disease owing to the lack of sensitivity–specificity relationship of HER-2 and EGFR ECD levels. Neither HER-2 nor EGFR ECD specific levels were associated with a particular prognosis of NSCLC patients receiving conventional therapy.

Trastuzumab in combination with cisplatin and gemcitabine in patients with Her2-overexpressing, untreated, advanced non-small cell lung cancer: report of a phase II trial and findings regarding optimal identification of patients with Her2-overexpressing disease

The purpose of this study was to evaluate the feasibility, efficacy, safety, and pharmacokinetics of trastuzumab plus cisplatin and gemcitabine in patients with Her2-overexpressing stages IIIB or IV non-small cell lung cancer (NSCLC) and to study the relationship between results from the two methods for determining levels of Her2 overexpression. Chemonaive patients were eligible if they had stages IIIB or IV NSCLC with either a Her2 score of at least 1+ by immunohistochemical (IHC) analysis or a serum Her2 shed antigen level of at least 15 ng/ml by enzyme-linked immunosorbent assay (ELISA). Treatment consisted of cisplatin 75 mg/m(2) day one plus gemcitabine 1250 mg/m(2) days one and eight plus trastuzumab 4 mg/kg day one and 2 mg/kg weekly thereafter on a 21-day cycle for six cycles followed by weekly maintenance trastuzumab therapy. Of the 21 patients enrolled, 8 (38%) patients had a partial response. The 1-year survival rate was 62% (13/21). Median time to progression was 36 weeks. Pharmacokinetic studies revealed no interaction between trastuzumab and gemcitabine plus cisplatin. In patients screened for this study, Her2 expression was zero in 283/360 (79%); 1+ in 32/360 (9%); 2+ in 27/360 (8%); and 3+ in 18/360 patients (5%). Serum Her2 shed antigen was >15 ng/ml in 27/ 288 (9%) patients. Of patients who had both Her2 assays, 24% (4/17) with ELISA scores >15 ng/ml had IHC scores of 3+, compared with only 2% (3/145) of the patients <15 ng/ml and 4% (7/162) of all patients. The addition of trastuzumab to cisplatin and gemcitabine was well tolerated, but further study will be required to determine whether this combination is superior to chemotherapy alone. This may be demonstrated if only those patients with Her2, having a score of IHC 3+ were eligible. Since IHC 3+ is rare in NSCLC, performing IHC in only those patients with serum Her2 shed antigen >15 ng/ml would greatly increase the efficiency of IHC screening though at the cost of excluding nearly half the patients with Her2 scores of 3+ on IHC analysis. Thus, if sequential screening consisting of serum ELISA followed by IHC analysis is implemented, it may make a trastuzumab trial feasible but should ultimately be supplanted by another screening system if trastuzumab is shown to be beneficial to some patients with IHC Her2 scores of 3+.

c-erbB-2 protein in serum of primary lung cancer patients

We determined c-erbB-2 protein level in serum of 86 primary lung cancer patients (78 non-small cell lung carcinomas (NSCLC), 3 small cell carcinomas, 5 not histologically defined) and in 61 controls. Aim of this study was to evaluate the clinical usefulness of c-erbB-2 as marker for lung cancer diagnosis. The protein was measured with a commercially available sandwich enzyme immunoassay. Mean levels of c-erbB-2 were 72.8 +/- 122.3 fmol/ml in lung cancers and 64.6 +/- 17.5 fmol/ml in controls (P = 0.2). No association was found between c-erbB-2 levels and histotype, tumor stage, sex and smoking habits. Among NSCLC, only four patients showed a c-erbB-2 concentration higher than the selected cut-off value of 99.6 fmol/ml. Subjects with levels higher than the 75th percentile in tumors (73 fmol/ml) had a shorter median survival than those with lower levels (6.3 months versus 10.0 months, P = 0.003). Our results indicated that serum c-erbB-2 protein is not a reliable diagnostic marker. There is, however, a suggestion of a possible clinical usefulness in terms of survival prediction.

Association between the ras p21 oncoprotein in blood samples and breast cancer

To assess the potential of using oncoprotein levels in blood as a marker of breast cancer status, we measured ras p21 in blood samples taken from 34 breast cancer cases and 60 non-cancer controls including 26 women with benign breast disease (BBD) and 34 healthy women. Plasma samples drawn before surgery or at routine office visit were analyzed for ras p21 by Western blot with computer aided image analysis to measure staining intensity in integrated pixel units (IPU). We found detectable levels of ras p21 in 53% of the blood samples of cases, in 27% of the BBD controls and 26% of the healthy controls. Comparing cases to the combined control group (n=60) and controlling for known breast cancer risk factors, ras p21 was associated with breast cancer status (odds ratio=5.22, 95% CI=1.58-17.23). The median levels of ras p21 staining were higher in cases (7.04 IPU, P=0.03) compared to BBD controls (0.00 IPU) or healthy controls (0.00 IPU). The sensitivity of the assay for detecting breast cancer was 50% which compares favorably with that seen for erbB-2 ( approximately 10%), a more extensively studied blood-borne tumor marker. Ras p21 may be useful in the early detection of breast tumors and in post-surgical follow-up of patients, giving patients and physicians new tools for managing breast cancer.

Non-small cell lung cancer clinical trials with trastuzumab: their foundation and preliminary results

The overexpression of HER2, a transmembrane glycoprotein tyrosine kinase, has been implicated in mitogenesis, cell survival, invasion and angiogenesis. Preclinical evidence suggests that HER2 overexpression contributes to tumor progression in non-small cell lung cancer (NSCLC) and retrospective clinical correlative studies show that it is probably associated with poor clinical outcome. Trastuzumab (Herceptin, Genentech Inc., South San Francisco, CA) is a recombinant humanized monoclonal antibody that targets HER2 and is currently approved for use in the treatment of patients with HER2-overexpressing metastatic breast cancer. Two primary mechanisms proposed for the activity of trastuzumab are downregulation of HER2 and induction of antibody-dependent cell-mediated cytotoxicity. Evidence from preclinical studies of trastuzumab in NSCLC and other cell lines, the presence of HER2 overexpression in NSCLC clinical specimens and the clinical benefit derived from trastuzumab in phase II and III metastatic breast cancer trials have led to the development of clinical trials of trastuzumab in NSCLC. Phase II studies of trastuzumab in patients with stage IIIB or IV NSCLC are being conducted to test the efficacy of trastuzumab as a single agent or in combination with chemotherapy. Preliminary results show combinations of chemotherapy plus trastuzumab are well tolerated, with encouraging response rates of 21-40%. A randomized phase II trial of chemotherapy with or without trastuzumab showed promise in a small subgroup of patients with 3+ HER2 overexpression by immunohistochemistry or HER2 DNA amplification by fluorescence in situ hybridization. Taken together, these data indicate that trastuzumab warrants further investigation in a clinical study in selected patients with NSCLC.

The impact of immune responses on lung cancer and the development of new treatment modalities

OBJECTIVE

This presentation covers predominantly review data in relation with immune responses initiating and accompanying lung carcinogenesis or- on the contrary-contributing to novel therapeutic developments. Occasionally, personal findings will be considered. RESULTS 1 OF IMMUNE DEFICIENCY: It is known for several decades that cancer incidence (several sites) is increased in subjects receiving immunosuppressive therapy, e.g. to avoid transplant rejection, or suffering from AIDS. We have observed that in areas heavily polluted by industrial activities, resulting in immune deficiency, cancer incidence is increased, notably for lung cancer. On the other hand, neoplastic cells are able to escape the host's immune responses by inducing apoptosis of the effector T lymphocytes. Apoptosis in T-cells is triggered by the interaction of the membrane receptor Fas with its normal ligand Fas L, or an activating antibody. Now lung carcinoma cells have been shown to express Fas L, enabling them to destroy cytolytic T cells. RESULTS 2 OF IMMUNE TREATMENT: It is well over a century ago that interest in the immunotherapy of cancer was aroused by the observation of tumour regressions concomitant with bacterial infection, an observation leading to the development of 'Coley's toxin', a mixture of killed bacteria (presently known to act through the presence of TNF-alpha). Since these long-standing empirical attempts, a lasting search for immune control of cancer has been initiated, comprising such different approaches as active non-specific immunotherapy, active specific immunotherapy, approaches based on the use of monoclonal antibodies, as well as those depending on cellular immunity and the development of adoptive immunotherapy, and the use of peptide vaccines. These different approaches will be described and their results presented.

CONCLUSION

Present state-of-the-art will be discussed and new pathways for development evoked; better understanding of immune mechanisms is opening new avenues for improved treatment efficacy.

Automated Assay for HER-2/neu in Serum

Background: The extracellular domain of the HER-2/neu oncogene product is increased in sera of some patients with epithelial cancers. Our aim was to develop an automated serum assay for the extracellular domain of the HER-2/neu protein.

Methods: We used a monoclonal antibody labeled with fluorescein for capture and a monoclonal Fab′ fragment labeled with alkaline phosphatase for detection. Separation of bound and free detection conjugate was performed with magnetizable particles coated with monoclonal antibody to fluorescein. Alkaline phosphatase activity was measured kinetically at 405 or 450 nm.

Results: The assay was linear from 0.1 to 250 μg/L. No hook effect was evident up to 10 000 μg/L. Within-run imprecision (CV) was 0.8–1.2%, and total imprecision was 1.1–1.7%. Cross-reactivity with human epidermal growth factor receptor, which has extensive homology with HER-2/neu extracellular domain, was &lt;0.6%. Human anti-mouse antibodies, heterophilic antibodies, and rheumatoid factor did not interfere, nor did the therapeutic monoclonal antibody Herceptin®. In 51 healthy females, the mean value was 9.3 μg/L with a range of 6.4–14.0 μg/L. No reagent lot-to-lot variability was detected over four lots of reagents tested.

Conclusion: The Bayer Immuno 1TM assay for HER-2/neu was precise and resistant to interferences, characteristics that are essential for longitudinal monitoring of cancer patients.

Increased serum concentrations of growth factor receptors and Neu in workers previously exposed to asbestos

OBJECTIVES

Epidermal growth factor receptor (EGFR) and oncogene Neu belong to a family of growth factor receptors which may play a part in carcinogenesis. Although increased serum concentrations of Neu and EGFR have been shown in several patients with asbestosis who later developed cancer, serum concentrations have not been studied in workers exposed in the past to asbestos but without asbestos related diseases.

METHODS

Serum concentrations of secreted growth factor receptors were studied in 300 workers exposed in the past to asbestos and the results were compared with those of 70 controls.

RESULTS

In the controls 4.3% (3/70) had EGFR values > 912 units/ml, compared with 39% (117/299) of the exposed group (p < 0.001). The difference in high values was even more pronounced for Neu with 4.3% of controls having Neu values > 2580 fmol/ml compared with 72% (216/299) of the exposed workers (p < 0.001). Pleural plaques predicted lower serum concentrations of EGFR but not lower Neu concentrations, and this finding remained significant after adjustment for age, exposure time, smoking, and time from initial exposure.

CONCLUSIONS

Enhanced secretion of EGFR and Neu was found in a large cohort of retired asbestos workers with a wide range of exposure and latency periods. They did not have asbestosis or cancer and their EGFR values were higher in those without plaques. Further studies are needed to confirm our results, to determine the source of the secreted growth factor receptors, and to study their possible value as risk factors in the development of cancer.

Molecular markers of carcinogenesis

The protein products of oncogenes and tumor suppressor genes play critical roles in the development of many cancers. The expression of a number of these proteins can be detected in extracellular fluids such as blood. This article reviews the literature on the application of methods for the detection of the proteins of oncogenes and tumor suppressor genes in the blood of humans with cancer or at risk for the development of cancer. The detection of these proteins in blood may be useful molecular markers of carcinogenesis that could play an important part in cancer diagnosis, prognosis, and prevention.

The molecular epidemiology of lung cancer

One in ten tobacco smokers develops bronchogenic carcinoma over a lifetime. The study of susceptibility of an individual and a population to lung cancer traditionally has been limited to the study of tobacco smoke dose and family history of cancer. New insights into lung carcinogenesis have made the study of molecular markers of risk possible in human populations in the emerging field of molecular epidemiology. This review summarizes data addressing the relationships of human lung cancer to polymorphisms of phase I procarcinogen-activating and phase II-deactivating enzymes and intermediate biomarkers of DNA mutation, such as DNA adducts, oncogene and tumor suppressor gene mutation, and polymorphisms. These parameters are reviewed as they relate to tobacco smoke exposure, procarcinogen metabolizing polymorphisms, and the presence of lung cancer. Problem areas in biomarker validation, such as cross-sectional data interpretation; tissue source, race, statistical power, and ethical implications are addressed.

Intracellular diacylglycerol: a mitogenic second messenger proposable as marker of transformation in squamous cell carcinoma of the lung

In this study, we examined 50 patients with documented lung cancer projecting in the bronchial lumen unilaterally. Bronchial lavage from the affected and unaffected sides provided neoplastic and normal cells in which we studied an intracellular mitogenic second messenger, diacylglycerol, associated with transformation. The levels of diacylglycerol in cells from the affected side were compared with that from the healthy side, thus providing an internal control for each patient. Our data show that the levels of diacylglycerol in lavage fluid relative to affected bronchus are elevated in 56% of all the patients examined. This elevation reaches 77% in patients with squamous cell carcinoma, a value of sensitivity higher than 'traditional' markers for cancer of the lung. Thus, these findings may have significant implications for the use of diacylglycerol measurement as a novel biomarker for early detection of lung cancer, and for monitoring recurrences after treatment.

Serum level and tissue expression of c-erbB-2 protein in lung adenocarcinoma

Serum levels of c-erbB-2 protein were measured by an enzyme immunoassay in 64 patients with lung adenocarcinoma. Immunohistochemical staining was performed in 40 of these tumors. The mean serum concentration was 16.5 +/- 8.5 U/mL (range: 3.4 to 49.0) in patients with lung adenocarcinoma, whereas it was 14.0 +/- 3.7 U/mL (range: 6.9 to 20.9) in 15 controls (1 U/mL = 0.61 ng/mL). Elevated concentrations (> or = 22.0 U/mL, control mean + 2 SD) were observed in 17/64 lung adenocarcinoma patients (26.6%), as compared with none of the control subjects (p < 0.05). Patients with stage IIIB or T4 disease had increased serum levels. The serum concentration was decreased significantly by surgical tumor ablation. Tissue overexpression was obtained in 17/40 cases (42.5%), and serum levels in patients with tissue overexpression were higher than in patients without overexpression. Serum c-erbB-2 protein may be a useful indicator of tumor burden in patients with lung adenocarcinoma.

Eduard Buchner

Background

The HER2 extracellular domain shed in blood (HER2ECD) is reported to rise and fall in parallel with HER2+ breast cancer behavior. In this study, we evaluated the clinical relevance of plasma HER2ECD values in patients with metastatic breast cancer treated in the SAKK22/99 trial comparing trastuzumab monotherapy followed by trastuzumab-chemotherapy combination at progression versus upfront combination therapy.

Methods

Quantitative assessment of plasma HER2ECD was performed in 133 patients at baseline; after 2–24 h; at 3 weeks; at first response evaluation (8–9 weeks); and at tumor progression. Associations with tumor characteristics, disease course and trial treatment were evaluated.

Results

Baseline HER2ECD levels were stable within 24 h after the first trastuzumab injection. These plasma values correlated positively with the HER2 gene ratio (rs = 0.39, P < 0.001) and HER2 protein expression levels (rs = 0.36, P < 0.001) but not with ER/PR status of the primary tumor. HER2ECD baseline levels were positively associated with the presence of visceral disease (P = 0.05) and poor patients’ outcome (Cox-regression: P = 0.009). Patients with high baseline levels (> 35 ng/ml) had the worst overall survival (P = 0.03) if treated with upfront combination therapy. Conversely, patients with low HER2ECD baseline values (< 15 ng/ml) had longer time to progression on combined trastuzumab-chemotherapy when first treated with trastuzumab monotherapy (P = 0.02). Monitoring HER2ECD levels during the course of the trial revealed significant time (P = 0.001) and time-treatment arm interactions (P = 0.0007). Under upfront trastuzumab alone, the HER2ECD levels remained stable until just before disease progression. In patients responding to combination treatment HER2ECD levels decreased to > 20%.

Conclusions

Plasma HER2ECD levels in patients with metastatic breast cancer reflect HER2 disease status. This robust biomarker might help identifying patients without visceral disease profiting from a sequential treatment’s modality. Monitoring HER2ECD levels during trastuzumab monotherapy could help defining the optimal time to introduce chemotherapy.

Trial registration

Registration Number by ClinicalTrials.gov: NCT00004935, Trial number: SAKK22/99. Registered on 27 January 2003.