Uses and abuses of tumor markers in the diagnosis, monitoring, and treatment of primary and metastatic breast cancer

Predictive tests for individualization of pharmacological cancer treatment

BACKGROUND

The selection of cancer drugs for an individual patient is still based mostly on cancer type and stage. Predictive tests are needed to make individualized and more efficient pharmacological cancer treatment possible.

OBJECTIVE

To provide an overview of available, possible future development and principles for development of predictive tests for individualized selection of cancer drugs.

METHODS

Overview of published data.

RESULTS/CONCLUSION

Despite increased knowledge in cancer biology, only limited progress has been made in the development and use of predictive tests. However, rapid progress in this field will be possible using already available and emerging technologies, but requires a paradigm shift in principles for the development and use of cancer drugs. Assessment of drug activity in intact tumor cells and tumor cell gene expression signatures are considered to have greatest potential for the development of versatile predictive tests.

Publication of tumor marker research results: the necessity for complete and transparent reporting

Clinical management decisions for patients with cancer are increasingly being guided by prognostic and predictive markers. Use of these markers should be based on a sufficiently comprehensive body of unbiased evidence to establish that benefits to patients outweigh harms and to justify expenditure of health care dollars. Careful assessments of the clinical utility of markers by using comparative effectiveness research methods are urgently needed to more rigorously summarize and evaluate the evidence, but multiple factors have made such assessments difficult. The literature on tumor markers is plagued by nonpublication bias, selective reporting, and incomplete reporting. Several measures to address these problems are discussed, including development of a tumor marker study registry, greater attention to assay analytic performance and specimen quality, use of more rigorous study designs and analysis plans to establish clinical utility, and adherence to higher standards for reporting tumor marker studies. More complete and transparent reporting by adhering to criteria such as BRISQ [Biospecimen Reporting for Improved Study Quality] criteria for reporting details about specimens and REMARK [Reporting Recommendations for Tumor Marker Prognostic Studies] criteria for reporting a multitude of aspects relating to study design, analysis, and results, is essential for reliable assessment of study quality, detection of potential biases, and proper interpretation of study findings. Adopting these measures will improve the quality of the body of evidence available for comparative effectiveness research and enhance the ability to establish the clinical utility of prognostic and predictive tumor markers.

Design of tumor biomarker-monitoring trials: a proposal by the European Group on Tumor Markers

A major application of tumor biomarkers is in serial monitoring of cancer patients, but there are no published guidelines on how to evaluate biomarkers for this purpose. The European Group on Tumor Markers has convened a multidisciplinary panel of scientists to develop guidance on the design of such monitoring trials. The panel proposes a 4-phase model for biomarker-monitoring trials analogous to that in use for the investigation of new drugs. In phase I, biomarker kinetics and correlation with tumor burden are assessed. Phase II evaluates the ability of the biomarker to identify, exclude, and/or predict a change in disease status. In phase III, the effectiveness of tumor biomarker-guided intervention is assessed by measuring patient outcome in randomized trials. Phase IV consists of an audit of the long-term effects after biomarker monitoring has been included into standard patient care. Systematic well-designed evaluations of biomarkers for monitoring may provide a stronger evidence base that might enable their earlier use in evaluating responses to cancer therapy.

Why Hasn't Genomic Testing Changed the Landscape in Clinical Oncology?

The "omics" revolution produced great optimism that tumor biomarker tests based on high-order analysis of multiple (sometimes thousands) of factors would result in truly personalized oncologic care. Unfortunately, 10 years into the revolution, the promise of omics-based research has not yet been realized. The factors behind the slow progress in omics-based clinical care are many. First, over the last 15 years, there has been a gradual recognition of the importance of conducting tumor biomarker science with the kind of rigor that has traditionally been used for therapeutic research. However, this recognition has only recently been applied widely, and therefore most tumor biomarkers have insufficiently high levels of evidence to determine clinical utility. Second, omics-based research offers its own particular set of concerns, especially in regard to overfitting computational models and false discovery rates. Researchers and clinicians need to understand the importance of analytic validity, and the difference between clinical/biologic validity and clinical utility. The latter is required to introduce a tumor biomarker test of any kind (single analyte or omics-based), and are ideally generated by carefully planned and properly conducted "prospective retrospective" or truly prospective clinical trials. Only carefully planned studies, which take all three of these into account and in which the investigators are aware and recognize the enormous risk of unintended bias and overfitting inherent in omics-based test development, will ultimately result in translation of the exciting new technologies into better care for patients with cancer.

Ki-67: level of evidence and methodological considerations for its role in the clinical management of breast cancer: analytical and critical review

Clinicians can use biomarkers to guide therapeutic decisions in estrogen receptor positive (ER+) breast cancer. One such biomarker is cellular proliferation as evaluated by Ki-67. This biomarker has been extensively studied and is easily assayed by histopathologists but it is not currently accepted as a standard. This review focuses on its prognostic and predictive value, and on methodological considerations for its measurement and the cut-points used for treatment decision. Data describing study design, patients’ characteristics, methods used and results were extracted from papers published between January 1990 and July 2010. In addition, the studies were assessed using the REMARK tool. Ki-67 is an independent prognostic factor for disease-free survival (HR 1.05–1.72) in multivariate analyses studies using samples from randomized clinical trials with secondary central analysis of the biomarker. The level of evidence (LOE) was judged to be I-B with the recently revised definition of Simon. However, standardization of the techniques and scoring methods are needed for the integration of this biomarker in everyday practice. Ki-67 was not found to be predictive for long-term follow-up after chemotherapy. Nevertheless, high KI-67 was found to be associated with immediate pathological complete response in the neoadjuvant setting, with an LOE of II-B. The REMARK score improved over time (with a range of 6–13/20 vs. 10–18/20, before and after 2005, respectively). KI-67 could be considered as a prognostic biomarker for therapeutic decision. It is assessed with a simple assay that could be standardized. However, international guidelines are needed for routine clinical use.

p53 Expression in node-positive breast cancer patients: results from the Cancer and Leukemia Group B 9344 Trial (159905)

PURPOSE

p53 as a prognostic and predictive factor in early-stage breast cancer has had mixed results. We studied p53 protein expression, by immunohistochemistry, in a randomized clinical trial of stage II patients treated with adjuvant doxorubicin and cyclophosphamide with or without paclitaxel [Cancer and Leukemia Group B (CALGB) 9344, INT0148].

PATIENTS AND METHODS

Epithelial p53 expression was evaluated using two immunohistochemical antibodies (DO7 and 1801) in formalin-fixed, paraffin-embedded tissue from patients with node-positive breast cancer who were randomized to four cycles of cyclophosphamide and one of three doses of doxorubicin (60, 75, or 90 mg/m(2); AC) and to receive four subsequent cycles of paclitaxel (T) or not. Prognostic and predictive value of p53 protein expression was assessed, independent of treatment assignment, for escalating doses of doxorubicin or addition of T with endpoints of relapse-free (RFS) and overall survival (OS).

RESULTS

Of 3,121 patients, 1,887 patient specimens treated on C9344 were obtained, passed quality control, and evaluated for p53 expression. Expression was 23% and 27% for mAbs 1801 and D07, respectively, with 92% concordance. In univariate analysis, p53 positivity was associated with worse OS with either antibody, but only p53 staining with monoclonal antibody 1801 had significantly worse RFS. In multivariate analysis, p53 was not predictive of RFS or OS from either doxorubicin dose escalation or addition of paclitaxel regardless of the antibody.

CONCLUSION

Nuclear staining of p53 by immunohistochemistry is associated with worse prognosis in node-positive patients treated with adjuvant doxorubicin-based chemotherapy but is not a useful predictor of benefit from doxorubicin dose escalation or the addition of paclitaxel.

Targeting a common collaborator in cancer development

In this issue of Science Translational Medicine, Wallin et al. have identified a subset of breast and ovarian cancer cell lines that show synergistic response to the combination of doxorubicin and GDC-0941, a class IA phosphatidylinositol 3-kinase (PI3K) inhibitor. Here, we discuss the potential implications of these data on the clinical development of PI3K pathway inhibitors as cancer therapeutics.

Polymorphisms of Lewis and Secretor genes are related to breast cancer and metastasis in axillary lymph nodes

ABH and Lewis antigen expression has been associated with cancer development and prognosis, tumor differentiation, and metastasis. Considering that invasive ductal breast carcinoma (IDC) presents multiple molecular alterations, the aim of the present study was to determine whether the polymorphism of ABO, Lewis, and Secretor genes, as well as ABO phenotyping, could be associated with tumor differentiation and lymph nodes metastasis. Seventy-six women with IDC and 78 healthy female blood donors were submitted to ABO phenotyping/genotyping and Lewis and Secretor genotyping. Phenotyping was performed by hemagglutination and genotyping by the polymerase chain reaction with sequence-specific primers. ABO, Lewis, and Secretor genes were classified by individual single nucleotide polymorphism at sites 59, 1067, 202, and 314 of the Lewis gene, 428 of the Secretor gene, and 261 (O1 allele), 526 (O2 and B allele), and 703 (B allele). No association was found between breast cancer and ABO antigen expression (P = 0.9323) or genotype (P = 0.9356). Lewis-negative genotype was associated with IDC (P = 0.0126) but not with anatomoclinical parameters. Nonsecretor genotype was associated with axillary lymph node metastasis (P = 0.0149). In conclusion, Lewis and Secretor genotyping could be useful to predict respectively breast cancer susceptibility and axillary lymph nodes metastasis.

Is it prime time for personalized medicine in cancer treatment?

Over the last decade, with rapidly advancing biotechnology, the understanding of cancer has changed. The genomic era has resulted in an explosion of targeted therapies and prognostic and predictive biomarkers. This article aims to illustrate the advances made in the practice of oncology as well as the potential and limitations of personalized medicine in cancer.

Molecular circuits of solid tumors: prognostic and predictive tools for bedside use

The explosion of knowledge in cancer biology in the past two decades has led to the identification of specific molecular circuits in solid tumors. These pathways reflect specific abnormalities thought to drive malignant progression. This knowledge has also generated a vast panel of cancer biomarkers although many of these biomarkers lack sufficient research and validation to be used in the clinic. This Review discusses relevant molecular prognostic and/or predictive biomarkers in the six leading tumors with the highest contribution to cancer mortality: breast, lung, colorectal, prostate, pancreatic and ovarian cancer. Each biomarker is described according to its associated clinicopathological presentation and specific associated molecular interactions. Despite only few biomarkers being currently implemented in clinical practice, a new generation of predictors is emerging that could modify the classic organ-based cancer classification (for example, defects in DNA repair, aberrant MAPK signaling and aberrant PI3K/Akt/mTOR signaling). The advent of high-throughput strategies will also probably substitute monobiomarker strategies.

Assessing the reproductive competence of individual embryos: a proposal for the validation of new "-omics" technologies

Rapid technological advances now provide the tools needed to evaluate the molecular genetics, proteomics, and microenvironment of an individual embryo in an effort to predict its reproductive competence. Rigorous criteria for accepting any test as a validated marker of embryonic reproductive competence should be established, and practitioners should be cautious about applying these tests clinically before the availability of comprehensive and convincing evidence.

Elevated levels of the acute-phase serum amyloid are associated with heightened lung cancer risk

BACKGROUND

The authors investigated whether early stage lung cancer could be identified by proteomic analyses of plasma.

METHODS

For the first case-control study, plasma samples from 52 patients with lung cancer and from a group of 51 controls were analyzed by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry. In a second case-control study, a classifier of 4 markers (mass-to-charge ratio, 11,681, 6843, 5607, and 8762) also was tested for validation on plasma from 16 consecutive patients with screen-detected cancer versus 406 healthy individuals. The most relevant marker was identified, and an enzyme-linked immunosorbent assay-based analysis revealed that signal intensity was correlated with concentration.

RESULTS

The classifier had a sensitivity of 94.23% and a specificity of 76.47% in the first study but lost predictive value in the second study. Nevertheless, the 11,681 cluster, which was identified as serum amyloid protein A (SAA), resulted in a multiple logistic regression model that indicated a strong association with lung cancer. When both studies were considered as a together, the odds ratio (OR) for an SAA intensity > or =0.5 was 10.27 (95% confidence interval [CI], 4.64-22.74), whereas an analysis restricted to stage I cancers (TNM classification) revealed an OR of 8.45 (95% CI, 2.76-25.83) for T1 lung cancer and 21.22 (95% CI, 5.62-80.14) for T2 lung cancer.

CONCLUSIONS

SAA levels were predictive of an elevated risk of lung cancer, supporting the general view that inflammation is implicated in lung cancer development.

Circulating tumor cells

Circulating tumor cells (CTCs) can be separated and characterized from normal hematopoietic cellular constituents by a variety of methods. Different strategies have included separation by physical characteristics, such as size or weight, or by biological characteristics, such as expression of epithelial or cancer-specific markers. Of the latter, rtPCR for epithelial-related gene message, such as cytokeratin, and immunoseparation techniques using monoclonal antibodies against epithelial cellular adhesion molecule, have gained the most widespread use in investigational and standard clinical application to date. Detection and monitoring of CTCs might be useful for screening, prognosis, prediction of response to therapy, or monitoring clinical course in patients with primary or metastatic cancer. Currently, monitoring patients with metastatic disease is the most practical application of CTCs. In this regard, several studies have demonstrated that approximately 50-70% of patients with metastatic breast, colon, and prostate cancers have elevated CTC levels, when evaluated using a highly automated immunomagnetic CTC assay system, designated CellSearch®. These studies demonstrate that elevated CTC levels prior to initiation of a new systemic therapy are associated with a worse prognosis than those that do not, and that persistently elevated or subsequent rising CTC levels strongly suggest that the therapeutic regimen with which the patient is being treated is not working. Similar results have been shown with rtPCR assays, although they are not as widely available for routine clinical use. New areas of research are directed toward developing more sensitive means of CTC detection and generating a variety of methods to characterize the molecular and biologic nature of CTCs, such as the status of hormone receptors, epidermal, and other growth factor receptor family members, and indications of stem-cell characteristics.

Clinical trial designs for evaluating the medical utility of prognostic and predictive biomarkers in oncology

Physicians need improved tools for selecting treatments for individual patients. Many diagnostic entities hat were traditionally viewed as individual diseases are heterogeneous in their molecular pathogenesis and treatment responsiveness. This results in the treatment of many patients with ineffective drugs, incursion of substantial medical costs for the treatment of patients who do not benefit and the conducting of large clinical trials to identify small, average treatment benefits for heterogeneous groups of patients. In oncology, new genomic technologies provide powerful tools for the selection of patients who require systemic treatment and are most (or least) likely to benefit from a molecularly targeted therapeutic. In the large amount of literature on biomarkers, there is considerable uncertainty and confusion regarding the specifics involved in the development and evaluation of prognostic and predictive biomarker diagnostics. There is a lack of appreciation that the development of drugs with companion diagnostics increases the complexity of clinical development. Adapting to the fundamental importance of tumor heterogeneity and achieving the benefits of personalized oncology for patients and healthcare costs will require paradigm changes for clinical and statistical investigators in academia, industry and regulatory agencies. In this review, I attempt to address some of these issues and provide guidance on the design of clinical trials for evaluating the clinical utility and robustness of prognostic and predictive biomarkers.

Use of archived specimens in evaluation of prognostic and predictive biomarkers

The development of tumor biomarkers ready for clinical use is complex. We propose a refined system for biomarker study design, conduct, analysis, and evaluation that incorporates a hierarchal level of evidence scale for tumor marker studies, including those using archived specimens. Although fully prospective randomized clinical trials to evaluate the medical utility of a prognostic or predictive biomarker are the gold standard, such trials are costly, so we discuss more efficient indirect "prospective-retrospective" designs using archived specimens. In particular, we propose new guidelines that stipulate that 1) adequate amounts of archived tissue must be available from enough patients from a prospective trial (which for predictive factors should generally be a randomized design) for analyses to have adequate statistical power and for the patients included in the evaluation to be clearly representative of the patients in the trial; 2) the test should be analytically and preanalytically validated for use with archived tissue; 3) the plan for biomarker evaluation should be completely specified in writing before the performance of biomarker assays on archived tissue and should be focused on evaluation of a single completely defined classifier; and 4) the results from archived specimens should be validated using specimens from one or more similar, but separate, studies.

Molecular markers of breast axillary lymph node metastasis

In breast cancer, axillary lymph node status is one of the most important prognostic variables and a crucial component to the staging system. Several clinico-histopathological parameters are considered to be strong predictors of metastasis; however, they fail to accurately classify breast tumors according to their clinical behavior and to predict which patients will have disease recurrence. Methods based on genome-wide microarray analyses have been used to identify molecular markers with respect to the development of axillary lymph node metastasis. Most of these markers can be detected in the primary tumors, which can potentially lead to the ability to identify patients at the time of diagnosis who are at high risk for lymph node metastasis, allowing for early intervention and more suitable adjuvant treatments.

Multigene classifiers, prognostic factors, and predictors of breast cancer clinical outcome

A series of multigene classifiers, prognostic and predictive tests have recently been introduced as potentially useful adjuncts for the management of recently diagnosed breast cancer patients. These tests have used both slide-based methods including immunohistochemistry and fluorescence in situ hybridization and nonmorphology driven molecular platforms including quantitative multiplex real time polymerase chain reaction and genomic microarray profiling. In this review, a series of partially and completely commercialized multigene assays are compared with the standard breast cancer clinico-pathologic variables and biomarkers and evaluated as to the level of their scientific validation, current clinical utility, regulatory approval status, and estimated cost-benefit. A comparison of the Oncotype Dx and MammaPrint assays indicates that the Oncotype Dx test has the advantages of an earlier commercial launch in the US, wide acceptance for payment by third party payors, the ease of use of formalin fixed paraffin embedded tissues, a recommendation as ready for use by the American Society of Clinical Oncology Breast Cancer Tumor Markers Update Committee, a continuous rather than dichotomous algorithm, inclusion of both estrogen receptor (ER) and human epidermal growth factor receptor 2 in the mRNA profile, an ability to serve as both a prognostic and predictive test for certain hormonal and chemotherapeutic agents, demonstrated cost-effectiveness in 1 published study, and a high accrual rate for the prospective validation clinical trial (Trial Assigning Individualized Options for Treatment Rx). The MammaPrint assay has the advantages of a 510(k) clearance by the US Food and Drug Administration, a larger gene number which may enhance further utility, and the potentially wider patient eligibility including lymph node-positive, ER-negative, and younger patients being accrued into the prospective trial (the Microarray in Node-negative Disease may Avoid ChemoTherapy). A number of other assays have specific predictive goals most often focused on the efficacy of tamoxifen in ER-positive patients such as the Two-gene Ratio test and the Cytochrome P450 CYP2D6 genotyping assay.

The gene expression signature of genomic instability in breast cancer is an independent predictor of clinical outcome

Recently, expression profiling of breast carcinomas has revealed gene signatures that predict clinical outcome, and discerned prognostically relevant breast cancer subtypes. Measurement of the degree of genomic instability provides a very similar stratification of prognostic groups. We therefore hypothesized that these features are linked. We used gene expression profiling of 48 breast cancer specimens that profoundly differed in their degree of genomic instability and identified a set of 12 genes that defines the 2 groups. The biological and prognostic significance of this gene set was established through survival prediction in published datasets from patients with breast cancer. Of note, the gene expression signatures that define specific prognostic subtypes in other breast cancer datasets, such as luminal A and B, basal, normal-like, and ERBB2+, and prognostic signatures including MammaPrint and Oncotype DX, predicted genomic instability in our samples. This remarkable congruence suggests a biological interdependence of poor-prognosis gene signatures, breast cancer subtypes, genomic instability, and clinical outcome.

Micrometastatic disease in breast cancer: clinical implications

The presence of bone marrow disseminated tumour cells (DTCs) was shown to predict poor clinical outcome in early breast cancer. However, peripheral blood is easier to obtain and allows for serial monitoring of minimal residual disease. Towards this aim, circulating tumour cells (CTCs) in the blood are detected using either direct methods, mainly antibody-based assays (immunocytochemistry, immunofluorescence and flow cytometry), or indirect methods, mainly nucleic acid-based assays (detection of mRNA transcripts by reverse transcriptase polymerase chain reaction, RT-PCR). The detection of CTCs using RT-PCR for CK19 was shown to be an independent prognostic factor in women with early breast cancer. Furthermore, considerable progress has been accomplished in genotyping, phenotyping and profiling micrometastatic cells. The challenge now is to integrate minimal residual disease as a prognostic and predictive tool in the management of breast cancer. This requires the standardisation of micrometastatic cell detection and characterisation, which will allow the incorporation of CTCs/DTCs into prospective clinical trials testing their clinical utility.

Tumor markers in clinical practice: General principles and guidelines

Tumor markers are assuming a growing role in all aspects of cancer care, starting from screening to follow-up after treatment, and their judicious application in clinical practice needs a thorough understanding of the basics of pathophysiology, techniques of identification or testing, reasons for out-of-range levels of tumor markers, as well as the knowledge of evidence of their role in any given malignancy. These are, at the most, just an adjunct to diagnosis, and establishing a diagnosis on the basis of tumor markers alone (especially a single result) is fraught with associated pitfalls because of the problem of nonspecificity. In reality an ideal tumor marker does not exist. Detection can be done either in tissue or in body fluids like ascitic or pleural fluid or serum. Clinical uses can be broadly classified into 4 groups: screening and early detection, diagnostic confirmation, prognosis and prediction of therapeutic response and monitoring disease and recurrence. In addition to variable sensitivity and specificity, the prevalence of a particular malignancy may be a major determinant in the application of a particular test as a screening tool. Serum levels, in certain situations, can be used in staging, prognostication or prediction of response to therapy. Monitoring disease is, perhaps, the most common clinical use of serum tumor markers. Rising trend in serum levels may detect recurrence of disease well before any clinical or radiological evidence of disease is apparent ("biochemical recurrence"). Sampling should ideally be repeated after 5-6 half-lives of the marker in question (or the marker with the longest half-life if multiple markers are being considered); but if found elevated, the next sampling after 2-4 weeks, for additional evidence, may be justified.

Detection of circulating tumor cells in bladder cancer patients

The methods employed for the detection of circulating bladder cancer cells (CBCs) and their use as a molecular staging tool in clinical settings are thoroughly reviewed. CBC isolation and enrichment methods are discussed according to their advantages and pitfalls along with the clinical data of PCR-based techniques used for CBC detection. In addition, we review the specificity of molecular markers that have been proposed so far for CBC identification, and we comment on the controversial clinical data, proposing laboratory approaches which may improve the clinical significance of CBC detection in bladder cancer.

The use of genomics in clinical trial design

Many cancer treatments benefit only a minority of patients who receive them. This results in an enormous burden on patients and on the health care system. The problem will become even greater with the increasing use of molecularly targeted agents whose benefits are likely to be more selective unless the drug development process is modified to include co-development of companion diagnostics. Whole genome biotechnology and decreasing costs of genome sequencing make it increasingly possible to achieve an era of predictive medicine in oncology therapeutics. The challenges are numerous and substantial but are not primarily technological. They involve organizing publicly funded diagnostics of deregulated pathways, adopting new paradigms for drug development, and developing incentives for industry to incur the complexity and expense of co-development of drugs and companion diagnostics. This article reviews some designs for phase III clinical trials that may facilitate movement to a more predictive oncology.

Commercialized multigene predictors of clinical outcome for breast cancer

In the past 5 years, a number of commercialized multigene prognostic and predictive tests have entered the complex and expanding landscape of breast cancer companion diagnostics. These tests have used a variety of formats ranging from the familiar slide-based assays of immunohistochemistry and fluorescence in situ hybridization to the nonmorphology-driven molecular platforms of quantitative multiplex real-time polymerase chain reaction and genomic microarray profiling. In this review, 14 multigene assays are evaluated as to their scientific validation, current clinical utility, regulatory approval status, and estimated cost-benefit ratio. Emphasis is placed on two tests: oncotype DX and MammaPrint. Current evidence indicates that the oncotype DX test has the advantages of earlier commercial launch, wide acceptance for payment by third-party payors in the U.S., ease of use of formalin-fixed paraffin-embedded tissues, recent listing by the American Society of Clinical Oncology Breast Cancer Tumor Markers Update Committee as recommended for use, continuous scoring system algorithm, ability to serve as both a prognostic test and predictive test for certain hormonal and chemotherapeutic agents, demonstrated cost-effectiveness in one published study, and a high accrual rate for the prospective validation clinical trial (Trial Assigning Individualized Options for Treatment). The MammaPrint assay has the advantages of a 510(k) clearance by the U.S. Food and Drug Administration, a larger gene number, which may enhance further utility, and a potentially wider patient eligibility, including lymph node-positive, estrogen receptor (ER)-negative, and younger patients being accrued into the prospective trial (Microarray in Node-Negative Disease May Avoid Chemotherapy). A number of other assays have specific predictive goals that are most often focused on the efficacy of tamoxifen in ER-positive patients, such as the two-gene ratio test and the cytochrome P450 CYP2D6 genotyping assay.

Clinical evaluation of the simultaneous determination of CA 15-3, CA 125 and sHER2 in breast cancer

OBJECTIVE

We investigated serum levels of CA 15-3, sHER2 and CA 125, and their usefulness in the detection of metastatic disease in breast cancer patients.

METHODS

The levels of CA 15-3, sHER2 and CA 125 tumour markers were determined in 60 patients, 40 with localized and 20 with metastatic breast carcinoma. The control group consisted of 10 healthy women.

RESULTS

We found that, at the time of diagnosis, serum levels of all three tumour markers were elevated in patients with distant metastases, but of minute importance in the detection of any breast cancer. When the data for the individual markers were combined the overall sensitivity of metastases detection with all three markers improved. In this regard, 90% of patients with distant metastases had an increase in serum level of at least one of tested tumour markers. Similar results were obtained using receiver operating characteristic curve (ROC). Moreover, using ROC we defined cut-off values for metastasis detection for each of the tested markers.

CONCLUSION

Our findings indicate that measurement of CA 15-3 serum values in conjunction with sHER2 and CA 15-3 can increase sensitivity in metastasis detection.

Prognostic value of the molecular detection of circulating tumor cells using a multimarker reverse transcription-PCR assay for cytokeratin 19, mammaglobin A, and HER2 in early breast cancer

PURPOSE

To investigate the prognostic value of the molecular detection of circulating tumor cells (CTCs) using three markers [cytokeratin 19 (CK19), mammaglobin A (MGB1), and HER2] in early breast cancer.

EXPERIMENTAL DESIGN

CK19mRNA+, MGB1mRNA+, and HER2mRNA+ cells were detected using real-time (CK19) and nested (MGB1 and HER2) reverse transcription-PCR in the peripheral blood of 175 women with stage I to III breast cancer before the initiation of adjuvant chemotherapy. The detection of CTCs was correlated with clinical outcome. In 10 patients, immunofluorescence staining experiments were done to investigate the coexpression of cytokeratin, MGB1, and HER2 in CTCs.

RESULTS

CK19mRNA+, MGB1mRNA+, and HER2mRNA+ cells were detected in 41.1%, 8%, and 28.6% of the 175 patients, respectively. Patients had one of the following molecular profiles: CK19mRNA+/MGB1mRNA+/HER2mRNA+ (n = 8), CK19mRNA+/MGB1mRNA+/HER2mRNA- (n = 1), CK19mRNA+/MGB1mRNA-/HER2mRNA+ (n = 42), CK19mRNA+/MGB1mRNA-/HER2mRNA- (n = 21), CK19mRNA-/MGB1mRNA+/HER2mRNA- (n = 5), and CK19mRNA-/MGB1mRNA-/HER2mRNA- (n = 98). Double-immunofluorescence experiments confirmed the following CTC phenotypes: CK+/MGB1+, CK+/MGB1-, CK-/MGB1+, CK+/HER2+, CK+/HER2-, MGB1+/HER2-, and MGB1+/HER2+. In univariate analysis, the detection of CK19mRNA+, MGB1mRNA+, and HER2mRNA+ cells was associated with shorter disease-free survival (DFS; P < 0.001, P = 0.001, and P < 0.001, respectively), whereas the detection of CK19mRNA+ and MGB1mRNA+ cells was associated with worse overall survival (P = 0.044 and 0.034, respectively). In multivariate analysis, estrogen receptor-negative tumors and the detection of CK19mRNA+ and MGB1mRNA+ cells were independently associated with worse DFS.

CONCLUSION

The detection of peripheral blood CK19mRNA+ and MGB1mRNA+ cells before adjuvant chemotherapy predicts poor DFS in women with early breast cancer.

Serum amyloid A as indicator of distant metastases but not as early tumor marker in patients with renal cell carcinoma

The aim of the present study was to evaluate the clinical significance of the concentration of serum amyloid A (SAA) in patients with renal cell carcinoma (RCC). SAA protein was determined with enzyme-linked immunosorbent assay in serum samples of 55 healthy controls and 98 RCC patients subdivided into groups with localized tumor (N0M0, n=40), with lymph node metastases (N1M0, n=13), and distant metastases (M1, n=45). SAA concentrations in controls and N0M0 group of RCC were not different while SAA concentrations were significantly elevated in M1 patients compared to the N1M0 and N0M0 patients. In this respect, SAA provided an accurate detection of distant metastases with the area under the ROC curve of 0.86. SAA was identified as a significant independent factor of survival in RCC patients using the multivariate Cox proportional hazards regression model. SAA could be a useful analyte in predicting the survival outcome of RCC patients.

Circulating tumor cells in breast cancer

PURPOSE OF REVIEW

To critically review the latest findings concerning the detection and characterization of circulating tumor cells in breast cancer.

RECENT FINDINGS

Various studies have used different methods and markers for circulating tumor cell detection in breast cancer. Data on the prognostic value of circulating tumor cell monitoring by the CellSearch system are now available in patients with measurable metastatic breast cancer receiving chemotherapy, whereas no such data are still available for adjuvant or neoadjuvant settings. The detection of cytokeratin 19 mRNA-positive cells before the initiation of adjuvant chemotherapy was shown to be an independent prognostic factor for worse clinical outcome in patients with early breast cancer. Interestingly, this was mainly observed in patients with triple-negative and HER2-positive, but not estrogen receptor-positive/HER2-negative, early breast cancer. Finally, gene-expression profiling of single cells was reported to be feasible with important implications for eliminating circulating tumor cells. Pilot studies have shown that phenotyping of circulating tumor cells could be used to predict response to targeted therapies.

SUMMARY

Circulating tumor cells might become a valuable tool to refine prognosis in early and metastatic breast cancer. Circulating tumor cell phenotyping/profiling may serve as a real-time tumor biopsy for individually-tailored targeted therapies.

Opportunities posed by novel patient selection biomarker approaches in oncology drug development: going beyond the cytotoxics

An area of unmet medical need in clinical oncology has been optimizing patient selection for a given therapeutic with the goal of getting the right drug to the right patient. Recent studies have developed preclinical approaches to identifying molecular ‘signatures of resistance’ for cytotoxic therapies and prospective validation of this strategy is ongoing in the clinic. New challenges in this setting include identifying approaches to patient selection for cytostatic compounds such as signaling pathway inhibitors and stem cell targets. Here, we discuss the biomarker methodologies developed using traditional cytotoxic drugs and how these approaches can be adapted to identify biomarkers of patient selection for novel signaling inhibitors and other novel targets. It has become increasingly clear that such biomarker discovery and validation needs to begin early and continue throughout the drug development process.

Osteopontin-c is a selective marker of breast cancer

While the acquisition of invasiveness is a critical step in early stage breast carcinomas (DCIS), no established molecular markers reliably identify tumor progression. The metastasis gene osteopontin is subject to alternative splicing, which yields 3 messages, osteopontin-a, osteopontin-b and osteopontin-c. Osteopontin-c is selectively expressed in invasive, but not in noninvasive, breast tumor cell lines, and it effectively supports anchorage independence. We evaluated osteopontin-c as a biomarker. The RNA message for osteopontin-c was present in 16 of 20 breast cancers (80%), but was undetectable in 22 normal specimens obtained from reduction mammoplasty. In contrast, osteopontin-a RNA was expressed at various levels in all 20 breast cancers, 11 tumor-surrounding tissues and 21 normal samples. The splice variant osteopontin-b was present at barely detectable levels in 18 of 20 cancers and in 6 of 22 normal breasts. By immunohistochemistry, 66 of 69 normal breasts were negative, while 3 showed low level staining. Among the breast cancers, 43 of 56 cores (77%) stained positive for osteopontin-c. When correlated with tumor grade, the staining for osteopontin-c increased from grade 1 to grade 3. In a total of 178 breast specimens analyzed, osteopontin-c was present in 78% of cancers, 36% of surrounding tissues and 0% of normal tissues. Furthermore, osteopontin-c detects a higher fraction of breast cancers than estrogen receptor (ER), progesterone receptor or HER2. In conjunction, osteopontin-c, ER and HER2 reliably predict grade 2-3 breast cancer. Hence, osteopontin-c is a diagnostic and prognostic marker that may have value in a diagnostic panel together with conventional breast cancer markers.

PI3 kinase activation and response to Trastuzumab Therapy: what's neu with herceptin resistance?

Trastuzumab is an established therapy for women with breast cancers that overexpress HER2. Despite its proven benefit in treating breast cancer, not all women derive benefit from this monoclonal antibody, and resistant disease can develop. In this issue of Cancer Cell, Berns et al. present evidence that activation of the PI3 kinase pathway, either via loss of the tumor suppressor PTEN or through oncogenic stimulation of PIK3CA, can mediate trastuzumab resistance. This study extends important work of others and forms the rationale for future investigations combining inhibitors of the PI3 kinase pathway in conjunction with trastuzumab therapy.

DNA microarrays in the clinic: how soon, how extensively?

Although DNA microarrays are now widely used in research settings, they have been slow to penetrate clinical practice in spite of their apparent advantages. This is due to the very different requirements for a clinical test in contrast to a research tool, and to a strict necessity for demonstrated clinical utility. There is a clear differentiation between two types of DNA array tests: "genomic" diagnostics, developed to ascertain the presence or absence of mutations, deletions or duplications, and for which clinical evidence is already established, and tests using expression profiling for prognosis or predictive purposes, in which case the clinical correlate must be proven. Most array diagnostics currently used belong, understandably, to the "genomic" variety. It is to be expected that future improvements in tailored technology, as well as a logical trend towards measuring an ever-increasing number of parameters, will ensure an important diagnostic role for DNA arrays in the coming decade.

Elevated plasma osteopontin as marker for distant metastases and poor survival in patients with renal cell carcinoma

PURPOSE

To evaluate diagnostic and prognostic significance of plasma osteopontin (OPN) in patients with renal cell carcinoma (RCC).

METHODS

The retrospective study included 80 patients with RCC (pN0M0, n = 32; pN1M0, n = 11; M1, and n = 37), and 52 healthy controls (27 females and 25 males). OPN, the bone marker bone-specific alkaline phosphatase (bALP) and carboxyterminal telopetide of type-I collagen (ICTP), and the enzymes alanine aminotransferase (ALAT), and gamma-glutamyltransferase (GGT) were evaluated together with Memorial Sloan-Kettering Cancer Center (MSKCC) laboratory parameters. Data were analyzed by receiver-operating characteristics (ROC), survival analysis, and Cox proportional hazards regression model.

RESULTS

OPN and ICTP levels in RCC patients with distant metastases were significantly elevated (medians 115 and 4.7 microg/l, P < 0.001) compared to those without metastases (31.1 and 2.5 microg/l) and controls (28.9 and 2.1 microg/l) but did not differ between patients with bone or non-bone metastases. Both bALP and ALAT were not different between all study groups, while GGT was only increased in patients with non-bone metastases. In ROC analysis, OPN showed the best discrimination between patients with and without metastases (area under the curve: 0.888). High OPN values were associated with poor survival (Kaplan-Meier analysis, log-rank test, P = 0.002). Multivariate Cox regression with forward and backward stepwise elimination confirmed plasma OPN as independent predictive survival factor in RCC patients.

CONCLUSIONS

Our results show that high plasma OPN levels are associated with distant metastases and poor survival in RCC patients. The use of OPN as potential marker to monitor new treatment strategies in patients with advanced RCC should be evaluated in prospective studies.

Is Molecular Profiling Ready for Use in Clinical Decision Making?

Molecular profiling, the classification of tissue or other specimens for diagnostic, prognostic, and predictive purposes based on multiple gene expression, is a technology that holds major promise for optimizing the management of patients with cancer. However, the use of these tests for clinical decision making presents many challenges to overcome. Assay development and data analysis in this field have been largely exploratory, and leave numerous possibilities for the introduction of bias. Standardization of profiles remains the exception. Classifier performance is usually overinterpreted by presenting the results as p-values or multiplicative effects (e.g., relative risks), while the absolute sensitivity and specificity of classification remain modest at best, especially when tested in large validation samples. Validation has often been done with suboptimal attention to methodology and protection from bias. The postulated classifier performance may be inflated compared to what these profiles can achieve. With the exception of breast cancer, we have little evidence about the incremental discrimination that molecular profiles can provide versus classic risk factors alone. Clinical trials have started to evaluate the utility of using molecular profiles for breast cancer management. Until we obtain data from these trials, the impact of these tests and the net benefit under real-life settings remain unknown. Optimal incorporation into clinical practice is not straightforward. Finally, cost-effectiveness is difficult to appreciate until these other challenges are addressed. Overall, molecular profiling is a fascinating and promising technology, but its incorporation into clinical decision making requires careful planning and robust evidence.

Guidelines for the Use of Tumor Marmers in Breast Cancer

Najbolje validovani markeri karcinoma dojke pripadaju tkivnim markerima i uključuju receptore za estrogen (ER), receptore za progesteron (PR), HER-2, urokinaza plazminogen aktivator (uPA) i plazminogen aktivator inhibitor 1 (PAI-1). Kod svih novodijagnostikovanih pacijenata sa karcinomom dojke određivanje ER, PR i HER-2 je danas obavezno. Mada je merenje uPA i PAI-1 tehnički validovano, do danas nije klinički rasprostranjeno i to uglavnom zbog zahteva za minimalnom količinom svežeg ili sveže zamrznutog tkiva. Određivanje ovih proteina može da se iskoristi kao pomoć pri selekciji »limfni čvor negativnih« pacijenata s karcinomom dojke kojima nije potrebna adjuvantna hemoterapija. Mada se dosta koristi u postoperativnom praćenju i praćenju terapije u poodmaklom oboljenju, klinička vrednost CA 15-3 i drugih serumskih markera nije joŠ uvek validovana u studijama nivoa dokaza I. Nedavna poboljšanja u razumevanju biologije karcinoma dojke i paralelno povećanje mogućih opcija tretmana treba da vode ka poboljšanju ishoda ove veoma hetrogene bolesti. Onkolozi joŠ uvek imaju teškoće u odabiru specifičnih strategija tretmana prema molekularnim karakteristikama oboljenja svakog pacijenta ponaosob.

Cross-talk between ER and HER2 in breast carcinoma

In tumors in which estrogen receptor (ER) and growth factor signaling pathways are simultaneously active, there is a bidirectional cross-talk that results in a positive feedback cycle of cell survival and proliferation stimuli. Beside the postulated inverse correlation between ER and HER2 (human epidermal growth factor receptor 2) as a consequence of repressive feedback signaling loop, there are also other mechanisms regarding ER-HER2 interactions. It seems that MAPK (mitogen-activated protein kinase) pathway has a central role in synergistic action between ER and HER2 in normal mammary gland development, as well in the breast cancer. MAPK pathway is hyperstimulated in cells that overexpress HER2 as a consequence of HER2 gene amplification. In ER+ tumors, MAPK phosphorylates and activates either ER itself or ER coregulators, enhancing the transcriptional activation potential of ER. ER and HER2 signaling could interact on multiple levels (genomic or non-genomic) and therefore might induce reduced ER expression or might increase ER function. Based on our own research, dominant effect of postulated cross-talk was not related to HER2-induced reduced expression of ER (no difference in quantitative levels of ER in ER+ tumors regarding their HER2 status and no difference in progression-free time between ER+HER2- and ER+HER2+ patients) as presented. The importance of understanding ER-HER2 cross-talk is not only because of its significance in breast cancer progression, but because it seems to be fundamental factor in endocrine resistance that can improve treatment strategies, especially targeting MAPK pathway. .