Tumor cell detection in peripheral blood and bone marrow

Using MMRFBiolinks R-Package for Discovering Prognostic Markers in Multiple Myeloma

Multiple myeloma (MM) is the second most frequent hematological malignancy in the world although the related pathogenesis remains unclear. Gene profiling studies, commonly carried out through next-generation sequencing (NGS) and Microarrays technologies, represent powerful tools for discovering prognostic markers in MM. NGS technologies have made great leaps forward both economically and technically gaining in popularity. As NGS techniques becomes simpler and cheaper, researchers choose NGS over microarrays for more of their genomic applications. However, Microarrays still provide significant benefits with respect to NGS. For instance, RNA-Seq requires more complex bioinformatic analysis with respect to Microarray as well as it lacks of standardized protocols for analysis. Therefore, a synergy between the two technologies may be well expected in the future. In order to take up this challenge, a valid tool for integrative analysis of MM data retrieved through NGS techniques is MMRFBiolinks, a new R package for integrating and analyzing datasets from the Multiple Myeloma Research Foundation (MMRF) CoMMpass (Clinical Outcomes in MM to Personal Assessment of Genetic Profile) study, available at MMRF Researcher Gateway (MMRF-RG), and at the National Cancer Institute Genomic Data Commons (NCI-GDC) Data Portal. Instead of developing a completely new package from scratch, we decided to leverage TC-GABiolinks, an R/Bioconductor package, because it provides some useful methods to access and analyze MMRF-CoMMpass data. An integrative analysis workflow based on the usage of MMRFBiolinks is illustrated.In particular, it leads towards a comparative analysis of RNA-Seq data stored at GDC Data Portal that allows to carry out a Kaplan Meier (KM ) Survival Analysis and an enrichment analysis for a Differential Gene Expression (DGE) gene set.Furthermore, it deals with MMRF-RG data for analyzing the correlation between canonical variants and treatment outcome as well as treatment class. In order to show the potential of the workflow, we present two case studies. The former deals with data of MM Bone Marrow sample types available at GDC Data Portal. The latter deals with MMRF-RG data for analyzing the correlation between canonical variants in a gene set obtained from the case study 1 and the treatment outcome as well as the treatment class.

Detection of Metastatic Tumor Cells in the Bone Marrow Aspirate Smears by Artificial Intelligence (AI)-Based Morphogo System

Introduction

Metastatic carcinomas of bone marrow (MCBM) are characterized as tumors of non-hematopoietic origin spreading to the bone marrow through blood or lymphatic circulation. The diagnosis is critical for tumor staging, treatment selection and prognostic risk stratification. However, the identification of metastatic carcinoma cells on bone marrow aspiration smears is technically challenging by conventional microscopic screening.

Objective

The aim of this study is to develop an automatic recognition system using deep learning algorithms applied to bone marrow cells image analysis. The system takes advantage of an artificial intelligence (AI)-based method in recognizing metastatic atypical cancer clusters and promoting rapid diagnosis.

Methods

We retrospectively reviewed metastatic non-hematopoietic malignancies in bone marrow aspirate smears collected from 60 cases of patients admitted to Zhongshan Hospital. High resolution digital bone marrow aspirate smear images were generated and automatically analyzed by Morphogo AI based system. Morphogo system was trained and validated using 20748 cell cluster images from randomly selected 50 MCBM patients. 5469 pre-classified cell cluster images from the remaining 10 MCBM patients were used to test the recognition performance between Morphogo and experienced pathologists.

Results

Morphogo exhibited a sensitivity of 56.6%, a specificity of 91.3%, and an accuracy of 82.2% in the recognition of metastatic cancer cells. Morphogo’s classification result was in general agreement with the conventional standard in the diagnosis of metastatic cancer clusters, with a Kappa value of 0.513. The test results between Morphogo and pathologists H1, H2 and H3 agreement demonstrated a reliability coefficient of 0.827. The area under the curve (AUC) for Morphogo to diagnose the cancer cell clusters was 0.865.

Conclusion

In patients with clinical history of cancer, the Morphogo system was validated as a useful screening tool in the identification of metastatic cancer cells in the bone marrow aspirate smears. It has potential clinical application in the diagnostic assessment of metastatic cancers for staging and in screening MCBM during morphology examination when the symptoms of the primary site are indolent.

Circulating tumor cells in germ cell tumors: are those biomarkers of real prognostic value? A review

Analysis of circulating tumor cells from patients with different types of cancer is nowadays a fascinating new tool of research and their number is proven to be useful as a prognostic factor in metastatic breast, colon and prostate cancer patients. Studies are going beyond enumeration, exploring the circulating tumor cells to better understand the mechanisms of tumorigenesis, invasion and metastasis and their value for characterization, prognosis and tailoring of treatment. Few studies investigated the prognostic significance of circulating tumor cells in germ cell tumors. In this review, we examine the possible significance of the detection of circulating tumor cells in this setting.

Comparison of molecular and immunocytochemical methods for detection of disseminated tumor cells in bone marrow from early breast cancer patients

BACKGROUND

Disseminated tumor cells (DTCs) have potential to predict the effect of adjuvant treatment. The purpose of this study was to compare two methods, reverse transcription quantitative PCR (RT-qPCR) and immunocytochemisty (ICC), for detecting breast cancer DTCs in bone marrow (BM) from early breast cancer patients.

METHODS

We investigated a subset (n = 313) of BM samples obtained from 271 early breast cancer patients in the "Secondary Adjuvant Taxotere Treatment" (SATT)-trial. All patients in this study had node positive or intermediate/high-risk node negative non-metastatic disease. The DTCs were detected by ICC using AE1-AE3 anti-cytokeratin monoclonal antibodies. Patients with DTCs detected in their BM by ICC after standard adjuvant fluorouracil, cyclophosphamide, epirubicin (FEC) chemotherapy were offered docetaxel treatment. For comparison, 5 × 106 mononuclear cells from the aliquoted BM samples were also analyzed by RT-qPCR using a multimarker (MM) assay based on the tumor cell mRNA markers keratin 19 (KRT19), mammaglobin A (hMAM), and TWIST1. In the MM-assay, a sample was defined as positive for DTCs if at least one of the mRNA markers was positive.

RESULTS

The MM RT-qPCR assay identified DTCs in 124 (40%) of the 313 BM samples compared with 23/313 (7%) of the samples analyzed by ICC. The concordance between the MM RT-qPCR and ICC was 61% (Kappa value = 0.04) and twelve of the BM samples were positive by both methods. By RT-qPCR, 46/313 (15%) samples were positive for KRT19, 97/313 (31%) for TWIST1, and 3/313 (1%) for hMAM mRNA. There were no statistically significant associations between the individual mRNA markers.

CONCLUSION

The RT-qPCR based method demonstrated more DTC-positive samples than ICC. The relatively low concordance of positive DTC-status between the two different assessment methods suggests that they may be complementary. The clinical relevance of the methods will be evaluated based on future clinical outcome data.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00248703.

Relevance of molecular characterization of circulating tumor cells in breast cancer in the era of targeted therapies

Development in circulating tumor cells (CTCs) technologies represents a valuable tool for the better understanding of tumor biology. The clinical relevance of CTCs as a prognostic factor is well established both in metastatic and early-stage breast cancer patients. The eradication or decrease of CTCs following treatment is associated with improved clinical outcomes. Because of the availability of novel cancer treatments that specifically target tumor cells underlying signaling pathways, molecular characterization of CTCs has strong potential to translate into personalized treatments. A handful of studies have explored relevant markers such as the estrogen and progesterone receptor, HER2 and EGF receptor. However, there is not a single validation of a molecular marker in CTCs that provides prognostic information or predicts response to cancer therapies. This review describes the latest results on the characterization of breast cancer CTCs with a focus on CTC biology and implications in clinical practice.

Circulating tumor cells as predictors of response and failure in breast cancer patients treated with preoperative chemotherapy

AIM

To explore the significance of circulating tumor cells (CTCs) detection in the course of preoperative chemotherapy (PC) and their effect on the outcomes.


METHODS

Fifty-five patients with stage II/III invasive breast cancer were enrolled into a preoperative clinical trial. Patients were given PC with sequential single-agent doxorubicin and paclitaxel vs paclitaxel followed by doxorubicin. Blood samples (8 mL) were collected from patients before PC, after each phase, and at 6 months intervals during follow-up. Peripheral blood mononuclear cells were isolated and enriched for epithelial cells. Quantitative RT-PCR was used to determine the presence of cytokeratin 19 (CK19) mRNA. Samples were considered positive when the PCR curve crossed the standard threshold curve.


RESULTS

After the first phase of chemotherapy, there was a 59% overall reduction in the median tumor volume. The percentage of volume reduction did not differ between patients who presented with detectable CTCs at baseline and those who did not (p=0.89). After the second phase of chemotherapy, there was a further decrease in the median tumor volume to 93% from baseline. There was no correlation between the lack of response and the presence of CTCs either after the first (p=0.36) or second (p=0.5391) phases of PC. The presence of CTCs was a predictor of local or distant relapse (p=0.0411). The detection of CTCs did not affect overall survival (p=0.2569).


CONCLUSION

CTCs can be used as predictors of relapse after definitive treatment of locally advanced breast cancer; however, CTCs detection in peripheral blood during the course of PC does not implicate a particular pattern of response to treatment.

Molecular biology techniques for the surgeon

New technologies are constantly being introduced into the medical and surgical fields. These technologies come in the form of newer medicines, imaging methods and prognostic tools, among others, and allow clinicians to make more rational and informed decisions on the care of their patients. Many of these technologies utilize advanced techniques which are at the forefront of many research fields and represent a transition of bench advances into the clinical realm. This review will highlight four technologies that are at the forefront in the treatment of oncology patients treated by surgeons on a daily basis. Circulating tumor cells, microarray analysis, proteomic studies and rapid sequencing technologies will be highlighted. These technologies will be reviewed and their potential use in the care of surgical patients will be discussed.

EPISPOT assay: detection of viable DTCs/CTCs in solid tumor patients

The enumeration and characterization of circulating tumor cells (CTCs) in the peripheral blood and disseminated tumor cells (DTCs) in bone marrow may provide important prognostic information and might help to monitor efficacy of therapy. Since current assays cannot distinguish between apoptotic and viable DTCs/CTCs, it is now possible to apply a novel ELISPOT assay (designated 'EPISPOT') that detects proteins secreted/released/shed from single epithelial cancer cells. Cells are cultured for a short time on a membrane coated with antibodies that capture the secreted/released/shed proteins which are subsequently detected by secondary antibodies labeled with fluorochromes. In breast cancer, we measured the release of cytokeratin-19 (CK19) and mucin-1 (MUC1) and demonstrated that many patients harbored viable DTCs, even in patients with apparently localized tumors (stage M(0): 54%). Preliminary clinical data showed that patients with DTC-releasing CK19 have an unfavorable outcome. We also studied CTCs or CK19-secreting cells in the peripheral blood of M1 breast cancer patients and showed that patients with CK19-SC had a worse clinical outcome. In prostate cancer, we used prostate-specific antigen (PSA) secretion as marker and found that a significant fraction of CTCs secreted fibroblast growth factor-2 (FGF2), a known stem cell growth factor. In conclusion, the EPISPOT assay offers a new opportunity to detect and characterize viable DTCs/CTCs in cancer patients and it can be extended to a multi-parameter analysis revealing a CTC/DTC protein fingerprint.

Circulating tumor cells measurements in hepatocellular carcinoma

Liver cancer is the fifth most common cancer in men and the seventh in women. During the past 20 years, the incidence of HCC has tripled while the 5-year survival rate has remained below 12%. The presence of circulating tumor cells (CTC) reflects the aggressiveness nature of a tumor. Many attempts have been made to develop assays that reliably detect and enumerate the CTC during the development of the HCC. In this case, the challenges are (1) there are few markers specific to the HCC (tumor cells versus nontumor cells) and (2) they can be used to quantify the number of CTC in the bloodstream. Another technical challenge consists of finding few CTC mixed with million leukocytes and billion erythrocytes. CTC detection and identification can be used to estimate prognosis and may serve as an early marker to assess antitumor activity of treatment. CTC can also be used to predict progression-free survival and overall survival. CTC are an interesting source of biological information in order to understand dissemination, drug resistance, and treatment-induced cell death. Our aim is to review and analyze the different new methods existing to detect, enumerate, and characterize the CTC in the peripheral circulation of patients with HCC.

'Omic approaches to preventing or managing metastatic breast cancer

Early detection of metastasis-prone breast cancers and characterization of residual metastatic cancers are important in efforts to improve management of breast cancer. Applications of genome-scale molecular analysis technologies are making these complementary approaches possible by revealing molecular features uniquely associated with metastatic disease. Assays that reveal these molecular features will facilitate development of anatomic, histological and blood-based strategies that may enable detection prior to metastatic spread. Knowledge of these features also will guide development of therapeutic strategies that can be applied when metastatic disease burden is low, thereby increasing the probability of a curative response.

Prognostic value of hematogenous dissemination and biological profile of the tumor in early breast cancer patients: a prospective observational study

Background

The aim of this study was to investigate the incidence and prognostic value of disseminated tumor cells in bone marrow of breast carcinoma patients with early disease, and to analyze this finding in relation to lymph node involvement, determined by sentinel lymph node (SLN) biopsy analysis, and to prognostic factors of interest.

Methods

104 patients with operable (T < 3 cm) breast cancer and clinically- and sonographically-negative axillary lymph nodes were scheduled for SLN biopsy. Bone marrow aspirates were collected before the start of surgery from both iliac crests, and mononuclear cell layers were separated by density centrifugation (Lymphoprep). Slide preparations were then examined for the presence of disseminated tumor cells by immunocytochemistry with anti-cytokeratin antibodies (A45-B/B3). Lymphoscintigraphy was performed 2 hours after intratumor administration of 2 mCi (74 MBq) of 99mTc colloidal albumin. The SLN was evaluated for the presence of tumor cells by hematoxylin-eosin staining and, when negative, by immunocytochemistry using anti-cytokeratin antibody (CAM 5.2). Survival analyses and comparative analyses were performed on the results of bone marrow determinations, SLN biopsy, and known prognostic factors, including breast cancer subtypes according to the simplified classification based on ER, PR and HER2.

Results

Lymph node and hematogenous dissemination occur in one-third of patients with early-stage breast cancer, although not necessarily simultaneously. In our study, disseminated tumor cells were identified in 22% of bone marrow aspirates, whereas 28% of patients had axillary lymph node involvement. Simultaneous lymph node and bone marrow involvement was found in only 5 patients (nonsignificant). In the survival study (60 months), a higher, although nonsignificant rate of disease-related events (13%) was seen in patients with disseminated tumor cells in bone marrow, and a significant association of events was documented with the known, more aggressive tumor subtypes: triple negative receptor status (21%) and positive ERBB2 status (29%).

Conclusions

Tumor cell detection in bone marrow can be considered a valid prognostic parameter in patients with early disease. However, the classic prognostic factors remain highly relevant, and the newer breast cancer subtypes are also useful for this purpose.

The challenges of integrating molecular imaging into the optimization of cancer therapy

We review novel, in vivo and tissue-based imaging technologies that monitor and optimize cancer therapeutics. Recent advances in cancer treatment centre around the development of targeted therapies and personalisation of treatment regimes to individual tumour characteristics. However, clinical outcomes have not improved as expected. Further development of the use of molecular imaging to predict or assess treatment response must address spatial heterogeneity of cancer within the body. A combination of different imaging modalities should be used to relate the effect of the drug to dosing regimen or effective drug concentration at the local site of action. Molecular imaging provides a functional and dynamic read-out of cancer therapeutics, from nanometre to whole body scale. At the whole body scale, an increase in the sensitivity and specificity of the imaging probe is required to localise (micro)metastatic foci and/or residual disease that are currently below the limit of detection. The use of image-guided endoscopic biopsy can produce tumour cells or tissues for nanoscopic analysis in a relatively patient-compliant manner, thereby linking clinical imaging to a more precise assessment of molecular mechanisms. This multimodality imaging approach (in combination with genetics/genomic information) could be used to bridge the gap between our knowledge of mechanisms underlying the processes of metastasis, tumour dormancy and routine clinical practice. Treatment regimes could therefore be individually tailored both at diagnosis and throughout treatment, through monitoring of drug pharmacodynamics providing an early read-out of response or resistance.

Emerging applications of fluorescent nanocrystals quantum dots for micrometastases detection

The occurrence of metastases is one of the main causes of death in many cancers and the main cause of death for breast cancer patients. Micrometastases of disseminated tumour cells and circulating tumour cells are present in more than 30% of breast cancer patients without any clinical or even histopathological signs of metastasis. Low abundance of these cell types in clinical diagnostic material dictates the necessity of their enrichment prior to reliable detection. Current micrometastases detection techniques are based on immunocytochemical and molecular methods suffering from low efficiency of tumour cells enrichment and observer-dependent interpretation. The use of highly fluorescent semiconductor nanocrystals, also known as "quantum dots" and nanocrystal-encoded microbeads tagged with a wide panel of antibodies against specific tumour markers offers unique possibilities for ultra-sensitive micrometastases detection in patients' serum and tissues. The nanoparticle-based diagnostics provides an opportunity for highly sensitive parallel quantification of specific proteins in a rapid and low-cost method, thereby providing a link between the primary tumour and the micrometastases for early diagnosis.

Bone marrow aspirate and biopsy: a pathologist's perspective. II. interpretation of the bone marrow aspirate and biopsy

Bone marrow examination has become increasingly important for the diagnosis and treatment of hematologic and other illnesses. Morphologic evaluation of the bone marrow aspirate and biopsy has recently been supplemented by increasingly sophisticated ancillary assays, including immunocytochemistry, cytogenetic analysis, flow cytometry, and molecular assays. With our rapidly expanding knowledge of the clinical and biologic diversity of leukemia and other hematologic neoplasms, and an increasing variety of therapeutic options, the bone marrow examination has became more critical for therapeutic monitoring and planning optimal therapy. Sensitive molecular techniques, in vitro drug sensitivity testing, and a number of other special assays are available to provide valuable data to assist these endeavors. Fortunately, improvements in bone marrow aspirate and needle technology has made the procurement of adequate specimens more reliable and efficient, while the use of conscious sedation has improved patient comfort. The procurement of bone marrow specimens was reviewed in the first part of this series. This paper specifically addresses the diagnostic interpretation of bone marrow specimens and the use of ancillary techniques.

Clinical relevance associated to the analysis of circulating tumour cells in patients with solid tumours

The distant growth of tumour cells escaping from primary tumours, a process termed metastasis, represents the leading cause of death among patients affected by malignant neoplasias from breast and colon. During the metastasis process, cancer cells liberated from primary tumour tissue, also termed circulating tumour cells (CTCs), travel through the circulatory and/or lymphatic systems to reach distant organs. The early detection and the genotypic and phenotypic characterisation of such CTCs could represent a powerful diagnostic tool of the disease, and could also be considered an important predictive and prognostic marker of disease progression and treatment response. In this article we discuss the potential relevance in the clinic of monitoring CTCs from patients suffering from solid epithelial tumours, with emphasis on the impact of such analyses as a predictive marker for treatment response.

Circulating tumor cells: evolving evidence and future challenges

Circulating tumor cells (CTCs) are rare malignant cells found in the peripheral blood that originate from the primary tumor or metastatic sites. New techniques have been developed to isolate and characterize these cells. CTC enumeration has been incorporated into different fields of oncology as a prognostic marker, a tool to monitor therapy response, and a method to understand basic tumor characteristics. This review covers the different techniques available for isolation of CTCs, the clinical utility of CTCs in breast, prostate, and colon cancer, and future directions in this field.

Clinical Relevance of Disseminated Tumor Cells in the Bone Marrow and Circulating Tumor Cells in the Blood of Breast Cancer Patients

Subclinical tumor cell spread, as the putative precursor stage of subsequent solid metastases, can be assessed in breast patients via the detection of disseminated tumor cells (DTC) in bone marrow aspirates or circulating tumor cells (CTC) in the peripheral blood with immunocytochemical and molecular techniques. In the context of a growing number of treatment strategies for cancer patients in the adjuvant setting as well as in the metastatic situation, markers predicting therapy efficacy are urgently needed. The detection of DTC or CTC may become one of the most interesting parameters not just for the prediction of survival or therapy monitoring but also for the characterization and specific targeting of residual tumor cells. Progress in this field now permits clinical studies that should lead to improvements in the treatment of breast cancer patients.

In situ cytotoxic and memory T cells predict outcome in patients with early-stage colorectal cancer

PURPOSE

Many patients who present with early-stage colorectal cancer (International Union Against Cancer TNM stages I and II) are nevertheless at high risk of relapse. We hypothesized that intratumoral immune reaction could influence their prognosis.

PATIENTS AND METHODS

The intratumoral immune reaction was investigated in 29 tumors by large-scale real-time polymerase chain reaction. Cytotoxic (CD8) and memory (CD45RO) T cells were quantified by immunohistochemical analyses of tissue microarrays from the center (CT) and the invasive margin (IM) of the 602 tumors from two independent cohorts. The results were correlated with tumor recurrence and patient survival.

RESULTS

Patients with a strong infiltration of CD45RO(+) cells in the tumor exhibited an increased expression of T-helper 1 and cytotoxicity-related genes. Densities of CD45RO(+) and CD8(+) cells in tumor regions (CT/IM) classified the patients into four distinct prognostic groups based on the presence of high density of each marker in each tumor region. The four groups were associated with dramatic differences in disease-free, disease-specific, and overall survival (all P < .0001). Five years after diagnosis, only 4.8% (95% CI, 0.6% to 8.8%) of patients with high densities of CD8(+) plus CD45RO(+) cells had tumor recurrence, and 86.2% (CI, 79.4% to 93.6%) survived. In contrast, the tumor recurred in 75% (95% CI, 17% to 92.5%) of patients with low densities of these cells, and only 27.5% (95% CI, 10.5% to 72%) survived (all P < .0001). Multivariate analyses showed that the immune criteria had independent effects on the rates of complete remission and survival.

CONCLUSION

The combined analysis of CD8(+) plus CD45RO(+) cells in specific tumor regions could provide a useful criterion for the prediction of tumor recurrence and survival in patients with early-stage colorectal cancer.

Metastasis mechanisms

Metastasis, the spread of malignant cells from a primary tumor to distant sites, poses the biggest problem to cancer treatment and is the main cause of death of cancer patients. It occurs in a series of discrete steps, which have been modeled into a "metastatic cascade". In this review, we comprehensively describe the molecular and cellular mechanisms underlying the different steps, including Epithelial-Mesenchymal Transition (EMT), invasion, anoikis, angiogenesis, transport through vessels and outgrowth of secondary tumors. Furthermore, we implement recent findings that have broadened and challenged the classical view on the metastatic cascade, for example the establishment of a "premetastatic niche", the requirement of stem cell-like properties, the role of the tumor stroma and paracrine interactions of the tumor with cells in distant anatomical sites. A better understanding of the molecular processes underlying metastasis will conceivably present us with novel targets for therapeutic intervention.

Circulating and disseminated tumor cells in the management of breast cancer

Despite the advances in early detection and treatment of cancer, patients continue to die of the disease even when they seek care at an early stage. For patients with breast cancer, it is now possible to detect circulating tumor cells (CTCs) in the bloodstream and disseminated tumor cells (DTCs) in the bone marrow by using immunocytochemical and molecular methods. CTCs and DTCs have been found to share similar genotypic and phenotypic characteristics with so-called breast cancer stem cells, a finding that could potentially explain the eventual relapse of disease in a patient previously considered to have been cured by primary therapy. In some studies, the presence of CTCs or DTCs at the time of diagnosis of breast cancer is an independent adverse prognostic variable. However, before CTC/DTC testing can achieve standard-of-care status, there must be improvement in the sensitivity, precision, and reproducibility of the detection methods.

The detection of circulating tumor cells of breast cancer patients by using multimarker (Survivin, hTERT and hMAM) quantitative real-time PCR

OBJECTIVES

To develop a specific, reliable assay for detecting circulating tumor cells (CTC) in peripheral blood of breast cancer patients.

DESIGN AND METHODS

94 breast cancer patients, 35 patients with benign breast tumor, 40 healthy individuals, and 25 patients with other solid tumors were evaluated by quantitative real-time reverse transcription-PCR (qRT-PCR) for detecting Survivin, hTERT, and hMAM mRNA in peripheral blood (PB) of breast cancer patients. In addition, analyses were carried out for their correlation with patients' clinicopathologic features.

RESULTS

The sensitivity of Survivin, hTERT, and hMAM mRNA in the PB of breast cancer patients was 36.2%, 59.6% and 33.0%, respectively. Survivin and hTERT were detected in the PB patients with solid tumors other than breast cancer, but hMAM mRNA was only detected in breast cancer patients. The sensitivity of three combined markers in the parallel test was 70.2%.Compared to that of single marker detection, the three combined markers' percentage was significantly higher. However, the specificity of three combined markers of serial test was 100%. The expression of the three mRNAs significantly correlated with TNM stage, and lymph node metastasis.

CONCLUSIONS

Survivin, hTERT and hMAM mRNA assays are powerful methods for detection of CTC of breast cancer patients. With combination of the three markers for detection of CTC of breast cancer, the parallel test increases the sensitivity. This analysis can offer a simple, noninvasive, and promising adjuvant tool for the early detection of micrometastatic tumor cells in breast cancer patients.

Circulating tumor cell detection predicts early metastatic relapse after neoadjuvant chemotherapy in large operable and locally advanced breast cancer in a phase II randomized trial

PURPOSE

Circulating tumor cells in blood from metastatic breast cancer patients have been reported as a surrogate marker for tumor response and shorter survival. The aim of this study was to determine whether circulating tumor cells are present in the blood of patients with large operable or locally advanced breast cancer before neoadjuvant chemotherapy and after neoadjuvant chemotherapy before surgery.

EXPERIMENTAL DESIGN

Blood samples of 7.5 mL were obtained on CellSave tubes from patients included in a phase II trial (REMAGUS 02). Circulating tumor cells were immunomagnetically separated and fluorescently stained by the CellSearch system. Blood from 20 metastatic breast cancer patients was used as a positive control.

RESULTS

From October 2004 to July 2006, preneoadjuvant chemotherapy and/or postneoadjuvant chemotherapy blood samples were obtained from 118 patients. At least 1 circulating tumor cell was detected in 22 of 97 patients with preneoadjuvant chemotherapy samples (23%; 95% confidence interval, 15-31%; median, 2 cells; range, 1-17 cells). Circulating tumor cell positivity rates were 17% in 86 postneoadjuvant chemotherapy samples and 27% in all 118 patients. Persistence of circulating tumor cells at the end of neoadjuvant chemotherapy was not correlated with treatment response. After a short median follow-up of 18 months, the presence of circulating tumor cells (P=0.017), hormone receptor negativity, and large tumor size were independent prognostic factors for shorter distant metastasis-free survival.

CONCLUSION

Circulating tumor cells can be detected by the CellSearch system at a low cutoff of 1 cell in 27% of patients receiving neoadjuvant chemotherapy. Circulating tumor cell detection was not correlated to the primary tumor response but is an independent prognostic factor for early relapse.

Circulating tumor cells and bone marrow micrometastasis

Sensitive immunocytochemical and molecular assays allow the detection of single circulating tumor cells (CTC) in the peripheral blood and disseminated tumor cells (DTC) in the bone marrow as a common and easily accessible homing organ for cells released by epithelial tumors of various origins. The results obtained thus far have provided direct evidence that tumor cell dissemination starts already early during tumor development and progression. Tumor cells are frequently detected in the blood and bone marrow of cancer patients without clinical or even histopathologic signs of metastasis. The detection of DTC and CTC yields important prognostic information and might help to tailor systemic therapies to the individual needs of a cancer patient. In the present review, we provide a critical review of (a) the current methods used for detection of CTC/DTC and (b) data on the molecular characterization of CTC/DTC with a particular emphasis on tumor dormancy, cancer stem cell theory, and novel targets for biological therapies; and we pinpoint to (c) critical issues that need to be addressed to establish CTC/DTC measurements in clinical practice.

Review: Biological relevance of disseminated tumor cells in cancer patients

The prognosis of cancer patients is largely determined by the occurrence of distant metastases. In patients with primary tumors, this relapse is mainly due to clinically occult micrometastasis present in secondary organs at primary diagnosis but not detectable even with high resolution imaging procedures. Sensitive and specific immunocytochemical and molecular assays enable the detection and characterization of disseminated tumor cells (DTC) at the single cell level in bone marrow (BM) as the common homing site of DTC and circulating tumor cells (CTC) in peripheral blood. Because of the high variability of results in DTC and CTC detection, there is an urgent need for standardized methods. In this review, we will focus on BM and present currently available methods for the detection and characterization of DTC. Furthermore, we will discuss data on the biology of DTC and the clinical relevance of DTC detection. While the prognostic impact of DTC in BM has clearly been shown for primary breast cancer patients, less is known about the clinical relevance of DTC in patients with other carcinomas. Current findings suggest that DTC are capable to survive chemotherapy and persist in a dormant nonproliferating state over years. To what extent these DTC have stem cell properties is subject of ongoing investigations. Further characterization is required to understand the biology of DTC and to identify new targets for improved risk prevention and tailoring of therapy. Our review will focus on breast, colon, lung, and prostate cancer as the main tumor entities in Europe and the United States.

Micrometastatic spread in breast cancer: detection, molecular characterization and clinical relevance

Immunocytochemical or molecular assays allow the detection of single disseminated tumor cells (DTCs) in the bone marrow (BM) or the peripheral blood in 10% to 60% of breast cancer patients without signs of metastasis. Results from recently reported studies suggest that circulating tumor cell (CTC) levels may serve as a prognostic marker and be used for early assessment of therapeutic response in patients with metastatic breast cancer. In early stage breast cancer, however, the impact of CTCs is less well established than that of DTCs in BM, where several clinical studies demonstrated that such cells are an independent prognostic factor at primary diagnosis. The characterization of DTCs/CTCs has already shed new light on the complex process underlying early tumor cell dissemination and metastatic progression in cancer patients. Characterization of DTCs should help to identify novel targets for biological therapies aimed to prevent metastatic relapse. In addition, understanding tumor 'dormancy' and identifying metastatic stem cells might result in the development of new therapeutic concepts.

Bone marrow micrometastasis in breast cancer: review of detection methods, prognostic impact and biological issues

Immunocytochemical detection of disseminated tumour cells in the bone marrow of patients with primary breast cancer at surgery has been shown to be an independent prognostic factor in single institutional studies and in a large pooled analysis. However, bone marrow sampling and assessment of disseminated tumour cells is not a routine procedure in the clinical management of patients with breast cancer, but will certainly play a role in the near future for risk stratification and monitoring of therapeutic efficacy. Accurate identification of disseminated tumour cells in bone marrow must be based on standardised methodologies and procedures. This review describes these methodologies and the standardised morphological criteria used for disseminated tumour cell detection. The prognostic value of circulating tumour cells detection in peripheral blood is demonstrated in patients with metastatic disease but remains to be substantiated at early stage. The significance of disseminated tumour cells in bone marrow and in the blood for the prediction of response to therapy is briefly summarised. Finally, this review addresses the main biological questions raised by disseminated tumour cells, in particular understanding tumour dormancy and identifying metastatic stem cells.

Significance of micrometastasis in bone marrow and blood of operable breast cancer patients: research tool or clinical application?

Approximately 25% of breast cancer patients without lymph node metastases develop systemic relapse. A growing body of data supports the notion that hematogenous dissemination of breast cancer cells occurs independently of lymphatic spread of disease; however, current clinical practice does not involve routine analysis of circulating or disseminated cells. Recent studies have documented that both circulating tumor cells (CTCs) within the blood and disseminated tumor cells (DTCs) in bone marrow can be identified using a variety of techniques. It is now clear that the presence of DTCs correlates with subsequent development of clinically evident bone metastases, and a worse outcome from breast cancer. While there are data identifying prognostic significance of CTCs in patients with metastatic breast cancer, there are few data regarding CTCs in operable patients. Factors such as presence of a cancer stem cell phenotype and/or certain microenvironmental conditions are involved in the establishment of distant metastases from a primary breast cancer, emphasizing the need for further studies within this area. The purpose of this report is to review the data regarding CTCs and DTCs in patients with operable breast cancer.

Current status in human breast cancer micrometastasis

PURPOSE OF REVIEW

Current research and clinical developments on hematogeneous micrometastasis in breast cancer patients are summarized.

RECENT FINDINGS

Distant metastasis is the leading cause of cancer-related death in breast cancer and bone marrow is a common homing organ for blood-borne disseminated tumor cells derived from primary breast carcinomas. Sensitive immunocytochemical or molecular assays now allow the detection of single disseminated tumor cells in bone marrow or the peripheral blood at a frequency of 10 and these cells are detected in 10-60% of breast cancer patients without clinical or even histopathologic signs of metastasis. Recently, evidence has emerged that the detection of disseminated tumor cells and circulating tumor cells may provide important prognostic information, and in particular might help to monitor efficacy of therapy. Moreover, the characterization of disseminated tumor cells/circulating tumor cells has shed new light on the complex process underlying early tumor cell dissemination and metastatic progression in cancer patients.

SUMMARY

Research on disseminated tumor cells/circulating tumor cells will help to identify novel targets for biological therapies aimed at preventing metastatic relapse and to monitor the efficacy of these therapies. In particular, understanding tumor dormancy and identifying metastatic stem cells might result in the development of new concepts for antimetastatic therapies.

Analysis of surrogate markers for target-specific therapy in breast carcinomas using archival materials

Recent development of target-specific therapy may have the potential to revolutionize cancer therapy. Target-specific therapy such as trastuzumab or imatinib requires the presence of its specific target in cancer cells. Therefore, it has become very important to identify these targets as a surrogate marker such as HER2/neu for trastuzumab in breast cancer or c-kit for imatinib in gastrointesitinal stromal tumor for these treatments to exert maximum clinical benefits on the patients with these malignancies. Archival or 10% formalin-fixed and paraffin-embedded materials could be the most accessible materials available for examining these surrogate markers for therapy, especially in patients with breast carcinoma. In addition, correlation of the findings with histological features that are pivotal in an evaluation of the findings obtained and retrospective analysis are both possible in these analyses. Immunohistochemistry or FISH for HER2/neu have been widely performed in numerous institutions and provide the gold standard for the treatment of trastuzumab in patients with breast carcinoma. In addition, an analysis of potential surrogate markers at DNA, mRNA and protein levels has become possible using archival materials of human breast carcinoma. However, it is very important to make these analyses widely available or possible to perform in any of the regular diagnostic laboratories without technical difficulties and financial burden on the patients. In addition, it is necessary to standardize the following when using surgical pathology materials for the analysis of these markers, especially in terms of quality control or reproducibility of the results obtained by the analysis: (1) fixation or specimens preparation, (2) methodology to be used and (3) interpretation and/or assessment of the findings.

Digital quantification of mutant DNA in cancer patients

PURPOSE OF REVIEW

The accumulation of somatic mutations is the major driving force for tumorigenesis. These mutations uniquely differentiate tumor cells from their normal counterparts. Mutations within tumor cells and mutant DNA released by tumor cells into blood, lymph, stool, tissues and other bodily compartments can thereby be used for cancer detection. Here we discuss technologies available for the detection and quantification of mutant DNA in clinical samples and the value of such measurements for patient management.

RECENT FINDINGS

Conventional mutation detection technologies are either qualitative or only roughly estimate the abundance of mutant DNA molecules. Recently-developed approaches, however, use single molecule counting to determine the genotype of each individual member of a DNA population, providing a more accurate and precise digital output.

SUMMARY

In this review, we discuss the clinical utility of mutant DNA quantification in cancer patients in the context of recent technical advances made in digital mutation detection.

The relevance of RT-PCR detection of disseminated tumour cells is hampered by the expression of markers regarded as tumour-specific in activated lymphocytes

Marker genes, commonly used to detect circulating tumour cells in RT-PCR-based tests: squamous-cell carcinoma antigen, epidermal growth factor receptor, mammaglobin, small breast epithelial mucin, but not carbonic anhydrase 9, were shown to be expressed in normal, mitogen-stimulated peripheral blood mononuclear cells (PBMNC). Thus, considering the inflammatory reactions often accompanying cancer development, to reduce false-positive results of the metastatic tumour cell tests, molecular markers should be validated not against normal peripheral blood, but against activated lymphoid cells, such as in vitro mitogen-stimulated PBMNC.