Breast Cancer–Specific mRNA Transcripts Presence in Peripheral Blood After Adjuvant Chemotherapy Predicts Poor Survival Among High-Risk Breast Cancer Patients Treated With High-Dose Chemotherapy With Peripheral Blood Stem Cell Support

Estrogen Receptor and HER2 Status on Disseminated Tumor Cells and Primary Tumor in Patients with Early Breast Cancer

BACKGROUND: We evaluated both estrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2) status on disseminated tumor cells (DTCs) in the bone marrow of 54 patients with early breast cancer and compared these with the corresponding primary tumor (PT). MATERIALS AND METHODS: Bone marrow aspirates were obtained at the time of first surgery, and ER and HER2 status on DTCs was assessed simultaneously by immunocytochemistry using a triple fluorescence staining method. RESULTS: The median number of DTCs was 13 (range 1-95). The concordance rate between ER status on DTC and PT was 74%. Patients with an ER-positive PT were significantly more likely to have at least one ER-positive DTC (34 out of 42) than patients with an ER-negative PT (6 out of 12; P = .031). Thirty-nine (93%) of the 42 patients with ER-positive PT had at least one ER-negative DTC. The concordance rate between HER2 status on DTC and PT was 52%. The probability of having at least one HER2-positive DTC was not related to the HER2 status of the PT (P = 0.56). Twenty-two (46%) of the 48 patients with a HER2-negative PT had at least one HER2-positive DTC. All the six patients with a HER2-positive PT had at least one HER2-negative DTC. CONCLUSION: Taken together, our study confirms that ER and/or HER2 status may differ between DTC and PT. This discordance could be important for patients lacking ER or HER2 expression on the PT but showing ER-positive or HER2-positive DTC because they might benefit from an endocrine and/or HER2-targeted therapy.

Evaluation of proliferation and apoptosis markers in circulating tumor cells of women with early breast cancer who are candidates for tumor dormancy

Introduction

Clinical dormancy is frequently observed in breast cancer. In the present study, we aimed to characterize circulating tumor cells (CTCs) in dormancy candidates (DC) with early breast cancer in terms of proliferation and apoptosis.

Methods

Cytospins of peripheral blood mononuclear cells (PBMCs) were obtained from DC (n = 122) who were disease-free for at least 5 years and from metastatic patients (n = 40) who relapsed more than 5 years after surgery. Sequential samples from eight DC (n = 36) who maintained a prolonged disease-free status and from eight DC (n = 27) presenting late relapse during follow-up, were also analyzed. PBMCs were triple stained with a pancytokeratin, antibody along with anti-Ki67 and anti-M30 antibodies as proliferation and apoptosis markers, respectively.

Results

CTCs were identified in 40 (33%) of 122 DC and in 15 (37.5%) of 40 metastatic patients. In total, twenty-five (62.5%) DC had exclusively dormant (Ki67(-)/M30(-)), seven (17.5%) had proliferative Ki67(+)/M30(-), four (10%) had apoptotic Ki67(-)/M30(+) and four (10%) had both phenotypes of proliferative and apoptotic CTCs. In comparison, 53.4% of CTC-positive metastatic patients had exclusively dormant and 46.6% had proliferative CTCs; none had apoptotic CTCs (P = 0.039). Among all CTCs detected in DC patients, 82.4% were dormant, whereas in the nondormant population, 32.5% were proliferative and 67.5% apoptotic. The respective percentages in metastatic patients were 59.1%, 100% and 0% (P <0.0001). Moreover, apoptotic CTCs prevailed among nondormant CTCs detected in sequential samples from DC who remained in a prolonged disease-free status compared to those presenting late relapse during follow-up (70.6% versus 43.5% (P = 0.0002)).

Conclusions

The apoptotic index of CTCs is increased during clinical dormancy, whereas the proliferation index is increased on relapse. In addition, apoptotic CTCs are more frequently encountered during follow-up in DC patients who remain disease-free compared to those with subsequent late relapse, suggesting that monitoring proliferation and apoptosis in CTCs during clinical dormancy merits further investigation as a tool for predicting late disease recurrence.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-014-0485-8) contains supplementary material, which is available to authorized users.

Circulating tumor cells in non-metastatic triple-negative breast cancer

Circulating tumor cells (CTCs) can be identified in approximately 25 % of stage I-III breast cancer patients; CTCs presence is a predictor of poor outcome in metastatic breast cancer, but little is known regarding the prognostic significance of CTCs in non-metastatic triple-negative breast cancer (TNBC) patients. The aim of this study was to determine whether CTCs predict worse outcome in non-metastatic TNBC patients. We evaluated CTCs in 113 patients with stages I-III TNBC at the time of definitive surgery. CTCs were assessed using the CellSearch System^®. Progression-free and overall survival were defined as time elapsed between date of diagnosis and either date of clinical disease progression, death, or last follow-up. Log-rank test and Cox regression analysis were used to determine associations of CTCs with progression-free and overall survival. The median follow-up was 40 months. CTCs were identified in 23/113 (20 %) of patients. No primary tumor characteristic or lymph node status predicted the presence of CTCs. The identification of ≥2 CTCs predicted shorter progression-free (log rank P ≤ 0.001; hazard ratio 8.30, 95 % CI 2.61–26.37) and overall survival (log rank P = 0.0004; hazard ratio 7.19, 95 % CI 1.98–26.06) versus survival for patients with <2 CTCs. Two or more CTCs predict shorter progression-free and overall survival in TNBC patients. Larger studies are needed to determine whether CTC assessment provides beneficial information that could be used in stratifying TNBC patients at increased risk for disease progression. Finally, CTCs characterization could facilitate the development of novel treatment approaches for TNBC.

Clinical significance of EpCAM mRNA-positive circulating tumor cells in hepatocellular carcinoma by an optimized negative enrichment and qRT-PCR-based platform

PURPOSE

This study aimed to construct a novel platform for the detection of circulating tumor cells (CTC) in patients with hepatocellular carcinoma (HCC) and to investigate the clinical significance of epithelial cell adhesion molecule mRNA-positive (EpCAM(mRNA+)) CTCs using this platform.

EXPERIMENTAL DESIGN

An optimized platform for CTC detection was constructed by evaluating different negative enrichment, mRNA isolation, and cDNA synthesis procedures and compared with the CellSearch system. A total of 299 patients with HCC were recruited into this prospective study; of these, 157 who received curative resection, 76 who received transcatheter arterial chemoembolization (TACE), and 66 who received radiotherapy were tested using our platform. The diagnostic value of EpCAM(mRNA+) CTCs was investigated in 122 patients with HCC who underwent resection and 120 control subjects.

RESULTS

The optimized negative enrichment and quantitative real-time PCR (qRT-PCR)-based CTC detection platform had high sensitivity, specificity, and reproducibility and a low sample volume requirement. This platform showed a potential diagnostic value in patients with HCC and exhibited 76.7% consistency with the CellSearch system (r = 0.54, P < 0.050). Pretreatment CTC level showed prognostic significance in patients with HCC treated with resection, TACE, and radiotherapy (all P < 0.050). Most of the patients showed a decrease in CTC levels after treatment that reflected tumor response. In contrast, patients with an increased CTC level showed disease progression after treatment.

CONCLUSIONS

We established an optimized platform based on negative enrichment and qRT-PCR for highly sensitive, specific, and reproducible CTC detection. This platform might be clinically useful in auxiliary diagnosis, treatment response assessment, and early decision-making to tailor the most effective antitumor strategies.

Detection of Circulating Tumour Cells from Blood of Breast Cancer Patients via RT-qPCR

Breast cancer is still the most frequent cause of cancer-related death in women worldwide. Often death is not caused only by the primary tumour itself, but also by metastatic lesions. Today it is largely accepted, that these remote metastases arise out of cells, which detach from the primary tumour, enter circulation, settle down at secondary sites in the body and are called Circulating Tumour Cells (CTCs). The occurrence of such minimal residual diseases in the blood of breast cancer patients is mostly linked to a worse prognosis for therapy outcome and overall survival. Due to their very low frequency, the detection of CTCs is, still a technical challenge. RT-qPCR as a highly sensitive method could be an approach for CTC-detection from peripheral blood of breast cancer patients. This assumption is based on the fact that CTCs are of epithelial origin and therefore express a different gene panel than surrounding blood cells. For the technical approach it is necessary to identify appropriate marker genes and to correlate their gene expression levels to the number of tumour cells within a sample in an in vitro approach. After that, samples from adjuvant and metastatic patients can be analysed. This approach may lead to new concepts in diagnosis and treatment.

Detection and prognostic significance of circulating tumor cells in nonmetastatic breast cancer patients

SUMMARY Distant metastasis remains the primary cause of death for breast cancer patients. Metastasis is a complex, multistep process wherein a subset of cells from a heterogeneous tumor acquire the ability to disseminate from the primary tumor and invade the blood and/or lymph nodes. Although tumor size, tumor characteristics and axillary lymph node status are the most common parameters utilized to predict disease recurrence in nonmetastatic patients, a significant number of lymph node-negative patients with localized disease will develop distant metastases despite successful primary treatment. These data suggest that tumor cell dissemination can occur early in disease progression, sometimes bypassing the lymphatic system. Occult micrometastases, or circulating tumor cells in the blood, are rare tumor cells that remain undetected by standard histopathogical and high-resolution imaging methodologies. This review focuses on current methodologies used to detect circulating tumor cells and their prognostic significance in nonmetastatic breast cancer patients.

Differential effect of adjuvant taxane-based and taxane-free chemotherapy regimens on the CK-19 mRNA-positive circulating tumour cells in patients with early breast cancer

Background:

To determine the effect of adjuvant taxane-free and taxane-based chemotherapy regimens on the elimination of circulating tumour cells (CTCs) in patients with early breast cancer.

Methods:

The presence of CK-19 mRNA-positive CTCs in the peripheral blood was evaluated before and after chemotherapy, using a real-time RT–PCR assay, in a historical comparison of two cohorts of women with stage I–III breast cancer treated with adjuvant taxane-free (N=211; FE₇₅C or E₇₅C) and taxane-based (N=334; T/E₇₅C or T/E₇₅) chemotherapy.

Results:

Taxane-based chemotherapy resulted in a higher incidence of CTCs' elimination than taxane-free regimens since 49.7% (74 of 149) and 33.0% (29 of 88) of patients with detectable CTCs before chemotherapy, respectively, turned negative post-chemotherapy (P=0.015). Patients treated with taxane-free regimens had a significantly lower disease-free survival (DFS) (P=0.035) than patients treated with taxane-based regimens; this difference was observed in patients with but not without detectable CTCs before chemotherapy (P=0.018 and P=0.481, respectively). The incidence of deaths was significantly higher in the taxane-free cohort of patients with but not without detectable CTCs before chemotherapy compared with that of the taxane-based cohort (P=0.002). Multivariate analysis revealed that the chemotherapy regimen was significantly associated with prolonged DFS (HR: 2.00; 95% CI=1.20–3.34).

Conclusion:

Elimination of CK-19 mRNA-positive CTCs during adjuvant chemotherapy seems to be an efficacy indicator of treatment and is associated with a favourable clinical outcome of patients with detectable CTCs before chemotherapy.

Markers of circulating breast cancer cells

The detection of circulating tumor cells (CTC) aids in diagnosis of disease, prognosis, disease recurrence, and therapeutic response. The molecular aspects of metastasis are reviewed including its relevance in the identification and characterization of putative markers that may be useful in the detection thereof. Also discussed are methods for CTC enrichment using molecular strategies. The clinical application of CTC in the metastatic disease process is also summarized.

Organ-specific markers in circulating tumor cell screening: an early indicator of metastasis-capable malignancy

Circulating tumor cells (CTCs) represent an important biological link in the spread of primary solid tumors to the metastatic disease responsible for most cancer mortality. Their detection in the peripheral blood of patients with many different carcinomas has shown that tumor-cell dissemination can proceed at an early stage of tumor development and their presence is associated with poor clinical outcomes, particularly in metastatic disease. In this article we describe how the increasingly sensitive isolation and detailed molecular characterization of CTCs has greatly improved our understanding of metastatic proliferation. We focus on how CTC detection and knowledge of the molecular architecture of these cells can serve as biomarkers to signal metastasis-capable disseminating cells and predict therapy-specific response. This has marked clinical utility for improved selection of systemic therapies to the individual needs of a cancer patient, real-time monitoring of metastatic disease treatments and the development of new targeted therapies.

Cytokeratin-19 mRNA-positive circulating tumor cells during follow-up of patients with operable breast cancer: prognostic relevance for late relapse

BACKGROUND

The detection of cytokeratin-19 (CK-19) mRNA-positive circulating tumor cells (CTC) before and/or after adjuvant chemotherapy in patients with operable breast cancer is associated with poor clinical outcome. Reliable prognostic markers for late disease relapse are not available. In this study we investigated the value of CTC detection during the first five years of follow-up in predicting late disease relapse.

METHODS

Blood was analyzed from 312 women with operable breast cancer who had not experienced disease relapse during the first two years of follow-up. A real-time reverse transcriptase polymerase chain reaction (RT-PCR) for CK-19 mRNA was used to detect CTC three months after the completion of adjuvant chemotherapy and every six months thereafter for a follow-up period of five years.

RESULTS

Eighty patients (25.6% of the study population) remained CTC free throughout the five-year period. A change in CTC status was observed in 133 patients (42.6%); 64 patients (20.5%) with initially CK-19 mRNA-positive CTC during the first 24 months turned CTC-negative afterwards while 69 (22.1%) who were initially CTC-negative became CTC-positive. Ninety-nine patients (31.7%) remained persistently CK-19 mRNA-positive. After a median follow-up period of 107 months (range: 38 to 161 months), the persistently CTC-positive patients with either hormonal receptor positive or negative tumors, had a higher risk of late-disease relapse compared to the persistently CTC-negative patients (36.4% versus 11.2%, P <0.001). Multivariate analysis revealed that persistently CTC-positive patients also had a shorter disease-free (P = 0.001) and overall survival (P = 0.001).

CONCLUSIONS

Persistent detection of CK-19 mRNA-positive CTC during the first five years of follow-up is associated with an increased risk of late relapse and death in patients with operable breast cancer and indicates the presence of chemo-and hormonotherapy-resistant residual disease. This prognostic evaluation may be useful when deciding on subsequent adjuvant systemic therapy.

Germline polymorphisms discovered via a cell-based, genome-wide approach predict platinum response in head and neck cancers

Identifying patients prior to treatment who are more likely to benefit from chemotherapeutic agents or more likely to experience adverse events is an aim of personalized medicine. Pharmacogenomics offers a potential means of achieving this goal through the discovery of predictive germline genetic biomarkers. When applied particularly to the treatment of head and neck cancers, such information could offer significant benefit to patients as a means of potentially reducing morbidity associated with platinum-based chemotherapy. We developed a genome-wide, cell-based approach to identify single nucleotide polymorphisms (SNPs) associated with platinum susceptibility and then evaluated these SNPs as predictors for response and toxicity in head and neck cancer patients treated with platinum-based therapy as part of a phase II clinical trial. Sixty head and neck cancer patients were evaluated. Of 45 genome-wide SNPs examined, we found that 2 SNPs, rs6870861 (P=0.004; false discovery rate [FDR] <0.05) and rs2551038 (P=0.005; FDR <0.05), were associated significantly with overall response to carboplatin-based induction chemotherapy when incorporated into a model along with total carboplatin exposure. Interestingly, these 2 SNPs are associated strongly with the baseline expression of >20 genes (all P ≤10(-4)), and that 2 genes (SLC22A5 and SLCO4C1) are important organic cation/anion transporters known to affect platinum uptake and clearance. Several other SNPs were associated nominally with carboplatin-related hematologic toxicities. These findings demonstrate importantly that a genome-wide, cell-based model can identify novel germline genetic biomarkers of platinum susceptibility, which are replicable in a clinical setting with treated cancer patients and seem clinically meaningful for potentially enabling future personalization of care in such patients.

Relevance of circulating tumor cells, extracellular nucleic acids, and exosomes in breast cancer

Early detection of cancer is vital to improved overall survival rates. At present, evidence is accumulating for the clinical value of detecting occult tumor cells in peripheral blood, plasma, and serum specimens from cancer patients. Both molecular and cellular approaches, which differ in sensitivity and specificity, have been used for such means. Circulating tumor cells and extracellular nucleic acids have been detected within blood, plasma, and sera of cancer patients. As the presence of malignant tumors are clinically determined and/or confirmed upon biopsy procurement-which in itself may have detrimental effects in terms of stimulating cancer progression/metastases-minimally invasive methods would be highly advantageous to the diagnosis and prognosis of breast cancer and the subsequent tailoring of targeted treatments for individuals, if reliable panels of biomarkers suitable for such an approach exist. Herein, we review the current advances made in the detection of such circulating tumor cells and nucleic acids, with particular emphasis on extracellular nucleic acids, specifically extracellular mRNAs and discuss their clinical relevance.

Detection and HER2 expression of circulating tumor cells: prospective monitoring in breast cancer patients treated in the neoadjuvant GeparQuattro trial

PURPOSE

This study was aimed at detecting and characterizing circulating tumor cells (CTC) before and after neoadjuvant therapy (NT) in the peripheral blood of patients with breast cancer.

EXPERIMENTAL DESIGN

The clinical trial GeparQuattro incorporated NT approaches (epirubicin/cyclophosphamide prior to randomization to docetaxel alone, docetaxel in combination with capecitabine, or docetaxel followed by capecitabine) and additional trastuzumab treatment for patients with HER2-positive tumors. We used the Food and Drug Administration-approved CellSearch system for CTC detection and evaluation of HER2 expression and developed HER2 immunoscoring for CTC.

RESULTS

We detected > or =1 CTC/7.5 mL in 46 of 213 patients (21.6%) before NT and in 22 of 207 patients (10.6%) after NT (P = 0.002). Twenty (15.0%) initially CTC-positive cases were CTC-negative after NT, whereas 11 (8.3%) cases were CTC-positive after NT, although no CTC could be found before NT. CTC detection did not correlate with primary tumor characteristics. Furthermore, there was no association between tumor response to NT and CTC detection. HER2-overexpressing CTC were observed in 14 of 58 CTC-positive patients (24.1%), including 8 patients with HER2-negative primary tumors and 3 patients after trastuzumab treatment. CTC scored HER2-negative or weakly HER2-positive before or after NT were present in 11 of 21 patients with HER2-positive primary tumors. HER2 overexpression on CTC was restricted to ductal carcinomas and associated with high tumor stage (P = 0.002).

CONCLUSION

CTC number was low in patients with primary breast cancer. The decrease in CTC incidence during treatment was not correlated with standard clinical characteristics and primary tumor response. Information on the HER2 status of CTC might be helpful for stratification and monitoring of HER2-directed therapies.

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.

Derlin-1 and stanniocalcin-1 are differentially regulated in metastasizing canine mammary adenocarcinomas

Derlin-1, stanniocalcin-1, epithelial glycoprotein-2 (EGP-2) and maspin are associated with the metastasis of human breast cancer cells. This study reports the potential role of these molecules in metastasis of canine mammary tumours. Laser microdissected tissue samples were prepared from normal canine mammary gland and from simple adenomas, adenocarcinomas and their lymph node metastases. The expression of genes encoding the molecules of interest in these tissues was determined by real-time quantitative reverse transcriptase polymerase chain reaction (RT-PCR). Most adenomas displayed reduced expression of derlin-1 mRNA. Few adenocarcinomas overexpressed derlin-1 mRNA, but all lymph node metastases overexpressed this gene product. Stanniocalcin-1 mRNA was not expressed within adenomas and was reduced in adenocarcinomas and their lymph node metastases. EGP-2 gene expression did not differ between normal, benign and malignant neoplastic tissues. Maspin gene expression varied markedly among the tumours with reduced or increased expression compared with normal mammary gland. Taken together, these results suggest that malignant behaviour of canine mammary adenocarcinoma is associated with reduced transcription of the stanniocalcin-1 gene and overexpression of the derlin-1 gene.

The presence of circulating total DNA and methylated genes is associated with circulating tumour cells in blood from breast cancer patients

Circulating tumour cells (CTC) and tumour-related methylated DNA in blood have been separately assessed for their utility as a marker for subclinical metastasis in breast cancer. However, no studies have looked into the relation between the both molecular markers in this type of cancer. In this study, we investigated the correlations between total/methylated DNA and CTC in the blood from metastatic breast cancer patients. We simultaneously obtained whole blood, plasma and serum samples from 80 patients and 20 controls. The CellSearch System was used to enumerate CTC in blood samples. Plasma total DNA levels were determined by a QPCR method. Sera were analysed by methylation-specific QPCR for three markers: adenomatous polyposis coli (APC), ras association domain family protein 1A (RASSF1A) and oestrogen receptor 1 (ESR1). Total DNA levels in patients were significantly increased when compared with controls (P<0.001) and correlated with the number of CTC (r=0.418, P<0.001). Hypermethylation of one or more genes was detected in 42 (53%) serum samples from breast cancer patients and in three (16%) serum samples from controls (P=0.003). APC was hypermethylated in 29%, RASSF1A in 35% and ESR1 in 20% of breast cancer cases. Detection of a methylated gene in serum was associated with the detection of CTC in blood (P=0.03). The detection of large amounts of circulating total/methylated DNA correlated with the presence of CTC in the blood from patients with breast cancer. This can be interpreted in two ways: (a) CTC are a potential source of circulating tumour-specific DNA; (b) high numbers of CTC and circulating methylated DNA are both a phenotypic feature of more aggressive tumour biology.

Circulating tumor cells (CTCs): detection methods and their clinical relevance in breast cancer

The enumeration of circulating tumor cells has long been regarded as an attractive diagnostic tool, as circulating tumor cells are thought to reflect aggressiveness of the tumor and may assist in therapeutic decisions in patients with solid malignancies. However, implementation of this assay into clinical routine has been cumbersome, as a validated test was not available until recently. Circulating tumor cells are rare events which can be detected specifically only by using a combination of surface and intracellular markers, and only recently a number of technical advances have made their reliable detection possible. Most of these new techniques rely on a combination of an enrichment and a detection step. This review addresses the assays that have been described so far in the literature, including the enrichment and detection steps and the markers used in these assays. We have focused on breast cancer as most clinical studies on CTC detection so far have been done in these patients.

Cytokeratin-19 mRNA-positive circulating tumor cells after adjuvant chemotherapy in patients with early breast cancer

PURPOSE

To evaluate the prognostic significance of cytokeratin-19 (CK-19) mRNA-positive circulating tumor cells (CTCs) in peripheral blood of women with early-stage breast cancer after the completion of adjuvant chemotherapy.

PATIENTS AND METHODS

Blood was obtained from 437 patients with early breast cancer before the start and after the completion of adjuvant chemotherapy, and the presence of CK-19 mRNA-positive CTCs was assessed by real-time reverse transcriptase polymerase chain reaction. Interaction with known prognostic factors and association of CTCs with clinical outcome were investigated.

RESULTS

CK-19 mRNA-positive CTCs were detected before chemotherapy in 179 patients (41.0%). After adjuvant chemotherapy, a significant change in CK-19 status was observed, as status for 51% of patients with initially CK-19 mRNA-positive disease turned negative, and status for 22% of patients with initially CK-19 mRNA-negative disease became positive (McNemar test P = .004). The detection of CK-19 mRNA-positive CTCs postchemotherapy was associated with involvement of more than three axillary lymph nodes (P = .026). Clinical relapses and disease-related deaths were significantly increased in patients with detectable postchemotherapy CK-19 mRNA-positive CTCs (both P < .001, respectively). Disease-free and overall survival were significantly reduced in patients with detectable CK-19 mRNA-positive CTCs postchemotherapy (P < .001 and P = .001, respectively). In multivariate analysis, the detection of CK-19 mRNA-positive CTCs before and after adjuvant chemotherapy was an independent factor associated with reduced disease-free survival (P < .001) and overall survival (P = .003).

CONCLUSION

The detection of CK-19 mRNA-positive CTCs in the blood after adjuvant chemotherapy is an independent risk factor indicating the presence of chemotherapy-resistant residual disease.

Molecular diagnosis of sentinel lymph node metastases in cervical cancer using squamous cell carcinoma antigen

PURPOSE

To clarify the prognostic value of molecular diagnosis of SLN metastases in cervical cancer using SCCA.

EXPERIMENTAL DESIGN

All SLNs and primary tumors, part of non-SLNs, were harvested from 36 patients with cervical cancer. Expression levels of SCCA, cytokeratin 19 (CK19), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA in 178 samples (29 primary tumors, 5 histologic positive nodes, 60 histologic negative SLNs, 69 non-SLNs, and 15 normal nodes) were assessed by quantitative reverse transcription-PCR assay. The quantitative value of SCCA or CK19 mRNA was described as each value relative to GAPDH mRNA. The cutoff value was set at the upper limit of the quantitative value of nodes from noncancer patients, and those above this value constituted the molecular metastasis group.

RESULTS

The SCCA mRNA expression values were more than 1 x 10(3) in 28 primary tumors and all histologic positive nodes, and its expression levels in SLNs were higher than in non-SLNs. SLNs from patients with adverse prognostic features had higher SCCA mRNA expression levels. Four histologic negative SLNs were diagnosed molecular metastases based on SCCA mRNA. Two cases with histologically uninvolved pelvic nodes recurred. Survival analysis indicates that molecular lymphatic metastasis based on elevated SCCA mRNA level is the best predictor of recurrence. However, CK19 is not a suitable marker due to its low specificity and relative higher baseline expression in normal nodes.

CONCLUSIONS

SCCA mRNA levels for molecular diagnosis of SLN metastases in cervical cancer more accurately identifies patients at risk for recurrence than the routine histology does.

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.

Detection, clinical relevance and specific biological properties of disseminating tumour cells

Most cancer deaths are caused by haematogenous metastatic spread and subsequent growth of tumour cells at distant organs. Disseminating tumour cells present in the peripheral blood and bone marrow can now be detected and characterized at the single-cell level. These cells are highly relevant to the study of the biology of early metastatic spread and provide a diagnostic source in patients with overt metastases. Here we review the evidence that disseminating tumour cells have a variety of uses for understanding tumour biology and improving cancer treatment.

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.

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.