Persistent evidence of circulating tumor cells detected by means of RT-PCR for CEA mRNA predicts early relapse: A prospective study in node-negative breast cancer

Circulating tumor cells are associated with poor outcomes in early-stage hepatocellular carcinoma: a prospective study

BACKGROUND

Previous studies evaluating association between circulating tumor cells (CTCs) and clinical outcomes in hepatocellular carcinoma (HCC) have shown inconsistent results due to suboptimal detection methods and patient heterogeneity.

METHODS

Patients undergoing surgery for early-stage HCC were prospectively enrolled. The CTC numbers were determined using a tapered slit platform, which detects CTCs based on the cell size and morphology. Survival and recurrence were evaluated, and Cox proportional hazards models were used to demonstrate the prognostic significance of CTC.

RESULTS

Of 105 patients, 25 had increased CTC numbers after surgery (ΔCTC > 0, defined as positive) and a significantly higher level of recurrence (p = 0.042). A positive ΔCTC was seen to be an independent predictor of recurrence (hazard ratio 2.28), along with hepatitis B virus infection, alanine aminotransferase level, and the presence of satellite nodules (all p < 0.05). Subgroup analyses showed that a positive ΔCTC was associated with lower survival and higher recurrence among patients with low alpha-fetoprotein levels and cirrhosis (all p < 0.05).

CONCLUSION

Calculation of ΔCTC based on the physical properties of the cells is predictive of recurrence in patients with early HCC undergoing surgery.

Detection of Cytokeratin 19, Human Mammaglobin, and Carcinoembryonic Antigen-Positive Circulating Tumor Cells by Three-Marker Reverse Transcription-Pcr Assay and Its Relation to Clinical Outcome in Early Breast Cancer

Aims

To investigate the diagnostic, predictive, and prognostic value of the detection of circulating tumor cells (CTCs) using a three-marker (CK19, hMAM and CEA) RT-PCR assay in patients with early breast cancer.

Patients and methods

Peripheral blood was obtained from 50 patients with early-stage breast cancer before any systemic adjuvant therapy and analyzed for the presence of CK-19, hMAM and CEA mRNA-positive CTCs using an RT-PCR assay. The specificity of the primers used was evaluated in 20 healthy individuals, 24 patients with benign breast disease, and 30 patients with metastatic breast cancer. The detection of CTCs was correlated with clinical outcome.

Results

The detection rate of three-marker-positive CTCs in the blood of patients with early breast cancer was 54.0%, significantly higher than in patients with benign breast disease and healthy blood donors (p=0.002 and p=0.000, respectively). The three-marker RT-PCR assay had 58.8% sensitivity in the parallel test and 100% specificity for CTC detection in the serial test, which was higher than the sensitivity and specificity of single-marker assays. For early breast cancer, correlation analysis between detection of three-marker-positive CTCs and clinicopathological characteristics indicated that detection of three-marker-positive CTCs was significantly correlated with elevated serum CEA levels (p=0.001). After three years of follow-up, 13 of the 27 patients with three-marker-positive CTCs in their blood had relapsed and detection of three-marker-positive CTCs was significantly associated with locoregional recurrence and/or distant metastasis (p=0.002). Detection of three-marker-positive CTCs in peripheral blood was an independent risk factor for reduced median relapse-free interval (p=0.000).

Conclusion

The three-marker RT-PCR assay can enhance the sensitivity and specificity of CTC detection compared to single-marker assay. Detection of three-marker-positive CTCs was associated with relapse and might have important predictive and prognostic implications in early breast cancer.

CK19, CK20, EGFR and HER2 Status of Circulating Tumor Cells in Patients with Breast Cancer

Aims and background

The major cause of death in breast cancer patients is metastasis. Various biomarkers have been used for the early detection of circulating tumor cells in the peripheral blood of breast cancer patients. The aims of the current study were to analyze circulating tumor cells in the blood of breast cancer patients by investigating EGFR, CK19, CK20 and HER2 expression profiles and to evaluate their prognostic importance.

Methods

CK19, CK20 and EGFR gene expression profiles were evaluated in the blood samples of 84 female patients with primary invasive ductal breast cancer and 20 healthy female volunteers using SYBR green-based real-time qPCR assays. HER2 expression analyses were conducted in 46 patients who had an HER2-positive primary tumor and in 30 healthy women to determine the cutoff level of positivity.

Results

The positive rates of CK20, EGFR, CK19 and HER2 mRNA expression in the peripheral blood were 28.57% (24/84), 20.23% (17/84), 5.95% (5/84) and 2.17% (1/46), respectively. The high positive ratio of CK20 mRNA expression in the peripheral blood of breast cancer was identified for the first time in the current study. Significant differences were identified in CK20 expression status and several clinical parameters related with aggressiveness of tumors using a binary logistic regression analysis. Higher CK20-positive levels were observed in patients who had lymph node metastasis and advanced-grade primary tumors, which were estrogen receptor-negative. We have demonstrated that CK20 may be a novel biomarker that is useful to identify circulating tumor cells and predict breast cancer progression.

Conclusions

The results suggest that the investigation of CK20 mRNA with other biomarkers in the peripheral blood of breast cancer patients may be useful to monitor the presence of disseminated tumor cells in the blood circulation and to predict the prognosis of breast cancer.

Combination of miR-21 with Circulating Tumor Cells Markers Improve Diagnostic Specificity of Metastatic Breast Cancer

Circulating miR-21 is upregulated in breast cancer. However, correlation of miR-21 expression with clinic pathologic characteristics remains questionable. In this study, we investigate whether combination of circulation miR-21 with circulating tumor cells (CTCs) marker (EpCAM, MUS1, HER2) could improve diagnostic specificity of metastatic breast cancer. Total 223 breast cancer patients were included. 89 % patients were associated with upregulation of miR-21 compared with health control. 20 % patients were detected for CTCs marker positive. For higher specificity purpose, triple marker positive samples were selected as true CTCs positive, which only occupied 59.5 % of total metastatic breast cancer patients. Specificity of detection of CTCs was 96.7 %. Furthermore, 59.5 % metastatic breast cancer patients were shown both abnormal miR-21 and true CTCs positive according to distribution of true CTCs positive and abnormal miR-21; Combination of miR-21 and CTCs was increased specificity of metastatic detection to 100 %. Our findings suggested that combination of miR-21 with CTCs marker could be used for better diagnosis of metastatic breast cancer in the future.

Expression of two basic mRNA biomarkers in peripheral blood of patients with non-small cell lung cancer detected by real-time rt-PCR, individually and simultaneously

Introduction: Although extensive research has been conducted on lung cancer markers, a singular clinically applicable marker has not been found yet. The objective of this study was to evaluate the sensitivity and the specificity of carcinoembryonic antigen (CEA) mRNA and lung-specific X protein (LUNX) mRNA biomarkers in peripheral blood to detect lung cancer individually and simultaneously. Methods: Thirty patients affected by lung cancer and 30 healthy individuals were studied in this research. Three vials of cDNA were made from each sample after taking peripheral blood samples and extracting total RNA. Each sample was examined by the real-time RT-PCR technique. The result from each vial was then compared with the sensitivity of overall marker. Results: The CEA mRNA was positive in 24 out of 30 lung cancer patients. Hence, its sensitivity was determined at 80%, differing significantly from that observed in healthy individuals, where 11 positive cases were seen. The overall sensitivity of this marker was significantly associated with positivity in vials 2 and 3 but not in vial 1. The LUNX mRNA was positive in 21 out of 30 patients, indicating 70% sensitivity. This finding significantly differed from that in healthy individuals. The overall sensitivity of this marker was significantly associated with positivity in vials 1 and 3, but not in vial 2. In 93.3% of the patients, at least one positive marker was observed. Conclusion: The mentioned mRNA could be suggested as sensitive and specific markers in peripheral blood for primary diagnosis of lung cancer.

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.

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.

Detection of α-Methylacyl-Coenzyme-A Racemase Transcripts in Blood and Urine Samples of Prostate Cancer Patients

BACKGROUND

Alpha-methylacyl-coenzyme-A racemase (AMACR) has been shown to be a highly specific marker for prostate cancer cells, even in the earliest stages of malignant progression. It is expressed at much higher levels than prostate-specific antigen (PSA) in malignant tissues, and is not expressed at appreciable levels in normal prostatic epithelium. In this study, we demonstrate the quantitative detection of AMACR transcripts in peripheral blood of prostate cancer patients using real-time RT-PCR. In addition, we have undertaken a pilot study to demonstrate the potential application of this technique for the detection of prostate tumor cells in urine samples from patients with prostate cancer.

METHODS

A real-time RT-PCR assay was developed for detection of the expression of AMACR in prostate cancer patients. Blood samples from 163 patients were tested at various stages of disease progression, with or without therapy. Blood specimens from patients with benign prostate disorders and other types of cancer were also evaluated.

RESULTS

In 28 of 58 samples from patients with known metastatic disease who were undergoing treatment, an AMACR expression signal above the cut-off value was detected, consistent with the presence of circulating tumor cells. In 39 of 88 patients with presumptive organ-confined disease, there was evidence of low levels of circulating tumor cells. Comparison of AMACR RT-PCR with known serum PSA values indicated that a combination of these parameters significantly increased the sensitivity for detection of progressive disease. In a pilot study analyzing urine samples from seven prostate cancer patients, elevated AMACR expression levels were detected in the urine sediments of four of six stage-T1 prostate cancer patients and in the one patient with stage-T2 prostate cancer.

CONCLUSION

The data presented in this study indicates that AMACR real-time RT-PCR may aid in the detection and staging of prostate cancer.

Molecular markers in peripheral blood of Iranian women with breast cancer

A biomarker is a quantifiable laboratory measure of a disease specific biologically relevant molecule that can act as an indicator of a current or future disease state. The purpose of this study is to detect the expression of RNA biomarkers using Cytokeratin 19 (CK-19), Mammaglobin (MAM), Carcinoembryonic antigen (CEA), Mucin (MUC), C-Myc, erb-B2, a proliferation marker (Ki-67), Epidermal growth factor receptor (Her2/neu) and Estrogen receptor (ER) in Iranian women who were diagnosed with breast cancer. In this study, 90 samples; 60 cancer patients and 30 healthy controls were considered. 73.4 % patients were in stage I/II and 26.6 % were in stage III/IV. Patients were selected prior to the administration of any adjuvant systemic therapy. Total RNA extraction was obtained from peripheral blood of each patient and healthy control. Reverse transcription polymerase chain reaction (RT-PCR) method was used for detection of mRNA of the selected biomarkers of circulating breast cancer cells in blood. Molecular characterization is assessed as a method for early detection of breast cancer. For this purpose, eleven specific primers were selected and RT-PCR was used. The data of RT-PCR revealed that expression of MUC1, CK19, CEA, MAM, erbB-2, Ki67 and C-Myc biomarkers were significantly different between breast cancer patients and healthy controls. On the other hand, ERα, ERβ and Her2 markers were not significantly different between the two mentioned groups. Biomarkers detection of breast cancer patients could be assessed as a diagnostic factor and its potential for conveying as a prognostic factor require further studies, with a larger number of patients.

Usefulness of transcription-reverse transcription concerted reaction method for detecting circulating tumor cells in patients with colorectal cancer

PURPOSE

The CellSearch system (Veridex, LLC) is useful for detecting circulating tumor cells (CTCs) in various carcinomas, including colorectal cancer (CRC); however, there are some problems associated with its clinical use. A transcription-reverse transcription concerted reaction (TRC) method, which is a PCR-based technique producing more stable and reliable results, because it is a more simplified process compared with the conventional techniques, has been introduced for detecting micrometastasis in some carcinomas. We aimed to demonstrate the effectiveness of TRC method in the CTC detection.

METHODS

We compared the two methods for the sensitivity for CTC detection using the colon cancer cell line and 42 whole-blood samples from patients with advanced or metastatic CRC. Furthermore, 25 patients with metastatic CRC were enrolled to investigate the correlation between CTC detection and prognosis in both methods.

RESULTS

The sensitivity of the TRC method was similar to that of the CellSearch system. The overall survival rate was significantly worse in the patients diagnosed as CTC-positive by the TRC method than in those diagnosed as CTC-negative; this finding was similar to the prognosis indicated by the CellSearch system. However, clinically, the TRC method could detect CTCs more rapidly and at a reduced cost compared with the CellSearch system.

CONCLUSIONS

The TRC method seems to be a useful alternative to the CellSearch system for clinically detecting CTCs in patients with metastatic CRC.

The prognostic role of circulating tumor cells (CTCs) detected by RT-PCR in breast cancer: a meta-analysis of published literature

The prognostic significance of circulating tumor cells (CTCs) in patients with breast cancer is controversial. We performed a meta-analysis of published literature to assess whether the detection of CTCs in patients diagnosed with primary breast cancer can be used as a prognostic factor. We searched Medline, Science Citation Index, and Embase databases as well as reference lists of relevant articles (including review articles) for studies that assessed the prognostic relevance of tumor cell detection in the peripheral blood (PB). A total of 24 eligible studies with 4,013 cases and 1,333 controls were included. Meta-analyses were performed using a random-effects model, using the hazard ratio (HR) and 95% confidence intervals (95% CIs) as effect measures. The positive detection of CTCs in patients was significantly associated with poor overall survival (OS) (HR = 3.00 [95% CI 2.29-3.94], n = 17, P < 0.0001) and recurrence-free survival (RFS) (HR = 2.67 [95% CI 2.09-3.42], n = 22, P < 0.0001). CTC-positive breast cancers were significantly associated with high histological grade (HR = 1.21 [95% CI 1.09-1.35], n = 34, P < 0.0001), tumor size (>2 cm) (HR = 1.12 [95% CI 1.02-1.22], n = 31, P = 0.01). and nodal status (≥1) (HR = 1.10 [95% CI 1.00-1.21], n = 32, P = 0.037), but cytokeratin-19 (CK-19) mRNA-positive CTCs were not associated with these clinicopathological parameters of breast cancer. Furthermore, the presence of CTCs was not associated with estrogen receptor (ER) negativity, progesterone receptor (PR) negativity, or human epidermal growth factor receptor type 2 (HER2) positivity. Detection of CTCs in the PB indicates poor prognosis in patients with primary breast cancer. Larger clinical studies are required to further evaluate the role of these markers in clinical practice.

Prognostic significance of the detection of peripheral blood CEACAM5mRNA-positive cells by real-time polymerase chain reaction in operable colorectal cancer

PURPOSE

To evaluate the clinical relevance of circulating CEACAM5mRNA-positive cells in patients with operable colorectal cancer (CRC).

METHODS

Peripheral blood was obtained from 265 patients with operable CRC before the initiation of adjuvant systemic therapy from 96 normal donors and RNA prepared from the Lovo and ARH-77 CRC and leukemic cell lines, respectively, was used as positive and negative controls. The detection of CEACAM5mRNA-positive cells was done using a real-time PCR assay. The association with known prognostic factors and the effect of CEACAM5mRNA-positive cells on patients' prognosis was investigated.

RESULTS

The analytical detection limit of the method was found to correspond to 0.7 Lovo cell equivalence/5 μg RNA, with a sensitivity of 1 tumor cell/10(5) normal cells and a specificity of 97%. Ninety-eight (37%) patients had detectable circulating CEACAM5mRNA-positive cells. Detection of CEACAM5mRNA-positive cells was significantly associated with higher relapse rate (P < 0.001), decreased disease-free survival (DFS; P < 0.001), higher death rate (P = 0.017), and decreased median overall survival (P = 0.025). Multivariate analysis revealed that the detection of circulating CEACAM5mRNA-positive cells was an independent prognostic factor for decreased DFS [HR = 3.4; 95% CI: 2.0-5.9; P < 0.001].

CONCLUSIONS

Detection of peripheral blood CEACAM5mRNA-positive cells is an adverse prognostic factor correlated with poor clinical outcome in patients with operable CRC.

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.

Detection and characterization of circulating tumor cells in blood of primary breast cancer patients by RT-PCR and comparison to status of bone marrow disseminated cells

INTRODUCTION

The role of circulating tumor cells (CTCs) in blood of primary breast cancer patients is still under investigation. We evaluated the incidence of CTCs in blood, we evaluated the correlation between CTCs and disseminated tumor cells (DTCs) in the bone marrow (BM), and we characterized CTCs for the expression of HER2, the estrogen receptor (ER) and the progesterone receptor (PR).

METHODS

Blood of 431 patients with primary breast cancer were analyzed for EpCAM, MUC1 and HER2 transcripts with the AdnaTest BreastCancer (AdnaGen AG, Germany). Expression of the ER and PR was assessed in an additional RT-PCR. BM aspirates from 414 patients were analyzed for DTCs by immunocytochemistry using the pan-cytokeratin antibody A45-B/B3.

RESULTS

DTCs were found in 107/414 patients (24%), CTCs were detected in 58/431 (13%) patients. DTCs were associated with PR status of the primary tumor (P = 0.04) and CTCs significantly correlated with nodal status (P = 0.04), ER (P = 0.05), and PR (P = 0.01). DTCs in the BM weakly correlated with CTCs (P = 0.05) in blood. Interestingly, the spread of CTCs was mostly found in triple-negative tumors (P = 0.01) and CTCs in general were mostly found to be triple-negative regardless of the ER, PR and HER2 status of the primary tumor.

CONCLUSIONS

(1) Due to the weak concordance between CTCs and DTCs the clinical relevance may be different. (2) The biology of the primary tumor seems to direct the spread of CTCs. (3) Since the expression profile between CTCs and the primary tumor differs, the consequence for the selection of adjuvant treatment has to be evaluated.

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.

Molecular profiling and predictive value of circulating tumor cells in patients with metastatic breast cancer: an option for monitoring response to breast cancer related therapies

PURPOSE

We analyzed circulating tumor cells (CTC) in blood of metastatic breast cancer patients (n = 42) and determined the ability of this method to predict therapy response.

METHODS

CTC from blood were analyzed before and during therapy for EpCAM, MUC1 and HER2 transcripts with the AdnaTest BreastCancer. The estrogen (ER) and progesterone (PR) receptor expression was assessed by RT-PCR.

RESULTS

The overall detection rate for CTC was 52% (thereof 86% EpCAM; 86% MUC1; 32% HER2; 35% ER; 12% PR). CTC were ER, PR and HER2 negative in 45% (ER), 78% (PR) and 60% (HER-2) of patients with steroid receptor-positive tumors. 29% of patients with HER2-negative tumors had HER2-positive CTC. The test predicted therapy response in 78% of all cases. Persistence of CTC significantly correlated with shorter overall survival (P = 0.005).

CONCLUSIONS

Molecular profiling of CTC may offer superior prognostic information with regard to risk assessment for recurrence and predictive judgement of therapeutical regimens.

Circulating tumor cells: detection, molecular profiling and future prospects

Disseminated malignancy is responsible for the vast majority of cancer-related deaths. During this process, circulating tumor cells (CTC) are generated, spread from the primary tumor, colonize distant organs and lead to overt metastatic disease. CTC are essential for establishing metastasis; however, they are not sufficient as this process is highly inefficient and most will fail to grow in target sites. Several CTC die during migration while others remain dormant for several years and very few grow into macrometastases. CTC have been well documented in the bloodstream of cancer patients; however, the clinical relevance of this detection is still the subject of controversies and their biology is poorly understood. Indeed, available markers fail to distinguish between subgroups of CTC, and several current methods lack sensitivity, specificity or reproducibility in CTC characterization and detection. The advent of more precise technologies is renewing the interest in CTC biology. We will review herein recent findings on CTC biology, on the role of host-tumor interactions in CTC shedding and implantation, available methods of CTC detection and future perspectives for the molecular characterization of the CTC subset(s) responsible for the development of metastasis. Ultimately, understanding CTC biology and host-tumor 'complementarities' will help define metastasis-related biomarkers providing formidable and tailored novel therapeutic targets.

Detection of circulating tumor cells in early-stage breast cancer metastasis to axillary lymph nodes

PURPOSE

Clinical and pathologic prognostic factors do not always accurately predict disease outcome. Patients with early-stage breast cancer may harbor clinically significant but undetected systemic disease. We hypothesized that a multimarker quantitative real-time reverse transcription-PCR (qRT) assay could detect circulating tumor cells (CTC) in patients with early-stage breast cancer and correlate with sentinel lymph node (SLN) and non-SLN metastasis status.

EXPERIMENTAL DESIGN

Blood samples from 90 women with the American Joint Committee on Cancer stages I to III breast cancer and 39 age-matched normal healthy volunteers were assessed by qRT for mRNA expression of three markers: stanniocalcin-1 (STC-1), N-acetylgalactosaminyltransferase (GalNacT), and melanoma antigen gene family-A3 (MAGE-A3). CTC biomarker detection was correlated with overall axillary LN (ALN), SLN, and non-SLN histopathology status.

RESULTS

CTCs were detected in 39 of 90 (43%) patients, but not in normal volunteers. At least one CTC biomarker was detected in 10 of 35 (29%) stage I patients, 19 of 42 (45%) stage II patients, and 10 of 13 (77%) stage III patients. In multivariate analysis, only lymphovascular invasion and >or=2 CTC biomarkers detected significantly correlated with ALN metastasis [odds ratio (OR), 12.42; 95% confidence interval (95% CI), 3.52-43.77, P<0.0001; and OR, 3.88; 95% CI, 1.69-8.89, P=0.001, respectively]. The number of CTC biomarkers detected similarly correlated with SLN and non-SLN metastasis status (P=0.0004). At least one CTC biomarker was detected in 10 of 11 (91%) patients with non-SLN metastases.

CONCLUSION

The detection of CTCs offers a novel means to assess the presence of systemic disease spreading relative to SLN and ALN histopathology status.

Neutrophil elastase and cancer

This mini-review summarizes our recent experimental and clinical studies on neutrophil elastase (NE) and cancer based on our original view point. Neoplasms metastasize as a result of a complex series of events. This process requires various degradative enzymes including proteases. NE has broad substrate specificity under physiological conditions, and excessive NE results in digestion of not only elastin, but also other extracellular matrix proteins. Several cell lines from human breast cancer and human lung cancer produce immunoreactive NE. The amount of immunoreactive NE in tumor tissue is an independent prognostic indicator of patients with breast cancer and lung cancer. Furthermore, a specific NE inhibitor completely suppressed growth of cancer cells transplanted into severe combined immunodeficiency mice. The use of NE inhibitor would seem to be a promising way to prevent the invasion and metastasis of cancer.

Neuroblastoma-derived secretory protein messenger RNA levels correlate with high-risk neuroblastoma

BACKGROUND/PURPOSE

In advanced-stage neuroblastoma, bulky disease and systemic dissemination can be controlled with intense surgical and medical therapies; however, recurrence rates are very high in this group indicating that residual disease is rarely eradicated. The need to detect residual disease and predict prognosis is critical to planning appropriate treatment regimens for these patients. Recently, neuroblastoma-derived secretory protein (NDSP) was identified and cloned from neuroblastoma.

METHODS

Using quantitative real-time PCR, we tested NDSP messenger RNA (mRNA) expression in 45 neuroblastoma tumor samples and 5 bone marrow samples. Correlation between NDSP expression and age at diagnosis, International Neuroblastoma Staging System, MYCN amplification, and Children's Oncology Group risk stratification was analyzed using Spearman nonparametric correlation.

RESULTS

Neuroblastoma tissue samples show much higher NDSP mRNA levels above control in 43 of 45 samples (96%); moreover, these levels correlate with the Children's Oncology Group neuroblastoma risk group assignment. We also found that bone marrow samples with known tumor infiltration had much higher NDSP mRNA levels than bone marrow from patients without metastasis.

CONCLUSION

From these data, we conclude that NDSP mRNA levels in neuroblastoma tumor tissue correlate with risk group assignment and may serve as a marker for metastasis in bone marrow.

Squamous cell carcinoma-antigen messenger RNA level in peripheral blood predicts recurrence after resection in patients with esophageal squamous cell carcinoma

BACKGROUND

The aim of this study was to clarify whether preoperative squamous cell carcinoma-antigen messenger RNA (SCC-Ag mRNA) level in peripheral blood can be used to predict tumor recurrence after curative resection for esophageal squamous cell carcinoma.

METHODS

A prospective analysis was conducted for 46 consecutive patients who underwent curative esophagectomy and who had no residual tumor. The SCC-Ag mRNA level in the peripheral blood of each patient was measured preoperatively by using quantitative reverse transcriptase-polymerase chain reaction. Median follow-up period was 34 months.

RESULTS

Receiver operating characteristic analysis demonstrated that the optimal cutoff level of SCC-Ag mRNA was 40. Patients were divided into the high SCC-Ag mRNA level group (n = 14) and the low SCC-Ag mRNA level group (n = 32). The cumulative probabilities of tumor recurrence were higher in the high SCC-Ag mRNA level group (probability of recurrence was 71% at 2 years) than in the low group (22% at 2 years; P = .0005). SCC-Ag mRNA level (relative risk, 3.00; 95% confidence interval, 1.05-8.54; P = .040) was the strongest independent predictor of recurrence by multivariate analysis.

CONCLUSIONS

Preoperative SCC-Ag mRNA levels in the peripheral blood are the best predictive factor for recurrence in patients with esophageal squamous cell carcinoma who undergo curative resection (R0).

Circulating tumor cells: the 'leukemic phase' of solid cancers

It is well known that malignant cells circulate in the bloodstream of patients with solid tumors. However, the biological significance of circulating tumor cells (CTCs) and the clinical relevance of their detection are still debated. Besides technical issues regarding CTC-detection methods, discontinuous shedding of CTCs from established cancer deposits, genomic instability and metastatic inefficiency might underlie the conflicting results currently available. Nevertheless, technological advances and recent clinical findings are prompting researchers to dissect CTC biology further. Here, we review these recent findings, and discuss the prospects for the identification and molecular characterization of the CTC subset that is responsible for metastasis development. This would provide a formidable tool for prognosis evaluation, anticancer-drug development and, ultimately, cancer-therapy personalization.

Prospective validation of quantitative CEA mRNA detection in peritoneal washes in gastric carcinoma patients

Prediction of peritoneal relapse is extremely important for gastric cancer patients after curative surgery. The present study prospectively validates the prognostic ability of quantifying carcinoembryonic antigen (CEA) mRNA in peritoneal washes by real-time reverse transcriptase-polymerase chain reaction. Based on a retrospective study of 197 curatively resected gastric cancer patients (training set), we determined a cutoff value of CEA mRNA using receiver-operating characteristic curve. We used this cutoff value to validate the risk of peritoneal recurrence in a new cohort of 86 gastric cancer patients (validation set) between July 2000 and December 2002 in a prospective study. During the median 30 months of postoperative surveillance, 20 of the 86 patients died, and 13 of the 20 developed peritoneal metastases. Peritoneal recurrence-free survival as well as overall survival was significantly worse in patients with positive CEA mRNA (P<0.0001). Multivariate analysis with the Cox proportional hazards model showed that positive CEA mRNA was a significant independent risk factor with both survival (P=0.0130) and peritoneal recurrence-free survival (P=0.0006) as end points. These results indicate that quantitation of CEA mRNA in peritoneal washes is a reliable prognostic indicator of peritoneal recurrence in the clinical setting.

Simultaneous detection of multiple mRNA markers CK19, CEA, c-Met, Her2/neu and hMAM with membrane array, an innovative technique with a great potential for breast cancer diagnosis

The objective of this study was mainly to develop and evaluate a membrane array-based method simultaneously detecting the expression levels of a multiple mRNA marker panel in the peripheral blood for used in complementary breast cancer diagnosis. The mRNA markers employed included cytokeratin 19 (CK-19), carcinoembryonic antigen (CEA), c-Met, Her2/neu, and mammaglobin (hMAM). The specimens of peripheral blood were collected from 80 healthy women and 102 female patients with breast cancer. The expression levels of molecular markers were evaluated by real-time Q-PCR and membrane array. Data obtained from real-time Q-PCR and membrane array were subjected to linear regression analysis, revealing that there was a high degree of correlation between the results of these two methods (r=0.979, P<0.0001). The result of membrane array assay with a combined panel of five mRNA markers was demonstrated to achieve sensitivity of 80.6%, and specificity of 83.8% for breast cancer detection, much higher than those of analysis of single marker. In addition, we demonstrated that the membrane array method could detect circulating cancer cells at a density as low as five cancer cells per 1 ml of blood. The analysis of correlation between the outcome of membrane array and clinicopathological characteristics indicated that overexpression of the multiple marker panel was significantly correlated with tumor size (P=0.030) and TNM stage (0.009). In conclusion, the detection of circulating cancer cells by means of membrane array simultaneously monitoring five mRNA markers could significantly enhance the sensitivity and specificity for cancer cell detection.

Screening and identification of differentially expressed transcripts in circulating cells of prostate cancer patients using suppression subtractive hybridization

BACKGROUND

Tumor metastasis and changes in host immunosurveillance are important components in cancer development. Tumor cell invasion into the bloodstream is an essential step for systemic metastasis. Currently, the detection of tumor cells in the circulation is mainly dependent upon the utilization of known epithelial cell markers. However, expression of these molecules is not limited to cancer patients; healthy people also have a small number of epithelial cells in their circulation. Utilizing these markers to detect circulating tumor cells (CTCs) cannot adequately explain the mechanisms of tumor cell survival or their development of metastatic potential in peripheral blood. The immune system can also evolve along with the cancer, actually promoting or selecting the outgrowth of tumor variants. Unfortunately, both metastasis and immunosurveillance remain mysterious and are debatable because we have yet to define the molecules that participate in these processes. We are interested in identifying the existence of expressed genes, or mRNA species, that are specifically associated with circulating cells of cancer-bearing patients using prostate cancer (PCa) as a model.

RESULTS

We established two comprehensive subtracted cDNA libraries using a molecular technique called suppression subtractive hybridization. This technique selectively amplifies transcripts that are specifically expressed in circulating cells of either PCa patients or healthy men. Following sequencing reaction, we showed that 17 out of 23 (73.9%) sequenced clones did not match any mRNAs in the GenBank database. This result suggests that genes associated with alterations in circulating cells of cancer-bearing patients are largely unknown. Semi-quantitative RT-PCR confirmed that two genes are up-regulated in circulating cells of PCa patients, whereas another two genes are down-regulated in the same patients.

CONCLUSION

The comprehensive gene expression analysis is capable of identifying differentially expressed genes in circulating cells of healthy men and PCa patients. We did not attempt to enrich specific cell types in this study because phenotypes of CTCs and subsets of leukocytes participating in immunosurveillance remain largely unknown. Continuous studies of these differentially expressed genes will eventually lead us to understand the mechanisms involved in tumor metastasis and immune modulation during cancer development.

Circulating tumor cells detected by reverse transcription-polymerase chain reaction for carcinoembryonic antigen mRNA: Distinguishing follicular thyroid carcinoma from adenoma

BACKGROUND

We prospectively tested whether circulating tumor cells could be detected in peripheral blood of patients with thyroid tumors by a reverse transcription-polymerase chain reaction (RT-PCR) to detect carcinoembryonic antigen (CEA) messenger RNA (mRNA).

METHODS

We assayed for CEA mRNA by RT-PCR in peripheral blood sampled before and 2 to 3 weeks after curative surgery for thyroid tumors in 121 patients. Blood samples from 7 patients with chronic thyroiditis and 7 healthy subjects served as controls.

RESULTS

No control samples were positive for CEA mRNA by RT-PCR. Of 121 preoperative samples from patients with thyroid tumor, 6 were positive (5.0%). Preoperative frequencies of CEA mRNA positivity in benign tumor, papillary carcinoma, follicular variant papillary carcinoma, minimally invasive follicular carcinoma, and widely invasive follicular carcinoma were 0%, 0%, 0%, 44.4% (4/9), and 50.0% (2/4), respectively. Among positive patients only one, who had widely invasive follicular carcinoma, remained positive after surgery.

CONCLUSIONS

RT-PCR detection of tumor cells in preoperative blood often can distinguish malignant from benign follicular thyroid tumors.