Sensitive detection of circulating breast cancer cells by reverse-transcriptase polymerase chain reaction of maspin gene

Detection of Breast Cancer Cells in the Bone Marrow or Peripheral Blood: Methods and Prognostic Significance

Tumor cells can reach every anatomic district, organ and tissue through the peripheral blood circulation. Tumor cell shedding is considered an early event in the multi-phase process of metastasis, and the possibility of detecting tumor cells in the bloodstream and/or bone marrow before clinical evidence of distant metastases needs to be explored. The use of new sophisticated diagnostic and investigative techniques has boosted the study of tumor cell contamination of bone marrow and peripheral blood. Molecular techniques, such as reverse-transcriptase polymerase chain reaction, may be useful tools to reach this target, but, today, immunocytochemistry is still considered the gold standard to assess new techniques to detect isolated tumor cells in hematopoietic tissue. Little is known about the biology of isolated tumor cells in the peripheral blood or bone marrow. Two crucial points need to be evaluated: the identification of specific markers of breast cancer cells with clonogenic potential and their biologic properties, and the prognostic impact of the detection of isolated tumor cells in the bone marrow or peripheral blood stem cell collections.

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.

Identification of six potential markers for the detection of circulating canine mammary tumour cells in the peripheral blood identified by microarray analysis

The presence of circulating tumour cells (CTCs) in the peripheral blood is a prognostic factor for survival of human breast cancer patients. CTCs in the peripheral blood of dogs with mammary tumours have not been reported definitively. The present pilot study identifies mRNA markers for CTCs by comparing the transcriptome of canine mammary carcinoma cell lines CMM26 and CMM115 and peripheral blood leucocytes (PBLs). Genes with a 200-fold or higher mRNA expression in carcinoma cell lines were tested for specificity and sensitivity to detect CTCs using reverse transcriptase polymerase chain reaction (PCR). Six mRNA markers, AGR2, ATP8B1, CRYAB, F3 IRX3 and SLC1A1 were expressed in cell lines, but not PBL. All PCRs were able to detect one carcinoma cell admixed in 10(6) or more PBLs. The six mRNA markers may be suitable for detection of canine mammary CTCs and allow the analysis of their spatiotemporal distribution in dogs with mammary tumours.

SERPINB5 and AKAP12 - expression and promoter methylation of metastasis suppressor genes in pancreatic ductal adenocarcinoma

BACKGROUND

Early metastasis and infiltration are survival limiting characteristics of pancreatic ductal adenocarcinoma (PDAC). Thus, PDAC is likely to harbor alterations in metastasis suppressor genes that may provide novel diagnostic and therapeutic opportunities. This study investigates a panel of metastasis suppressor genes in correlation to PDAC phenotype and examines promoter methylation for regulatory influence on metastasis suppressor gene expression and for its potential as a diagnostic tool.

METHODS

Metastatic and invasive potential of 16 PDAC cell lines were quantified in an orthotopic mouse model and mRNA expression of 11 metastasis suppressor genes determined by quantitative RT-PCR. Analysis for promoter methylation was performed using methylation specific PCR and bisulfite sequencing PCR. Protein expression was determined by Western blot.

RESULTS

In general, higher metastasis suppressor gene mRNA expression was not consistent with less aggressive phenotypes of PDAC. Instead, mRNA overexpression of several metastasis suppressor genes was found in PDAC cell lines vs. normal pancreatic RNA. Of the investigated metastasis suppressor genes, only higher AKAP12 mRNA expression was correlated with decreased metastasis (P < 0.05) and invasion scores (P < 0.01) while higher SERPINB5 mRNA expression was correlated with increased metastasis scores (P < 0.05). Both genes' promoters showed methylation, but only increased SERPINB5 methylation was associated with loss of mRNA and protein expression (P < 0.05). SERPINB5 methylation was also directly correlated to decreased metastasis scores (P < 0.05).

CONCLUSIONS

AKAP12 mRNA expression was correlated to attenuated invasive and metastatic potential and may be associated with less aggressive phenotypes of PDAC while no such evidence was obtained for the remaining metastasis suppressor genes. Increased SERPINB5 mRNA expression was correlated to increased metastasis and mRNA expression was regulated by methylation. Thus, SERPINB5 methylation was directly correlated to metastasis scores and may provide a diagnostic tool for PDAC.

Small breast epithelial mucin (SBEM) has the potential to be a marker for predicting hematogenous micrometastasis and response to neoadjuvant chemotherapy in breast cancer

To investigate the potential role of small breast epithelial mucin (SBEM) as a marker for detecting hematogenous micrometastasis in breast cancer and explore its clinical significance in neoadjuvant chemotherapy. SBEM protein expression in 82 tissue specimens of primary breast cancer was detected using immunohistochemistry (IHC), and SBEM expression in peripheral blood (PB) samples of 109 primary breast cancer patients (94 cases at stage I-III, 15 cases at stage IV) was detected by flow cytometry (FCM) and reverse transcription polymerase chain reaction (RT-PCR). Moreover, SBEM mRNA expression was monitored by quantification real-time PCR (QPCR) before and after 3 cycles' neoadjuvant chemotherapy. SBEM expression correlated with tumor node metastasis (TNM) staging and lymph node metastasis at both mRNA and protein levels. SBEM expression in PB of breast cancer patients was markedly higher than that of healthy donors and other cancer patients. SBEM was found expressed in PB of 50 cases among 94 cases at stage I-III and expressed in PB of 11 cases among 15 cases at stage IV. After 3 cycles' neoadjuvant chemotherapy, SBEM expression levels were significantly down-regulated in up to 58% breast cancer patients. SBEM has the potential to be a specific marker for predicting hematogenous micrometastasis and response to neoadjuvant chemotherapy in breast cancer.

Mammaglobin and maspin transcripts in blood may reflect disease progression and the effect of therapy in breast cancer

Detection of residual tumor cells in the circulation can provide prognostic as well as therapeutic information and help in identifying patients at high risk for developing metastases. Maspin and mammaglobin are two molecules that are specifically associated with breast cancer. We looked for mammaglobin and maspin transcripts in the peripheral blood of patients with breast cancer and evaluated their utility as a marker of the response to therapy. Maspin and mammaglobin transcripts were analyzed in 85 breast-cancer patients by nested RT-PCR, prior to and after treatment. Before therapy, 10 patients were found positive for mammaglobin and 20 patients were positive for maspin. In four patients, both transcripts were detected. Immediately following treatment, only one patient was still positive for mammaglobin while maspin transcripts persisted in three patients. Disease progression was observed mainly in patients in whom maspin transcripts were not detectable. Molecular detection of circulating tumor cells during therapy based on analysis for mammaglobin and maspin transcripts is an easy and practical method that can be applied to follow-up patients. We suggest that detection of mammaglobin mRNA is useful to determine the effect of therapy while maspin transcripts may indicate more aggressive disease.

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.

DETECTION OF DISSEMINATED TUMOR CELLS IN PERIPHERAL BLOOD

Metastases are the major cause of cancer-related deaths in patients with solid epithelial malignancies, such as breast, colorectal and prostate carcinomas. Hematogenous spreading of tumor cells from a primary tumor can be considered as a crucial step in the metastasis cascade leading eventually to the formation of clinically manifest metastases. Consequently, as shown in recent studies, the detection of disseminated tumor cells in peripheral blood might be of clinical relevance with respect to individual patient prognosis and staging or monitoring of therapy. However, the rarity of disseminated tumor cells in peripheral blood renders the application of sensitive techniques mandatory for their detection. The emergence of highly sophisticated reverse transciptase-polymerase chain reaction (RT-PCR) assays, combining a preanalytical enrichment step with the assessment of multiple molecular tumor markers expressed in disseminated tumor cells, provides a powerful tool in detecting disseminated tumor cells with high sensitivity and specificity. This review will discuss currently used tumor markers as well as experimental means to enhance the sensitivity and specificity of RT-PCR assays to detect disseminated tumor cells in the peripheral blood of patients with breast, colorectal, and prostate cancers, and their clinical relevance assessed in recent studies.

Epithelial molecular markers in the peripheral blood of patients with colorectal cancer

Despite the modest improvements in patient survival from colorectal cancer in the last few decades, the overall five-year survival rate remains at 40 to 45 percent. Surgical resection is the mainstay of treatment for colorectal cancer; however, nearly one-half of all patients who undergo a potentially curative resection will relapse because of undetected micrometastasis. The fact that the overall survival rate remains poor strongly suggests that the dissemination of these cells occurs early in the disease process and emphasizes the need for finding feasible diagnostic methods with sufficient sensitivity and specificity. The most commonly used technique for the detection of nucleic acid material of disseminated tumor cells is the polymerase chain reaction. We critically review the literature on DNA and messenger ribonucleic acid molecular markers that have been used for the detection of circulating tumor cells in the peripheral blood of patients with colorectal cancer and other solid tumors as appropriate for comparison. The cytokeratins, particularly cytokeratin 19 and cytokeratin 20, are the most investigated prognostic markers, but even for these questions remain about their clinical value, and hence most recent studies are utilizing a combination of factors. There is an urgent need for standardized isolation and analysis techniques to be adopted thus allowing large-scale, appropriately controlled, multicenter trials to be undertaken on the most promising candidate markers.

Circulating HER2 mRNA-positive cells in the peripheral blood of patients with stage I and II breast cancer after the administration of adjuvant chemotherapy: evaluation of their clinical relevance

BACKGROUND

The purpose of this study was to evaluate the prognostic value of circulating tumor cells (CTCs) expressing HER2 messenger RNA (mRNA) after the administration of adjuvant chemotherapy in women with operable breast cancer.

PATIENTS AND METHODS

HER2 mRNA-positive CTCs were detected by nested RT-PCR in the peripheral blood of 214 patients with stage I and II breast cancer after the completion of adjuvant chemotherapy.

RESULTS

HER2 mRNA-positive CTCs were detected in 45 (21%) patients. Adjuvant chemotherapy could eliminate HER2 mRNA-positive CTCs in 16 (30.2%) prechemotherapy-positive patients. Moreover, HER2 mRNA-positive CTCs were detected in eight (5%) of 161 prechemotherapy-negative patients. The detection of HER2 mRNA-positive CTCs after chemotherapy was associated with reduced disease-free interval (DFI) (P = 0.006) but not with overall survival (P = 0.2); this effect was mainly observed in node-negative patients (P = 0.04) and to a lesser extent in node-positive (P = 0.06). Multivariate analysis revealed that the detection of HER2 mRNA-positive CTCs was an independent predictive factor for DFI (hazard ratio 3.238, P < 0.0005).

CONCLUSIONS

The detection of HER2 mRNA-positive CTCs after the completion of adjuvant chemotherapy may provide clinically useful information concerning the efficacy of treatment and the prognosis of patients with operable breast cancer.

The clinical significance of disseminated tumor cells in breast cancer

The presence of tumor cells in the bone marrow of primary breast cancer patients at surgery has been shown to be an independent prognostic indicator of relapse. Tumor cells have been detected either directly, using immunocytochemical staining, or indirectly, using reverse transcription-polymerase chain reaction (RT-PCR). Studies have been initiated to determine whether the presence of disseminated cells can be monitored during the therapy of patients with primary breast cancer, and thus potentially be used to predict relapse before overt metastases are detectable. Studies are also ongoing to improve methods of detection, such as immunobead enrichment followed by staining and real-time RT-PCR, and to find alternative markers for the disseminated cells. Studies of patients with overt metastases have shown that there is a large tumor load in the peripheral blood and that this predicts overall survival. This article reviews the published literature on studies carried out in both primary and metastatic breast cancer patients, the methodologies and markers used, and improvements in detection methodologies that are being investigated including real-time RT-PCR, novel markers, enrichment and automated image analysis.

RT-PCR determination of maspin and mammaglobin B in peripheral blood of healthy donors and breast cancer patients

BACKGROUND

The aim of the present study was to evaluate the accuracy of two markers, maspin and mammaglobin B, singly or in combination, to detect breast cancer. To define better the potential and limits of the two markers for diagnostic purposes, blood positivity was analyzed in relation to clinical, pathological and biological tumor characteristics.

PATIENTS AND METHODS

The markers were determined in peripheral blood (PB) samples from 27 healthy donors and 140 previously untreated patients using nested reverse transcriptase polymerase chain reaction (RT-PCR).

RESULTS

Positivity for maspin in blood samples was observed in 24% of patients with an 89% specificity. For mammaglobin B, positivity was observed in 7% of patients and never in healthy donors. The presence of maspin was correlated with cell proliferation of the primary tumor (P = 0.015), whereas mammaglobin B positivity correlated with pathological stage (P = 0.013). The presence of either marker was significantly related to nodal status.

CONCLUSIONS

Our results indicate that the two markers in association could represent a potentially useful non-invasive tool to detect breast cancer. The validation of these markers as indicators of high risk of relapse is ongoing in a series of patients with an adequate follow-up.

Effect of different cytokines on mammaglobin and maspin gene expression in normal leukocytes: possible relevance to the assays for the detection of micrometastatic breast cancer

In cancer patients, the ability to detect disseminated tumour cells in peripheral blood or bone marrow could improve prognosis and consent both early detection of metastatic disease and monitoring of the efficacy of systemic therapy. These objectives remain elusive mainly due to the lack of specific genetic markers for solid tumours. The use of surrogate tissue-specific markers can reduce the specificity of the assays and give rise to a clinically unacceptable false-positive rate. Mammaglobin (MAM) and maspin are two putative breast tissue-specific markers frequently used for detection of occult tumour cells in the peripheral blood, bone marrow and lymph nodes of breast cancer patients. In this study, it was evaluated whether MAM and maspin gene expression may be induced in the normal blood and bone marrow cells exposed to a panel of cytokines, including chemotactic factors (C5a, interleukin (IL)-8), LPS, proinflammatory cytokines (TNF-α, IL-1β) and growth factors (IL-3, granulocyte-macrophage colony-stimulating factor, granulocyte colony-stimulating factor). The experimental data show that all cytokines included in the panel, except for IL-8, were able to induce maspin expression; on the contrary, MAM gene was never induced. These results suggest that MAM is more specific than maspin and that the possible interference of cytokines should be taken into account in interpreting molecular assays for detection of isolated tumour cells.

Mammaglobin Expression in Leukapheresis Products Is a Predictive Marker of Poor Prognosis in Women with High-Risk Breast Cancer

PURPOSE

The purpose of this study was to investigate the incidence and prognostic relevance of tumor cell detection in granulocyte colony-stimulating factor-mobilized peripheral blood progenitor cell collections (PBPCCs) using cytokeratin (CK), maspin (MAS), and mammaglobin (MAM) genes as epithelial cell markers. The population on which the study was conducted was drawn from stage III breast cancer patients undergoing high-dose chemotherapy and autologous transplantation with PBPCCs.

EXPERIMENTAL DESIGN

One hundred and ninety-four patients were enrolled in the study and analyzed for tumor cell detection on the basis of 481 PBPCCs gathered before administration of chemotherapy. CK, MAS, and MAM gene expressions were investigated by means of the reverse transcription nested polymerase chain reaction, and those samples expressing CK were further hybridized with a radiolabeled internal probe to reduce false-positive results. Sensitivity and specificity were assessed on 37 controls (12 cell lines, 12 healthy donors, and 13 nonepithelial malignancies). Each of the known prognostic variables (age, stage, lymph node status, receptor status, c-ErbB2 status, and Ki67 status) was then analyzed (both individually and together with CK, MAS, and MAM expression on PBPCCs) in relation to patient overall survival (OS) and relapse-free survival (RFS).

RESULTS

After a 3-year follow-up, an estimated 83% (95% confidence interval, 77.1-88.8%) of the patients were alive and an estimated 67% (95% confidence interval, 60.1-74.6%) were free of relapse. One hundred and seventy-six of the 194 patients (91%) had contaminated PBPCCs evidenced by at least one positive sample for any of the markers evaluated. The PBPCC frequency of CK, MAS, and MAM positivity (+) was 71%, 36%, and 16%, respectively. MAM expression on PBPCC was associated with an increased risk of relapse (P = 0.003), whereas CK and MAS expressions were not associated with changes in either RFS or OS.

CONCLUSIONS

MAM gene expression on leukapheresis products of high-risk breast cancer patients is an indicator of poor prognosis. The method of evaluation is simple and reproducible and provides new tools for evaluating the role played by tumor cells in apheresis products and their potential in causing metastasis.

The detection of circulating breast cancer cells in blood

At present, sampling of the lymph nodes or bone marrow for the detection of regions of metastatic disease in patients with breast cancer can only be undertaken at the time of initial diagnosis and surgery. However, the sampling of these tissues and the methods used are inaccurate, time consuming, and cannot be used for easy routine screening to determine disease recurrence and response to treatment. Because of the problems encountered with current methods and tissues sampled at the time of breast cancer diagnosis, this review discusses the urgent requirement for and potential development of a quick, simple, and accurate diagnostic test utilising the haematogenous system, a source of circulating tumour cells in patients with breast cancer, and highly sensitive molecular biological techniques, such as reverse transcription polymerase chain reaction. In addition, this review also highlights potential problems that may be encountered and should be avoided when devising such a test.

Prognostic significance of maspin in pancreatic ductal adenocarcinoma

BACKGROUND

Maspin is a serpin family of protease inhibitors. Althouth maspin has been considered a tumor suppressor that inhibits the motility, invasion, and metastasis of breast and prostatic cancer cells, there are many conflicting reports about maspin expression and cancer prognosis.

METHODS

To investigate whether the expression of maspin could be used as a prognostic marker in pancreatic cancer, 72 paraffin-embedded pancreatic ductal adenocarcinomas were analyzed using immunohistochemistry. We examined the prognostic value of maspin as well as its relationship with clinicopathological features.

RESULTS

Maspin expression was observed in all pancreatic ductal adenocarcinoma. Unlike cancer tissues, however, faint or no expression was observed in the corresponding normal pancreatic tissues. In the Cox proportional hazard model, high maspin expression predicted a high hazard rate. Maspin expression had a positive correlation with tumor stage, but there were also no statistically significant relationships between maspin expression and other clinicopathological features.

CONCLUSION

These findings suggest maspin expression to have biological relevance in the progression of pancreatic cancers, with potential use as a prognostic marker for pancreatic neoplasm with epithelial origin.

Breast cancer micrometastases: different interactions of carcinoma cells with normal and cancer patients' bone marrow stromata

The apparently dormant breast cancer micrometastases in haemopoietic marrow are correlated with distant metastatic carcinoma dissemination. We studied in vitro interactions of carcinoma cells with adjacent stromata, using connective tissue cell cultures from breast and bone marrow samples of normal donors, comparing them to the pericancerous breast tissue and bone marrows of 12 selected patients with invasive breast carcinomas. Cancer cells were detected by immunocytochemistry and RT-PCR in all the bone marrows and in most blood samples of the studied patients. We monitored the growth and interaction of carcinoma MCF-7 cells with the stromata. The normal breast stroma sustained typical massive cancer growth. The pericancerous breast stroma induced the invasive mesenchymal pattern of growth. Normal bone marrow stroma induced the same conversion and was highly adhesive, retaining the cells in the stroma, but carcinoma patients' bone marrow stromata underwent low adhesive interactions with cancer cells, releasing them potentially into the circulation. The semi-quantitative RT-PCR indicated an enhanced expression of the hepatocyte growth factor and its receptor c-met in breast and bone marrow stromata of cancer patients. The input of cancer cells into the normal bone marrow may induce modifications of the local microenvironment, favourable for growth and release of carcinoma cells into the systemic circulation, which correlate with the poor prognosis of patients with bone marrow micrometastases.

Measurement of thyroglobulin mRNA in peripheral blood as an adjunctive test for monitoring thyroid cancer

AIMS

Monitoring treated patients with thyroid cancer for recurrent or metastatic disease is currently based upon the serial measurement of circulating plasma thyroglobulin (Tg) concentrations. However, the clinical usefulness of Tg immunoassays is limited by poor sensitivity and interference from anti-Tg antibodies. This study investigated whether the detection of Tg mRNA in peripheral blood, using reverse transcriptase polymerase chain reaction (RT-PCR), is of value in the biochemical surveillance of patients with thyroid cancer.

METHODS

RNA was extracted from peripheral blood of five normal controls, six patients with abnormal thyroid function tests, and 28 patients who had undergone thyroidectomy for well differentiated thyroid cancer. From each, an 87 bp product from base pair 262 to 348 in the cDNA sequence of the thyroglobulin gene was amplified by RT-PCR.

RESULTS

Tg mRNA was detected in normal individuals and patients with thyroid cancer. In the group of patients studied, identification of metastatic thyroid tissue by radioiodine scanning correlated better with Tg mRNA assay results than with serum Tg concentrations (accuracy 84% v 75%). No interference from circulating Tg antibodies was apparent. In patients studied prospectively over a 12 month period, there was a significant correlation between detectable Tg mRNA in peripheral blood and the presence or absence of metastatic disease, as demonstrated by radioiodine scanning.

CONCLUSIONS

These results suggest that detection of Tg mRNA in blood is a more sensitive marker for metastatic thyroid disease than Tg immunoassay, and appears to be unaffected by the presence of circulating anti-Tg antibodies.

Expression and regulation of tumor suppressor gene maspin in breast cancer

Maspin (mammary serpin) is an inhibitor of serine proteases with tumor suppressor activity in breast cancer. Maspin was originally identified by subtractive hybridization in normal breast epithelial cells, but its expression decreased during tumor progression. The loss of maspin gene expression with increasing malignancy is by transcriptional regulation. Maspin is known to be involved in invasion and metastasis, interact with the p53 tumor suppressor pathway, and act as an inhibitor of angiogenesis. The immunohistochemical analysis and reverse-transcription polymerase chain reaction of maspin in normal human breast tissue and breast carcinoma indicated a stepwise reduction of maspin expression during the progression from ductal carcinoma in situ to invasive carcinoma to lymph node metastasis. The lack of maspin expression in breast cancer seems to be associated with a short disease-free survival and supports maspin's function as an indicator for tumor aggressiveness and metastatic potential. New studies on the gene regulation of maspin provide evidence for promising potential of possible re-expression of maspin in tumor cells. The function of maspin as a tumor suppressor gene involved in tumor invasion, metastasis, and angiogenesis may not be limited to breast cancer.

Breast tumor contamination of PBSC harvests: tumor depletion by positive selection of CD34(+) cells

BACKGROUND

Positive selection of CD34(+) cells may reduce or eliminate tumor cells contaminating PBSC harvests of breast cancer (BrCa) patients. However, to assess tumor purging accurately methods may be needed that are of higher sensitivity than standard immunocytochemistry (ICC) assays.

METHODS

BrCa-cell depletion, resulting from CD34(+) cell selection, was evaluated using a novel, highly sensitive assay based upon immunomagnetic enrichment with ICC detection in 36 BrCa patients undergoing highdose chemotherapy with autologous PBSC support.

RESULTS

The prevalence of BrCa-cell contamination was significantly lower (P = 0.0078) in selected CD34(+) cell fractions (17/35, 49%) from apheresis collections compared with CD34(-) cell fractions (25/35, 71%). In 8/34 (24%) patients, BrCa cells were detected in CD34(-) cell fractions, but not in paired CD34(+) cell fractions. Significantly lower total numbers (P < 0.0005) of BrCa cells were enumerable in CD34(+) cell fractions compared with corresponding apheresis harvests. The median total BrCa-cell content of selected CD34(+) cell fractions with measurable contamination was 22 BrCa cells (range, 6-73 BrCa cells), compared with 3297 BrCa cells (range, 10-98 400 BrCa cells) in apheresis harvests. The median log depletion of BrCa cells achieved by positive CD34(+) cell selection in specimens with detectable contamination both before and after selection was 2.2 (range, 1.7-4.0). Total pre-selection BrCa cell number was significantly predictive (P = 0.004) of residual detectable post-selection contamination.

DISCUSSION

Positive CD34(+) cell selection is an effective tumor purging strategy. The prevalence of PBSC contamination in BrCa patients is substantially higher than formerly appreciated.

Nonmyeloablative conditioning followed by hematopoietic cell allografting and donor lymphocyte infusions for patients with metastatic renal and breast cancer

The feasibility and toxicity of allogeneic stem cell transplantation after nonmyeloablative conditioning including thiotepa, fludarabine, and cyclophosphamide have been investigated in 6 patients with breast cancer and 7 patients with renal cell cancer. The program included the use of escalating doses of donor lymphocyte infusions (DLI) and/or interferon alpha (IFNalpha) for patients showing no tumor response and no graft-versus-host disease (GVHD). Patients were at high risk of transplant-related mortality (TRM) because of age, advanced stage, and previous treatments. We observed a partial remission in 4 renal cancer and in 2 breast cancer patients (one at the molecular level in the bone marrow), occurring after cyclosporine withdrawal or after DLI and/or IFNalpha. All the responses were accompanied by the occurrence of acute GVHD. We conclude that reduced-intensity allogeneic stem cell transplantation is a feasible procedure in renal and breast cancer, and that the exploitation of graft-versus-tumor effect after DLI is a promising finding.

Expression of maspin in pancreatic neoplasms: application of maspin immunohistochemistry to the differential diagnosis

Maspin is a unique member of the serpin family, which inhibits tumor invasion and metastasis of the human breast and prostate cancers. Immunohistochemical evaluation of the maspin expression in pancreatic neoplasms has never been performed. The authors examined the expression of maspin in various pancreatic neoplasms to investigate its usefulness as an adjunct diagnostic marker. Formalin-fixed, paraffin-embedded tissue sections from 107 pancreatic neoplasms were immunostained with anti-maspin antibody using an EnVision+ System. Maspin was expressed in all ductal adenocarcinomas, of which 78.9% (30/38) were high expressors and 21.1% (8/38) were low expressors. All 13 intraductal papillary mucinous tumors and 11 of the 13 mucinous cystic tumors reacted to maspin with stronger expressions in carcinomatous lesions. In contrast, acinar cell carcinoma, pancreatic endocrine tumors, solid-pseudopapillary tumors, and serous cystadenomas demonstrated no maspin expression. In addition, nonneoplastic pancreatic parenchyma and chronic pancreatitis lacked expression. The current study suggests that maspin may be of importance in the pathobiology of pancreatic neoplasms with epithelial origin, especially pancreatic tumors that are composed of mucin-producing cells. It may be useful in separating ductal adenocarcinoma from acinar cell carcinoma, pancreatic endocrine tumor, solid-pseudopapillary tumor, and chronic pancreatitis, especially in needle biopsy specimens.

Maspin and mammaglobin genes are specific markers for RT-PCR detection of minimal residual disease in patients with breast cancer

BACKGROUND

This study evaluates the specificity of some reverse-transcriptase polymerase chain reaction (RT-PCR) assays for the detection of residual tumor cells in breast cancer patients. The following markers have been analysed: carcinoembryonic antigen (CEA), cytokeratins (CK19 and CK20), polymorphic epithelial mucin (MUC-1), epidermal growth factor receptor (EGFR), maspin, and mammaglobin. RT-PCR was employed to detect breast cancer cells in peripheral blood (PB), bone marrow (BM), and stem cell leukoaphereses (PBPC).

PATIENTS AND METHODS

We evaluated the specificity of our RT-PCR assays on a panel of breast cancer specimens (n = 30), on PBPC in patients undergoing high-dose chemotherapy (n = 38), on BM (n = 7) and PB (n = 5) samples obtained from patients with breast cancer. Marrow cells, PB, and PBPC from normal subjects or hematological tumor patients were tested as negative controls.

RESULTS

Only maspin and mammaglobin met the criteria of sensitivity and specificity required for the detection of residual disease; they were expressed in 80% and 97% of breast cancer specimens, respectively, and not expressed in normal controls. CK19, CK20. EGFR, MUC-1, and CEA were sometimes expressed in normal blood cells and/or hematological tumors.

CONCLUSIONS

Our data support the notion that maspin and mammaglobin are useful markers for RT-PCR detection of minimal residual disease (MRD) in breast cancer patients, and that perspective clinical studies are needed to determine wether RT-PCR assays will be useful in assessing prognosis, tailoring therapy, or developing new strategies for ex vivo purging.

High tumour contamination of leukaphereses in patients with small cell carcinoma of the lung: a comparison of immunocytochemistry and RT-PCR

In small-cell lung carcinoma (SCLC) tumour cell contamination of leukaphereses is unknown. The present study was performed to define appropriate markers for reverse transcriptase polymerase chain reaction (RT-PCR), then to assess the contamination rate of leukaphereses and corresponding bone marrow samples. Immunocytochemistry (ICC) and RT-PCR methods were also compared. Among the 33 patients included, analyses were performed in 16 who had multiple leukaphereses and 17 who had only bone marrow. Leukapheresis products and bone marrow were analysed by ICC using several specific monoclonal antibodies against neural-cell adhesion molecule (N-CAM), epithelial glycoprotein (EGP-40) and cytokeratins (CK). Samples were also analyzed by RT-PCR for expression for N-CAM, synaptophysin, neuron-specific enolase, chromogranin, cytokeratin-18/-19, CEA, EGP-40, apomucin type 1 (MUC-1) and human endothelial cell-specific molecule (ESM-1). Using ICC staining, contaminating tumour cells were detected in 34% of leukaphereses (27% in patients with limited disease and 43% in those with extensive disease). N-CAM was the most reliable marker for detection of contamination. For RT-PCR, CK-19 and CEA were the only appropriate markers. Positive signal rate in leukaphereses increased to 78% (89% for patients with limited disease and 67% for extensive disease). In bone marrow, both techniques were in agreement whereas in leukaphereses, RT-PCR was better than ICC. A high rate of tumour cell contamination was demonstrated not only in bone marrow but also in leukaphereses from SCLC patients. The most appropriate technique was RT-PCR mainly in patients with limited disease.

Reverse-transcriptase polymerase chain reaction of the maspin gene in the detection of bone marrow breast carcinoma cell contamination

BACKGROUND

Maspin is a molecular marker used for the detection of contaminating breast carcinoma (BC) cells in peripheral blood and lymph nodes. However, its specificity has been questioned recently. The objective of this study was to verify the specificity of this marker and to determine the incidence of positive bone marrow results in patients with BC who are eligible for high-dose chemotherapy (HDT) both in early and advanced disease stages and before and after treatment.

METHODS

Bone marrow specimens from 41 patients with BC as well as from 35 normal volunteers and 17 patients with hematologic tumors were examined for maspin transcript expression by a modified nested reverse transcriptase-polymerase chain reaction technique.

RESULTS

Maspin transcript was found in all normal and neoplastic breast tissues and in none of the 35 normal bone marrow specimens (specificity, 100%; 95% confidence interval, 90-100%). However, the transcript was found in 40% of the bone marrow samples from patients with hematologic malignancies. Thus, this marker appears very specific for discriminating between normal controls and patients with BC, but it cannot be considered disease specific. Among patients with BC, bone marrow was positive for the maspin transcript in 32% of patients with early-stage disease and in 75% of patients with metastatic disease before chemotherapy. After treatment, in 75% of patients with early-stage disease and in 50% of patients with metastatic disease, the bone marrow results became maspin negative.

CONCLUSIONS

On the basis of the current data, although it is not disease specific, maspin is a reliable marker for detecting bone marrow molecular disease in patients with BC and should be considered for prospective studies as a prognostic indicator and as an assay for monitoring residual disease.

Expression of the p53 and Maspin protein in primary prostate cancer: correlation with clinical features

The serine protease inhibitor Maspin has been reported to inhibit the invasiveness and motility of prostate cancer tumor cells. Additionally, a p53-dependent regulatory pathway of Maspin in prostate cancer cell lines has been indicated. The first aim of our study was to determine the prognostic value of Maspin protein expression for the recurrence-free survival of patients undergoing radical prostatectomy for the treatment of clinically localized prostate cancer. Secondly, Maspin expression was correlated to p53 protein expression in order to gain additional information on a possible and previously suggested regulatory influence of the wild-type p53 protein on the Maspin protein expression. Tumor specimens obtained from 84 patients undergoing radical prostatectomy for localized prostate cancer were investigated for the expression of the Maspin and p53 protein by an immunohistochemic approach. Maspin protein expression was correlated with further patients' and tumor characteristics such as tumor stage, histologic grading, regional lymph node status, p53 protein expression and recurrence-free survival of the patients following radical prostatectomy. After a median follow-up of 64 months (24-197 months), 23 of 40 patients (58%) with a negative or decreased Maspin expression (group 1) developed local recurrence or systemic tumor progression in contrast to 8 of 44 patients (18%) with a retained expression of the Maspin protein (group 2) (p = 0.02; log-rank test). The median recurrence-free survival following radical prostatectomy was 26 months (12-37 months) for group 1 patients and 41 months (5-134 months) for patients from group 2 (p = 0.04). A positive immunohistochemic staining reaction for the p53 protein was significantly correlated with a decreased expression of the Maspin protein (p = 0.015; Spearman correlation coefficient). Additionally, loss of Maspin protein expression was correlated to higher tumor stages (p = 0.002) and an increasing histologic dedifferentiation (p = 0.03). This is the first study to indicate that Maspin protein possibly functions as a clinically relevant inhibitor of tumor progression, preventing the local invasiveness and further systemic progression of prostate cancer. Our investigation delivers first hints for a p53-dependent regulatory pathway of the Maspin protein in human prostate cancer.

mRNA markers of breast cancer nodal metastases: comparison between mammaglobin and carcinoembryonic antigen in 248 patients

Histological detection of axillary lymph node metastases is still the most valuable prognostic parameter for breast cancer, but about 30% of node-negative patients relapse within five years, suggesting that current methods are inadequate for identifying metastatic disease. More sensitive, PCR-based methods for the detection of metastatic cells are now available, enabling the amplification of cancer cell-specific mRNA messages by the RT-PCR assay. An ideal tumour marker, consistently expressed in tumour samples and not at all in normal lymph nodes, remains to be identified. The present study first investigated the expression of seven mRNA markers, CEA, CK19, c-Met, mammaglobin, MUC-1, beta1-->GalNAc-T and p97, selected on the basis of their previously reported specificity for breast cancer cells. Eighteen lymph nodes were examined from patients without tumours. Only mammaglobin mRNA and CEA mRNA were not expressed in normal nodes. All of the other markers showed a band of expression in 17%-55% of cases, indicating that they are not breast cancer-specific. CEA mRNA and mammaglobin mRNA expression could be detected in 15/20 (75%) and 19/20 (95%) primary breast carcinomas, respectively. The expression of mammaglobin mRNA and CEA mRNA was then compared in axillary lymph nodes from 248 consecutive breast cancer patients, 89 with histologically documented lymph node metastasis and 159 without histological evidence of metastatic disease. Ninety-seven per cent of the patients with histologically involved nodes showed expression of mammaglobin mRNA, whereas CEA mRNA was expressed in 79% of these cases. In the group of patients with histologically negative lymph nodes, 46 (29%) and 32 (20%) were found to be positive for mammaglobin and CEA expression, respectively, indicating the presence of metastases not detected by routine histological examination of one lymph node section. These results show that both mammaglobin RT-PCR and CEA RT-PCR are useful tools for the detection of breast cancer metastases in axillary lymph nodes. The detection sensitivity of the mammaglobin RT-PCR is far superior to that of the CEA RT-PCR, allowing the diagnosis of occult metastases in nearly one-third of cases.

Down regulation of the tumor suppressor gene maspin in breast carcinoma is associated with a higher risk of distant metastasis

BACKGROUND

Maspin (mammary serpin) is a relatively novel serine protease inhibitor with tumor suppressing function in breast cancer. Maspin expression was found in normal breast epithelial cells, but was decreased during tumor progression. Only a few systematic analyses of this phenomenon have been undertaken so far. In this study we developed specific nested reverse transcription polymerase chain reaction (RT-PCR) conditions for the detection of maspin expression in human breast carcinoma and assessed maspin's association with the clinical behavior of primary breast cancers.

METHODS

Tumor specimens obtained from 45 primary breast cancer patients were analyzed for maspin expression by a nested RT-PCR assay. Recurrence free survival was evaluated and correlated to maspin expression.

RESULTS

The maspin transcript was detected in 29 (64%) breast cancer specimens whereas no expression was found in 16 (36%) cancer specimens. This expression was unrelated to any of the established prognostic factors. However, 6 out of 8 patients who developed distant metastasis (lymph nodes, lung, liver, bone, pleura) within 3 yr after their initial diagnosis showed no maspin expression of the primary breast cancer (p < 0.05).

CONCLUSIONS

The lack of maspin expression in breast cancer seems to be associated with a short disease free survival and supports maspin's function as an indicator of tumor aggressiveness and metastatic potential. Nested RT-PCR is a sensitive method to determine maspin expression in human breast cancer tissue.

Detection of occult metastasis in patients with breast cancer

The most important factor affecting the outcome of patients with invasive cancer is whether the tumor has spread, either regionally (to regional lymph nodes) or systemically. However, a proportion of patients with no evidence of systemic dissemination will develop recurrent disease after primary "curative" therapy. Clearly, these patients had occult systemic spread of disease that was undetectable by routinely employed methods (careful pathological, clinical, biochemical, and radiological evaluation). In addition, the success of adjuvant therapy is assumed to stem from its ability to eradicate occult metastases before they become clinically evident. Therefore, methods for the detection of occult metastases in patients with the earliest stage of cancer, i.e., prior to detection of metastases by any other clinical or pathological analysis, have received a great deal of attention.

Bone marrow micrometastases detected by RT-PCR for mammaglobin can be an alternative prognostic factor of breast cancer

PURPOSE

To evaluate a new prognostic factor of breast cancer, bone marrow micrometastases which was detected by RT-PCR for mammaglobin, a sensitive molecular marker of breast cancer, was examined.

MATERIALS AND METHODS

One hundred and eleven samples from stage I-III breast cancer patients were examined. Bone marrow micrometastases and clinicopathological parameters, which were age, tumor size, lymph node metastasis and status of the estrogen receptor, were evaluated for the prognostic factor by statistical analysis.

RESULTS

Median follow-up time was 21.1 months. Thirty-three (29.7%) out of 111 samples were RT-PCR positive. Eight cases (24.2%) in this group showed recurrent lesions in the distant organs. Whereas six (7.7%) out of 78 RT-PCR negative patients had distant recurrences. In the premenoposal patients, and in the patients with axillary lymph node metastases, RT-PCR positive cases showed significantly higher distant recurrent rate. Bone marrow micrometastases, axillary nodal status, and estrogen receptor were independent prognostic factors for breast cancer by both univariate and multivariate analysis.

CONCLUSIONS

Bone marrow micrometastases detected by RT-PCR for mammaglobin can be a useful predictive marker for early distant recurrence of breast cancer.

Maspin--a novel protease inhibitor with tumor-suppressing activity in breast cancer

Maspin (mammary serpin) is a novel serine protease inhibitor related to the serpin family with a tumor-suppressing function in breast cancer. Maspin was originally identified from normal mammary epithelium by subtractive hybridization and might function as a class II tumor-suppressor gene. Maspin's decreased expression with increased level of malignancy and its loss in metastatic cells is regulated at the transcriptional level. Cytosin methylation and heterochromatinization in the promoter region might account for this down-regulation of maspin. Transfection of tumor cells with maspin cDNA inhibits invasion and motility and decreases tumor growth and metastatic ability in nude mice. Maspin interacts with the p53 tumor-suppressor pathway and function as an inhibitor of angiogenesis in vitro and in vivo. The progressive loss of expression of maspin during tumor progression makes this new protein an interesting diagnostic and prognostic marker. The re-expression of maspin by pharmacological intervention potentially offers a promising approach as a therapeutic option in breast cancer therapy.

Molecular characterization of minimal residual cancer cells in patients with solid tumors

The failure to reduce the mortality of patients with solid tumors is mainly a result of the early dissemination of cancer cells to secondary sites, which is usually missed by conventional diagnostic procedures used for tumor staging. PCR was shown to be superior to conventional techniques in detecting circulating tumor cells and micrometastases allowing the identification of one tumor cell in up to 10(7) normal cells in various sources such as blood, bone marrow, lymph nodes, urine or stool. The methods used are based on the detection of either genomic alterations in oncogenes and tumor suppressor genes or on the mRNA expression of tissue-specific and tumor-associated genes. The additional implementation of techniques for cancer cell purification had a significant impact on analytical sensitivity and specificity of MRCC detection. For patients with e.g. melanoma, breast, colorectal or prostate cancer it was demonstrated that the presence of disseminated cancer cells defines a subgroup of patients with reduced time to recurrence. The possibility to use easily accessible body fluids as a source for MRCC detection enables longitudinal observations of the disease. In this review we discuss the potential of molecular characterization of MRCC as a tool to improve prognostication, therapy selection and drug targeting as well as therapy monitoring.

Thyroglobulin messenger ribonucleic acid levels in the peripheral blood of children with benign and malignant thyroid disease

Reverse transcriptase-PCR has identified thyroglobulin mRNA (Tg mRNA) in peripheral blood of normal adults and adults with thyroid cancer. However, no children were studied. The primary objective of this study was to determine whether whole blood Tg mRNA levels differ between benign and malignant thyroid disease in children. The secondary goals were to determine whether whole blood Tg mRNA levels vary with age or pubertal development among children with thyroid disease. Whole blood Tg mRNA levels were determined in 38 children (29 girls, nine boys; median age, 14.5 y; range, 4.8-20.4 y) with benign and malignant thyroid disease and correlated with diagnosis, age, pubertal status, thyroid size, and serum levels of free thyroxine, TSH, and Tg protein. Tg mRNA levels ranged from 3.3 to 104 pg Eq/microg total thyroid RNA (mean, 28 +/- 20.2 pg Eq/microg total thyroid RNA) and were similar in benign and malignant disorders (p = 0.67). However, in children with previously treated papillary thyroid cancer, Tg mRNA levels directly correlated with total body (131)I uptake (p = 0.026) and serum Tg protein (p = 0.037). There was no difference between boys and girls, and no change with pubertal maturation. In children with benign thyroid disease, Tg mRNA levels correlated with serum TSH (p = 0.031), but not with diagnosis, age, Tanner stage, or thyroid size. We conclude that Tg mRNA levels are similar in children with benign and malignant thyroid disease and unchanged by age or pubertal status, but correlated with tumor burden in previously treated papillary thyroid cancer.

Detection of breast cancer cell contamination in leukapheresis product by real-time quantitative polymerase chain reaction

Identification of sensitive techniques for breast cancer cell detection might be relevant for high-dose chemotherapy programs with autologous stem cell transplantation. We investigated the feasibility of Maspin, Mammaglobin and c-ErbB-2 amplification by real-time quantitative polymerase chain reaction (RQ-PCR) for the detection of breast cancer cells in leukaphereses. Expression of the three markers was determined in primary breast cancers and cell lines. Peripheral blood (PB), bone marrow (BM), and leukapheresis samples from patients with malignancies other than breast cancer were used as controls. Sensitivity was evaluated by dilution of primary tumors and cell lines with mononuclear blood cells. We found expression of the three markers in all primary tumors and most cell lines. No blood specimen from control patients had the Maspin transcript, while only one was positive for Mammaglobin. Weak c-ErbB-2 expression was detectable in most PB, all BM and all leukapheresis samples from controls. We observed a low sensitivity of Maspin RQ-PCR and a sensitivity of Mammaglobin RQ-PCR up to one tumor cell in 10(6) mononuclear cells. One out of 18 leukaphereses from breast cancer patients screened for the presence of Mammaglobin mRNA was positive. We conclude that Mammaglobin RQ-PCR might be a useful tool for detection of leukapheresis contamination.

High-sensitivity array analysis of gene expression for the early detection of disseminated breast tumor cells in peripheral blood

Early detection is an effective means of reducing cancer mortality. Here, we describe a highly sensitive high-throughput screen that can identify panels of markers for the early detection of solid tumor cells disseminated in peripheral blood. The method is a two-step combination of differential display and high-sensitivity cDNA arrays. In a primary screen, differential display identified 170 candidate marker genes differentially expressed between breast tumor cells and normal breast epithelial cells. In a secondary screen, high-sensitivity arrays assessed expression levels of these genes in 48 blood samples, 22 from healthy volunteers and 26 from breast cancer patients. Cluster analysis identified a group of 12 genes that were elevated in the blood of cancer patients. Permutation analysis of individual genes defined five core genes (P < or = 0.05, permax test). As a group, the 12 genes generally distinguished accurately between healthy volunteers and patients with breast cancer. Mean expression levels of the 12 genes were elevated in 77% (10 of 13) untreated invasive cancer patients, whereas cluster analysis correctly classified volunteers and patients (P = 0.0022, Fisher's exact test). Quantitative real-time PCR confirmed array results and indicated that the sensitivity of the assay (1:2 x 10(8) transcripts) was sufficient to detect disseminated solid tumor cells in blood. Expression-based blood assays developed with the screening approach described here have the potential to detect and classify solid tumor cells originating from virtually any primary site in the body.

A real-time quantitative reverse transcriptase polymerase chain reaction (RT-PCR) to detect breast carcinoma cells in peripheral blood

BACKGROUND

The detection of occult carcinoma cells in patients with breast cancer has been shown to predict disease recurrence and metastasis.

MATERIALS AND METHODS

To improve on molecular detection of breast carcinoma cells in blood, we have developed a sensitive and quantitative assay using real-time quantitative RT-PCR identifying transcripts of the cytokeratin-19 (CK19) gene.

RESULTS

This real-time quantitative RT-PCR is sensitive, accurate and has a high reproducibility within a wide dynamic range, which permits simultaneous quantitative analysis of samples with varying input concentrations. Furthermore, the procedure offers several technical advantages over classic quantitative PCR methods (competitive RT-PCR, Northern blotting) such as decreased likelihood of contamination due to absence of post-PCR manipulations, high sample throughput because of absence of post-PCR processing time (no agarose gel electrophoresis). In this pilot study, we detected significantly elevated CK19 transcript levels in < 10% of the volunteers, in +/- 30% of stage I-IIIa patients preoperatively and in > 70% of the and stage IV breast cancer patients.

CONCLUSIONS

Analyses using this real time quantitative RT-PCR for CK19 mRNA may prove to have clinical implications in the assessment of circulating tumour cells in peripheral blood, micrometastases in bone marrow or lymph nodes in breast cancer patients. Application of this technique in a clinical population may improve diagnosis and monitoring of metastatic breast cancer and its validation is currently ongoing.

Breast tumor contamination of peripheral blood stem cell harvests: increased sensitivity of detection using immunomagnetic enrichment

Contaminating tumor cells in peripheral blood stem cell (PBSC) grafts infused for hematopoietic rescue after high-dose chemotherapy could potentially contribute to relapse in BrCa patients. To date the prevalence of PBSC contamination in BrCa patients, as determined by standard immuno-cytochemistry (ICC) assays, has generally been found to be relatively low. However, assay sensitivity may have an important impact on the ability to detect contamination. In this investigation a novel and highly sensitive BrCa cell assay using immunomagnetic enrichment with a panel of antiBrCa monoclonal antibodies (MAbs) and detection by ICC has been characterized. The immunomagnetic enrichment with ICC detection (IE-ICC) assay was directly compared with standard ICC in ability to detect BrCa contamination of PBSC specimens from patients with high-risk stage II/III and metastatic disease. The sensitivity of the IE-ICC assay was approximately 50-fold greater than that of standard ICC. As determined by standard ICC assay, BrCa cells were present in 1/14 patients (7%) and 2/26 (8%) specimens. In contrast, with IE-ICC assay the proportions of positive findings in patients (12/14, 86%) and specimens (19/26, 73%) were significantly higher (p = 0.001 and p < 0.0005, respectively). These preliminary findings suggest that the prevalence of PBSC contamination may be substantially higher than previously appreciated. Consequently, measures to reduce tumor contamination in the graft may have the potential to improve patient outcomes. Higher sensitivity assays such as the IE-ICC assay may play an important role in assessing the risks associated with tumor contamination and the effectiveness of tumor-purging approaches such as positive selection of CD34+ cells and in monitoring patient response to therapy.

Detection of circulating tumor cells by reverse transcriptase polymerase chain reaction of maspin in patients with breast cancer undergoing conventional-dose chemotherapy

PURPOSE

To establish, in patients with breast cancer subjected to primary conventional chemotherapy and enrolled in a prospective study, the mobilizing effect of therapy on potentially neoplastic cells by means of a reverse transcriptase polymerase chain reaction (RT-PCR) assay for mRNA of maspin, a protein related to the serpin family of protease inhibitors.

PATIENTS AND METHODS

Peripheral-blood samples were collected from 30 patients with histologically proven breast cancer before and 4 and 8 days after conventional chemotherapy for three consecutive courses. A total of 216 samples were screened for the presence of maspin mRNA by RT-PCR.

RESULTS

Before therapy, all samples but one were negative. After chemotherapy, 11 patients (38%) had positive samples. No difference in the rate of positivity was observed between groups defined according to initial stage, type of chemotherapy, Ki-67-related proliferative activity, or CA 15.3 expression.

CONCLUSION

Our results confirm that RT-PCR for maspin mRNA is a sensitive assay for the study of circulating potentially neoplastic mammary cells in patients with breast cancer. Moreover, our findings indicate a marked effect of conventional-dose chemotherapy on the mobilization of these cells in breast tumors. In our series of patients, this phenomenon does not seem to be associated with other known risk factors. Finally, the data suggest, without proving, an association between the presence of circulating maspin positive cells and a higher risk of disease progression. If this association could be confirmed, then the assay could have prognostic significance. However, larger confirmatory studies are necessary.

Immunohistochemical detection of maspin is a useful adjunct in distinguishing radial sclerosing lesion from tubular carcinoma of the breast

Maspin is a recently described member of the serpin family of protease inhibitors that is consistently expressed at high levels in mammary myoepithelial cells. This feature was used in the immunohistochemical evaluation of tubular carcinoma (TC) and radial sclerosing lesion (RSL) of the breast, and compared with other markers of myoepithelial cells. Ten cases of TC and 11 cases of RSL were studied for the expression of maspin, alpha-smooth muscle actin (alpha-SMA), metallothionein (MT), and S-100 protein by immunohistochemistry. Myoepithelial cells stained strongly and diffusely for maspin creating a pattern of an outer continuous ring surrounding the epithelium of tubules of all RSLs. This pattern was absent in all TCs; however, the single-layered epithelium comprising the tubules of two TCs was positive for maspin with a moderate to strong intensity. Myoepithelial cells were not positive for MT in a consistent manner. Benign nonproliferative epithelium stained focally and weakly for maspin in four of 11 cases of RSL and was negative for MT in all 11 cases. Foci of mild to moderate epithelial hyperplasia noted in five of 11 cases of RSL stained diffusely with a weak to moderate intensity for maspin and focally with a strong intensity for MT. alpha-SMA was consistently expressed in myoepithelial cells but also in stromal myofibroblasts and blood vessels, creating a pattern that was less satisfactory than maspin in distinguishing RSL from TC. Immunohistochemical staining for S-100 protein was of no differential diagnostic value. In conclusion, immunohistochemical staining for maspin is diagnostically useful and superior to MT, S-100, and alpha-SMA, in distinguishing RSL from TC. The epithelial immunoreactivity for maspin in two of 10 TCs merits further investigation from a prognostic viewpoint.

Molecular detection of low-level disease in patients with cancer

The accurate detection of low-level disease in patients with cancer is essential to improve the staging of disease and consequently to define appropriate treatment strategies. Most methods currently used for staging are based on imaging studies and histological and immunocytochemical analysis of tissues such as bone marrow aspirates, or antibody assays for marker proteins secreted into the circulation. These methods have limited sensitivity. However, assays for nucleic acid-based markers may be valuable tools for the sensitive detection, assessment, and monitoring of disease status in asymptomatic cancer patients. Application of these methods may allow the early detection of cancer, when the tumour burden is smaller and the disease potentially more curable. The last decade has seen the application of polymerase chain reaction (PCR)-based methods to the detection of tumour in a wide variety of compartments, including peripheral blood, bone marrow, lymph nodes, urine, sputum, faeces, pancreatic juice, and more recently plasma. Molecular detection of disease by PCR has targeted DNA and RNA markers, including mutations, microsatellites, and tissue-specific gene expression. It is likely that these molecular methods will provide important clinical information, though their current clinical utility remains unclear. The current status of nucleic acid-based assays for the detection and assessment of disease status in the management of patients with solid tumours is reviewed.

Detection of circulating tumour cells in patients with breast or ovarian cancer by molecular cytogenetics

Detection of micrometastases in patients with solid tumours may aid the establishment of prognosis and development of new therapeutic approaches. This study was designed to investigate the presence and frequency of tumour cells in the peripheral blood (PB) of patients with breast or ovarian cancer by using a combination of magnetic activated cell sorting (MACS) and fluorescence in situ hybridization (FISH). Separated tumour cell and PB-samples from 48 patients (35 breast cancers, 12 ovarian tumours, one uterine sarcoma) were analysed for the presence of numerical aberrations of chromosomes 7, 12, 17 and 17 q11.2-q12. Twenty-five patients had primary disease and 23 had relapsed. The technique allows the detection of one tumour cell in 106 normal cells. Circulating tumour cells were detected in 35/48 cases (17 patients had relapsed and 13 primary carcinoma with lymph node or solid metastases) by the expression of anti-cytokeratin and the presence of numerical chromosomal abnormalities. PB-tumour cells of patients with a primary carcinoma and without solid metastases had a significantly lower percentage of chromosomal aberrations, especially for chromosome 12 (P = 0.035; P = 0.038) compared to those with relapsed disease and solid metastases. Detection and quantification of minimal residual disease may monitor the response to cytotoxic or hormonal therapy and may identify women at risk of relapse.

Analysis of potential markers for detection of submicroscopic lymph node metastases in breast cancer

We have developed sensitive assays for cytokeratin (K) 8, 16, 19, stromelysin 3 (ST3), MUC1 and maspin mRNAs using reverse transcription polymerase chain reaction (RT-PCR) and used these to assess lymph node status in patients undergoing surgery for breast cancer. In addition the RT-PCR assays were tested against lymph nodes from non-cancer patients to determine their specificity. Despite high sensitivity RT-PCR assays for K8, K16, K19, ST3 and maspin were not found to be useful as markers of submicroscopic disease as transcripts of these genes were detected in the great majority of control lymph nodes tested. Expression of MUC1 was also not found to be useful as it was both insensitive and non-specific. The importance of assessing potential markers against an adequately sized control population is demonstrated, as failure to do so can lead to erroneous conclusions.

Comparison of immunocytochemistry, reverse transcriptase polymerase chain reaction, and nucleic acid sequence-based amplification for the detection of circulating breast cancer cells

Detection of tumor cells in blood and bone marrow is increasingly used for the staging of patients with breast cancer and to evaluate the presence of tumor cells in peripheral blood progenitor cell collections to be used after high-dose therapy. We evaluated the sensitivity and specificity of three different methods for detection of tumor cells among non-tumor tissue. An immunocytochemical assay using antibodies directed against epitopes of the cytokeratin-19 (CK19) protein and two RNA-based methods: reverse transcriptase polymerase chain reaction (RT-PCR) and Nucleic Acid Sequence-Based Amplification (NASBA) for the same target gene were tested. With all the three methods, false-positive results were observed when peripheral blood mononuclear cells (PBMC) of healthy volunteers were tested. There was no concordance between the RNA-based assays and the immunocytochemical assay. The false-positive results in the RNA-based assays may be due to 'illegitimate expression' of epithelial genes in normal PBMC. The false-positive results in the immunocytochemical assay resulted from background staining of monocytes and granulocytes. This study demonstrates that CK19 is not a suitable target to detect the presence of breast tumor tells in PBMC. To reliably detect circulating tumor cells with RNA methods, the selection of suitable target genes is required, which are highly expressed in tumors but not at all in normal cells of blood and bone marrow. Genes with such characteristics may be identifiable with novel differential display techniques.

Quantitative Reverse Transcription-PCR Measurement of Thyroglobulin mRNA in Peripheral Blood of Healthy Subjects

Background: Thyroglobulin mRNA can be detected qualitatively in the peripheral blood of patients with metastatic thyroid cancer, thyroid cancer patients with residual thyroid bed uptake, and individuals with no known thyroid disease with intact thyroid glands by use of a lengthy, highly sensitive extraction technique. To improve and broaden the clinical usefulness of this assay, we developed a quantitative reverse transcription (RT)-PCR assay for thyroglobulin mRNA, using RNA recovered from whole blood with a simplified extraction technique.

Methods: Whole blood was drawn from 32 healthy subjects in standard EDTA blood collection tubes. Total RNA was extracted from whole blood, using the PUREscript RNA Isolation Kit. RT-PCR using intron-spanning primers was used to quantitatively amplify thyroglobulin mRNA, using the ABI PRISM 7700 Sequence Detection System with a fluorescent-labeled, thyroglobulin-specific oligonucleotide probe. Thyroid RNA calibration curves were created using total RNA recovered from a single nondiseased thyroid gland.

Results: Qualitative RT-PCR demonstrated the presence of thyroglobulin mRNA in the whole blood sample of each healthy subject. The mean concentration of thyroglobulin mRNA detected in these subjects was 433 ± 69 ng of total thyroid RNA per liter of whole blood (range, 26–1502 ng/L). Overall assay imprecision (CV) was 24% for five samples analyzed 10 times each in separate analytical runs on different days.

Conclusions: Thyroglobulin mRNA can be accurately detected and quantified in peripheral blood from healthy subjects. This new quantitative technique may improve the clinical utility of circulating thyroglobulin mRNA detection in patients with thyroid disease.