Limitations of reverse-transcriptase polymerase chain reaction analyses for detection of micrometastatic epithelial cancer cells in bone marrow

Detecting AFP mRNA in peripheral blood of the patients with hepatocellular carcinoma, liver cirrhosis and hepatitis

BACKGROUND

The low frequency of disseminated carcinoma cells in the blood now makes immunomagnetic bead sorting and reverse transcriptase-polymerase chain reaction (RT-PCR) technique more popular.

METHODS

Three milliliters of peripheral blood were collected from 91 patients and 18 normal donors. The circulating carcinoma cells were enriched with CD45 and Ber-EP4 immunomagnetic beads. The alpha-fetoprotein (AFP) mRNA was amplified with nested RT-PCR.

RESULTS

The total positive detection rate was 72.1%, 43.8%, 25.0%, 100%, and 66.7% in patients with hepatocellular carcinoma (HCC) untreated, liver cirrhosis (LC), hepatitis, metastasis liver cancer, and postsurgery of hepatocellular carcinoma, respectively. There was a significant difference among the patients with HCC, LC and hepatitis (HCC vs. LC, P<0.05; HCC vs. hepatitis, P<0.01) and between Class A and B of the HCC patients (P<0.05). Meanwhile, AFP mRNA was markedly expressed in HCC patients compared to the patients with no HCC (LC and hepatitis). The levels of aspartate transaminase (AST) and gamma-glutamyltranspeptidase (GGT) were significantly different in AFP mRNA-positive patients with autoimmune chronic active hepatitis B (CAHB) or LC in contrast to the corresponding negative patients.

CONCLUSION

Combining negative and positive immunomagnetic bead sorting and RT-PCR technique can effectively detect circulating tumor cells. AFP mRNA is a more reliable marker of metastasis compared to serum AFP.

Detection and quantification of circulating tumor cells in mouse models of human breast cancer using immunomagnetic enrichment and multiparameter flow cytometry

BACKGROUND

Circulating tumor cells (CTCs) in the peripheral blood of breast cancer patients may be an important indicator of metastatic disease and poor prognosis. However, the use of experimental models is required to fully elucidate the functional consequences of CTCs. The purpose of this study was to optimize the sensitivity of multiparameter flow cytometry for detection of human tumor cells in mouse models of breast cancer.

METHODS

MDA-MB-468 human breast cancer cells were serially diluted in whole mouse blood. Samples were lysed and incubated with a fluorescein isothiocyanate-conjugated anti-human leukocytic antigen antibody and a phycoerythrin-conjugated anti-mouse pan-leukocyte CD45 antibody. Samples were then immunomagnetically depleted of CD45-positive leukocytes, fixed, permeabilized, and stained with propidium iodide before flow cytometric analysis.

RESULTS

Human breast cancer cells could be differentiated from mouse leukocytes based on increased light scatter, cell surface marker expression, and aneuploid DNA content. The method was found to have a lower sensitivity limit of 10(-5) and was effective for detecting human breast cancer cells in vivo in the circulation of experimental mice carrying primary human mammary tumors.

CONCLUSIONS

This technique has the potential to be a valuable and sensitive tool for investigating the biological relevance of CTCs in experimental mouse models of breast cancer.

Detection and molecular characterisation of disseminated tumour cells: Implications for anti-cancer therapy

Haematogenous distant metastasis is the leading cause of cancer-related death in solid tumours. By applying sensitive immunocytochemical and molecular assays, disseminated tumour cells (DTC) in bone marrow (BM) can be detected in 20-40% of cancer patients without any clinical or even histopathological signs of metastasis, and the presence of these DTC at primary diagnosis predicts the subsequent occurrence of overt metastases in bone and other organs. The detection and characterisation of DTC in BM may lead to a better understanding of the biology initiating metastatic spread in cancer patients and will eventually contribute to the development of more effective strategies to eliminate DTC. In this review, we will therefore discuss the detection and characterisation of DTC in the light of new therapeutic strategies targeting tumour-associated molecules and signalling pathways.

Detection of Micrometastatic Disease in Bone Marrow: Is It Ready for Prime Time?

Minimal residual disease (MRD), or isolated tumor cells (ITCs) in bone marrow, may be the source of potentially fatal overt distant metastases in solid tumors even years after primary treatment. MRD can be detected by immunohistochemical methods using antibodies directed against cytokeratins or cell-surface markers or molecular, polymerase chain reaction-based techniques. Among solid tumors, the clinical relevance of MRD has been most extensively studied in breast cancer patients. Recently, the highest level of evidence for the prognostic impact of MRD in primary breast cancer was reached by a pooled analysis comprising more than 4,000 patients, showing poor outcome in patients with MRD at primary therapy. Yet the clinical application of MRD detection is hampered by the lack of a standardized detection assay. Moreover, clinical trial results demonstrating the benefit of a therapeutic intervention determined by bone marrow status are still absent. Recent results suggest that, in addition to its prognostic impact, MRD can be used for therapy monitoring or as a potential therapeutic target after phenotyping of the tumor cells. Persistent MRD after primary treatment may lead to an indication for extended adjuvant therapy. However, until clinically relevant data regarding successful therapy of MRD are available, treatment interventions on the basis of MRD should only be performed within clinical trials.

Lacking immunocytological GD2 expression in neuroblastoma: report of 3 cases

Immunocytological bone marrow assessment for contamination with neuroblastoma cells is based on their characteristic GD2 surface staining. Neuroblastoma without GD2 expression have been rarely and only after antibody therapy reported. Conventional cytology was performed using Pappenheim staining. For immunocytology, the APAAP method was utilized with the 14G2a anti-GD2 mouse monoclonal antibody. 7 x 10(5) cells on cytospin preparations were investigated. In 2003, 288 bone marrow samples from 191 neuroblastoma patients were investigated by cytology and immunocytology. Three cases demonstrated GD2 negativity on cytologically unambiguous neuroblastoma cells. Two female cases (94 and 37 months of age) with stage 4 neuroblastoma had GD2 expressing neuroblastoma cells in bone marrow at diagnosis. At 2nd relapse 25 and 23 months after diagnosis and 8 months and 12 months after anti-GD2 antibody treatment (ch14.18), the bone marrow infiltrating neuroblastoma cells lacked GD2 staining. The third patient, a 63-month-old girl with bone marrow replacement by neuroblastoma cells showed at diagnosis a mixture of GD2-unstained tumor clumps and very weakly stained neuroblastoma cells. Neuroblastoma cells may lack GD2 expression at diagnosis and at recurrence. This observation has diagnostic and therapeutic implications.

The use of a panel of monoclonal antibodies to enrich circulating breast cancer cells facilitates their detection

OBJECTIVE

Metastatic relapse due to early dissemination of tumor cells is associated with poor prognosis for epithelial cancer. The molecular characterization of these single cells or cell clusters that have evaded the tumor is indispensable in order to evaluate their biological behavior and metastatic potential. In this study, we established a sensitive immunomagnetic method to isolate rare cancer cells from peripheral blood based on their expression of epithelial- or tumor-cell-specific markers.

METHODS

Low numbers of cells of breast cancer cell lines - ZR-75-1, MCF-7, HBL-100 - were spiked into peripheral blood specimens of healthy volunteers. Enrichment of tumor cells was performed using either pre-coupled HEA and/or ErbB2 microbeads or a mixture of three monoclonal antibodies against HEA, ErbB2 and EGFR.

RESULTS

The recovery rate of spiked tumor cells correlated with the expression of the corresponding antigens. ZR-75-1 cells high expressing all three genes could be isolated to 60-71%. MCF-7 cells, which hardly express EGFR, showed a significant better recovery by using two specific antibodies in combination (50-68%) than one pre-coupled bead alone (31-42%). HBL-100 cells little expressing HEA could not be isolated with HEA microbeads and only to 27% in combination with ErbB2 beads -in contrast the use of an antibody cocktail achieved 38%.

CONCLUSION

As tumor and epithelial specific cell marker antigens are expressed differently in disseminated tumor cells, the immunomagnetic enrichment from peripheral blood is most robust and reliable when using a combination of specific antibodies compared to single antibodies.

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.

Quantitative real-time reverse transcription: polymerase chain reaction of prostate-specific antigen (PSA) for detection of circulating prostatic cells in patients with clinically localized prostate cancer

OBJECTIVE

To evaluate the clinical utility of using the real-time reverse transcriptase-polymerase chain reaction (RT-PCR) to quantify prostate-specific antigen (PSA) mRNA in peripheral blood samples from patients with prostate cancer as a predictor of extraprostatic extension of the disease and to assess any correlations with known predictive markers of this condition.

METHODS

Immediately before radical prostatectomy, peripheral blood samples were taken from 42 men with clinically localized prostate cancer and analysed for PSA and 18S ribosomal (endogenous control) genes using real-time RT-PCR (with gene expression assays and the comparative CT-cycle threshold-method for quantifying). A total of 30 healthy male blood donors aged <50 y was taken as a control group. The relationships between PSA mRNA values, pathological and clinical features were analysed. PSA mRNA value, PSA level and biopsy Gleason score were then compared as predictors of extraprostatic extension.

RESULTS

PSA gene expression was 3.73 times significantly higher in patients with clinically localized prostate cancer than in healthy men (P<0.05). There was no relationship between PSA real-time RT-PCR values and pathological stage pT2 or pT3 (P=0.5), and no association between PSA mRNA value and serum PSA level (P=0.9) or the Gleason score of the preoperative biopsy (P=0.9).

CONCLUSION

There was no significant advantage in using the real-time RT-PCR assay of PSA mRNA before surgery to stage prostate cancer and to discriminate between organ-confined and extraprostatic extension.

Evaluation of a Panel of Tumor Markers for Molecular Detection of Circulating Cancer Cells in Women with Suspected Breast Cancer

PURPOSE

We examined the feasibility of using molecular characterization of circulating tumor cells as a method for early detection of breast cancer.

RESEARCH DESIGN

Women without a prior history of cancer who had a breast abnormality detected on imaging followed by a breast biopsy were enrolled in this study. Density gradient centrifugation and immunomagnetic capture were used to enrich for epithelial cells from approximately 20 mL of blood. Real-time reverse transcription-PCR was used to quantitate the expression levels of the highly breast-specific genes, mammaglobin, gamma-aminobutyric acid type A receptor pi subunit (GABA A(pi)), B305D-C, and B726P in the epithelial cell-enriched samples.

RESULTS

The assay was technically feasible in 154 of 199 accrued patients. From their clinical assessment, 100 patients had benign breast disease, 10 patients had ductal carcinoma in situ, and 44 patients had invasive breast cancer. We constructed a diagnostic test that classified patients with mammaglobin levels of at least 32.2 copies/pg beta-actin (units) in their circulating epithelial cells as positive for invasive breast cancer. This resulted in a sensitivity and specificity of 63.3% and 75.0%, respectively. A diagnostic test that classified patients as positive for invasive breast cancer when either mammaglobin levels were >46.3 units or B305D-C levels were >11.6 units increased the sensitivity and specificity to 70.5% and 81.0%, respectively. In the latter test, 12 of the 14 node-positive breast cancer patients were correctly identified. Including GABA A(pi) and B726P in the test did not increase its diagnostic potential.

CONCLUSIONS

These results suggest that molecular characterization of circulating epithelial cells using mammaglobin and B305D-C offers potential for early detection of invasive breast cancer.

Colorectal cancer metastasis: in the surgeon's hands?

Background

Lymphovascular ligation before tumour manipulation during colorectal cancer resection is termed the 'no-touch isolation' technique. It aims to reduce the intra-operative dissemination of colorectal cancer cells. Recently, the detection of circulating tumour cells has been enhanced by molecular biology techniques. This paper reviews the evidence for the no-touch isolation technique in light of the recent developments in circulating tumour cell detection.

Methods

Studies investigating the effect of colorectal cancer surgery on circulating tumour cells were identified by a Medline search using the subject headings colorectal neoplasms and neoplasm circulating cells together with the map term 'no-touch isolation technique'. Further references were obtained from key articles.

Results

Molecular biological techniques have improved the detection of circulating colorectal cancer cells. There is a trend towards reduced tumour cell dissemination with the no-touch technique compared with the conventional method. However the benefit in terms of improved patient survival remains unproven.

Conclusion

The no-touch isolation technique reduces circulating tumour cell dissemination but further work is needed to determine the significance of this with regards to patient survival.

Quantification of colorectal cancer micrometastases in lymph nodes by nested and real-time reverse transcriptase-PCR analysis for carcinoembryonic antigen

PURPOSE

Reverse-transcriptase PCR (RT-PCR) assays for carcinoembryonic antigen (CEA) have been described to identify lymph node micrometastases. These assays are not quantitative and can be confounded by false-positive results. The purpose of this study was to determine whether quantification of CEA in lymph nodes could more readily identify clinically relevant groups.

EXPERIMENTAL DESIGN

Specimens included 400 lymph nodes from 64 patients undergoing colon resections. Specimens were tested by immunohistochemistry and by RT-PCR using nested primers for CEA. Specimens from 59 patients that were positive by nested RT-PCR were further quantified by detection of CEA mRNA fluorescence increase at a threshold PCR cycle.

RESULTS

CEA was detected by nested RT-PCR analysis in 4 of 34 (12%) nodes of nonneoplastic disease, 2 of 13 (15%) nodes from T(1)N(0) patients, 32 of 81 (40%) nodes of T(2)N(0) patients, 49 of 109 (45%) nodes from T(3)N0 patients, and 92 of 163 (56%) nodes from T(1-4)N(1-2) patients. The overall presence of any RT-PCR-detectable CEA in nodes did not differentiate patient groups. Immunohistochemistry was positive in nodes from 7% of T(3)N(0) patients and 100% of T(1-3)N(1-2) patients. CEA quantification revealed that 0 of 7 patients with nonneoplastic disease and 2 of 17 (12%) patients with stage I T(1-2)N(0) cancers had one or more lymph nodes with >/=1.0 x 10(2) CEA transcripts per sample. In contrast, 4 of 13 (31%) patients with stage II T(3)N(0) cancer and 10 of 22 (45%) stage III patients with known metastases had lymph nodes with >/=1.0 x 10(2) CEA transcripts.

CONCLUSIONS

These data suggest that quantification of CEA levels in lymph nodes may more accurately identify patients at risk for cancer recurrence than does routine nested RT-PCR or immunohistochemistry.

Accurate Molecular Detection of Non-small Cell Lung Cancer Metastases in Mediastinal Lymph Nodes Sampled by Endoscopic Ultrasound-Guided Needle Aspiration

OBJECTIVES

The recurrence of disease after the complete resection of early stage non-small cell lung cancer (NSCLC) indicates that undetected metastases were present at the time of surgery. Quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) is a highly sensitive technique for detecting rare gene transcripts that may indicate the presence of cancer cells, and endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) is a minimally invasive technique for the nonoperative sampling of mediastinal lymph nodes. The aim of this study was to determine whether these two techniques could enhance the preoperative detection of occult metastases.

METHODS

Patients with NSCLC were evaluated with chest CT and positron emission tomography scans. Those patients without evidence of metastases (87 patients) underwent EUS-guided FNA. Lymph nodes from levels 2, 4, 5, 7, 8, and 9 were sampled and evaluated by standard cytopathology and real-time RT-PCR. Normal control FNA specimens were obtained from patients without cancer who were undergoing EUS for benign disease (17 control specimens). For each sample, messenger RNA was extracted and real-time RT-PCR was used to quantitate the expression of six lung cancer-associated genes (ie, CEA, CK19, KS1/4, lunx, muc1, and PDEF) relative to the expression of an internal control gene (beta(2)-microglobulin).

RESULTS

Clinical thresholds of marker positivity were set at 100% specificity, as determined by the receiver operating characteristic curve analysis. Of the cytology-positive lymph nodes (27 lymph nodes), the expression of the KS1/4 gene was above its respective clinical threshold in 25 of 27 samples (93%), making this the most sensitive marker for the detection of metastatic NSCLC. At least one of the six lung cancer-associated genes was overexpressed in 18 of 61 cytology-negative patients (30%), of which KS1/4 was overexpressed in 15 of 61 patients (25%).

CONCLUSIONS

Based on the high accuracy of EUS-guided FNA/RT-PCR, we predict that some of the patients in the cytology-negative/marker-positive category will have high NSCLC recurrence rates. Among the genes used in our marker panel, KS1/4 appears particularly useful for the detection of overt or occult metastatic disease.

Design of a real time quantitative PCR assay to assess global mRNA amplification of small size specimens for microarray hybridisation

BACKGROUND

Low RNA yields from clinical samples are a limiting step for microarray technology.

AIMS

To design an accurate real time quantitative polymerase chain reaction (PCR) assay to assess the crucial step of global mRNA amplification performed before microarray hybridisation, using less than 1 microg total RNA.

METHODS

Three RNA extraction procedures were compared for small size samples. Total RNA was amplified from universal RNA or the BC-H1 breast cancer micrometastatic cell line using three different protocols. Real time quantitative PCR technology was used for accurate measurement of urokinase plasminogen activator receptor and cytokeratin 8 RNA amplification rates and ratios, using primer sets binding at various distances from the 3' end of transcripts. A 50 mer oligomeric array targeting 87 genes potentially involved in breast cancer metastatic progression was built and hybridised with amplified RNA.

RESULTS

Eighteen nanograms of total RNA could be purified from 1000 BC-H1 micrometastatic cells. Amplification rates of 25,000 to 100,000 were achieved with as little as 10 ng of starting material. However, results were highly variable, depending on the amount of starting material, gene characteristics, sample quality, and protocols used. Oligomeric array hybridisation with 20 microg reference RNA resulted in specific and reproducible signals for 83% of the genes, whereas mRNA amplification from less than 400 ng of starting material resulted in selective detection of signals from highly expressed genes.

CONCLUSIONS

Improvements in the design of global mRNA amplification procedures and oligomeric arrays are needed to extract informative gene expression data from clinical samples containing limited cell numbers.

Epithelial cell adhesion molecule (KSA) expression: pathobiology and its role as an independent predictor of survival in renal cell carcinoma

PURPOSE

Epithelial cell adhesion molecule (EpCAM) is a widely expressed adhesion molecule in epithelial cancers. The purpose of this study is to determine the protein expression patterns of EpCAM in renal cell carcinoma (RCC) using tissue arrays linked to a clinicopathological database to evaluate both its predictive power in patient stratification and its suitability as a potential target for immunotherapeutic treatment strategies.

EXPERIMENTAL DESIGN

The University of California, Los Angeles kidney cancer tissue microarray contains specimens from 417 patients treated with nephrectomy. EpCAM protein expression in tumors and matched morphologically normal renal tissues was evaluated using anti-EpCAM immunohistochemistry. The resultant expression reactivity was correlated with clinicopathological variables.

RESULTS

EpCAM is consistently expressed in the distal nephron on normal renal epithelium. Clear cell RCCs show minimal and infrequent EpCAM expression, whereas chromophobe and collecting duct RCCs both demonstrate intense and frequent expression. Of 318 clear cell carcinomas used in the analysis, 10% were EpCAM positive in > or = 50% of cells, and 8% of patients would be considered candidates for EpCAM-based therapy, based on high expression [> or = moderate intensity and frequent (> or = 50%) expression] and the need for systemic treatment. EpCAM expression was an independent prognostic factor for improved disease-specific survival, with a multivariate hazard ratio of 0.63 (P = 0.017; 95% confidence interval, 0.43-0.92).

CONCLUSIONS

EpCAM is a novel prognostic molecular marker in RCC patients, and its positive expression is an independent predictor associated with improved survival. However, high expression in morphologically normal renal tissues and minimal or absent expression in clear cell carcinomas will likely limit the utility of this epithelial marker in targeted treatments of this most common RCC type.

Detection of lymph node micrometastasis in gastric cancer by MUC2 RT-PCR: usefulness in pT1 cases

BACKGROUND AND OBJECTIVES

The objectives of this study were to evaluate the clinical utility of MUC2-specific reverse transcriptase-polymerase chain reaction (RT-PCR) in gastric cancer patients and to compare MUC2-specific RT-PCR to carcinoembryonic antigen (CEA)-specific RT-PCR.

METHODS

A total of 305 lymph nodes from 28 patients with gastric cancer were histologically examined and analyzed by MUC2 RT-PCR and CEA RT-PCR.

RESULTS

MUC2 and CEA were expressed in 17.1 and 7.0% of the 286 histologically negative lymph nodes, respectively. The detection rate of MUC2 was significantly higher than that of CEA (P < 0.01). MUC2 RT-PCR revealed no false positive results in control specimens. Lymph node micrometastases in pT1 gastric cancer were expressed only in perigastric lymph nodes near the tumor and were not detected in tumor less than 30 mm in patients with mucosal cancer.

CONCLUSIONS

MUC2-specific RT-PCR is a sensitive and specific method to detect lymph node micrometastases in gastric cancer patients. The distribution of lymph node micrometastases detected by this method may be useful in minimally invasive procedures for gastric cancer, especially pT1 cases.

Gastric cancer cell detection in peritoneal lavage: RT-PCR for carcinoembryonic antigen transcripts versus the combined cytology with peritoneal carcinoembryonic antigen levels

Free cancer cells exfoliated from the serosal surfaces of primary cancers are considered to be responsible for peritoneal dissemination, which are both the most frequent pattern of treatment failure and the most important cause of death in gastric cancer patients. Detection of free cancer cells in the peritoneal cavity at the time of surgery, therefore, is thought to be of great value in predicting peritoneal recurrence and accordingly the prognosis of gastric cancer patients. This study was designed to determine whether free cancer cells in peritoneal lavage fluid from gastric cancer patients could be identified by a reverse-transcriptase polymerase chain reaction (RT-PCR) method specific to carcinoembryonic antigen (CEA) mRNA. Simultaneously, the results from conventional cytological examination were evaluated and the levels of CEA in peritoneal lavage were determined. Of the 40 gastric cancer patients enrolling in this investigation, 11 (27.5%) were positive for CEA mRNA in their peritoneal lavage, whereas only 6 (15%) and 8 (20%) were shown to be positive by cytological examination and peritoneal CEA (pCEA) assay, respectively. Furthermore, RT-PCR positive for CEA mRNA was correlated with the depth of tumor invasion (P<0.001), lymph node metastases (P=0.004), the TNM stage (P<0.001) and peritoneal recurrence (P<0.001). The technique of RT-PCR was more sensitive than conventional cytological examination and pCEA levels in the detection of peritoneal free cancer cells as well as in the prediction of peritoneal recurrence. In addition, CEA RT-PCR had a high concordance rate (82.5%) with the combination of cytology with pCEA levels. These observations suggest that it is feasible to identify free cancer cells in peritoneal lavage by using a CEA mRNA-specific RT-PCR method, and this assay can be a promising diagnostic modality for evaluating the risk of peritoneal dissemination in gastric cancer patients following operations.

Clinical significance of immunocytochemical detection of tumor cells using digital microscopy in peripheral blood and bone marrow of breast cancer patients

PURPOSE

The presence of tumor cells in bone marrow has been reported to represent an important prognostic indicator in breast cancer, but the clinical significance of circulating cells in peripheral blood is less well known. The aim of this study was to evaluate the feasibility of identifying cytokeratin (CK)-expressing cells in peripheral blood with an automat-assisted immunohistochemical detection system and to compare it with detection of tumor cells in bone marrow samples.

EXPERIMENTAL DESIGN

Cytospun Ficoll fractions of peripheral blood and bone marrow were obtained simultaneously in 114 breast cancer patients at different stages of the disease (I to IV) before treatment with chemotherapy. The pancytokeratin (CK) monoclonal antibody A45-B/B3 (anti-CKs 8, 18, and 19) was used for epithelial cell detection. Immunostained cells were detected by an automated cellular imaging system (ChromaVision Medical System).

RESULTS

CK+ cells were detected in 28 (24.5%) patients in blood and in 67 (59%) patients in bone marrow. Twenty-six (93%) patients with CK-positive cells in blood also had positive bone marrow (P < 0.001). Positive cells were detected in peripheral blood in 3/39 (7.5%) operable breast cancers (stage I/II), 9 of 36 (25%) locally advanced breast cancers (stage III), and 16 of 39 (41%) patients with metastatic disease (stage IV; P = 0.017). In the subgroup of nonmetastatic patients (n = 75), prognostic factors for poor disease-free survival were: absence of estrogen receptor; presence of CK+ cells in bone marrow (P = 0.012); clinical nodal involvement; large tumor size (T4); and presence of tumor emboli. Presence of circulating CK+ cells in the peripheral blood was not statistically correlated with disease-free survival. On multivariate analysis, independent indicators for disease-free survival were: absence of estrogen receptor (P = 0.043) and presence of CK+ cells in bone marrow (P = 0.076).

CONCLUSIONS

The clinical relevance of circulating epithelial cells as a prognostic factor is not supported by the present data, especially in comparison with tumor cells in the bone marrow. However, this method of detection may be useful to monitor the efficacy of treatment in advanced or metastatic breast cancer.

A relevant immunomagnetic assay to detect and characterize epithelial cell adhesion molecule-positive cells in bone marrow from patients with breast carcinoma: immunomagnetic purification of micrometastases

BACKGROUND

The efficient detection and characterization of micrometastatic cells in the bone marrow of patients with breast carcinoma are of prognostic and therapeutic importance. The technique used must overcome the challenges that result from the small number of target cells (1 per 1 million hematopoietic cells) and the heterogeneous expression of micrometastatic cell markers. In this study, the authors assessed and improved the current methods for purifying and characterizing rare disseminated carcinoma cells.

METHODS

The authors developed a single-step assay that does not require density-gradient separation. This assay can be performed directly on crude human bone marrow aspirates and is based on the use of immunomagnetic beads coated with an antibody that recognizes an epithelial cell-surface epitope, the epithelial cell adhesion molecule (EpCAM). To determine the specificity of the assay, the authors evaluated bone marrow specimens from 46 control patients.

RESULTS

The novel method was highly reproducible and was capable of detecting as few as 10 carcinoma cells among 50 million hematopoietic cells. The yield was nearly 100%, with only 0.01% nonspecific cell draining. The authors found that 68 +/- 51 cells were trapped per 50 million cells in control crude aspirates and that density-gradient separation increased this number by 2-fold to 29-fold. These trapped cells expressed EpCAM, represented 1.4 x 10(-4) % of the sample, and were characterized as of hematopoietic cell origin (CD45 positive) or progenitor cell origin (CD34 positive).

CONCLUSIONS

The authors developed a highly efficient and reproducible, single-step immunomagnetic assay that may be performed directly on crude human bone marrow aspirates. The authors believe the current study is the first to demonstrate that some rare bone marrow cells (CD45-positive or CD34-positive cells) may express EpCAM and, to some extent, may contaminate the purified micrometastatic cell fraction. Thus, a universal marker for micrometastatic cells remains to be discovered.

Molecular detection of micrometastatic breast cancer in histopathology-negative axillary lymph nodes correlates with traditional predictors of prognosis: an interim analysis of a prospective multi-institutional cohort study

OBJECTIVE

We sought to establish the clinical relevance of micrometastatic disease detected by reverse transcription polymerase chain reaction (RT-PCR) in axillary lymph nodes (ALN) of breast cancer patients.

BACKGROUND

The presence of ALN metastases remains one of the most valuable prognostic indicators in women with breast cancer. However, the clinical relevance of molecular detection of micrometastatic breast cancer in sentinel lymph nodes (SLN) and nonsentinel ALN has not been established.

METHODS

Four hundred eighty-nine patients with T1-T3 primary breast cancers were analyzed in a prospective, multi-institutional cohort study. ALN were analyzed by standard histopathology (H&E staining) and by multimarker, real-time RT-PCR analysis (mam, mamB, muc1, CEA, PSE, CK19, and PIP) designed to detect breast cancer micrometastases.

RESULTS

A positive marker signal was observed in 126 (87%) of 145 subjects with pathology-positive ALN, and in 112 (33%) of 344 subjects with pathology-negative ALN. In subjects with pathology-negative ALN, a positive marker signal was significantly associated with traditional indicators of prognosis, such as histologic grade (P = 0.0255) and St. Gallen risk category (P = 0.022). Mammaglobin was the most informative marker in the panel.

CONCLUSION

This is the first report to show that overexpression of breast cancer-associated genes in breast cancer subjects with pathology-negative ALN correlates with traditional indicators of disease prognosis. These interim results provide strong evidence that molecular markers could serve as valid surrogates for the detection of occult micrometastases in ALN. Correlation of real-time RT-PCR analyses with disease-free survival in this patient cohort will help to define the clinical relevance of micrometastatic disease in this patient population.

Prognostic significance of occult tumor cells in the apheresis products of patients with advanced breast cancer receiving high-dose chemotherapy and autologous hematopoietic progenitor cell support

We prospectively evaluated the prognostic significance of occult tumor cells (OTCs) contaminating the peripheral blood progenitor cell apheresis products of patients with advanced breast cancer receiving high-dose chemotherapy. Immunocytochemistry of peripheral blood progenitor cells was performed in 242 patients with high-risk primary breast cancer (HRPBC) and in 111 patients with metastatic breast cancer (MBC). OTCs were detected in 6.6% of HRPBC patients and in 16.2% of MBC patients (P = .005). In HRPBC, OTCs correlated with worse prognostic scores and larger tumor sizes, but not with axillary nodal status, hormone receptors, or HER2. In the MBC group, OTCs correlated with bone marrow involvement and with disease status at transplantation. The number of apheresis procedures was not associated with the risk of contamination. In HRPBC patients, at a median follow-up of 7 years (range, 1.5-11 years), the presence of OTCs correlated with worse event-free survival (P = .007) and overall survival (P = .002). In the MBC group, OTCs correlated with worse event-free survival (P = .04), but not overall survival (P = .2). In multivariate analyses, the presence of OTCs had an independent adverse effect on outcome in HRPBC, but not MBC. Our observations imply a direct role of OTCs in posttransplantation relapse in HRPBC.

Circulating tumour cells in breast cancer

By use of modern immunological and molecular analytical techniques, cells with the characteristics of tumour cells can be detected in the blood of many patients with breast cancer. The ability to detect and characterise such cells routinely could have a profound influence on the early diagnosis of breast cancer, risk stratification in the adjuvant setting, early detection of relapse, and the development of new targeted strategies. In this review we discuss current techniques to detect circulating breast-cancer cells and the limitations of these approaches. We also review the clinical studies in breast cancer and discuss the potential relevance of this research to the future management of the disorder.

Quantitative real-time RT-PCR for detection of disseminated tumor cells in peripheral blood of patients with colorectal cancer using different mRNA markers

The detection of disseminated tumor cells in peripheral blood from colorectal cancer patients by RT-PCR could be an attractive method for selecting patients for adjuvant therapy. We here report on real-time RT-PCR assays (LightCycler) to quantitate potential mRNA markers. We investigated specimens from colon carcinoma and normal colon mucosa tissues, cell lines, blood samples from 129 patients with colorectal cancer (all stages) and 58 reference blood samples (healthy donors, persons suffering from inflammatory bowel or infectious diseases). The expression profile in tissues showed high values for CEA and CK20, whereas in cell lines ProtM was predominant. All markers were detected in reference and patient blood samples (ProtM, 22, 17%; CEA, 84, 86%; CK20, 85, 88%). After quantitative analysis, the definition of cutoff values for each marker and the combination of markers, 13% of patients were judged to have elevated marker concentrations in their blood, from which only 6 had values significantly differing from cutoff value. There were no differences between stages of disease. In the case of 19 patients, investigated prior to and 1 week after surgery, 2 samples revealed a significant postoperative increase in CEA or CK20 mRNA concentration. In spite of high expression levels in tissues and cell lines, we were not able to differentiate satisfyingly mRNA markers originating from tumor cells and those from illegitimate transcription in hematopoetic cells in blood. We conclude that either copy numbers of analyzed markers in circulating tumor cells are not sufficient for detection or, more probably, peripheral blood is not a suitable compartment for detection of tumor cells in colorectal cancer.

Quantitative evaluation of metastases in axillary lymph nodes of breast cancer

We have established a highly sensitive and quantitative reverse transcriptase–polymerase chain reaction (RT–PCR) method to detect axillary lymph node metastases of breast cancer. Amplifying cytokeratin 19 (CK19) mRNA transcripts using real-time TaqMan PCR made it possible to quantify axillary metastatic burden. Metastases in 358 axillary lymph nodes obtained from 23 breast cancers of 22 patients were investigated by conventional haematoxylin and eosin (H&E) staining, immunohistochemical staining and quantitative RT–PCR assay. The detection rates of axillary lymph node metastasis using H&E staining, immunohistochemistry and RT–PCR assay were 4.5, 5.9 and 13.1%, respectively. RT–PCR assay was the most sensitive of these three methods for detecting lymph node metastases. Cytokeratin 19 mRNA expression values of both histologically and immunohistochemically positive lymph nodes were significantly higher than the values for lymph nodes judged to be negative by both histological and immunohistochemical methods (P<0.0001), and those of histologically negative, but immunohistochemically positive lymph nodes were significantly higher than the values for lymph nodes judged to be negative by both histological and immunohistochemical methods (P<0.0001). Furthermore, metastatic rates of sentinel nodes were higher than the rates of nonsentinel lymph nodes as measured by all three methods. These results indicate that quantitative RT–PCR assay is a sensitive and reliable method for detecting lymph node metastasis. Furthermore, quantification of metastases in sentinel lymph nodes by quantitative RT–PCR assay may be useful to assess the entire axillary burden of breast cancer patients.

Evaluation of bone marrow in breast cancer patients: prediction of clinical outcome and response to therapy

Blood-borne distant metastasis is the leading cause of cancer-related death in breast cancer. The onset of this fundamental process can now be assessed in cancer patients by using ultrasensitive immunocytochemical and molecular assays able to detect even single metastatic cells. To date, clinical studies with large study populations, validated immunoassays, and adequate follow-up time provide evidence for the independent prognostic value of the presence of disseminated tumor cells in the bone marrow. At present, bone marrow evaluation may therefore be considered a diagnostic tool for improved risk assessment with regard to distant relapse and death, especially among potentially curable breast cancer patients. Except for promising pilot studies, no data are available to support the immediate use of bone marrow evaluation for treatment monitoring in order to enable the prediction of response to adjuvant therapy.

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.

Detection of micrometastatic breast cancer by means of real time quantitative RT-PCR and immunostaining in perioperative blood samples and sentinel nodes

The aim of our study was to detect micrometastatic breast cancer by epithelial glycoprotein-2 (EGP-2) and cytokeratin 19 (CK19), using immunostaining and real time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Fifty-eight breast cancer patients, 52 primary tumors, 75 sentinel nodes (SN) and 149 peripheral blood (PB) samples (from before, during and 4 days after operation) were examined. Immunostaining was performed with antibodies directed against EGP-2 and CK19. Detection limits were one Michigan Cancer Foundation-7 (MCF-7) breast cancer cell line cell/2.10(6) leukocytes (immunostaining) and one MCF-7 cell/10(6) leukocytes qRT-PCR. Control noncancer lymph nodes (n = 10) showed nonspecific CK19 staining, but were qRT-PCR negative; control healthy volunteer PB (n = 11) was always negative. Primary tumor samples, all positive with immunostaining, showed a wide variation of EGP-2 (>10(4) fold) and CK19 mRNA expression (>10(3) fold). SN (n = 19) from 16 patients were tumor-positive with routine haematoxylin-eosin (H&E) and/or immunostaining. SN tumor presence was positively correlated to qRT-PCR expression, but 3 tumor-positive SN were false negative with qRT-PCR. Three SN were qRT-PCR positive, while tumor negative with H&E and/or immunostaining. No immunostaining positive PB was observed, but 19 patients (33%) had one or more qRT-PCR positive PB samples. We concluded that primary tumors have varying expressions of EGP-2 and CK19 mRNA. Both markers can be used in qRT-PCR to obtain adequate sensitivity for single tumor cell detection. In SN, immunostaining appears more sensitive/specific than H&E or qRT-PCR for tumor detection. No immunostaining positivity was found in PB, while 33% of patients had qRT-PCR positive PB. The clinical value of these findings will have to be clarified.

Detection of MUC1 and keratin 19 mRNAs in the bone marrow by quantitative RT-PCR predicts the risk of distant metastasis in breast cancer patients

BACKGROUND

Early detection of micrometastasis in bone marrow is critical for the prognosis of breast cancer patients. Quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) has been used to detect cancer cells in bone marrow, but its utility as a prognostic factor still remains obscure.

MATERIALS AND METHODS

Bone marrow samples were aspirated from the anterosuperior iliac spine of 34 patients, immediately after their surgical procedures had been completed. Control samples were also obtained from 10 healthy adult volunteers. The total RNA was extracted from the mononuclear cells, and the expression levels ofbeta-actin, MUC1 and keratin 19 mRNAs were studied by quantitative RT-PCR. Each mRNA level was scored according to the expression level. The sum of these expression scores was defined as the composite expression score, which was employed as the basis of the evaluation.

RESULTS

The mean follow-up period was 45 months. Nine patients developed distant metastases, and one developed local recurrence. The 4-year disease relapse rates were 75% (RR=19.38; 95% CI: 1.94-193.20), 28% (RR=3.64; 95% CI: 0.43-31.18), and 8.3% for patients with composite expression scores of 5/6, 3/4 and 2, respectively. The difference among the three groups was statistically significant (log-rank test: p=0.0029), and multivariate analysis also found the composite expression score to be an independent prognostic factor.

CONCLUSIONS

Breast cancer patients who show a high composite expression score in bone marrow have a significantly higher risk of recurrence.

Detection of epidermal growth factor receptor mRNA in peripheral blood of cervical cancer patients

OBJECTIVE

Epidermal growth factor receptor (EGFR) has been reported to be expressed by immunohistochemistry in invasive cervical cancers. We evaluated the feasibility of detecting EGFR mRNA by EGFR-based reverse transcription polymerase chain reaction (RT-PCR) in peripheral blood of patients with cervical cancer.

METHODS

Expression of EGFR mRNA, cytokeratin (CK)-19 mRNA, and CK-20 mRNA was examined by RT-PCR in 12 human cervical cancer cell lines. All 12 cell lines expressed both EGFR mRNA and CK-19 mRNA, but only 4 of 12 (33.3%) cell lines expressed CK-20 mRNA. Peripheral blood samples from 20 healthy donors and 45 cervical cancer patients were also examined.

RESULTS

In peripheral blood from 20 healthy donors, neither EGFR mRNA nor CK-20 mRNA was expressed, but CK-19 mRNA was expressed in 13 of 20 (65%). In contrast, EGFR mRNA was expressed in 12 of 45 (26.7%) patients with cervical cancer (P = 0.0071, 2 test, patient vs control). On the other hand, expression of EGFR was observed in 98% of tumor tissues by immunohistochemistry. CK-19 mRNA and CK-20 mRNA were found in 35 of 45 (77.8%) and 0 of 45 (0%) patients, respectively (NS, chi(2) test, patient vs control). The rate of detection of EGFR mRNA in peripheral blood correlated with FIGO stage (P = 0.049).

CONCLUSION

Both CK-19 mRNA and CK-20 mRNA showed no diagnostic value as markers of circulating tumor cells in cervical cancers. However, EGFR mRNA in blood might be a useful marker of circulating tumor cells in cervical cancers.

Sensitive detection of small cell lung carcinoma cells by reverse transcriptase-polymerase chain reaction for prepro-gastrin-releasing peptide mRNA

BACKGROUND

Gastrin-releasing peptide (GRP) is an autocrine growth factor in patients with small cell lung carcinoma (SCLC). The authors developed a reverse transcriptase-polymerase chain reaction (RT-PCR) assay for the detection of SCLC cells in the peripheral blood and the pleural effusion using preproGRP mRNA as a target.

METHODS

The current study was conducted to determine the utility of preproGRP-specific nested RT-PCR on the peripheral blood, bone marrow, and pleural effusion samples from 32 patients with SCLC, 39 patients with non-small cell lung carcinoma (NSCLC), 28 patients with nonmalignant pulmonary disease, and 20 healthy volunteers. The internal primers were designed to amplify a 244-base pair PCR product, a sequence encompassing exon 1 and exon 2 by the nested RT-PCR assay.

RESULTS

Amplification of the preproGRP message was detected in SCLC cell lines (LU165, SBC1, SBC2, and SBC3) but not in other NSCLC cell lines (A549, ABC1, EBC1, and Oka-1). The SCLC cells (LU165) were detected in dilutions of tumor cells of up to 10(-7) in hematopoietic cells from healthy donors. The preproGRP mRNA was detected in 16 of 32 (50%) blood samples, 2 of 11 (18%) marrow samples, and in all 6 (100%) pleural effusion samples. Blood samples gave positive results in 11 of 19 (58%) patients with extensive disease compared with 5 of 13 (38%) patients with limited disease. In contrast, only 1 blood sample (2.6%) from a patient with lung adenocarcinoma gave a positive result among patients with NSCLC. No other samples of blood, bone marrow, and pleural effusion from patients with NSCLC and none of the blood samples from patients with nonmalignant diseases and healthy volunteers were positive.

CONCLUSIONS

The current RT-PCR approach may be a sensitive and specific assay to detect SCLC cells in circulating blood as well as in pleural effusions from SCLC patients.

Marker genes for circulating tumour cells predict survival in metastasized breast cancer patients

We investigated the prognostic significance of circulating breast cancer cells in peripheral blood detected by quantitative RT-PCR of marker genes in patients with advanced breast cancer. Blood samples from 94 breast cancer patients with metastatic disease (M1) were examined for circulating tumour cells by studying the mRNA expression of CK19, p1B, PS2 and EGP2 by real-time PCR. Using a score function, developed for predicting circulating tumour cells by quadratic discriminant analysis (QDA), the four expression levels were combined into a single discriminant value. Tumour cells were present in 24 out of 94 (31%) of the patients. In 77% (72 out of 94) of the patients distant metastatic disease was localised in the bone. In 36% (26 out of 72) of the patients with bone metastases at the time of blood sampling, a positive QDA for the four genes was found, in contrast to only 14% (three out of 22) without bone involvement. Overall survival rates by Kaplan-Meier revealed no prognostic effect for the presence of bone metastases (P=0.93). However, patients with a positive QDA value did have a progression-free survival at 1 year of 3% and overall survival at 2 years of 17%, against 22 and 36% for patients with a negative QDA value (P=0.015 and 0.0053, respectively). Breast cancer patients with metastatic disease have a significantly worse progression-free and overall survival when circulating tumour cells can be detected in their peripheral blood.

Disseminated tumor cells in bone marrow of patients with transitional cell carcinoma: immunocytochemical detection and correlation with established prognostic indicators

PURPOSE

Previous investigations have demonstrated the prognostic value of disseminated cytokeratin positive cells in bone marrow of patients with breast, gastric, colon and prostate cancer. We evaluated the potential of an immunocytochemical assay, using a monoclonal antibody against cytokeratin 18 (CK 18), for the detection of disseminated tumor cells in bone marrow aspirates of patients with transitional cell carcinoma.

MATERIALS AND METHODS

Bone marrow aspiration was performed preoperatively on 128 patients with transitional cell carcinoma of various stages and on 27 controls with nonmalignant disease. Cytospin preparations of mononuclear bone marrow cells were incubated with a monoclonal anti-CK 18 antibody and stained using the alkaline phosphatase anti-alkaline phosphatase technique.

RESULTS

Of the patients with transitional cell carcinoma 29.7% and none of the controls had a CK 18 positive bone marrow result. A significant correlation between the incidence of CK 18 positive cells in bone marrow and invasive transitional cell carcinoma (p <0.01), lymph node involvement (p <0.01), medium/high grade transitional cell carcinoma (p <0.01) and tumor progression in recurrent transitional cell carcinoma (p <0.05) was demonstrated. Furthermore, the mean number of CK 18 positive cells in bone marrow aspirates of patients with stage M+ and/or N+ disease was nearly 3 times as high as that of patients without clinically evident metastatic disease (10.4 versus 3.8 CK 18 positive cells per patient).

CONCLUSIONS

A significant correlation between the incidence of CK 18 positive bone marrow results in patients with transitional cell carcinoma and established risk factors could be demonstrated in our study. Further prospective followup studies should be performed to determine the prognostic value of these findings.

Detection of clinically significant, occult prostate cancer metastases in lymph nodes using a splice variant-specific rt-PCR assay for human glandular kallikrein

PURPOSE

To compare the detection of human glandular kallikrein 2 (hK2) mRNA expression in archival lymph nodes with disease progression, the development of prostate cancer metastases, and mortality in patients undergoing radical prostatectomy for locally advanced nonmetastatic prostate cancer.

PATIENTS AND METHODS

We evaluated total RNA extracted from fixed, paraffin-embedded, histopathologically normal pelvic lymph nodes, removed at radical prostatectomy, from 199 pT3N0 prostate cancer patients (150 extraprostatic extension only; 49 seminal vesicle involvement) for hK2-expressing cells using a novel reverse transcriptase polymerase chain reaction (RT-PCR)/hK2 assay. Cumulative incidence functions and Cox proportional hazards analyses were performed.

RESULTS

Forty patients (20%) had positive results, 80 patients (40%) had negative results, and 79 patients (40%) had equivocal results. RT-PCR/hK2 status was not associated with any pathologic characteristics (P >.05). In postoperative multivariable models, the RT-PCR/hK2 result was associated with prostate cancer progression (P =.001), development of distant metastases (P =.001), and prostate cancer-specific survival (P =.005). In patients experiencing biochemical progression (n = 33), RT-PCR/hK2 status was a predictor of failure to respond to salvage radiotherapy (P =.002).

CONCLUSION

RT-PCR/hK2 can detect biologically and clinically significant occult prostate cancer metastases in histopathologically normal lymph nodes. In patients with locally advanced prostate cancer, RT-PCR/hK2 is strongly associated with prostate cancer progression, failure following salvage radiation therapy, development of clinically evident metastases, and prostate cancer-specific mortality after surgery.

Tumour cells in the tumour draining vein of patients with non-small cell lung cancer: detection rate and clinical significance

OBJECTIVES

This prospective study was performed to examine whether tumour cells are detectable in the tumour draining vein of patients with non-small cell lung cancer. Furthermore, the impact of these cells on the clinical course was analysed.

PATIENTS AND METHODS

Sixty-two consecutive patients with completely resected primary non-small cell lung cancer (pT1-4 pN0-2 M0) were admitted to the study. Pulmonary venous blood was drawn at the time of surgery for primary non-small cell lung cancer. The tumour draining vein was punctured subsequent to thoracotomy prior to manipulation of the tumour. The blood samples were examined for occult tumour cells by immunocytochemical staining of cytospins using the pancytokeratin antibody A45-B/B3 (murine immunoglobulin G1; Micromet, Munich, Germany).

RESULTS

Disseminated cancer cells in pulmonary venous blood were observed in 11 of 62 patients (18%) and did not correlate with standard clinico-pathological parameters. In patients without involvement of mediastinal lymph nodes (pN0-pN1), detection of occult tumour cells was an independent prognostic parameter for unfavourable outcome: log rank analysis showed a significant association of occult tumour cells in pulmonary venous blood with shortened cancer-related survival (P=0.019) and multivariate regression analysis demonstrated an independently significant (P=0.004) prognostic impact.

CONCLUSION

The present study shows that disseminated cancer cells in the pulmonary venous blood are detectable in about 20% of the patients with operable non-small cell lung cancer and that they are associated with a poor clinical outcome. Therefore, the detection of such cells might be useful for the identification of patients who benefit from adjuvant therapy. Furthermore, in order to avoid an additional systemic spread of tumour cells intraoperatively, the pulmonary veins should be ligated first during lung cancer surgery.

Bone marrow micrometastasis in breast cancer

BACKGROUND

Several studies have demonstrated that bone marrow micrometastasis in patients with breast cancer is an independent prognostic factor for systemic recurrence and poorer survival.

METHODS

This review describes the detection and clinical significance of micrometastatic cells in bone marrow, and examines the correlation between such micrometastasis and established clinicopathological prognostic factors. The relevant English language literature on bone marrow micrometastasis in breast cancer was searched via Medline (1975-2002), cross-referencing with key articles on the subject.

RESULTS AND CONCLUSION

The balance of evidence favours the hypothesis that bone marrow micrometastasis impacts on disease-free and overall survival. Further prospective studies are required to examine this in greater detail, with particular reference to early node-negative breast cancer and the value of adjuvant systemic therapy in patients with bone marrow micrometastasis.

Minimal tumor contamination of hematopoietic harvests from breast cancer patients can be easily detected by liquid culture assay

BACKGROUND

Recurrence after PBSC transplantation in breast cancer (BC) patients may be related to the reinfusion of tumor cells contaminating the graft. We have developed a liquid culture (LC) method for the identification of viable epithelial tumor cells in PBSC collections.

METHODS

Mononuclear fraction from PBSC harvests of BC patients undergoing high dose chemotherapy (HDC) (adjuvant setting n = 60, metastatic disease n = 30) were seeded in petri dishes containing round cover slips. Cells were cultured for 3 weeks, then cover slips were stained with the pan-cytokeratin A45-B/B3 mAb and scored under a light microscope. Samples were considered positive when more than one adherent cell or a cluster of cells staining bright red was present. Results were compared with those obtained on cytospins prepared directly from the PBSC harvest. Specificity of the method was tested on lymphoma patients, collections: all were negative. The sensitivity, evaluated by serial dilutions of CG5 BC cell line, was 1 epithelial cell in 10(6) mononuclear cells.

RESULTS

The percentage of positivity was superimposable in the two groups (adjuvant 25%, metastatic 24%). However, a significantly higher proportion of positive samples from metastatic vs adjuvant patients has shown the presence of tumor clusters (86% vs 33%, p = 0.063). In 21% of all samples a discrepancy with the results obtained by immunocytochemical analysis (ICC) was found, mostly due to liquid-culture-positive/ICC-negative PBSCs.

DISCUSSION

Our data suggest that LC assay may enhance the identification of viable disseminated epithelial tumor cells in PBSC grafts and might provide insights about their growth capacity.

Detection of micrometastatic cells in breast cancer by RT-pCR for the mammaglobin gene

The detection of circulating cancer cells in the bone marrow (BM) and peripheral blood (PB) of patients with solid tumors may be useful for disease staging. To this aim, we evaluated the expression of the mammaglobin gene by reverse transcriptase polymerase chain reaction (RT-PCR) in 60 patients with breast cancer. Moreover, several controls were examined to test the specificity of this marker. The positive cases included 23.6% of the patients with and 9% of those without metastasis. Only 4/60 negative controls analyzed were positive by PCR. Our results show high specificity and a good correlation with disease status.

Detection of disseminated cancer cells in bone marrow of gastric cancer using real time quantitative reverse transcriptase polymerase chain reaction

Bone marrow is a prognostically relevant indicator organ for micrometastasis. In the present study, real time quantitative reverse transcriptase polymerase chain reaction (RT-PCR) was used to detect disseminated gastric cancer cells in bone marrow. We compared CEA, CK18 and CK20 expression using four gastric cancer cell lines and three normal tissue cell lines in order to select the most appropriate marker for detection of disseminated gastric cancer cell in bone marrow. CK20 proved to be the most promising marker since the expression level of normal cell lines was extremely low and about 50--100-fold differences were found between gastric carcinoma cell lines and normal tissue cell lines. We also screened bone-marrow RNA of 47 patients with gastric cancers, using this system. Among the three markers we tested, with only about CK20 could we find that 27 of 47 patients were positive. Though long-term clinical follow up studies are needed to evaluate the clinical significance of this method, real time quantitative RT-PCR is sensitive and quantitative for detection of micrometastasis in bone marrow.

Polymerase chain reaction in the detection of tumor cells: new approaches in diagnosis and follow-up of patients with thyroid cancer

Thyroid cancers are the most common endocrine malignancies and are being diagnosed with increasing frequency. In addition to other measures, diagnosis is based on fine-needle aspiration cytology examination. Recently, new assays using reverse transcription-polymerase chain reaction (PCR) are being tested to improve sensitivity and specificity of primary diagnosis and detection of recurrent thyroid cancer. In the preoperative diagnosis of thyroid cancer, several tissue- and/or tumor-specific mRNA have been described and in several cases, a higher sensitivity and specificity could be achieved using molecular techniques compared to conventional methods. In the postoperative follow-up of patients with thyroid cancer, conflicting data have been published and the use of PCR techniques revealed several problems of the molecular approach, which are based on some technical as well as biologic limitations. Despite these problems, which are discussed in detail in this review, molecular techniques may nevertheless improve the sensitivity and accuracy of fine-needle aspiration of thyroid nodules, fine-needle aspiration of metastases, and detection of recurrent disease in peripheral blood samples.

Detection of circulating cells expressing chromogranin A gene transcripts in patients with lung neuroendocrine carcinoma

High grade lung neuroendocrine carcinomas, like small and large cell neuroendocrine carcinomas, pose therapeutic problems. Most initially respond to chemotherapeutic agents, but early relapses are frequent and are resistant to the presently available treatments. Our study reports for the first time the development and evaluation of a test for detecting the presence of circulating tumour cells by measuring chromogranin A gene transcripts with reverse transcriptase-polymerase chain reaction (RT-PCR) and Southern blotting. The test is specific and sensitive (detection of 10 cancer cells/ml blood), and only minimally invasive. Positivity is statistically correlated to high grade neuroendocrine carcinomas and to a poor prognosis with a 3-fold higher lethal risk. The test now needs to be assessed for its usefulness as a tool in the initial staging procedures and follow-up by comparison with the recent immunoradiometric assay (RIA) for detection of chromogranin A in the serum.

Molecular Markers in Prostate Cancer: The Role in Preoperative Staging

Radical prostatectomy as a primary treatment for clinically localized prostate cancer has increased dramatically over the past decade due to prostate-specific antigen (PSA) screening and the awareness of the increased incidence of localized disease. Despite the stage migration to increase clinically localized disease, there are still vast numbers of men who harbor occult extraprostatic extension and develop recurrence after surgery. The study of molecular markers in the blood or tissue of surgical patients prior to treatment, called " molecular staging, " is the focus of this review. The reverse transcriptase- polymerase chain reaction (RT-PCR) test for PSA gene expression in peripheral blood or bone marrow has received considerable attention since its first report in 1992. The test detects messenger RNA species for prostate-specific/abundant genes such as PSA and prostate-specific membrane antigen. These messenger RNAs were not detected in normal blood or bone marrow, but were detected in some prostate cancer patients presumably due to circulating prostatic epithelial cells. These prostate epithelial cells are thought to be occult metastases cells, and early studies correlated a positive RT-PCR test with surgical pathology adverse features such as positive margins. Despite the many studies over the past few years, there have been inconsistent results, and the most recent studies have not been able to confirm clinical utility. Bone marrow RT-PCR has been more promising; however, it is still a research tool that needs further study. The study of molecular markers in tissue material, ie, prostate biopsy samples prior to radical prostatectomy, is problematic due to the sampling error inherent in a multifocal heterogeneous tumor such as prostate cancer. The tumor suppressor proteins p53 and p27, Bcl-2 oncoprotein, Ki-67 proliferation index protein, E-cadherin, and microvessel density have been assessed in preradical prostatectomy needle biopsy. Results have been conflicting, and none are yet accepted as a clinically useful marker. Current and future work is focusing on analysis of multiple gene expressions or proteins simultaneously via gene chip or proteomics technology. While these expression profiles might be of value in whole prostate surgical specimens where tissues are well characterized, it is unclear how this new technology will be applied to the needle biopsy samples. Although molecular staging of radical prostatectomy patients has been under study for a decade, all assays remain research tools. Still, this area holds great promise for improving the accuracy of staging and providing a more accurate prognosis of individual men with clinically localized prostate cancer.

Monoclonal antibody 9C4 recognizes epithelial cellular adhesion molecule, a cell surface antigen expressed in early steps of erythropoiesis

OBJECTIVE

Monoclonal antibody (mAb) 9C4 detects a surface antigen expressed on immature erythroid progenitor cells and epithelial tumor cell lines. The aim of this study was to identify the recognized surface antigen and to analyze a potential role of this molecule in early steps of erythropoiesis.

MATERIALS AND METHODS

A pituitary-derived retroviral cDNA library was used to generate viruses and infect NIH-3T3 fibroblasts. The transfected cells were stained with mAb 9C4; positive cells were sorted by FACS; and a clonal cell line binding mAb 9C4 was established. cDNA encoding the 9C4-binding protein was amplified by polymerase chain reaction and cloned. Reactivity of mAb 9C4 with human bone marrow (BM) cells was analyzed by flow cytometry.

RESULTS

Sequence analysis of the isolated cDNA uncovered a 100% identity with the epithelial cellular adhesion molecule (Ep-CAM). Two-color flow cytometric analysis revealed that almost 100% of Ep-CAM(+) BM cells coexpressed CD105, E-cadherin, and high levels of CD71. Fractions of Ep-CAM(+) BM cells also were CD34(+) but lacked glycophorin A expression, suggesting that Ep-CAM(+) cells represent immature erythroid cells. Reverse transcriptase polymerase chain reaction analysis of BM mononuclear cells revealed that the 9C4(+) erythroblast population but not the 9C4(-) fraction expressed Ep-CAM mRNA. Peripheral blood CD34(+) cells induced in vitro to differentiate into the erythroid lineage showed strong Ep-CAM expression on days 3 to 7 of culture. The addition of Ep-CAM-specific mAbs 9C4 or KS1/4 to the culture resulted in two- to three-fold up-regulation of Ep-CAM protein expression.

CONCLUSION

mAb 9C4 recognizes Ep-CAM, a molecule expressed in the early steps of erythropoiesis.

Limitations of cytokeratin 20 RT-PCR to detect disseminated tumour cells in blood and bone marrow of patients with colorectal cancer: expression in controls and downregulation in tumour tissue

AIMS

Despite informative staging of patients with colorectal cancer, some patients with localised disease at diagnosis will develop recurrence or metastasis. Attempts to improve staging include sensitive detection of disseminated tumour cells in blood and bone marrow by reverse transcriptase polymerase chain reaction (RT-PCR). The results of this study have been considered in relation to the controversial results in the literature to elucidate the usefulness of cytokeratin 20 (CK20) RT-PCR to detect disseminated tumour cells further.

PATIENTS/METHODS

Blood and bone marrow samples from 30 patients with colorectal cancer were studied by CK20 RT-PCR. Specificity was evaluated in 47 blood and 15 bone marrow samples from non-cancer controls. In addition, the expression of CK20 mRNA and protein was studied in normal and tumour colon tissue samples.

RESULTS

CK20 expression was detected in nine of 30 and nine of 19 of the blood and bone marrow samples from patients with colorectal cancer, respectively. In non-cancer control blood and bone marrow samples, CK20 expression was detected in 10 of 47 and four of 15, respectively. A difference between patient and control samples may be observed in terms of frequency of positive PCR tests. In tissue samples, CK20 mRNA expression was downregulated in tumour compared with normal colon tissue.

CONCLUSIONS

CK20 expression was downregulated in tumour tissue compared with normal colon and a background expression of CK20 was seen in some control blood and bone marrow samples. Despite a lack of standardisation (which hampers comparison of studies), these results, together with other reports in the literature, suggest that CK20 may still be a suitable marker, but that background expression and threshold setting should be studied further.

Optimisation of the RT-PCR detection of immunomagnetically enriched carcinoma cells

BACKGROUND

Immunomagnetic enrichment followed by RT-PCR (immunobead RT-PCR) is an efficient methodology to identify disseminated carcinoma cells in the blood and bone marrow. The RT-PCR assays must be both specific for the tumor cells and sufficiently sensitive to enable detection of single tumor cells. We have developed a method to test RT-PCR assays for any cancer. This has been investigated using a panel of RT-PCR markers suitable for the detection of breast cancer cells.

METHODS

In the assay, a single cell line-derived tumor cell is added to 100 peripheral blood mononuclear cells (PBMNCs) after which mRNA is isolated and reverse transcribed for RT-PCR analysis. PBMNCs without added tumor cells are used as specificity controls. The previously studied markers epidermal growth factor receptor (EGFR), mammaglobin 1 (MGB1), epithelial cell adhesion molecule (EpCAM/TACSTD1), mucin 1 (MUC1), carcinoembryonic antigen (CEA) were tested. Two new epithelial-specific markers ELF3 and EphB4 were also tested.

RESULTS

MUC1 was unsuitable as strong amplification was detected in 100 cell PBMNC controls. Expression of ELF3, EphB4, EpCAM, EGFR, CEA and MGB1 was found to be both specific for the tumor cell, as demonstrated by the absence of a signal in most 100 cell PBMNC controls, and sensitive enough to detect a single tumor cell in 100 PBMNCs using a single round of RT-PCR.

CONCLUSIONS

ELF3, EphB4, EpCAM, EGFR, CEA and MGB1 are appropriate RT-PCR markers for use in a marker panel to detect disseminated breast cancer cells after immunomagnetic enrichment.

Multiparameter flow cytometry as a tool for the detection of micrometastatic tumour cells in the sentinel lymph node procedure of patients with breast cancer

AIM

To investigate whether multiparameter flow cytometry (MP-FCM) can be used for the detection of micrometastasis in sentinel lymph nodes (SLNs) in breast cancer.

METHODS

Formalin fixed, paraffin wax embedded sentinel lymph nodes (n = 238) from 98 patients were analysed. For each lymph node, sections for haematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) for cytokeratin (MNF116) were cut at three levels with a distance of 500 microm. The intervening material was used for MP-FCM. Cells were immunostained with MNF116, followed by an incubation with fluorescein isothiocyanate (FITC) labelled goat antimouse immunoglobulin. DNA was stained using propidium iodide. From each lymph node 100,000 cells were analysed on the flow cytometer.

RESULTS

Thirty eight of the 98 patients with breast carcinoma showed evidence of metastatic disease in the SLN by one ore more of the three methods. In 37 of 38 cases where metastatic cells were seen in the routine H&E and/or IHC, more than 1% cytokeratin positive cells were detected by MP-FCM. In 24 patients, metastatic foci were more than 2 mm (macrometastasis) and in 14 these foci were smaller than 2 mm (micrometastasis). In three of these 14 cases, MP-FCM revealed positive SLNs, although this was not seen at first glance in the H&E or IHC sections. After revision of the slides, one of these three remained negative. However, MP-FCM analysis of the cytokeratin positive cells showed an aneuploid DNA peak, which was almost identical to that of the primary breast tumour. Duplicate measurements, done in 41 cases, showed a 99% reproducibility. In five of 14 patients with micrometastasis, one or two metastatic foci were found in the non-SLN. However, in 15 of 24 macrometastases multiple non-SLNs were found to have metastatic tumour. All micrometastases except for the remaining negative one mentioned above showed only diploid tumour cells, despite the fact that their primary tumours contained both diploid and aneuploid tumour cells. In primary tumours with more than 60% aneuploid cells, predominantly aneuploid macrometastasis were found, whereas diploid primary tumours only showed diploid micrometastases or macrometastases in their SLN. Aneuploid SLN macrometastases were associated with non-SLN metastases in five of seven patients, whereas diploid cases showed additional non-SLN metastases in only seven of 16 patients.

CONCLUSION

In all cases, MP-FCM was sufficient to detect micrometastatic tumour cells in a large volume of lymph node tissue from SLNs. In some cases it was superior to H&E and IHC staining. Approximately 30% of SLN micrometastases are accompanied by additional non-SLN metastases. The size of the aneuploid fraction (> 60%) in the primary tumour may influence the risk of having both SLN and non-SLN metastases.