Quantitative real-time RT-PCR detection of breast cancer micrometastasis using a multigene marker panel

Expression ofRPIP9 (Rap2 interacting protein 9) is activated in breast carcinoma and correlates with a poor prognosis

MDR1 is upregulated in many tumors. We have previously detected activation of the MDR1 upstream promoter in metastatic breast cancer cells. MDR1 overlaps with an uncharacterized gene transcribed from the opposite strand, coding for Rap2 interacting protein 9 (RPIP9). Rap2 belongs to the Ras superfamily of GTPases, whose role in breast cancer remains unknown. We developed sensitive methods for detecting and quantifying RPIP9 mRNA and used it to identify these transcripts in normal human tissues, 60 biopsies of primary breast carcinoma, in isolated epithelial cells both from the primary tumor and from associated lymph nodes, and from bone marrow biopsies of 74 breast cancer patients. RPIP9 is expressed at high levels in normal testis, brain and adrenal gland, and at very low levels in normal breast. Tumorigenic breast carcinoma cell lines expressed RPIP9, whereas MCF-10A and HBL-100 that do not form tumors in nude mice had undetectable levels of RPIP9 mRNA. RPIP9 was activated in a high proportion of breast carcinomas (61.6%; n = 60) and a significant correlation with metastatic lymph node invasion (N = 0-3 vs. N > 3, where N = number of lymph nodes invaded; p = 0.031) was found. RPIP9 mRNA could be detected in malignant epithelial cells isolated from the primary tumor and from metastasized lymph nodes as well as in the bone marrow of significantly more poor-prognosis (N > 3) than better-prognosis (N = 0-3) patients (p = 0.001). Therefore, activation of RPIP9 occurs during the malignant breast epithelial transformation and increases with progression toward an invasive phenotype.

Clinical significance of the loss of KiSS-1 and orphan G-protein-coupled receptor (hOT7T175) gene expression in esophageal squamous cell carcinoma

PURPOSE

Lymph node metastasis is the most important predictor of prognosis in esophageal squamous cell carcinoma (ESCC). Recently, KiSS-1 was cloned as a human metastasis suppressor gene, and an orphan G-protein-coupled receptor (hOT7T175) was identified as the endogenous receptor of the KiSS-1 product. However, the clinical importance of KiSS-1 and hOT7T175 gene expression in ESCC remains unclear.

EXPERIMENTAL DESIGN

In this study, total RNA was extracted from tumors and noncancerous epithelia of 71 patients with ESCC who underwent surgical esophageal resection. The expression levels of KiSS-1, hOT7T175, and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNAs were analyzed quantitatively by real-time reverse transcription-PCR and compared with the clinical findings.

RESULTS

The mean KiSS-1:GAPDH and hOT7T175:GAPDH ratios of the tumors were 1.2 and 0.3 and were at the same levels as those in the noncancerous epithelia. The loss of KiSS-1 and hOT7T175 gene expression was detected in 38% and 61% of tumors. Loss of KiSS-1 and/or hOT7T175 gene expression was not correlated with tumor size or degree of tumor invasion but was found to be a significant predictor of lymph node metastasis.

CONCLUSIONS

Loss of KiSS-1 or hOT7T175 gene expression may be an important biomarker for detection of lymph node metastasis in ESCC.

EpCAM is overexpressed in breast cancer and is a potential target for breast cancer gene therapy

EpCAM (epithelial cell adhesion molecule) is a cell surface molecule that is known to be highly expressed in colon and other epithelial carcinomas. EpCAM is involved in cell-to-cell adhesion and has been the target of antibody therapy in several clinical trials. To assess the value of EpCAM as a novel target for breast cancer gene therapy, we performed real-time reverse transcription-PCR to quantify the level of EpCAM mRNA expression in normal breast tissue and primary and metastatic breast cancers. We found that EpCAM is overexpressed 100- to 1000-fold in primary and metastatic breast cancer. Silencing EpCAM gene expression with EpCAM short interfering RNA (siRNA) resulted in a 35-80% decrease in the rate of cell proliferation in four different breast cancer cell lines. EpCAM siRNA treatment decreased cell migration by 91.8% and cell invasion by 96.4% in the breast cancer cell line MDA-MB-231 in vitro. EpCAM siRNA treatment was also associated with an increase in the detergent-insoluble protein fraction of E-cadherin, alpha-catenin, and beta-catenin, consistent with the known biology of EpCAM as a regulator of cell adhesion. Our hypothesis is that modulation of EpCAM expression can affect cell migration, invasion, and proliferation by enhancing E-cadherin-mediated cell-to-cell adhesion. These data provide compelling evidence that EpCAM is a potential novel target for breast cancer gene therapy and offer insights into the mechanisms associated with EpCAM gene silencing.

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.

Multidestructive pathways triggered in photoreceptor cell death of the rd mouse as determined through gene expression profiling

In the rd/rd mouse, photoreceptor degeneration is due to a mutation of the rod-specific enzyme cGMP phosphodiesterase, resulting in permanently opened cGMP-gated cation channels in the rod outer segment membrane that allow Na(+) and Ca(2+) ions to enter the cell, resulting in possibly toxic levels of Ca(2+). To identify pathways involved in cell death of the rd/rd rods, we evaluated gene expression in the rd/rd and wild type (wt) mouse retina (U74A oligonucleotide arrays (Affymetrix)) over the known time course of photoreceptor degeneration. 181 genes passed the selection criteria (low standard deviation and high correlation between replicates), falling into six clusters. For any given pair of genes, an expression profile correlation distance and a semantic distance (one for each class of gene ontology terms) were established using newly designed software. Gene expression in rd/rd started to deviate from wt by postnatal day 10. The reduction in photoreceptor-specific genes followed the known time course of photoreceptor degeneration. Likewise the increase in transcription factors and apoptosis- and neuroinflammation-specific genes followed the kinetics of the rise in intracellular cGMP in the rod photoreceptors. In addition, genes coding for calcium-binding proteins and those implicated in tissue and vessel remodeling were increased. These results suggest that photoreceptor degeneration in the rd/rd mouse is a process starting with Ca(2+) toxicity followed by secondary insults involving multidestructive pathways such as apoptosis and neuroinflammation, presumably boosting morphological changes. All of these components need to be addressed if rods are to be successfully protected.

Lunx is a superior molecular marker for detection of non-small cell lung cancer in peripheral blood [corrected]

The clinical management of non-small cell lung cancer (NSCLC) would benefit greatly by a test that was able to detect small amounts of NSCLC in the peripheral blood. In this report, we used a novel strategy to enrich tumor cells from the peripheral blood of 24 stage I to IV NSCLC patients and determined expression levels for six cancer-associated genes (lunx, muc1, KS1/4, CEA, CK19, and PSE). Using thresholds established at three standard deviations above the mean observed in 15 normal controls, we observed that lunx (10 of 24, 42%), muc1 (5 of 24, 21%), and CK19 (5 of 24, 21%) were overexpressed in 14 of 24 (58%) peripheral blood samples obtained from NSCLC patients. Patients who overexpressed either KS1/4 (n = 2) or PSE (n = 1) also overexpressed either lunx or muc1. Of patients with presumed curable and resectable stage I to II disease (n = 7), at least one marker was overexpressed in three (43%) patients. In advanced stage III to IV patients (n = 17), at least one marker was overexpressed in 11 patients (65%). These results provide evidence that circulating tumor cells can be detected in NSCLC patients by a high throughput molecular technique. Further studies are needed to determine the clinical relevance of gene overexpression.

Detection of metastases in sentinel lymph nodes of breast cancer patients by multiple mRNA markers

Disseminated breast tumour cells in sentinel lymph nodes (SNs) were evaluated by quantitative real-time PCR and the sensitivity of this assay was compared to the routine histological analysis. First, several candidate marker genes were tested for their specificity in axillary lymph nodes (ALN) of 50 breast cancer patients and 43 women without breast cancer. The marker gene panel selected, designed to detect the mRNA of CK19, p1B, EGP2 and SBEM, was subsequently applied to detect metastases in 70 SNs that were free of metastases as determined by standard histological evaluation. Remarkably, seven negative SNs showed increased marker gene expression, suggesting the presence of (micro) metastases. Four of these seven SNs positive by real-time PCR proved to contain tumour deposits after careful review of the slides or further sectioning of the paraffin-embedded material. In three PCR positive SNs, however, no tumour cells were found by haematoxylin and eosin staining (H&E) and immunohistologically analysis. The quantitative real-time PCR assay with multiple mRNA markers for the detection of disseminated breast cancer cells in SNs thus resulted in an upstaging of SNs containing metastastic disease of 10% compared to the routine histological analysis. The application of this technique may be of clinical relevance, as it is suggested that micrometastatic disease in SNs are associated with further nodal non-SN metastases in breast cancer.

Detection of cancer cells in the axillary drainage using RT-PCR after operations for breast cancer

The object of this study was to examine whether MUC-1 can be detected in the axillary lymphatic drainage of patients who have undergone conservative surgery for breast cancer and to assess the correlations between the presence of MUC-1 and prognostic factors in breast cancer. Sixty-eight women with invasive ductal carcinoma of the breast underwent wide local excision and axillary lymph node dissection. Axillary drains were inserted in all these cases, and the presence of MUC-1 and beta-actin was evaluated by RT-PCR in the lymphatic fluid collected after the operation. Prognostic factors included tumour size and grade, vascular and lymphatic invasion, clearance margins of the resected specimens and status of the axillary lymph nodes. RT-PCR assays for MUC-1 in the axillary fluid were positive in 17 patients (25%). The presence of MUC-1 was associated with increased tumour size and showed a positive correlation with axillary lymph node metastases and incomplete resection of the tumour. RT-PCR can disclose cancer cells in the axillary fluid after conservative surgery for breast cancer. The presence of MUC-1 in the axillary drainage may be associated with poor prognostic features, and its detection may have implications for therapy as it suggests that re-excision should be considered.

Mammaglobin: a candidate diagnostic marker for breast cancer

Mammaglobin, known for its mammary tissue specificity, has been discussed as a promising diagnostic marker in breast cancer for almost 10 years. In particular, the application of mammaglobin RT-PCR to detect disseminated breast cancer cells has been reported. More than 25 publications evaluate the detection of mammaglobin mRNA in lymph node, blood, and bone marrow specimens of breast cancer patients. Recently, structural details about the mammaglobin complex have been discovered, and these findings can be implemented to optimize detection of the secreted protein. This review summarizes the findings of almost 50 published studies and the current knowledge about the diagnostic utility of mammaglobin.

Mammaglobin is associated with low-grade, steroid receptor-positive breast tumors from postmenopausal patients, and has independent prognostic value for relapse-free survival time

PURPOSE

The tumor mRNA expression levels of mammaglobin, a novel breast-specific and breast cancer-associated marker, were correlated with disease outcome in 280 patients with primary breast cancer.

PATIENTS AND METHODS

Mammaglobin expression levels were assessed by quantitative reverse transcriptase polymerase chain reaction in frozen tumor tissue from breast cancer patients with a median age of 60 years (range, 30 to 88 years) and a median follow-up of 85 months (range, 2 to 169 months).

RESULTS

High expression levels were associated with low-grade tumors (P =.018), with positive estrogen and progesterone receptor status (P <.001), and postmenopausal status (P =.010). In the analysis of all patients, low tumor mammaglobin expression levels predicted an early relapse both in Cox univariate (hazard ratio [HR], 0.52; 95% CI, 0.34 to 0.79; P =.002) and multivariate regression analyses corrected for the traditional prognostic factors (HR, 0.55; 95% CI, 0.35 to 0.88; P =.012). The association of mammaglobin expression with the rate of relapse was particularly favorable in patients who received adjuvant tamoxifen treatment (HR, 0.35; 95% CI, 0.17 to 0.71; P =.004).

CONCLUSION

These results demonstrate that the assessment of the tumor mRNA expression level of the breast-specific protein mammaglobin could be useful to stratify patients for individual adjuvant treatment strategies.

Expression of matrix metalloproteinases MMP-2, MMP-9 and their tissue inhibitors TIMP-1, -2, and -3 in benign and malignant tumours of the salivary gland

AIMS

The balance between matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) is involved in the morphogenesis of the normal salivary gland as well as in mechanisms of tumour invasion and metastasis. Our aim was to analyse protein and mRNA expression of MMPs and TIMPs in normal salivary gland tissue and in various salivary gland neoplasms.

METHODS AND RESULTS

Immunohistochemistry for MMP-2, MMP-9, TIMP-1, -2 and -3 was performed in 20 malignant and six benign salivary gland tumours. The immunoscores of MMP-2 were significantly higher in carcinomas compared with adenomas (P = 0.0028). The MMP/TIMP ratio was significantly higher in carcinomas than in adenomas (P = 0.0097). In mucoepidermoid carcinomas MMP-2 expression was preferentially observed in the intermediate cell type. Neoplastic acinar cells of acinic cell carcinoma demonstrated de novo expression of MMP-2, MMP-9, TIMP-1, and TIMP-2. Immunoscores of TIMP-3 were not decreased in malignant tumours compared with adenomas. In accordance with the immunostaining of MMP-2 and -9, gelatinolytic activity could be demonstrated by in-situ zymography. The mRNA expression of MMPs and TIMPs analysed by real-time reverse transcriptase-polymerase chain reaction in three malignant and two benign tumours and their corresponding normal tissue did not generally correlate with their protein expression.

CONCLUSIONS

Our findings suggest a disturbed balance between MMP and TIMP in malignant salivary gland tumours. MMP-2 expression in particular seems to be related to the invasive properties and the malignant potential of these tumours.

Down-regulation of sphingosine kinase-1 by DNA damage: dependence on proteases and p53

Sphingosine kinase 1 (SK1), a key enzyme in sphingosine 1-phosphate (S1P) synthesis, regulates various aspects of cell behavior, including cell survival and proliferation. DNA damaging anti-neoplastic agents have been shown to induce p53, ceramide levels, and apoptosis; however, the effects of anti-neoplastic agents on SK have not been assessed. In this study, we investigated the effects of a DNA damaging agent, actinomycin D (Act D), on the function of sphingosine kinase (SK1). Act D caused a reduction in the protein levels of SK1, as indicated by Western blot analysis, with a concomitant decrease in SK activity. The down-regulation was post-transcriptional, because the mRNA levels of SK1 remained unchanged. Similar decreases in SK1 protein were observed with other DNA damaging agents such as doxorubicin, etoposide, and gamma-irradiation. ZVAD, the pancaspase inhibitor, and Bcl-2 annulled the effect of Act D on SK1, demonstrating a role for cysteine proteases downstream of Bcl-2 in the down-regulation of SK1. Inhibition of caspases 3, 6, 7, and 9 only partially reversed Act D-induced SK1 loss. Inhibition of cathepsin B, a lysosomal protease, produced a significant reversal of SK1 decline by Act D, suggesting that a multitude of ZVAD-sensitive cysteine proteases downstream of Bcl-2 mediated the SK1 decrease. When p53 up-regulation after Act D treatment was inhibited, SK1 down-regulation was rescued, demonstrating p53 dependence of SK1 modulation. Treatment of cells with S1P, the product of SK1, partially inhibited Act D-induced cell death, raising the possibility that a decrease in SK1 may be in part necessary for cell death to occur. Furthermore, the knockdown of SK1 by small interfering RNA in MCF-7 cells resulted in a significant reduction in cell viability. These studies demonstrate that SK1 is down-regulated by genotoxic stress, and that basal SK1 function may be necessary for the maintenance of tumor cell growth.

Breast cancer biomarkers and molecular medicine

The first part of this two-part review of established and emerging breast cancer biomarkers and molecular diagnostics considers breast cancer predisposition, screening tests for diagnosis, diagnosis using small specimens and metastatic lesions, micrometastatic disease and breast cancer prognosis assessment. Prognostic factors covered in this review include: cytogenetic markers, DNA ploidy and S phase determination, cell proliferation markers, cell cycle regulators and growth factor measurements including epithelial growth factor receptor, HER-2/neu and a variety of other relevant molecules controlling proliferation, differentiation and angiogenesis. The first section of part two will continue the consideration of breast cancer prognostic factors including oncogenes, tumor suppressor genes, cell adhesion molecules, invasion-associated proteins and proteases, hormone receptor proteins, drug resistance proteins, apoptosis regulators, transcription factors, telomerase, DNA repair and methylation and transcriptional profiling using high-density genomic microarrays. The second section of part two will consider the prediction of therapy response using the techniques of pharmacogenetics and pharmacogenomics.

Combination of cytology, fluorescence in situ hybridization for aneuploidy, and reverse-transcriptase polymerase chain reaction for human mammaglobin/mammaglobin B expression improves diagnosis of malignant effusions

PURPOSE

The identification of malignant cells in effusions by conventional cytology is hampered by its limited sensitivity. The aim of this study was to improve tumor cell detection in effusions by molecular approaches.

MATERIALS AND METHODS

A total of 157 effusions from patients with tumors and 72 effusions from patients without a history or evidence of malignancy were included in this study. All effusion specimens were evaluated in parallel by cytology, fluorescence in situ hybridization (FISH) for aneuploidy, and reverse-transcriptase polymerase chain reaction (RT-PCR) for expression of human mammaglobin (hMAM) and mammaglobin B (hMAM-B).

RESULTS

In effusions from patients with tumors, the sensitivities of tumor cell detection by cytology, FISH, and hMAM and hMAM-B detection were 46.2%, 53.3%, 36.4%, and 57.7%, respectively. The corresponding specificities were 94.4%, 97.0%, 87.1%, and 88.6%. Notably, a high percentage of effusions containing malignant cells were in fact transudates, indicating the necessity for molecular diagnostic work-up of transudates collected from patients with tumors. Dependent on the tumor type, the use of appropriate marker combinations improved tumor cell detection in effusions significantly. By combining all four diagnostic tests, a positive test result indicating the presence of malignancy was achieved in 81.1%, with a fairly good specificity of 70.1%.

CONCLUSION

Molecular techniques are definitely useful to detect malignancy in cytologically negative effusions. Tumor cell detection in effusions can be significantly improved by FISH and PCR techniques applying appropriate molecular markers. This finding should help to improve tumor staging, prognostic assessment, and treatment monitoring.

Prognostic significance of micrometastasis in non-small-cell lung cancer

Accurate staging of non-small-cell lung cancer (NSCLC) determines prognosis and facilitates decisions regarding treatment options. Unfortunately, even after an apparently complete resection in patients with stage I disease, the recurrence rates range from 25% to 50%, and overall survival is not encouraging. One possible reason for this may be that those patients with a poor outcome actually have more extensive disease, with occult locoregional and/or distant metastasis than originally identified by routine pathologic staging techniques. There is now a sizable body of literature on the detection and possible prognostic role of occult disease in lung cancer. The majority of these studies are based on immunohistochemical analysis of lymph nodes and/or bone marrow, but a handful of studies use molecular approaches. The purpose of this review is to summarize and critique the current literature on occult tumor cell spread to lymph nodes and bone marrow in patients with NSCLC. Based on this literature, we believe that the prognostic significance of bone marrow micrometastasis remains unclear. However, the majority of studies indicate that occult lymph node disease is associated with a poor outcome. Thus, our ability to detect individual tumor cells could result in more accurate staging of NSCLC in patients and would potentially lead to the development of novel therapies, as well as influence decisions regarding the use of appropriate multimodality treatment strategies, the choice of surgical technique, and extent of dissection. As data accumulate, the presence or absence of occult nodal involvement should probably be considered at the next revision of the staging system for NSCLC.

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.

The molecular detection of micrometastatic breast cancer

BACKGROUND

The rapid evolution of molecular technology and novel markers provides the opportunity to establish a more effective means to detect micrometastatic breast cancer. Given the controversies concerning application and clinical relevance, this review critically evaluates the current status of these molecular staging technologies.

DATA SOURCES

Breast cancer literature addressing (1). molecular detection methodologies (immunohistochemistry, reverse transcriptase polymerase chain reaction, and microarray analysis); (2). specific tissue applications such as lymph nodes, bone marrow aspirate, and peripheral blood; (3). expert commentary concerning the clinical applications and pitfalls of these technologies; and (4). recent data from our molecular diagnostics laboratory.

CONCLUSIONS

Molecular detection technologies such as reverse transcriptase polymerase chain reaction and microarray analyses are being developed that will likely have future application as cancer diagnostics. Further work is needed to establish assays that are validated by prospective clinical studies. Early identification of clinically relevant disease could lead to new treatment or staging approaches for breast cancer.

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.

Quantitative reverse transcriptase polymerase chain reaction analysis for KiSS-1 and orphan G-protein-coupled receptor (hOT7T175) gene expression in hepatocellular carcinoma

PURPOSE

KiSS-1 has been cloned as a human metastasis suppressor gene and an orphan G-protein-coupled receptor (hOT7T175) identified as the endogenous receptor of the KiSS-1 product. In the present study, we evaluated the clinical importance of KiSS-1 and hOT7T175 gene expression in hepatocellular carcinoma (HCC).

METHODS

The expression levels of KiSS-1, hOT7T175 and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) messenger RNAs (mRNAs) were analyzed quantitatively by real-time reverse transcriptase polymerase chain reaction (RT-PCR) in 60 surgically resected HCCs. The KiSS-1/GAPDH and hOT7T175/GAPDH ratios of tumors were compared with clinicopathological findings.

RESULTS

Loss of KiSS-1 mRNA expression was not detected in HCCs. The mean KiSS-1/GAPDH ratio did not change between non-cancerous cirrhotic livers and carcinomas. On the other hand, the average hOT7T175/GAPDH ratios increased from non-cancerous livers (0.08) to carcinomas (0.48). Overexpression of KiSS-1 and hOT7T175 genes was recognized in 6 tumors, which were in an advanced stage and showed poor survival.

CONCLUSION

Overexpression of KiSS-1 and hOT7T175 genes was frequently observed and correlated with HCC progression; thus, the possibility that overexpressed KiSS-1 and hOT7T175 peptides mediate growth signals into cancer cells in HCCs is suggested.

Staging system for breast cancer: revisions for the 6th edition of the AJCC Cancer Staging Manual

Since its inception, the AJCC staging system for breast cancer has been in an almost constant state of evolution, striving with each revision to reflect the most up-to-date clinical research as well as the widespread consensus among physicians about appropriate diagnostic and treatment standards. To date, these revisions have essentially represented a "fine-tuning" of the initial judgment that tumor size, lymph node status, and presence of distant metastases are the most significant prognostic factors for breast cancer. With the problems of standardization and reproducibility being resolved, it is likely that histologic grade will join this group of independent markers and be incorporated into the AJCC staging system in the near future. Over the last 15 years. considerable attention has been focused on the discovery of new markers visualized with immunohistochemistry and RT-PCR that may be validated as independent prognostic indicators (reviewed by Mirza et al). To date, the usefulness of many of these markers has been limited by lack of standardization in measurement techniques, but several show great promise for the future. By increasing the number of prognostic markers that can give independent information about patient outcome, physicians will be better able to determine optimal treatment approaches for individual patients.

Sensitive detection of human telomerase reverse transcriptase mRNA in the serum of patients with hepatocellular carcinoma

BACKGROUND/AIM

Telomerase reverse transcriptase protein (hTERT) mRNA has been reported to be detectable by reverse transcription polymerase chain reaction (RT-PCR) in the serum of patients with breast cancer. We measured serum hTERT mRNA in patients with hepatocellular carcinoma (HCC), and examined its clinical usefulness.

METHODS

We performed RT-PCR to detect the expression of hTERT mRNA in 78 patients with HCC, 10 with liver cirrhosis (LC), 12 with chronic hepatitis (CH), and 34 healthy individuals without any liver diseases and cancers, and statistically analyzed the association with clinical parameters which include age, sex, etiology, Child classification, underlying liver disease, biochemical data, alpha-fetoprotein (alpha-AFP) number and size of tumor, and histological differentiation of HCC regarding HCC patients.

RESULTS

70 of 78 (89.7%) patients with HCC, 7 of 10 (70.0%) with LC, and 5 of 12 (41.7%) with CH were positive for hTERT expression, whereas all healthy individuals were negative for it. A multivariate analysis showed that positivity of hTERT mRNA was independently associated with AFP, tumor size, and differentiation degree.

CONCLUSIONS

These results suggest that this assay is sensitive enough to detect hTERT mRNA in serum, and that it would be applicable for early detection and diagnosis of HCC or other cancers by a quantitative method.

Intrinsic variability in the detection of micrometastases in lymph nodes for re-staging of colorectal cancer. effect of individual markers and tissue samples

In this study, we investigated whether (a) carcinoembryonic antigen (CEA), cytokeratin-20 (CK-20) and guanylyl cyclase C (GCC) are clinically useful markers for the molecular detection of submicroscopic metastases in colorectal cancer (CRC) and (b) whether overexpression of CEA, CK-20 and GCC can be reliably detected in formalin-fixed, paraffin-embedded tissues as well as frozen lymph nodes. We studied 175 frozen lymph nodes and 158 formalin-fixed, paraffin-embedded lymph nodes from 28 cases of CRC. CEA or CK-20 or GCC-specific polymerase chain reaction (PCR) was carried out on mRNA transcripts extracted from the nodal tissues. Ten out of 11 Dukes' B CRC cases had detectable CEA and CK-20 while 6 out of 11 Dukes' B CRC cases had detectable GCC. In general, the difference of re-staged cases when comparing frozen and paraffin-embedded samples was marked; the only statistically significant correlation between frozen and paraffin tissue was for the CEA marker. Our results indicated a high incidence (>50%) of detecting micrometastases in histologically-negative lymph nodes at the molecular level.

Cytokeratin staining and other sentinel node controversies

Sentinel lymph node (SLN) biopsy for breast cancer staging has been widely accepted because it is more sensitive and less morbid than axillary dissection. Sentinel nodes can be thoroughly scrutinized using a variety of techniques increasing the detection of micrometastases; however, the clinical relevance of micrometastases has been challenged. The available data suggest that the prognostic significance of axillary metastases is related to the size of the metastases, and the best data suggest that outcome for patients with metastases < 0.2 mm is similar to patients with node-negative disease. This would argue against the use of ultrasensitive tests such as reverse transcriptase polymerase chain reaction. Immunohistochemistry upstages 2%-20% of hematoxylin and eosin-negative sentinel nodes, and additional nodal metastases are identified in approximately 10% of completion axillary dissections prompted by an immunohistochemistry (IHC)-positive sentinel node. This would appear to be a good reason to perform IHC and act on the results. Because micrometastases can be artifactual, SLN biopsy in ductal carcinoma in situ can lead to harmful overtreatment and is best performed in the context of clinical trials. Lymphoscintigraphy has allowed the detection of alternate drainage patterns to internal mammary, infraclavicular, and supraclavicular lymph nodes. Although patients are occasionally identified who have metastases to these basins but not the axilla, this information will not impact the decision for chemotherapy in most cases. Internal mammary SLN biopsy may have value in patients with tumors < 1 cm, but requires additional evaluation in clinical trials.

Quantitative analysis of heparanase gene expression in esophageal squamous cell carcinoma

BACKGROUND

Heparan sulfate proteoglycans, the main components of the extracellular matrix, are recognized as important components of signal transduction and play an important role in tumor progression. Heparanase (hep) degrades heparan sulfate proteoglycans, but the clinical importance of hep is unclear. In this study, we investigated the clinicopathologic importance of hep messenger RNA (mRNA) expression in esophageal squamous cell carcinoma (ESCC).

METHODS

Fresh tumors and noncancerous epithelia were obtained from 57 ESCC patients after esophagectomy. Expression levels of hep and glyceraldehyde-3-phosphate dehydrogenase mRNA were quantitatively analyzed by real-time reverse transcriptase-polymerase chain reaction. Apoptotic cancer cells and microvessel density were evaluated immunohistochemically.

RESULTS

The relative hep mRNA expression level (hep:glyceraldehyde-3-phosphate dehydrogenase ratio) in ESCC was lower than in noncancerous tissue (P <.001). Tumor hep expression decreased according to tumor progression and correlated with the occurrence of apoptotic cancer cells, but not with tumor microvessel density. Moreover, low hep expression correlated with poor patient survival.

CONCLUSIONS

Reduced hep mRNA expression might result in abnormal cell growth and correlate with ESCC progression.

Clinical relevance of reverse transcriptase-polymerase chain reaction for the detection of axillary lymph node metastases in breast cancer

BACKGROUND

The mammary sentinel lymph node procedure can increase the detection of axillary metastases by 45% compared with standard axillary dissection. Some investigators have reported that reverse transcriptase-polymerase chain reaction (RT-PCR) increases metastasis detection even more, but it is uncertain whether a positive RT-PCR test in the face of a negative histological evaluation is clinically meaningful.

METHODS

RT-PCR for epithelial glycoprotein 2 and cytokeratin 19 was performed on sentinel and pooled nonsentinel axillary lymph nodes from 108 women with clinical stage I or II breast cancer who were followed up for a median of 40 months.

RESULTS

Axillary metastases were detected on standard tissue sections in 26% and by RT-PCR in 30%. Results for the two tests were concordant for 80% of the cases. RT-PCR upstaged 16%. Tumors from women whose lymph nodes were positive only by RT-PCR were phenotypically similar to those from women with no metastases detected by any method. Moreover, 4-year actuarial distant disease-free survival was 100% for women with metastases detected by RT-PCR only, as compared with 74% for those with metastases detected by routine histology (P =.03) and 93% for those with no metastases detected by either method (P =.04).

CONCLUSIONS

Analysis of sentinel lymph nodes by RT-PCR for epithelial glycoprotein 2 and cytokeratin 19 is unlikely to provide clinically useful information.

Reliability of quantitative reverse-transcriptase-PCR-based detection of tumour cells in the blood between different laboratories using a standardised protocol

Differences in methods of reverse-transcriptase (RT)-polymerase chain reaction (PCR)-based detection of tumour cells in the blood gives rise to conflicting results, and standardisation is urgently needed. This pilot study aimed to assess the variation of RT-PCR-based detection of tumour cells in blood between four different laboratories using a commercially available kit with a standardised protocol. This kit allows comparison of results from different laboratories and facilitates the investigation of the influence of pre-analytical parameters. All laboratories analysed identical sets of blood samples spiked with tumour cells in a concentration range of 1-100 tumour cells/ml. To study at which level variation was introduced, three kinds of sample sets were generated in which (i) tumour cell RNA was spiked in the RNA of mononuclear cells (MNC), (ii) tumour cells were spiked in isolated MNC, and (iii) tumour cells were spiked in blood. Real-time quantitative RT-PCR was used to detect and quantify cytokeratin 20 (CK20) expression, which is indicative for the presence of epithelial tumour cells. All laboratories were able to detect CK20 expression in all spiked-RNA samples with limited variation in expression levels between laboratories. There was a positive correlation between the amount of spiked tumour cell RNA and CK20 expression level. RT-PCR analysis of spiked-MNC samples resulted in more variation in the CK20 expression levels between laboratories, however again all spiked samples were reported to be positive by all of the laboratories. The evaluation of spiked-blood samples gave rise to considerable quantitative and qualitative variation between the laboratories. Our results underline the importance and need for standardisation and extended quality control studies in the field of pre-analytics.

Heparanase gene expression and its correlation with spontaneous apoptosis in hepatocytes of cirrhotic liver and carcinoma

Heparanase (hep) degrades heparan sulphate proteoglycans (HSPGs), which are the main components of the extracellular matrix. This process has been considered as the first step of tumour invasion or metastasis. However, HSPGs play an important role in signal transduction. Thus, the degradation of HSPGs by hep may suppress tumour cell growth. In the present study, we investigated the clinicopathological importance of enhanced hep mRNA expression in 48 hepatocellular carcinomas (HCCs) and in 48 non-cancerous liver samples obtained from the same patients by quantitative real-time reverse transcriptase polymerase chain reaction (RT-PCR). Spontaneous apoptosis in the hepatocytes was evaluated by immunohistochemistry. The relative hep mRNA expression levels were described as hep/glyceraldehyde-3-phosphate dehydrogenase (GAPDH) ratios. The hep mRNA levels of HCCs were significantly lower than those of non-cancerous livers (P<0.001). Hep mRNA levels decreased with increasing liver fibrosis. A significant positive correlation between hep gene expression and spontaneous apoptosis was detected. Hep expression in the tumours did not correlate with tumour differentiation or with tumour stage. However, low hep gene expression was associated with a poor disease-free survival of the patients. Thus, hep gene expression may play an important role in programmed cell death and this gene expression may be lost during the malignant transformation of hepatocytes.

Quantitative analysis of apoptosis-related gene expression in hepatocellular carcinoma

BACKGROUND

The suppression of apoptosis is an important factor in tumor progression in hepatocellular carcinoma (HCC). However, to the authors knowledge the clinicopathologic importance of the expression of apoptosis-related genes (bcl-2, bax, and survivin) in HCC remains unclear. In the current study, the authors investigated the correlation between expression of apoptosis-related genes and the occurrence of spontaneous apoptosis in HCC. In addition, the prognostic significance of the expression of apoptosis-related genes in patients with HCC was analyzed.

METHODS

Tissue samples were obtained through surgical resection of the liver in 53 patients with HCC and 5 patients without HCC. The expression levels of bcl-2, bax, survivin, and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA were analyzed using real-time reverse transcriptase-polymerase chain reaction (RT-PCR). The bcl-2/bax ratio and survivin/GAPDH ratio of the tumors were compared with clinicopathologic findings. In addition, apoptotic tumor cells and the proliferative activity of tumor cells were detected using immunohistochemistry.

RESULTS

The bcl-2/bax ratios of the tumors were not different from those of noncancerous liver tissue samples obtained from regions distant from the tumors and were not found to correlate with apoptosis or with clinical importance in HCC. In contrast, the survivin/GAPDH ratios of the tumors were significantly higher than those of noncancerous liver tissue and demonstrated a negative correlation with apoptosis and a positive correlation with the proliferative activity of tumor cells. Moreover, patients who had tumors with a high survivin/GAPDH ratio were found to have a high incidence of disease recurrence.

CONCLUSIONS

The real-time RT-PCR method appears to be a useful technique with which to detect reliable gene expression in tissues, and the detection of survivin mRNA expression by this method may be a useful marker for identifying patients with HCC who have a high risk of disease recurrence.

Quantitative analysis of heparanase messenger RNA expression in hepatocellular carcinoma

BACKGROUND AND OBJECTIVES

In the process of tumor invasion, cancer cells secrete enzymes including heparanase that degrade extracellular matrices and basement membranes of blood vessels. In the present study, the clinical importance of enhanced expression of heparanase messenger RNA (mRNA) in hepatocellular carcinoma (HCC) was evaluated.

METHODS

Fresh tumor and noncancerous liver tissue adjacent to a tumor were obtained from 50 patients with HCC immediately after hepatic resection. The expression levels of heparanase mRNA were analyzed quantitatively, using the real-time reverse transcriptase-polymerase chain reaction (RT-PCR) method, and were compared with clinicopathological findings.

RESULTS

Relative heparanase mRNA expression level in HCC was significantly lower than that of noncancerous liver tissue (P < 0.001). Tumor heparanase expression did not correlate with tumor differentiation, tumor stage, or patient prognosis.

CONCLUSIONS

Enhanced heparanase mRNA expression may not be a good biological marker in HCC. J. Surg. Oncol. 2002;81:148-154.

survivin messenger RNA expression is a good prognostic biomarker for oesophageal carcinoma

Oesophageal squamous cell carcinoma is one of the most malignant tumours. To identify patients with a high risk of recurrence of oesophageal squamous cell carcinoma, we investigated the prognostic significance of survivin mRNA expression in oesophageal squamous cell carcinoma, which has recently been reported to be a good marker for unfavourable prognosis in various tumours. Tumours and non-cancerous epitheliums adjacent to tumours were obtained by surgical resection from 57 patients with oesophageal squamous cell carcinoma. Expression levels of survivin and glyceraldehyde-3-phosphate dehydrogenase mRNA were analysed quantitatively by real-time reverse transcriptase polymerase chain reaction (RT-PCR). The survivin/glyceraldehyde-3-phosphate dehydrogenase ratios of tumours were higher than those of non-cancerous tissues (P=0.0003). Tumour-survivin/glyceraldehyde-3-phosphate dehydrogenase ratio did not correlate with histologic type, lymph node metastasis, and stage of tumours. In 53 surviving patients, the 5-year survival rate of 17 patients with high survivin mRNA expressed oesophageal squamous cell carcinoma (14.1%) was significantly poorer than that of 36 with low survivin mRNA expressed oesophageal squamous cell carcinoma (46.8%, P=0.0018). In these patients, tumour-survivin mRNA expression was recognised as a good marker of cancer recurrence independently from tumour stage. These findings indicate that survivin mRNA expression in oesophageal squamous cell carcinoma may be a good biomarker for identifying patients with high risk of cancer recurrence.

Distinct and complementary information provided by use of tissue and DNA microarrays in the study of breast tumor markers

Emerging high-throughput screening technologies are rapidly providing opportunities to identify new diagnostic and prognostic markers and new therapeutic targets in human cancer. Currently, cDNA arrays allow the quantitative measurement of thousands of mRNA expression levels simultaneously. Validation of this tool in hospital settings can be done on large series of archival paraffin-embedded tumor samples using the new technique of tissue microarray. On a series of 55 clinically and pathologically homogeneous breast tumors, we compared for 15 molecules with a proven or suspected role in breast cancer, the mRNA expression levels measured by cDNA array analysis with protein expression levels obtained using tumor tissue microarrays. The validity of cDNA array and tissue microarray data were first verified by comparison with quantitative reverse transcriptase-polymerase chain reaction measurements and immunohistochemistry on full tissue sections, respectively. We found a good correlation between cDNA and tissue array analyses in one-third of the 15 molecules, and no correlation in the remaining two-thirds. Furthermore, protein but not RNA levels may have prognostic value; this was the case for MUC1 protein, which was studied further using a tissue microarray containing approximately 600 tumor samples. For THBS1 the opposite was observed because only RNA levels had prognostic value. Thus, differences extended to clinical prognostic information obtained by the two methods underlining their complementarity and the need for a global molecular analysis of tumors at both the RNA and protein levels.

Quantitative real-time PCR identifies a critical region of deletion on 22q13 related to prognosis in oral cancer

Quantitative real time PCR was performed on genomic DNA from 40 primary oral carcinomas and the normal adjacent tissues. The target genes ECGFB, DIA1, BIK, and PDGFB and the microsatellite markers D22S274 and D22S277, mapped on 22q13, were selected according to our previous loss of heterozygosity findings in head and neck tumors. Quantitative PCR relies on the comparison of the amount of product generated from a target gene and that generated from a disomic reference gene (GAPDH-housekeeping gene). Reactions have been performed with normal control in triplicates, using the 7700 Sequence Detection System (PE Applied Biosystems). Losses in the sequences D22S274 (22q13.31) and in the DIA1 (22q13.2-13.31) gene were detected in 10 out of 40 cases (25%) each. Statistically significant correlations were observed for patients with relative copy number loss of the marker D22S274 and stages T3-T4 of disease (P=0.025), family history of cancer (P=0.001), and death (P=0.021). Relative copy number loss involving the DIA1 gene was correlated to family history of cancer (P<0.001), death (P=0.002), and consumption of alcohol (P=0.026). Log-rank test revealed a significant decrease in survival (P=0.0018) for patients with DIA1 gene loss. Relative copy number losses detected in these sequences may be related to disease progression and a worse prognosis in patients with oral cancer.

The myc oncogene: MarvelouslY Complex

The activated product of the myc oncogene deregulates both cell growth and death check points and, in a permissive environment, rapidly accelerates the affected clone through the carcinogenic process. Advances in understanding the molecular mechanism of Myc action are highlighted in this review. With the revolutionary developments in molecular diagnostic technology, we have witnessed an unprecedented advance in detecting activated myc in its deregulated, oncogenic form in primary human cancers. These improvements provide new opportunities to appreciate the tumor subtypes harboring deregulated Myc expression, to identify the essential cooperating lesions, and to realize the therapeutic potential of targeting Myc. Knowledge of both the breadth and depth of the numerous biological activities controlled by Myc has also been an area of progress. Myc is a multifunctional protein that can regulate cell cycle, cell growth, differentiation, apoptosis, transformation, genomic instability, and angiogenesis. New insights into Myc's role in regulating these diverse activities are discussed. In addition, breakthroughs in understanding Myc as a regulator of gene transcription have revealed multiple mechanisms of Myc activation and repression of target genes. Moreover, the number of reported Myc regulated genes has expanded in the past few years, inspiring a need to focus on classifying and segregating bona fide targets. Finally, the identity of Myc-binding proteins has been difficult, yet has exploded in the past few years with a plethora of novel interactors. Their characterization and potential impact on Myc function are discussed. The rapidity and magnitude of recent progress in the Myc field strongly suggests that this marvelously complex molecule will soon be unmasked.

Temperature-controlled Primer Limit for Multiplexing of Rapid, Quantitative Reverse Transcription-PCR Assays: Application to Intraoperative Cancer Diagnostics

Background: Rapid-cycling, real-time PCR instruments bring the opportunity for improved intraoperative detection of metastasis to sentinel lymph nodes. Rapid, standardized, and internally controlled assays need to be developed that are sensitive and accurate.

Methods: We describe rapid, multiplexed, internally controlled, quantitative reverse transcription-PCR (QRT-PCR) assays for tyrosinase and carcinoembryonic antigen mRNAs on the SmartCycler (Cepheid). We used a temperature-controlled primer-limiting approach to eliminate amplification of the endogenous control gene as soon as its signal had reached threshold. Positive-control oligonucleotide mimics were incorporated into all reactions to differentiate failed reactions from true negative samples.

Results: The optimized assays for rapid QRT-PCR yielded results with threshold cycle values that were only 1–2 cycles higher than slower, more conventional protocols. In rapid PCR, the temperature-controlled multiplex assay was quantitative over a dynamic range of at least 15 cycles, compared with only 6 cycles for conventional multiplexing methods. All histologically positive lymph nodes examined were also QRT-PCR positive for the appropriate marker, and the exogenous, internal positive-control mimics produced signals in all negative samples.

Conclusion: Internally controlled, rapid QRT-PCR assays can be performed in an intraoperative time frame and with sufficient sensitivity to detect histologically identified metastases to lymph nodes.

Application of a Multigene Reverse Transcription-PCR Assay for Detection of Mammaglobin and Complementary Transcribed Genes in Breast Cancer Lymph Nodes

Background: Mammaglobin mRNA expression is found in 70–80% of primary and metastatic breast tumor biopsies. The potential breast tumor markers B305D, B726P, and γ-aminobutyrate type A receptor π subunit (GABAπ) complement the expression of mammaglobin. Collectively the expression profile of these four genes could be used as a diagnostic and prognostic indicator for breast cancer.

Methods: A multigene reverse transcription-PCR (RT-PCR) assay was established to detect the expression of mammaglobin, GABAπ, B305D, and B726P simultaneously. Specific primers and TaqMan® probes were used to analyze combined mRNA expression profiles in primary breast tumors and metastatic lymph node specimens.

Results: The multigene RT-PCR assay detected substantial expression signals in 27 of 27 primary tumor and 50 of 50 metastatic breast lymph node samples. Specificity studies demonstrated no significant expression signal in 27 non-breast cancer lymph nodes, in 22 various healthy tissue samples, or in 14 colon tumor samples.

Conclusion: The novel RT-PCR-based assay described here provides a sensitive detection system for disseminated breast tumor cells in lymph nodes. In addition, this multigene assay could also be used to test peripheral blood and bone marrow samples.

Prostate-Specific Ets (PSE) factor: a novel marker for detection of metastatic breast cancer in axillary lymph nodes

Prostate Specific Ets factor is a recently identified transcriptional activator that is overexpressed in prostate cancer. To determine whether this gene is overexpressed in breast cancer, we performed a virtual Northern blot using data available online at the Cancer Genome Anatomy Project website. Ninety-five SAGE libraries were probed with a unique sequence tag to the Prostate Specific Ets gene. The results indicate that Prostate Specific Ets is expressed in 14 out of 15 breast cancer libraries (93%), nine out of 10 prostate cancer libraries (90%), three out of 40 libraries from other cancers (7.5%), and four out of 30 normal tissue libraries (13%). To determine the possibility that the Prostate Specific Ets gene is a novel marker for detection of metastatic breast cancer in axillary lymph nodes, quantitative real-time RT-PCR analyses were performed. The mean level of Prostate Specific Ets expression in lymph nodes containing metastatic breast cancer (n=22) was 410-fold higher than in normal lymph node (n=51). A receiver operator characteristic curve analysis indicated that Prostate Specific Ets was overexpressed in 18 out of 22 lymph nodes containing metastatic breast cancer (82%). The receiver operator characteristic curve analysis also indicated that the diagnostic accuracy of the Prostate Specific Ets gene for detection of metastatic breast cancer in axillary lymph nodes was 0.949. These results provide evidence that Prostate Specific Ets is a potentially informative novel marker for detection of metastatic breast cancer in axillary lymph nodes, and should be included in any study that involves molecular profiling of breast cancer.

Polymerase chain reaction in the staging of solid tumors

Polymerasechain reaction (PCR) is a molecular biology technique that holds great promise as a way to perform molecular staging of cancer by detecting very early metastatic disease. Significant data suggest that PCR analysis may play an important role in the management of colorectal cancer in the future. However, for PCR staging of breast cancer, progress awaits identification of gene markers that have sufficient sensitivity and specificity. Within the next few years, the results of the Sunbelt Melanoma Trial and other ongoing studies will determine whether PCR evaluation of sentinel lymph nodes and peripheral blood cells has prognostic relevance in melanoma. The future of cancer management will likely revolve around the molecular staging of tumors, and PCR is but one method that may better define subgroups of patients that are appropriate candidates forvarious anticancer therapies.

Quantitative assessment of minimal residual disease in childhood lymphoid malignancies using an allele-specific oligonucleotide real-time quantitative polymerase chain reaction

We developed an assay using a real-time quantitative polymerase chain reaction (RQ-PCR) for the quantitative assessment of minimal residual disease (MRD) in childhood lymphoid malignancies by using a consensus V-region probe combining a allele-specific oligonucleotide (ASO) reverse primer. Our strategy employs a set consisting of a consensus V-region probe, an ASO reverse primer, and a patient-specific forward primer for clonal antigen-receptor (IgH, immunoglobulin heavy chain; TCR, T-cell receptor) gene rearrangements (IgH-ASO and TCR-ASO RQ-PCR assays). The limit of detection in both assays was 5 copies of the target/10(5) cell equivalents. We tested the assays in 17 childhood malignancies (14 cases of acute lymphoblastic leukemia and 3 of non-Hodgkin's lymphoma). High correlation coefficients of the standard curves (>0.980) and PCR efficiency (>0.95) were achieved with all primer/probe sets. In 2 (12%) of the 17 patients, ASO primers could not be designed because there was no junctional N-sequence. The quantitative data suggest that the copy number of clonal antigen receptors markedly decreased after induction therapy in 15 of 17 patients and that 1 patient relapsed and died of the disease. Consensus probes make it possible to examine a large number of patients with only a limited number of probes. The strategy used for IgH-ASO and TCR-ASO RQ-PCR assays is accurate and reliable in the clinical prospective study of MRD in childhood lymphoid malignancies.

Molecular pathology of tumor metastasis. II. Molecular staging and differential diagnosis

Molecular Pathology of Tumor Metastasis With the development of non-invasive methods, diagnosis of metastasis from various solid malignancies has become a routine task for diagnostic pathology. However, the differential diagnosis between primary and metastatic cancers and the precise identification of various metastatic cancer types requires the coordinated use of various morphological (light- and electron microscopic-), immunological and molecular techniques. The detection of the lymphatic spread of the primary tumor may now based on the sentinel lymph node technology while the identification of the hematogenous progression may be based on the analysis of the peripheral blood and the bone marrow. More and more frequently these techniques employ highly sensitive immunological and molecular techniques. Accordingly, clinical staging is now confronted with the results of molecular staging, where the only techniques which are able to detect cancer cells are immunocytochemistry or nucleic acid-based methodology. Although several clinical studies have provided evidences for the impact of the immunocytochemistry-based identification of micrometastases on the survival of patients with various type of cancers, none of these methods have become part of standard diagnostic protocols. Although more sensitive molecular techniques are being introduced to identify micrometastasis, their clinical significance is yet unknown. Multicentric clinical trials are now warranted to establish the clinical impact of molecular staging in various cancer types. Without the integration of these methods into the prognostic/predictive pathological protocols it is difficult to envision significant improvement in the results of cancer therapy.

Cellular activation of MMP-2 (gelatinase A) by MT2-MMP occurs via a TIMP-2-independent pathway

The role of membrane-type (MT) 2-matrix metalloproteinase (MMP) in the cellular activation of MMP-2 and the tissue inhibitor of matrix metalloproteinase (TIMP) requirements for this process have not been clearly established. To address these issues a TIMP-2-free cell line derived from a Timp2-/- mouse was transfected for stable cell surface expression of hMT2-MMP. Untransfected cells did not activate endogenous or exogenous TIMP-2-free MMP-2 unless both TIMP-2 and concanavalin A (ConA) were added. Transfected cells expressing hMT2-MMP efficiently activated both endogenous and exogenous MMP-2 (within 4 h) via the 68-kDa intermediate in the absence of TIMP-2 and ConA. In contrast, activation of MMP-2 by Timp2-/- cells expressing recombinant hMT1-MMP occurred more slowly (12 h) and required the addition of 0.3-27 nm TIMP-2. Addition of TIMP-2 or TIMP-4 did not enhance MMP-2 activation by MT2-MMP at any concentration tested; furthermore, activation was inhibited by both TIMPs at concentrations >9 nm, consistent with the similar association rate constants (k(on)) calculated for the binding of TIMP-4 and TIMP-2 to MT2-MMP (3.56 x 10(5) m(-1) s(-1) and 6.52 x 10(5) m(-1) s(-1), respectively). MT2-MMP-mediated activation involved cell surface association of the MMP-2 in a hemopexin carboxyl-terminal domain (C domain)-dependent manner: Exogenous MMP-2 hemopexin C domain blocked activation, and cells expressing hMT2-MMP did not bind or activate a truncated form of MMP-2 lacking the hemopexin C domain. These studies demonstrate the existence of an alternative TIMP-2-independent pathway for MMP-2 activation involving MT2-MMP, which may be important in mediating MMP-2 activation in specific tissues or pathologies where MT2-MMP is expressed.