Detection of genetic alterations in micrometastatic cells in bone marrow of cancer patients by fluorescence in situ hybridization

Should Positive Cytology Revealed by Intraoperative Lavage Preclude Radical Resection in Resectable Pancreatic Cancer?: A Systemic Review and Meta-analysis

OBJECTIVES

The aims of this review were to determine whether positive peritoneal lavage cytology (CY+) precludes radical resection in pancreatic cancer and to propose prospections for future studies.

METHODS

MEDLINE, Embase, and Cochrane Central were searched for related articles. Dichotomous variables and survival outcomes were analyzed with the estimation of odds ratio and hazards ratio (HR), respectively.

RESULTS

A total of 4905 patients were included, of which 7.8% were CY+. Positive peritoneal lavage cytology was correlated with poor overall survival (univariate survival analysis [HR, 2.35; P < 0.00001]; multivariate analysis [HR, 1.62; P < 0.00001]), poor recurrence-free survival (univariate survival analysis [HR, 2.50; P < 0.00001]; multivariate analysis [HR, 1.84; P < 0.00001]), and higher initial peritoneal recurrence rate (odds ratio, 5.49; P < 0.00001).

CONCLUSIONS

Although CY+ predicts poor prognosis and a higher risk of peritoneal metastasis after curative resection, it is not sufficient to preclude curative resection based on the current evidence, and high-quality trials should be conducted to assess the prognostic impact of operation among resectable CY+ patients. In addition, more sensitive and accurate methods to detect peritoneal exfoliated tumor cells and more effective comprehensive treatment for resectable CY+ pancreatic cancer patients are clearly warranted.

A high-risk 70-gene signature is not associated with the detection of tumor cell dissemination to the bone marrow

PURPOSE

The 70-gene signature (70-GS) is a prognostic tool, grouping patients in risk groups to assess their need for adjuvant chemotherapy. Tumor cell dissemination to the bone marrow is a marker of minimal residual disease and associated with impaired survival. In this study, we aimed to evaluate whether 70-GS is associated with the presence of disseminated tumor cells (DTCs) in the bone marrow of patients with early breast cancer.

METHODS

In patients with hormone receptor-positive HER2-negative early breast cancer, the 70-GS was obtained and the presence of DTCs was immunohistochemically evaluated using cytokeratin staining with the A45-B/B3 antibody.

RESULTS

149 patients were included into the analysis. 40 (27%) had a high-risk 70-GS and 35 (23%) had detectable DTCs in their bone marrow. 9 (22%) of the 40 patients with high-risk 70-GS and 26 (24%) of the 109 patients with a low-risk 70-GS were positive for DTCs (p = 0.863).

CONCLUSIONS

As both 70-GS and DTC detection are known prognostic factors but do not seem to correlate, a follow-up on a larger cohort is warranted to evaluate if a combination of the two is able to better stratify the relapse risk in early breast cancer patients.

Diagnostic pathology of early systemic cancer: ERBB2 gene amplification in single disseminated cancer cells determines patient survival in operable esophageal cancer

Early metastatic dissemination and evolution of disseminated cancer cells (DCCs) outside the primary tumor is one reason for the failure of adjuvant therapies because it generates molecular genotypes and phenotypes different from primary tumors, which still underlie therapy decisions. Since ERBB2 amplification in esophageal DCCs but not in primary tumor cells predict outcome, we aimed to establish an assay with diagnostic reliability for single DCCs or circulating tumor cells. For this, we evaluated copy number alterations of more than 600 single DCCs from multiple cancer types to define reference regions suitable for quantification of target regions, such as ERBB2. We then compared ERBB2 quantitative PCR (qPCR) measurements with fluorescent in situ hybridization (FISH) data of various breast cancer cell lines and identified the aberration-calling threshold. The method was applied to two independent cohorts of esophageal cancer patients from Hamburg (n = 59) and Düsseldorf (n = 53). We found a high correlation between the single cell qPCR assay and the standard FISH assay (R = 0.98) and significant associations between amplification and survival for both patient cohorts (Hamburg (HH), p = 0.033; Düsseldorf (D), p = 0.052; pooled HH + D, p = 0.002) when applied to DCCs of esophageal cancer patients. Detection of a single ERBB2-amplified DCC was the most important risk factor for death from esophageal cancer (relative risk = 4.22; 95% CI = 1.91-9.32; p < 0.001). In our study, we detected ERBB2-amplified cells in 7% of patients. These patients could benefit from anti-ERBB2 targeting therapies.

The ex vivo purge of cancer cells using oncolytic viruses: recent advances and clinical implications

Hematological malignancies are treated with intensive high-dose chemotherapy, with or without radiation. This is followed by hematopoietic stem cell (HSC) transplantation (HSCT) to rescue or reconstitute hematopoiesis damaged by the anticancer therapy. Autologous HSC grafts may contain cancer cells and purging could further improve treatment outcomes. Similarly, allogeneic HSCT may be improved by selectively purging alloreactive effector cells from the graft rather than wholesale immune cell depletion. Viral agents that selectively replicate in specific cell populations are being studied in experimental models of cancer and immunological diseases and have potential applications in the context of HSC graft engineering. This review describes preclinical studies involving oncolytic virus strains of adenovirus, herpes simplex virus type 1, myxoma virus, and reovirus as ex vivo purging agents for HSC grafts, as well as in vitro and in vivo experimental studies using oncolytic coxsackievirus, measles virus, parvovirus, vaccinia virus, and vesicular stomatitis virus to eradicate hematopoietic malignancies. Alternative ex vivo oncolytic virus strategies are also outlined that aim to reduce the risk of relapse following autologous HSCT and mitigate morbidity and mortality due to graft-versus-host disease in allogeneic HSCT.

Consensus recommendations for advancing breast cancer: risk identification and screening in ethnically diverse younger women

A need exists for a breast cancer risk identification paradigm that utilizes relevant demographic, clinical, and other readily obtainable patient-specific data in order to provide individualized cancer risk assessment, direct screening efforts, and detect breast cancer at an early disease stage in historically underserved populations, such as younger women (under age 40) and minority populations, who represent a disproportionate number of military beneficiaries. Recognizing this unique need for military beneficiaries, a consensus panel was convened by the USA TATRC to review available evidence for individualized breast cancer risk assessment and screening in young (< 40), ethnically diverse women with an overall goal of improving care for military beneficiaries. In the process of review and discussion, it was determined to publish our findings as the panel believes that our recommendations have the potential to reduce health disparities in risk assessment, health promotion, disease prevention, and early cancer detection within and in other underserved populations outside of the military. This paper aims to provide clinicians with an overview of the clinical factors, evidence and recommendations that are being used to advance risk assessment and screening for breast cancer in the military.

Phenotypic and genetic characterization of circulating tumor cells by combining immunomagnetic selection and FICTION techniques

The presence of circulating tumor cells (CTCs) in breast cancer patients has been proven to have clinical relevance. Cytogenetic characterization of these cells could have crucial relevance for targeted cancer therapies. We developed a method that combines an immunomagnetic selection of CTCs from peripheral blood with the fluorescence immunophenotyping and interphase cytogenetics as a tool for investigation of neoplasm (FICTION) technique. Briefly, peripheral blood (10 ml) from healthy donors was spiked with a predetermined number of human breast cancer cells. Nucleated cells were separated by double density gradient centrifugation of blood samples. Tumor cells (TCs) were immunomagnetically isolated with an anti-cytokeratin antibody and placed onto slides for FICTION analysis. For immunophenotyping and genetic characterization of TCs, a mixture of primary monoclonal anti-pancytokeratin antibodies was used, followed by fluorescent secondary antibodies, and finally hybridized with a TOP2A/HER-2/CEP17 multicolor probe. Our results show that TCs can be efficiently isolated from peripheral blood and characterized by FICTION. Because genetic amplification of TOP2A and ErbB2 (HER-2) in breast cancer correlates with response to anthracyclines and herceptin therapies, respectively, this novel methodology could be useful for a better classification of patients according to the genetic alterations of CTCs and for the application of targeted therapies.

Clinical relevance of circulating CK-19 mRNA-positive cells detected during the adjuvant tamoxifen treatment in patients with early breast cancer

BACKGROUND

The purpose of this study was to evaluate the effect of adjuvant treatment with tamoxifen on the CK-19 mRNA+ cells in patients with early-stage breast cancer.

PATIENTS AND METHODS

CK-19 mRNA+ cells were prospectively and longitudinally detected using a specific real-time PCR assay for CK-19 mRNA in 119 patients with estrogen and/or progesterone receptor-positive tumors during the period of tamoxifen administration.

RESULTS

Twenty-two (18.5%) patients had detectable CK-19 mRNA+ cells after the completion of adjuvant chemotherapy and in 15 (68.2%) of them adjuvant tamoxifen could not eliminate these cells (persistently positive). In 68 (57.1%) patients, no CK-19 mRNA+ cells could be detected throughout the follow-up period (persistently negative). Seven (46.7%) of the 15 persistently positive and six (8.8%) of the 68 persistently negative patients developed disease recurrence (P = 0.00026). Persistency of CK-19 mRNA+ cells was associated with a significantly lower median disease-free interval (P = 0.0001) and overall survival (P = 0.0005). Multivariate analysis revealed that the detection of CK-19 mRNA+ cells during the administration of tamoxifen was associated with an increased risk of relapse [hazard ratio (HR) = 22.318, P = 0.00006] and death (HR = 13.954, P < 0.00001).

CONCLUSIONS

The detection of CK-19 mRNA+ cells throughout the period of adjuvant tamoxifen treatment is an independent poor prognostic factor in patients with early breast cancer.

Isolated tumour cells in pathological node-negative lymph nodes adversely affect prognosis in cancer of the oesophagus or oesophagogastric junction

AIMS

To determine the prevalence of isolated tumour cells (ITC) in lymph nodes of patients with pathological node-negative (pN0) tumours and to assess their impact on disease-free and overall survival.

METHODS

Paraffin embedded lymph nodes from oesophagogastrectomy specimens were examined immunohistochemically using monoclonal anti-cytokeratin antibody (MNF118). Clinical and pathological features were summarised and overall and relapse-free survival were estimated.

RESULTS

Isolated tumour cells were detected in 12 of 146 patients (8%), and 24 of 1694 (1%) lymph nodes. With a median follow-up time of 28 months (range 0-160 months), both relapse-free and overall survival were significantly (p<0.05) associated with the presence of ITC in pN0 lymph nodes. There was no significant difference in the prevalence of ITC between patients who underwent multimodal therapy and those treated with surgery alone.

CONCLUSIONS

ITC in pN0 lymph nodes may be less frequent than previously considered, but their presence is associated with poorer outcomes compared with true node negative disease.

Methods for isolating circulating epithelial cells and criteria for their classification as carcinoma cells

Novel assay methods developed for the isolation and characterization of circulating tumor cells (CTC) of epithelial origin offer the potential of markers for the non-invasive gathering of clinical information relevant to the diagnosis, evolution and treatment of carcinoma. Of the numerous techniques currently used to analyze CTC, slide-based assays are perhaps the most common. While traditional combined immunocytochemical/brightfield microscopy systems continue to be the most frequently employed, fluorescence-based analysis is gaining in importance. This is partly because fluorescence microscopy analysis of slide-mounted CTC can provide simultaneously cytogenetic as well as morphologic and multiple phenotypic information. In particular, fluorescence microscopy analysis of slide-mounted CTC can accurately determine genetic changes at the chromosomal level in patients with recurrent disease. More importantly, by identifying genetic aberrations in CTC, it becomes possible to choose those patients most likely to benefit from a given treatment. The potential of this technique has already been demonstrated by employing fluorescence in situ hybridization (FISH) methods to measure expression of the HER2/neu gene in tissue from patients with breast carcinoma for the specific purpose of identifying those patients most likely to respond to Trastuzumab targeted therapy. Here, we review the major methodologies used in the preparation and analysis of the slide-based assays.

Detection of CK-19 mRNA-positive cells in the peripheral blood of breast cancer patients with histologically and immunohistochemically negative axillary lymph nodes

BACKGROUND

To investigate the incidence of direct hematogenous spread of cancer cells in patients with early-stage breast cancer by studying the presence of occult tumor cytokeratin-19 (CK-19) mRNA(+) cells in the peripheral blood in relation to the status of sentinel (SLNs) and (ALNs) axillary lymph nodes.

PATIENTS AND METHODS

SLNs and ALNs from 111 patients with operable stage I-II breast adenocarcinoma were evaluated for the presence of tumor cells by hematoxylin-eosin (H&E) staining and, if negative, by immunohistochemistry (IHC) using an anti-CK-19 antibody. Peripheral blood was also analyzed for the presence of CK-19 mRNA(+) cells by nested RT-PCR, before the initiation of adjuvant treatment and in CK-19 mRNA(+) patients following the completion of adjuvant chemotherapy and hormonal treatment.

RESULTS

After both H&E staining and IHC analysis, 29 (26%) patients were ALN negative (N0). In 78 (70%) patients H&E staining and in four (3.6%) IHC analysis revealed tumors cells, and these patients were considered as ALN positive (N+). Peripheral blood CK-19 mRNA(+) cells were detected in nine (31%) out of 29 N0 and in 31 (38%) out of 82 N + patients (P=0.5) before any adjuvant treatment. Adjuvant chemotherapy and hormone treatment resulted in the disappearance of the CK-19 mRNA(+) cells in all N0 patients and in 15 out of 31 N + patients. After a median follow-up of 40 months, all the N0 CK-19 mRNA(+) patients were relapse-free whereas four (13%) N + CK-19 mRNA(+) patients had relapsed.

CONCLUSIONS

Direct hematogenous dissemination of occult tumor cells may occur in a substantial proportion of patients with early-stage breast cancer. The prognostic implication of the detection of these cells requires long follow-up periods and further studies.

The utility of fluorescence in-situ hybridization in the diagnosis of malignant pleural effusion

PURPOSE OF REVIEW

Molecular tools are used to refine the diagnosis of malignancy in pleural fluids. This review discusses the rationale and recent findings of the application of one of these tools, fluorescence in-situ hybridization, in pleural effusions.

RECENT FINDINGS

Aneuploidy (i.e., pronounced numeric and structural chromosomal changes) is a recurrent finding in cells of solid tumors. Different methods attempt to detect tumor-associated aneuploidy to prove micrometastasis in different compartments, such as urine, cerebrospinal fluid, bone marrow, and body fluids. In recent years, fluorescence in-situ hybridization analysis has proved viable for detecting metastasis based on the observation of matching patterns of chromosomal aneusomies in primary tumors and corresponding metastasis.

SUMMARY

Fluorescence in-situ hybridization analysis using specific probes for visualizing numeric aberrations in a microscopic evaluation (thus complementing routine cytologic evaluation) has been shown to be relatively simple, very robust, and thus applicable in material of lesser quality and more sensitive than routine cytology. Remarkably, dual-color fluorescence in-situ hybridization analysis allows for an efficient analysis in effusions, and the approach presented in this review proved to be more specific than other molecular procedures applied in effusions to detect malignancy, such as polymerase chain reaction. Prospective studies are needed to demonstrate that refinement of staging by fluorescence in-situ hybridization or polymerase chain reaction ('molecular upstaging') will translate into meaningful therapeutic consequences.

Comparative analysis between the HER2 status in primary breast cancer tissue and the detection of isolated tumor cells in the bone marrow

The presence of isolated tumor cells in the bone marrow (ITC-BM) of breast cancer patients is an independent prognostic parameter, indicating hematogenous tumor cell dissemination. While the HER2 status of breast cancer tissue has predictive value for the efficacy of different therapies, its prognostic relevance is controversial. To investigate the relationship between HER2 and ITC-BM, we retrospectively analyzed tumor tissues of 327 patients who underwent bone marrow aspiration at primary diagnosis or during the disease-free interval. Screening for ITC-BM was performed immunocytochemically, using the anti-cytokeratin antibody A45 B/B3. HER2 was determined by immunohistochemistry (IHC) with the antibody CB 11 (n = 277) and by fluorescence in situ hybridization (FISH, PathVision, Vysis, n = 206). ITC-BM were found in 83 of 327 patients (25.4%), with a median of 2.0 per 2 x 10(6 ) mononuclear cells. HER2 positivity (2+ /3+ ) was demonstrated in 18.8% of the tumors, amplification by FISH in 56 of 206 cases (27.2%). Established pathological parameters,tiviathological parameters, such as tumor size (p = 0.15), lymph node status (p = 0.93) and HER2 did not predict the presence of ITC-BM. After a median follow-up of 49 months (1-255), the presence of ITC-BM was a significant prognostic factor for distant disease free and overall survival, as well in univariate (log-rank-test, p = 0.024) as in multivariate analysis (cox-regression, p = 0.033 ). This also was confirmed in subgroups of patients by aease free survival (p = 0.013) and local recurrence (p = 0.003). The detection of ITC-BM is superior in predicting overall survival, compared to the HER2 status of the primary tumor. The direct identification of HER2 on ITC-BM is the aim of ongoing research, potentially synergizing the prognostic relevance of ITC-BM and the predictive value of the HER2 status.

Prognosis of Non–Small Cell Lung Cancer Patients by Detecting Circulating Cancer Cells in the Peripheral Blood with Multiple Marker Genes

Purpose: Current lung cancer staging and prognosis methods are based on imaging methods, which may not be sensitive enough for early and accurate detection of metastasis. This study aims to validate the use of a panel of markers for circulating cancer cell detection to improve the accuracy of cancer staging, prognosis, and as a rapid assessment of therapeutic response.

Experimental Design: We analyzed the National Cancer Institute-Cancer Genome Anatomy Project database to identify potential marker genes for the detection of circulating cancer cells in peripheral blood. Nested real-time quantitative PCR and a scoring method using cancer cell load Lc were employed to correlate the amount of circulating cancer cells with clinical outcomes in 54 non–small cell lung cancer (NSCLC) patients. The Kaplan-Meier method was employed for analysis of prognostic variables.

Results: A panel of four marker genes was identified and experimentally validated. With these marker genes, we achieved an overall positive detection rate of 72% for circulating cancer cells in the peripheral blood of NSCLC patients. Patients who had higher Lc values had worse outcomes and shorter survival times. Patients with poor therapeutic response were revealed by positive detection of circulating cancer cells after therapy. The results correlated well with the patients' survival time.

Conclusion: Circulating cancer cell detection by a panel of markers and the Lc scoring method can supplement the current tumor, node, metastasis staging method for improved prognosis and for rapid assessment of therapeutic response. Together, they may facilitate the design of better therapeutic strategies for the treatment of NSCLC patients.

Trastuzumab Administration Can Effectively Target Chemotherapy-Resistant Cytokeratin-19 Messenger RNA–Positive Tumor Cells in the Peripheral Blood and Bone Marrow of Patients With Breast Cancer

PURPOSE

The detection of disseminated occult breast cancer cells in peripheral blood and bone marrow is associated with poor prognosis. Since a high proportion of these cells express the HER-2 receptor, we evaluated the effectiveness of the anti-HER-2 antibody trastuzumab (Herceptin) administration to eliminate them.

EXPERIMENTAL DESIGN

Thirty patients with prior chemotherapy exposure were recruited to the study on the basis of having detectable cytokeratin-19 (CK-19) mRNA transcripts by nested reverse transcription (RT)-PCR in the peripheral blood and/or bone marrow. There were 13 patients with stage I, II, or III breast cancer and 17 with stage IV disease. They were treated in two cohorts with either 4 to 8 weekly infusions of trastuzumab at 2 mg/kg (4 mg/kg loading dose; 20 patients) or 2 to 3 infusions every 3 weeks at 6 mg/kg (8 mg/kg loading dose; 10 patients). All of the patients' samples were also analyzed for HER-2 by nested RT-PCR, but detectable HER-2 messenger RNA (mRNA) was not required for inclusion in the study. After trastuzumab infusions, patients were closely monitored by nested RT-PCR and real-time RT-PCR for the detection of CK-19 mRNA-positive cells.

RESULTS

Before trastuzumab infusions, CK-19 mRNA-positive cells were detected in the peripheral blood (n = 10), bone marrow (n = 14), or both (n = 6). In 25 of 30 patients (83%), HER-2 mRNA expression was detected by nested RT-PCR in the pretrastuzumab CK-19-positive sample. After trastuzumab infusions, overall, 28 of 30 (93%) patients became CK-19 mRNA negative by nested RT-PCR and 20 of 30 (67%) by real-time RT-PCR. After a median follow-up of 6 months (range 2 to 22+), the median duration of CK-19 mRNA negativity by nested RT-PCR was 9, 12, and 6 months for stage I/II, III, and IV disease, respectively.

CONCLUSIONS

Therapy-resistant CK-19 mRNA-positive cells in the peripheral blood and bone marrow can be effectively targeted by trastuzumab administration. Further studies are needed to evaluate the prognostic significance of the disappearance of these cells.

Beyond lymph node staging: molecular predictors of outcome in breast cancer

This article briefly reviews the exciting, yet unproven, reports of alternate methods of predicting outcomes in breast cancer and highlights new molecular methods of diagnosing, classifying, and treating this disease. The author starts by reviewing well-known factors in breast cancer with which all alternate methods of staging and predicting outcomes must be compared prospectively.

From latent disseminated cells to overt metastasis: genetic analysis of systemic breast cancer progression

According to the present view, metastasis marks the end in a sequence of genomic changes underlying the progression of an epithelial cell to a lethal cancer. Here, we aimed to find out at what stage of tumor development transformed cells leave the primary tumor and whether a defined genotype corresponds to metastatic disease. To this end, we isolated single disseminated cancer cells from bone marrow of breast cancer patients and performed single-cell comparative genomic hybridization. We analyzed disseminated tumor cells from patients after curative resection of the primary tumor (stage M0), as presumptive progenitors of manifest metastasis, and from patients with manifest metastasis (stage M1). Their genomic data were compared with those from microdissected areas of matched primary tumors. Disseminated cells from M0-stage patients displayed significantly fewer chromosomal aberrations than primary tumors or cells from M1-stage patients (P < 0.008 and P < 0.0001, respectively), and their aberrations appeared to be randomly generated. In contrast, primary tumors and M1 cells harbored different and characteristic chromosomal imbalances. Moreover, applying machine-learning methods for the classification of the genotypes, we could correctly identify the presence or absence of metastatic disease in a patient on the basis of a single-cell genome. We suggest that in breast cancer, tumor cells may disseminate in a far less progressed genomic state than previously thought, and that they acquire genomic aberrations typical of metastatic cells thereafter. Thus, our data challenge the widely held view that the precursors of metastasis are derived from the most advanced clone within the primary tumor.

From latent disseminated cells to overt metastasis: genetic analysis of systemic breast cancer progression

According to the present view, metastasis marks the end in a sequence of genomic changes underlying the progression of an epithelial cell to a lethal cancer. Here, we aimed to find out at what stage of tumor development transformed cells leave the primary tumor and whether a defined genotype corresponds to metastatic disease. To this end, we isolated single disseminated cancer cells from bone marrow of breast cancer patients and performed single-cell comparative genomic hybridization. We analyzed disseminated tumor cells from patients after curative resection of the primary tumor (stage M0), as presumptive progenitors of manifest metastasis, and from patients with manifest metastasis (stage M1). Their genomic data were compared with those from microdissected areas of matched primary tumors. Disseminated cells from M0-stage patients displayed significantly fewer chromosomal aberrations than primary tumors or cells from M1-stage patients (P < 0.008 and P < 0.0001, respectively), and their aberrations appeared to be randomly generated. In contrast, primary tumors and M1 cells harbored different and characteristic chromosomal imbalances. Moreover, applying machine-learning methods for the classification of the genotypes, we could correctly identify the presence or absence of metastatic disease in a patient on the basis of a single-cell genome. We suggest that in breast cancer, tumor cells may disseminate in a far less progressed genomic state than previously thought, and that they acquire genomic aberrations typical of metastatic cells thereafter. Thus, our data challenge the widely held view that the precursors of metastasis are derived from the most advanced clone within the primary tumor.

Peripheral blood circulating cytokeratin-19 mRNA-positive cells after the completion of adjuvant chemotherapy in patients with operable breast cancer

BACKGROUND

The purpose of this study was to evaluate the prognostic significance of the molecular detection of cytokeratin 19 (CK-19) mRNA-positive cells in the peripheral blood of women with operable breast cancer after the completion of adjuvant chemotherapy.

PATIENTS AND METHODS

Blood from 161 patients with stage I and II breast cancer, obtained after the completion of adjuvant chemotherapy, was tested by nested RT-PCR for CK-19 mRNA detection. Using univariate and multivariate analyses possible interactions with other prognostic factors and association of CK-19 mRNA detection with risk of relapse, disease-free interval (DFI) and overall survival were investigated.

RESULTS

After completion of adjuvant chemotherapy, 27.3% of patients had peripheral blood CK-19 mRNA-positive cells; there was no association of this finding with any other prognostic factors or the type of chemotherapy regimen used. For patients with less than four involved axillary lymph nodes the risk of relapse was 3.81 [95% confidence interval (CI) 1.06-13.71] times higher, and the DFI was significantly reduced (P = 0.028) if CK-19 mRNA-positive cells were detectable in the blood after the completion of adjuvant chemotherapy. In contrast, for patients with four or more involved lymph nodes, the presence of CK-19 mRNA-positive cells after adjuvant chemotherapy did not significantly affect the risk of relapse or DFI. Furthermore, the risk of relapse was higher (hazards ratio 3.70; 95% CI 1.09-13.89) and the DFI was reduced (P = 0.022) for patients with detectable CK-19 mRNA-positive cells following adjuvant cyclophosphamide, methotrexate and 5-fluorouracil (CMF) as compared with epirubicin, cyclophosphamide and 5-fluorouracil (FEC) or sequential taxotere-epirubicin and cyclophosphamide (T/EC) chemotherapy.

CONCLUSIONS

The detection of CK-19 mRNA-positive cells in the peripheral blood after adjuvant chemotherapy may be of clinical relevance for patients with early breast cancer and less than four involved axillary lymph nodes.

Relevance of disseminated tumour cells in blood and bone marrow of patients with solid epithelial tumours in perspective

Currently-used systems to predict prognosis in patients with solid epithelial tumours after surgical resection of the tumour do not give any guarantees for the individual patient. In this respect the clinical relevance of the presence of disseminated tumour cells in blood and bone marrow has been frequently studied. Because of growing awareness that information on merely the presence of disseminated tumour cells is not sufficient for prognostic and therapeutic purposes, attention for characterization of disseminated tumour cells has increased. Numerous reviews have already been published on the detection and clinical relevance of disseminated tumour cells. Therefore, this paper will mainly focus on the biological significance of these cells and discusses the (in)efficiency of the metastatic process, the genotypic and phenotypic characteristics of disseminated tumour cells, and their structure of appearance. Despite the fact that information gained on the several individual aspects is substantial, it did not render any solid solutions for individual patient management yet. Hence, a combined approach of several aspects of disseminated tumour cells together with characteristics and behaviour of the primary tumour is needed to substantially improve our knowledge on the role of disseminated tumour cells in the complex process of tumour metastasis.

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.

High-resolution genomic profiling of occult micrometastatic tumor cells

Metastasis is responsible for most deaths from cancer. Currently, little is known about the early genetic events in the metastatic evolution. Here we describe the application of a newly developed strategy for an in-depth characterization of genomic changes in micrometastatic cells. Unique tumor cell lines were established from bone marrow of patients with cancer of the prostate and analyzed by multiplex-FISH (M-FISH) and array CGH. M-FISH revealed that the occult disseminated cells were characterized by very complex numerical and structural aberrations. Many of these aberrations resulted in chromosomal gains and losses, such as losses of 8p, 13q, and 18q and gains of 8q, 9q, 20, and the X chromosome, which are typically observed in prostate cancer. Array CGH allowed an unprecedented high-resolution assessment of copy number changes, pinpointing commonly gained or lost regions, which should narrow down the identification of regions critically involved in metastasis. Thus, occult micrometastatic cells are now amenable to detailed analyses of their genome. Markers for prognosis and treatment decisions can now be established.

The Systemic Progression of Human Cancer: A Focus on the Individual Disseminated Cancer Cell—The Unit of Selection

The metastatic progression of solid tumors is discussed controversially. Because metastasis is usually lethal, it appears as an end point of successive cellular changes. This has led to the prevailing interpretation that genetic changes, in addition to those present in the most advanced clone of the primary tumor, are required to initiate invasion, dissemination, and growth at anatomically distant sites. It has become possible to detect and analyze single disseminated cancer cells at ectopic sites long before metastasis can be diagnosed by standard clinical techniques. Because the finding of single disseminated cancer cells correlates with the subsequent development of distant metastasis, these cells have been identified as the precursors of metastasis. Their direct molecular-genetic characterization, however, shows that dissemination occurs very early in the process of accumulation of genetic changes and suggests that metastases may seldom be derived from the dominant clone of the primary tumor. In contrast, it appears that cancer cell evolution explores a multitude of variant cells from which systemic cancer can develop independently. This review integrates data derived by different approaches into a model of systemic cancer progression.

Patterns of aneusomy for three chromosomes in individual cells from breast cancer tumors

Multi-color fluorescence in situ hybridization (FISH) can determine the changes in the copy numbers of several chromosomes simultaneously and can therefore be used to identify aneusomic patterns in individual cells. Aneusomic patterns may be useful for determining the malignant nature of rare epithelial cells in the blood of cancer patients. Touch preparations from 74 primary breast tumors were evaluated for aneusomy of chromosomes 1, 8 and 17 by tri-color-FISH. In the first part of the analysis, percentages of aneusomy for individual chromosomes and their combinations were determined. In the second part of the analysis, aneusomic patterns for these three chromosomes were analyzed in individual tumor cells and compared to aneusomic patterns observed in leukocytes and in individual cells from benign and normal breast tissue to determine aneusomic patterns indicative of malignancy. Ninety-two percentage of the primary breast carcinomas showed aneusomy for one or more enumerator probes. Comparison with benign breast tissue identified six aneusomic patterns in individual carcinoma cells indicative for malignancy by statistical analysis and not observed in leukocytes. Hence, certain patterns of aneusomy in individual cells involving chromosomes 1, 8 and 17 are indicative of malignancy in individual breast tumor cells and may be useful for determining malignancy of rare epithelial cells in the blood of breast cancer patients.

Molecular detection of cytokeratin-19-positive cells in the peripheral blood of patients with operable breast cancer: evaluation of their prognostic significance

PURPOSE

To evaluate the prognostic significance of molecular detection of cytokeratin 19 (CK-19) mRNA-positive cells by nested reverse transcriptase polymerase chain reaction (RT-PCR) in the peripheral blood of women with stages I and II breast cancer before adjuvant chemotherapy.

PATIENTS AND METHODS

The sensitivity and specificity of CK-19 mRNA detection by nested RT-PCR were investigated using MCF-7 and ARH-77 cells and blood from healthy women and patients with hematologic malignancies, metastatic colorectal cancer, and early and metastatic breast cancer. Peripheral blood from 148 patients with operable breast cancer, obtained before initiation of any adjuvant therapy, was tested for the presence of CK-19 mRNA-positive cells.

RESULTS

The nested RT-PCR assay for CK-19 mRNA detected one MCF-7 tumor cell in 10(6) normal peripheral blood mononuclear cells in four of five experiments; no signal was detected with the CK-19-negative ARH-77 cells. CK-19 mRNA was detected in the peripheral blood of 3.7% of healthy blood donors, 14.3% of patients with hematologic malignancies, and 3.2% of patients with metastatic colorectal cancer. Detection rates for CK-19 mRNA-positive cells in the bone marrow/blood of patients with early or metastatic breast cancer were 63%/30% and 74%/52%, respectively. For stages I and II breast cancer, detection of CK-19-positive cells in the peripheral blood before adjuvant therapy was associated with reduced disease-free interval (P =.0007) and overall survival (P =.01). In multivariate analysis, detection of peripheral-blood CK-19-positive cells was an independent prognostic factor for disease relapse and death.

CONCLUSION

Molecular detection of CK-19 mRNA-positive cells by RT-PCR in the peripheral blood of patients with stages I and II breast cancer before initiation of adjuvant therapy has independent prognostic value as a marker of poor clinical outcome.

Occult micrometastasis: enrichment, identification and characterization of single disseminated tumour cells

The decision as to whether systemic adjuvant therapy should be applied in breast cancer patients for secondary prevention of metastatic relapse is based solely on the statistical prognosis. For this reason, the direct identification of minimal residual cancer in distant organs (e.g. bone marrow) is of particular importance. In breast cancer 25-43% of the patients exhibit micrometastatic disease in bone marrow, following resection of their primary tumours. Successful enrichment, reliable identification and molecular profiling of disseminated tumour cells at the single cell level are still key issues in ongoing and future studies. In addition, first attempts have been reported to evaluate the biology of disseminated tumour cells using in vitro and in vivo models. Taken together, the advancing characterization of disseminated tumour cells opens the avenue for the development of new therapeutic approaches aimed at preventing metastatic relapse.

Evaluation of metastatic potential of gastric tumors by staining for proliferating cell nuclear antigen and chromosome 17 numerical aberrations

BACKGROUND

Aberrations in chromosome 17 are important in carcinogenesis. We recently reported that numerical aberrations in chromosome 17 were associated with tumor progression in gastric cancer. The aim of this study was to determine the biological characteristics of gastric tumor cells with chromosome 17 numerical aberrations.

METHODS

Gastric tumor sections (n = 105) and metastatic lymph nodes (n = 16) were stained simultaneously for PCNA (proliferating cell nuclear antigen) and chromosome 17 centromere. Cancers were classified as follows: Group 1: PCNA(+) and numerical chromosomal aberration(+); Group 2: PCNA(-) and numerical chromosomal aberration(+); Group 3: PCNA(+) and numerical chromosomal aberration(-); and Group 4: PCNA(-) and numerical chromosomal aberration(-).

RESULTS

The frequency of Group 1 cells correlated with lymphatic invasion (P < .0001), lymph node metastasis (P < .0001), and venous invasion (P < .01). The frequency of these cells in gastric lesions was lower than in metastatic lymph nodes (P < .01). Logistic regression analysis identified the depth of invasion followed by the frequency of Group 1 cells were two of the most significant independent factors that could predict lymph node metastasis and lymphatic invasion.

CONCLUSIONS

The frequency of gastric tumor cells positive for PCNA and chromosome 17 numerical aberrations may be an indicator of the metastatic potential of gastric cancers.

Disseminated tumor cells: diagnosis, prognostic relevance, and phenotyping

Malignant tumors of epithelial tissue are the most common form of cancer and are responsible for the majority of cancer-related deaths in Western industrialized countries. As a result of progress in surgical treatment of these tumors, lethality is linked increasingly with early metastasis, which is generally occult at the time of primary diagnosis. The decision as to whether systemic adjuvant therapy should be applied for secondary prevention of metastatic relapse following resection of the primary tumor is based solely on the statistical prognosis. For this reason, the direct identification of minimal residual cancer is of particular importance. The studies described below demonstrate the utility of immunocytochemical and molecular analysis in the diagnosis and characterization of minimal residual cancer. These methods give access for the first time to this critical stage of tumor progression and also contribute to the development of new approaches to therapy aimed at preventing manifest metastasis.

Comparative analysis of micrometastasis to the bone marrow and lymph nodes of node-negative breast cancer patients receiving no adjuvant therapy

PURPOSE

In node-negative patients, of whom up to 30% will recur within 5 years after diagnosis, markers are still needed that identify patients at high enough risk to warrant further adjuvant treatment. In the present study we analyzed whether a correlation exists between microscopic tumor cell spread to bone marrow and to lymph nodes and attempted to determine which route is clinically more important.

PATIENTS AND METHODS

According to a prospective design, bone marrow aspirates and axillary lymph nodes of level I (n = 1,590) from 150 node-negative patients with stage I or II breast cancer were analyzed immunocytochemically with monoclonal anticytokeratin (CK) antibodies. We investigated associations with prognostic factors and the effect of micrometastasis on patients' prognosis.

RESULTS

CK-positive cells in bone marrow aspirates were present in 44 (29%) of 150 breast cancer patients, whereas only 13 patients (9%) had such positive findings in lymph nodes; simultaneous microdissemination to bone marrow and lymph nodes was seen in merely two patients. No correlation of bone marrow micrometastases with other risk factors was assessed. Reduced 4-year distant disease-free and overall survival were each associated with a positive bone marrow finding (P =.032 and P =.014, respectively) but not with lymph node micrometastasis. Multivariate analysis revealed an independent prognostic effect of bone marrow micrometastasis on survival, with a hazards ratio of 6.1 (95% confidence interval, 1.2 to 31.3) for cancer-related death (P =.031) in our series.

CONCLUSION

Immunocytochemical detection of micrometastatic cells in bone marrow but not in lymph nodes is an independent prognostic risk factor in node-negative breast cancer that may have implications for surgery and stratification into adjuvant therapy trials.

Occult tumor cells in bone marrow of patients with locoregionally restricted ovarian cancer predict early distant metastatic relapse

PURPOSE

Based on conventional tumor staging, primary ovarian cancer is viewed as an intraperitoneal disease that rarely spreads to extraperitoneal organs. However, autopsy studies reveal a much higher rate of occult metastasis, indicating that extraperitoneal spread occurs with much greater frequency than previously appreciated. Consequently, we investigated the incidence of early hematogenous dissemination and its association with distant disease-free and overall survival.

PATIENTS AND METHODS

Bone marrow aspirates from 108 patients newly diagnosed with International Federation of Gynecology and Obstetrics stage I to III ovarian cancer were prospectively analyzed with the novel anti-cytokeratin (CK) antibody A45-B/B3. We investigated the frequency of CK-positive tumor cells in bone marrow and their effect on prognosis in relation to established risk factors for tumor progression.

RESULTS

Tumor cells in bone marrow were detected in 32 (30%) of 108 patients. A CK-positive finding was unrelated to established risk parameters, except for poor nuclear grading of the primary tumor. At a median follow-up of 45 months (range, 12 to 77 months), the presence of occult metastatic cells in bone marrow was associated with the occurrence of clinically overt, extraperitoneal (predominantly extraskeletal) distant metastasis (relative risk [RR], 16.5; 95% confidence interval [CI], 6.2 to 56.9; P < .0001) and death from cancer-related causes (RR, 2.3; 95% CI, 1.2 to 4.3; P = .01). Multivariate analysis identified a positive bone marrow finding as an independent prognostic factor of reduced distant disease-free survival for all patients (RR, 13.8; 95% CI, 5.4 to 52.9; P < .0001) and for the 64 stage R0-1 patients (RR, 7.3; 95% CI, 1.5 to 56.8; P = .0021).

CONCLUSION

Our data signal that hematogenous dissemination of tumor cells occurs early and throughout all stages of ovarian cancer. The clinical significance of our findings is supported by the unfavorable prognosis in association with the presence of occult metastatic cells, especially in those patients who received an effective locoregional therapy.

Quantitative analysis of disseminated tumor cells in the bone marrow by automated fluorescence image analysis

Accurate quantification of disseminated tumor cells in hematological samples is of fundamental importance in clinical oncology. However, even highly standardized protocols allow only a rough estimation of the total analyzed cell number, as sample processing may have adverse effects on the number of cells available for analysis. The fluorescence-based microscopic scanning system (MetaCyte) detects, counts, captures, and relocates immunolabeled tumor cells in hematopoietic samples. We report on a cell-counting approach that has been implemented into the scanning system to precisely quantify the number of cells per slide. The cell-counting function, which was designed to determine the number of all nucleated (DAPI-stained) cells on the slide, allows an accurate counting of the tumor cells and the total number of cells analyzed in the given microscopic sample. The reliability of the cell-counting approach was demonstrated by the analysis of DAPI-stained images with 18-1,363 nucleated cells. A good correlation (r(2) = 0.965) between the manually and automatically gained results was observed. The counting accuracy could even be optimized after implementing a correction factor. To prove or disprove an interslide variation, routine bone marrow cytospin preparations from neuroblastoma patients were immunostained for GD2/FITC and counterstained with DAPI. Automatic cell counting of cytospin preparations from the same patients showed significant differences in the total cell number (up to 67% cell loss during preparation, with a maximum interslide difference of 4.7 x 10(5) mononuclear cells). We conclude that determination of the tumor cell content in hematopoietic samples is only reliable when it is performed together with accurate cell counting.

Bone marrow micrometastases and gastrointestinal cancer detection and significance

Accurate staging of cancer is important, as the presence or absence of systemic spread determines treatment. The sensitivity of current imaging and biochemical techniques is suboptimal for the detection of minimal residual disease and latent metastases. This results in understaging and potential undertreatment. To improve detection of disseminated epithelial malignancy, immunohistochemical and molecular methods have been employed that search for epithelial cell-specific proteins in nonepithelial tissue. Bone marrow is mesenchymal tissue (that does not normally express epithelial cell components) and represents an accessible window for detection of micrometastatic carcinoma cells. Detection methods for epithelial cell components (cytokeratins, epithelial membrane antigen, carcinoembryonic antigen) include immunohistochemistry, flow cytometry, reverse transcriptase polymerase chain reaction (rt-PCR), and enzyme linked immunoassay (ELISA). Micrometastatic cells in bone marrow are viable, capable of proliferation, resistant to immune attack, and insensitive to s-phase chemotherapeutic agents. Patients with carcinomas of the lung, breast, prostate, or gastrointestinal tract and in whom bone marrow micrometastases are detected have a foreshortened interval to recurrence and impaired survival. Detection of micrometastases deserves serious consideration in treatment protocols, and standardization of methods is now required.

Selective interactions between epithelial tumour cells and bone marrow mesenchymal stem cells

This work is a comparative study on the features displayed by an epithelial metastatic breast cancer cell line (MCF-7) when set in co-culture with human bone marrow mesenchymal stem cells (MSC) or a feeder layer of 3T3 fibroblasts. MSC, a subset of non-haematopoietic cells in the marrow stroma, display a potential for self-renewal, proliferation and differentiation into precursors for bone, cartilage, connective and muscular tissue. Adhesion of MCF-7 cells to monolayers of MSC or 3T3 was high (95 and 85% respectively). Once attached, MCF-7 grow well on both monolayers. Morphology of MCF-7 cells, as analysed by light and epifluorescence microscopy, revealed that MCF-7 cells grow in clusters on 3T3, but disperse on MSC. Concomitant with the lost of their aggregation status, MCF-7 on MSC express low levels of the intercellular adhesion molecules, E-cadherin and epithelial-specific antigen (ESA). These results suggest that MSC represent an appropriate cell target to investigate the cellular and molecular events occurring at the interface of epithelial-marrow stromal interactions. Together, the model here described should permit to further evaluate the significance and prognostic impact of the shift of micrometastatic cells from a cluster-aggregated into a single-cell status.

Malignant cell detection by fluorescence in situ hybridization (FISH) in effusions from patients with carcinoma

Cytological diagnosis of malignant cells in effusions is hampered by difficulties in the differentiation from reactive mesothelial cells. Because interphase cytogenetics by fluorescence in situ hybridization (FISH) might complement cytological evaluation, we determined the power of tumor cell detection using FISH and cytology in 201 effusions from patients with advanced cancer. Furthermore, 9 primary breast tumors were FISH-karyotyped, and chromosomal aberrations were compared with those of corresponding metastatic effusion cells. By using centromeric probes representing chromosomes 7, 8, 11, 12, 17, and 18, a rate of malignancy-associated aneusomy combined for the 6 chromosomes was detected in an overall of 44.8% of effusion specimens (range, 31.8% to 39.3% for the individual chromosome), comparable to cytology (43.3%). The combination of just 2 FISH probes (namely, representing chromosome pairs 8/11 and 8/17) was almost equally efficient in the identification of aneusomy. Approximately one fourth of the cytologically negative effusions were FISH positive and vice versa. From the initially FISH-negative effusions, 18.9% could be subsequently classified positive with dual-color FISH by visualization of intranuclear chromosomal complexity in rare aneuploid cells. Thus, "overall FISH analysis," including dual-color evaluation, identified tumor cells in significantly more effusions (55.2%, P = .001) than conventional cytology, implying greater sensitivity. Finally, our finding that numerical aberration patterns in primary breast tumors and corresponding metastatic effusions are comparable indicates that FISH examination of primary tumors will indicate the centromeric probe(s) best suited for an efficient search for metastasis in the individual case.

Cytokeratin-positive cells in the bone marrow and survival of patients with stage I, II, or III breast cancer

BACKGROUND

Cytokeratins are specific markers of epithelial cancer cells in bone marrow. We assessed the influence of cytokeratin-positive micrometastases in the bone marrow on the prognosis of women with breast cancer.

METHODS

We obtained bone marrow aspirates from both upper iliac crests of 552 patients with stage I, II, or III breast cancer who underwent complete resection of the tumor and 191 patients with nonmalignant disease. The specimens were stained with the monoclonal antibody A45-B/B3, which binds to an antigen on cytokeratins. The median follow-up was 38 months (range, 10 to 70). The primary end point was survival.

RESULTS

Cytokeratin-positive cells were detected in the bone marrow specimens of 2 of the 191 control patients with nonmalignant conditions (1 percent) and 199 of the 552 patients with breast cancer (36 percent). The presence of occult metastatic cells in bone marrow was unrelated to the presence or absence of lymph-node metastasis (P=0.13). After four years of follow-up, the presence of micrometastases in bone marrow was associated with the occurrence of clinically overt distant metastasis and death from cancer-related causes (P<0.001), but not with locoregional relapse (P=0.77). Of 199 patients with occult metastatic cells, 49 died of cancer, whereas of 353 patients without such cells, 22 died of cancer-related causes (P<0.001). Among the 301 women without lymph-node metastases, 14 of the 100 with bone marrow micrometastases died of cancer-related causes, as did 2 of the 201 without bone marrow micrometastases (P<0.001). The presence of occult metastatic cells in bone marrow, as compared with their absence, was an independent prognostic indicator of the risk of death from cancer (relative risk, 4.17; 95 percent confidence interval, 2.51 to 6.94; P<0.001), after adjustment for the use of systemic adjuvant chemotherapy.

CONCLUSIONS

The presence of occult cytokeratin-positive metastatic cells in bone marrow increases the risk of relapse in patients with stage I, II, or III breast cancer.

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

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

Detection and clinical importance of micrometastatic disease

Metastatic relapse in patients with solid tumors is caused by systemic preoperative or perioperative dissemination of tumor cells. The presence of individual tumor cells in bone marrow and in peripheral blood can be detected by immunologic or molecular methods and is being regarded increasingly as a clinically relevant prognostic factor. Because the goal of adjuvant therapy is the eradication of occult micrometastatic tumor cells before metastatic disease becomes clinically evident, the early detection of micrometastases could identify the patients who are most (and least) likely to benefit from adjuvant therapy. In addition, more sensitive methods for detecting such cells should increase knowledge about the biologic mechanisms of metastasis and improve the diagnosis and treatment of micrometastatic disease. In contrast to solid metastatic tumors, micrometastatic tumor cells are appropriate targets for intravenously applied agents because macromolecules and immunocompetent effector cells should have access to the tumor cells. Because the majority of micrometastatic tumor cells may be nonproliferative (G0 phase), standard cytotoxic chemotherapies aimed at proliferating cells may be less effective, which might explain, in part, the failure of chemotherapy. Thus, adjuvant therapies that are aimed at dividing and quiescent cells, such as antibody-based therapies, are of considerable interest. From a literature search that used the databases MEDLINE(R), CANCERLIT(R), Biosis(R), Embase(R), and SciSearch(R), we discuss the current state of research on minimal residual cancer in patients with epithelial tumors and the diagnostic and clinical implications of these findings.

p53 gene mutations are not required for early dissemination of cancer cells

The p53 protein is involved in several central cellular processes, including gene transcription, DNA repair, cell cycling, genomic stability, chromosomal segregation, senescence, and apoptosis. p53 mutations frequently result in an immunocytochemically detectable accumulation of the p53 protein in tumor cells. To evaluate whether p53 gene mutations are required for the onset of hematogeneous tumor cell dissemination, we compared the p53 status of primary and micrometastatic tumor cells. Disseminated carcinoma cells could be detected in bone marrow aspirates obtained from 46 (40%) of 114 patients with various types of epithelial tumors without overt skeleton metastases. There was no correlation between the detection of p53 protein in primary lung carcinomas and the presence of tumor cells in bone marrow. Further analyses revealed that the disseminated carcinoma cells rarely accumulate mutated p53 protein and that 10 cell lines derived thereof did not harbor p53 mutations even in the presence of such mutations in the autologous primary tumors. These observations indicate that tumor cells can leave the primary tumor before mutations of the p53 gene occur and that these mutations are not essential for such early hematogeneous dissemination of cancer cells. Thus, the value of mutated p53 as a target for diagnosis and treatment of micrometastatic disease in cancer patients is questionable.

Hyperdiploidy and apparent aneusomy in mesothelial cells from non-malignant effusions as detected by fluorescence in situ hybridization (FISH)

Interphase cytogenetics by fluorescence in situ hybridization (FISH) can be used to detect malignant cells characterized by chromosomal aneuploidy. However, apparent aneusomy in normal "control" tissues has to be considered when using FISH as diagnostic tool. In effusions as model tissue exposed to metastasis, the definition of cut-off levels for background aneusomy by FISH was aimed in this study. Using centromeric probes representing chromosomes 7, 8, 11, 12, 17 and 18, extensive chromosome copy number enumeration by single-color FISH analysis was performed in pleural and ascitic effusions derived from 15 patients with various, non-malignant diseases. In all effusions, cells with gain of hybridization signals for several or all chromosomes tested were found (in up to 1.94% of cells). A consistent finding was high grade hyperdiploidy (>4 centromeric signals). Mesothelial elements mainly contributed to hyperdiploidy in effusions, as demonstrated by a combined analysis of FISH and immunocytochemistry with staining for cytokeratin. Dual-color FISH analysis showed that hyperdiploidy was predominantly corresponding to polyploidization; however, there were always minor cell populations classified as aneuploid by dual-color FISH. In conclusion, stringent criteria have to be applied to distinguish malignancy-related aneuploidy from background aneusomy by FISH.

Detection of chromosomal aberrations in tumor cells and tumor infiltrating lymphocytes by molecular cytogenetics in patients with gynecological cancer

Conventional cytogenetic studies of tumor cells from patients with breast or ovarian cancer have shown multiple chromosomal abnormalities including chromosomes 7, 12, and 17. This study was designed to analyze the cytogenetic features of tumor cells and tumor infiltrating lymphocytes (TILs) by using a combination of magnetic activated cell sorting (MACS) and fluorescence in situ hybridization (FISH). Tumor cell, peripheral blood (PB), and TIL samples from 37 patients (20 ovarian tumors, 13 breast cancers, 3 uterine sarcoma, 1 carcinoma of the filamentary tube) were analyzed for the presence of numerical aberrations of chromosomes 7, 12, and 17. All of the tumor cells showed a high frequency of numerical aberrations of chromosomes 7, 12, and 17, especially trisomies or tetrasomies. There was no statistically significant difference in the incidence of chromosomal abnormalities in tumor tissue and effusions, or between primary and relapsed disease in patients with breast or ovarian tumors. However, tumor cells from patients with solid metastatic disease had significantly higher numbers of aberrations of chromosome 7 in the primary tumor than in tumors from patients without metastases (P = 0.049), suggesting that chromosome 7 is frequently involved in the progression of disease. Monosomies and trisomies of chromosomes 7 and 12 also occurred at a low percentage of TILs without any statistically significant difference between primary and relapsed tumors. The presence of these aneuploidies might be responsible for treatment failures in the immunotherapy of gynecological cancer.

Aneuploidy of chromosome 8 as detected by interphase fluorescence in situ hybridization is a recurrent finding in primary and metastatic breast cancer

Previous work from our laboratory demonstrated aneuploidy for several chromosomes by interphase fluorescence in situ hybridization (FISH) in a high proportion of breast cancer specimens. In the literature, only limited data are available concerning chromosome 8 anomalies in breast cancer. To determine chromosome 8 ploidy status in primary and metastatic specimens from 81 breast cancer patients, FISH analysis with a DNA probe recognizing chromosome 8 centromeres was performed. In all primary tumor specimens (n = 30), significant proportions of cells were aneuploid exhibiting gain of chromosome 8 copy numbers; in 75% of effusion specimens previously classified as malignant by cytology and/or FISH for various chromosomes (n = 40), cell populations aneuploid for chromosome 8 were detected; effusions previously classified non-malignant (n = 11) were diploid in 10 cases, whereas one specimen contained rare hyperdiploid cells. Among these cells complex chromosomal aneuploidy could be demonstrated by two-color FISH, suggesting malignancy. Trisomic and tetrasomic clones were predominant in the majority of samples, but a marked intratumor cytogenetic heterogeneity was observed in most cases. Primary tumors and corresponding positive axillary lymph nodes revealed similar distributions of chromosome 8 copy numbers, analogous to previous findings with other chromosomes. This implies that, by using suitable FISH probes after examination of the respective primary tumor, an efficient search for (micro)metastasis might be feasible.

Minimal residual disease in solid tumor malignancies: a review

The increase in the number of patients treated with high-dose chemotherapy/autologous stem cell transplantation (HDC/ASCT) for solid tumor malignancies has generated concern about the infusion of tumor cell contamination in the graft. In an effort to study so-called minimal residual disease (MRD) in the HDC/ASCT setting, a variety of assay methods have been used. Although these assays vary in terms of sensitivity and specificity of tumor detection, they are in agreement as to the presence and viability of tumor cells in ASCT grafts. A growing body of evidence indicates that MRD is present in ASCT grafts from neuroblastoma, breast cancer, and ovarian cancer patients. More importantly, several retrospective studies have determined that the infusion of tumor cells with the ASCT graft is strongly associated with post-ASCT relapse. Gene-marking studies have directly demonstrated that infused tumor cells are present at sites of disease relapse. Thus, the issue of tumor contamination of autologous grafts is an area of growing concern. This review article details the current status of MRD in solid tumor malignancies, with emphasis on assay methodology, clinical utility, and clinical relevance in transplantation medicine.