Comparison of monoclonal antibodies for the detection of occult breast carcinoma metastases in bone marrow

Demonstration of Mucinous-Like Carcinoma-Associated Antigen in Bone Marrow and Lymph Node Biopsies from Patients with Breast Carcinoma

Two hundred and fifty bone marrow and 140 lymph nodal biopsies were analyzed immunocytochemically, using a mouse monoclonal antibody b-12 (MAb b-12), which reacts with MCA (mucinous-like carcinoma-associated antigen). The presence of MCA in bone marrow specimens was demonstrated in 102 out of 105 (97.1%) breast cancer metastases, 5 out of 8 (62.5%) gastric cancers, 5 out of 6 (83.3%) colon cancers, 3 out of 5 (60%) prostate cancers, 11 out of 26 (42.3%) lung cancers and 25 out of 30 (83.3%) unknown primary cancers, while no positivity to anti-MCA antibody was found in 30 cases of normal bone marrow biopsies, 5 cases of non epithelial malignancies and 30 cases of hemolymphoproliferative disease. Normal lymph nodes and non-epithelial lymph node metastases did not show any reaction to MAb b-12; on the contrary MCA positive staining was observed in 75 out of 75 (100%) lymph nodal metastases in breast cancer. These results suggest that application of MAb b-12 in immunohistochemistry is valid for the detection of bone marrow and lymph nodal micrometastases of epithelial origin.

Cytokeratin-positive cells in the bone marrow of breast cancer patients and noncancer donors

Detection of disseminated tumor cells in the bone marrow may provide important prognostic information in breast cancer patients. With few exceptions the number of stained cells scored as cancer is very low; there may be only 1 cell per slide. This makes definitive interpretation of cancer in marrow challenging. False-positive staining of marrow cells with cytokeratin (CK) antibody is relatively common and makes interpretation more difficult. In this report we focus on false-positive staining of marrow specimens from breast cancer patients and noncancer controls and demonstrate that the frequency of false-positive events is common. Bone marrow was collected from 23 cancer-free donors and 60 breast cancer patients. Samples were processed by Ficoll density gradient centrifugation and slides were prepared for immunocytochemical staining with CK and irrelevant (IR) antibody. Slides were evaluated manually and positive cells were categorized as tumor cells, hematopoetic cells, or questionable cells. False-positive staining events were commonly observed in noncancer cases stained with CK or IR antibodies and in breast cancer cases stained with IR antibody. There was little difference in the number of breast cancer marrow specimens scored as tumor cells regardless of whether the antibody used was CK or IR. It is important to devise improved criteria and methods for accurate detection and interpretation of disseminated tumor cells in the marrow of breast cancer patients.

Circulating tumor cells

Circulating tumor cells (CTCs) can be separated and characterized from normal hematopoietic cellular constituents by a variety of methods. Different strategies have included separation by physical characteristics, such as size or weight, or by biological characteristics, such as expression of epithelial or cancer-specific markers. Of the latter, rtPCR for epithelial-related gene message, such as cytokeratin, and immunoseparation techniques using monoclonal antibodies against epithelial cellular adhesion molecule, have gained the most widespread use in investigational and standard clinical application to date. Detection and monitoring of CTCs might be useful for screening, prognosis, prediction of response to therapy, or monitoring clinical course in patients with primary or metastatic cancer. Currently, monitoring patients with metastatic disease is the most practical application of CTCs. In this regard, several studies have demonstrated that approximately 50-70% of patients with metastatic breast, colon, and prostate cancers have elevated CTC levels, when evaluated using a highly automated immunomagnetic CTC assay system, designated CellSearch®. These studies demonstrate that elevated CTC levels prior to initiation of a new systemic therapy are associated with a worse prognosis than those that do not, and that persistently elevated or subsequent rising CTC levels strongly suggest that the therapeutic regimen with which the patient is being treated is not working. Similar results have been shown with rtPCR assays, although they are not as widely available for routine clinical use. New areas of research are directed toward developing more sensitive means of CTC detection and generating a variety of methods to characterize the molecular and biologic nature of CTCs, such as the status of hormone receptors, epidermal, and other growth factor receptor family members, and indications of stem-cell characteristics.

Detection of disseminated tumor cells in bone marrow of gastric cancer using magnetic activated cell sorting and fluorescent activated cell sorting

BACKGROUND AND AIM

Magnetic activated cell sorting (MACS) and fluorescent activated cell sorting (FACS) were employed to enrich and detect the gastric cancer cells from a cell line in a model system, and to enrich and detect disseminated tumor cells (DTCs) from bone marrow (BM) of patients with gastric cancer.

METHODS

Fifteen patients with benign gastric lesions and 35 patients with gastric cancer who received curative operations between December 2002 and June 2003 were selected. Mononuclear cells were separated from their BM. Cells from cell line OCUM-2M were seeded with 10-grade ratio into mononuclear cells from patients with benign gastric lesion. After labeling by MACS minibeads conjugated with cytokeratin (CK) 7/8 antibodies, anti-CK-fluorescein isothiocyanate (FITC), and anti-CD45-perdinin chlorophyll protein (PerCP), the samples were enriched twice using an MS+/RS+ positive separation column. The FACS analysis was conducted on these samples before and after MACS enrichment. The results were analyzed using clinopathological parameters.

RESULTS

Disseminated tumor cells were detected in the BM of 25 (71.43%) patients with gastric cancer. The frequencies of DTCs were 1.38 x 10(-8)-2.40 x 10(-5), 2.19 x 10(-7)-3.70 x 10(-5), 4.01 x 10(-6)-8.57 x 10(-5) in patients with well, moderately, and poorly differentiated carcinoma, respectively (P = 0.026). Disseminated tumor cells in BM had close correlation with tumor tumor-node-metastasis (TNM) stage (P = 0.034) and cancer-free survival (P = 0.035).

CONCLUSION

Disseminated tumor cells are very common in the BM of gastric cancer patients. Poor histological differentiation and more advanced TNM stage have more DTCs in the BM of gastric cancer patients. Patients with DTCs tend to have a poor prognosis.

The clinical significance of disseminated tumor cells in breast cancer

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

A concept for the standardized detection of disseminated tumor cells in bone marrow from patients with primary breast cancer and its clinical implementation

Numerous single-institutional studies and a large pooled analysis have demonstrated that the presence of disseminated tumor cells (DTCs) in the bone marrow (BM) from patients with primary, nonmetastatic breast cancer (Stages I-III) is associated with impaired prognosis. To date, sampling of BM and assessment of DTCs is not considered a routine procedure in the clinical management of breast cancer patients; however, emerging data suggest a future role for risk stratification and monitoring of therapeutic efficacy. Because these clinical options need to be evaluated in trials to verify the principle of this concept in the clinical setting, agreement on the standardized detection of DTCs is necessary. Consequently, the German, Austrian, and Swiss Societies for Senology recently formed a panel 1) to review and discuss the existing methodologies, 2) to find a consensus for a standardized detection of DTCs, and 3) to explore the options for its clinical implementation.

CDCP1 identifies a broad spectrum of normal and malignant stem/progenitor cell subsets of hematopoietic and nonhematopoietic origin

CUB-domain-containing protein 1 (CDCP1) is a novel transmembrane molecule that is expressed in metastatic colon and breast tumors as well as on the surface of hematopoietic stem cells. In this study, we used multiparameter flow cytometry and antibodies against CDCP1 to analyze the expression of CDCP1 on defined hematopoietic cell subsets of different sources. In addition, CDCP1 expression on leukemic blasts and on cells with nonhematopoietic stem/progenitor cell phenotypes was determined. Here we demonstrate that a subset of bone marrow (BM), cord blood (CB), and mobilized peripheral blood (PB) CD34+ cells expressed this marker and that CDCP1 was detected on CD34(+)CD38- BM stem/progenitor cells but not on mature PB cells. Analysis of leukemic blasts from patients with acute lymphoblastic leukemia, acute myeloid leukemia, and chronic myeloid leukemia in blast crisis revealed that CDCP1 is predominantly expressed on CD34(+)CD133+ myeloid leukemic blasts. However, CDCP1 was not strictly correlated with CD34 and/or CD133 expression, suggesting that CDCP1 is a novel marker for leukemia diagnosis. Stimulation of CD34+ BM cells with CDCP1-reactive monoclonal antibody CUB1 resulted in an increased (approximately twofold) formation of erythroid colony-forming units, indicating that CDCP1 plays an important role in early hematopoiesis. Finally, we show that CDCP1 is also expressed on cells phenotypically identical to mesenchymal stem/progenitor cells (MSCs) and neural progenitor cells (NPCs). In conclusion, CDCP1 is not only a novel marker for immature hematopoietic progenitor cell subsets but also unique in its property to recognize cells with phenotypes reminiscent of MSC and NPC.

Pharmacokinetics and clinical evaluation of 125I-radiolabeled humanized CC49 monoclonal antibody (HuCC49deltaC(H)2) in recurrent and metastatic colorectal cancer patients

INTRODUCTION

CC49 is an antitumor monoclonal antibody that is promising for use in radioimmunoguided surgery (RIGS). However, the murine antibody has been limited by human antimouse antibody (HAMA) response and slow clearance. This study examined the pharmacokinetics and tissue localization of a humanized domain-deleted CC49 antibody (HuCC49DeltaC(H)2 MAb) in humans.

METHODS

Twenty-one patients with colorectal carcinoma were given 1 mg intravenous (I.V.) bolus of HuCC49DeltaC(H)2 MAb radiolabeled with 2 mCi (125)I after thyroid blockade. The level of circulating HuCC49DeltaC(H)2 MAb was measured daily as precordial counts using a handheld gamma-detecting probe. Each patient underwent an exploratory laparotomy on postinjection days 3-20. Gamma counts were measured at normal organs, aortic bifurcation (AB), and both clinically evident and occult tumors.

RESULTS

Precordial and AB gamma counts showed an excellent linear correlation. HuCC49DeltaC(H)2 MAb followed a two-compartment pharmacokinetic model. Normal organs and AB showed similar exposures to HuCC49DeltaC(H)2 MAb, while HuCC49DeltaC(H)2 MAb favorably distributed into tumors from day 3. Intestinal and metastatic liver lesions showed the highest partition coefficients. All patients showed no HAMA response.

DISCUSSION

C(H)2 region deletion of HuCC49DeltaC(H)2 MAb did not alter the pharmacokinetics compared to murine CC49. The favorable partition coefficient K of HuCC49DeltaC(H)2 MAb into tumors supports its use in RIGS.

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.

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Residual tumor cell contamination in peripheral blood stem cells collections of 117 breast cancer patients evaluated by immunocytochemical technique

During the last years, high-dose chemotherapy and hematopoietic stem cell support have been thought to improve the treatment of poor-prognosis breast cancer. Nevertheless, the question remained as to whether the reinfusion of contaminating residual malignant cells could contribute to relapse. By using an immunocytochemical method, we have analyzed the tumor cell contamination of peripheral blood stem cells (PBSC) collected from advanced breast cancer patients. We studied 153 PBSC samples from 117 stage III and IV breast cancer patients and compared two screening methods-the usual microscopic observation and the automated cellular image analysis system (ACIS-assisted) screening. With manual observation, we found that 7 of 117 patients (5.9%) presented circulating epithelial tumor cells in 9 of 153 (5.8%) PBSC analyzed, whereas automated screening allowed positive detection in 15 of the same 117 patients (12.8%) and in 18 of the 153 PBSC (11.7%). No difference was found between presence or absence of circulating tumor cells and previous chemotherapy treatment (p = 0.5) or stage TNM (p = 0.13) in this group of poor-prognosis breast cancer. We did not find incidence of infusion of contaminated PBSC on overall survival or time to progression.

Simultaneous immunohistochemical detection of tumor cells in lymph nodes and bone marrow aspirates in breast cancer and its correlation with other prognostic factors

PURPOSE

We studied the prognostic and predictive value of immunohistochemically detected occult tumor cells (OTCs) in lymph nodes and bone marrow aspirates obtained from node-negative breast cancer patients. All were classified as distant metastases-free using conventional staging methods.

PATIENTS AND METHODS

A total of 484 patients with pT1-2N0M0 breast cancer and 70 with pT1-2N1M0 breast cancer and a single affected lymph node participated in our trial. Ipsilateral axillary lymph nodes and intraoperatively aspirated bone marrow were examined. All samples were examined for OTCs using monoclonal antibodies to cytokeratins 8, 18, 19. Immunohistological findings were correlated with other prognostic factors. The mean follow-up was 54 +/- 24 months.

RESULTS

OTCs were detected in 180 (37.2%) of 484 pT1-2N0M0 patients: in the bone marrow of 126 patients (26.0%), in the lymph nodes of 31 patients (6.4%), and in bone marrow and lymph nodes of 23 (4.8%) patients. Of the 70 patients with pT1-2N1MO breast cancer and a single involved lymph node, OTCs were identified in the bone marrow of 26 (37.1%). The ability to detect tumor cells increased with the following tumor features: larger size, poor differentiation, and higher proliferation. Tumors of patients with OTCs more frequently demonstrated lymph node invasion, blood vessel invasion, higher urokinase-type plasminogen activator levels, and increased PAI-1 concentrations. Patients with detected OTCs showed reduced disease-free survival (DFS) and overall survival (OAS) rates that were comparable to those observed in patients who had one positive lymph node. Multivariate analysis of prognostic factors revealed that OTCs, histological grading, and tumor size are significant predictors of DFS; OTCs and grading of OAS.

CONCLUSION

OTCs detected by simultaneous immunohistochemical analysis of axillary lymph nodes and bone marrow demonstrate independent metastatic pathways. Although OTCs were significantly more frequent in patients with other unfavorable prognostic factors, they were confirmed as an independent prognostic factor for pT1-2N0M0, R0 breast cancer patients.

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

PURPOSE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

Competitive cytokeratin 19 RT-PCR for quantification of breast cancer cells in blood cell suspensions

Detection of residual tumor cells in BM and PBPC products has been correlated with worse outcome of breast cancer patients. Still, there is a considerable demand for studies investigating the influence of the actual tumor cell number on prognosis, as quantification routinely has been cumbersome and time consuming and, thus, was evaded. We developed and evaluated a competitive RT-PCR-ELISA assay for cytokeratin 19 (CK19) with standard curve quantification that allows quantification of multiple samples within a working day; mRNA isolation, RT-PCR reaction, and automated ELISA detection were carried out using commercial kits. Results were expressed as OD420nm ratios of CK19 and an internal competitor. Values were then converted into tumor cell numbers using a standard curve of MCF-7 tumor cells. The assay had high specificity because of primers and capture probes with great heterogeneity to both published pseudogenes, which was confirmed by BLAST sequence alignment. We achieved a sensitivity of detecting 1 tumor cell per 10(6) mononuclear cells (MNC). Between-batch precision (n = 8) for quantification was consistent and reasonable, with a coefficient of variation around 25%. Therefore, this assay should be suitable and sufficient for routine quantification of tumor cell numbers in BM or PBPC samples.

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.

Bone marrow and lymph node assessment for minimal residual disease in patients with breast cancer

The immunocytological detection of disseminated epithelial cells in bone marrow in patients with breast cancer has been performed at many hospitals and institutes since the early 1980s. Despite numerous publications in this field, it has not been possible to standardize the method and establish the 'ideal' antibody, either nationally or internationally. Molecular biological methods using PCR technology could extend the diagnostic spectrum. However, one of the major problems in breast cancer is the lack of a disease-specific marker gene. As a result, immunocytology is still the standard procedure for tumour cell detection. The detection of disseminated single cells in bone marrow in primary breast cancer (also known as minimal residual disease) is a new prognostic factor for disease-free and overall survival. This has been demonstrated in two large (N > 300) groups and several small to medium groups (N = 50-300). As a marker of dissemination in a target organ for metastasis this prognostic factor corresponds much more closely to the tendency of breast cancer to early haematogenic spread. Tumour cell detection may predict the course of the disease better than the axillary lymph node status. Bone marrow aspiration and detection of disseminated cells might replace lymph node dissection, at least in those patients with small tumours and no clinical signs of lymph node involvement. This strategy will soon be investigated in appropriate studies. Another possible clinical use might be in deciding on whether or not to give adjuvant systemic therapy to node-negative patients. Patients with positive tumour cell detection are at a higher risk of subsequent metastasis, even if the axillary nodes are histologically normal. The immunohistological or molecular biological detection of tumour cells in axillary lymph nodes might also be very useful, now that it has been shown that a considerable subset of patients determined to be node-negative by means of conventional methods, are positive according to these new techniques. These methods could be a useful supplement to sentinel node biopsy. A further potential use of this method is in monitoring therapy with new treatment modalities such as gene therapy and immunotherapy. Repeated bone marrow aspiration can provide information on the success of therapy in minimal residual disease (cytoreduction). Immunocytochemical investigation of individual cells may be useful in studying the pathogenesis of metastasis, in particular in the skeleton. Phenotyping of cells might allow statements to be made on the metastatic potential of cells and the question of cell dormancy. It remains to be hoped that this aspect of minimal residual disease will be granted more attention in future.

Outcome of primary-breast-cancer patients with micrometastases: a long-term follow-up study

BACKGROUND

Bone-marrow micrometastases have been found in patients with primary breast cancer. We report long-term follow-up of women with primary breast cancer, diagnosed between 1981 and 1986, who had multiple aspirates taken at the time of initial surgery.

METHODS

350 women with primary breast cancer were examined immunocytochemically with antibody to epithelial membrane antigen. We investigated associations with various prognostic factors as well as the effect of micrometastases on relapse-free survival and overall survival.

FINDINGS

At median follow-up of 12.5 years, 151 patients had metastatic disease and 136 patients had died from breast cancer. 10-year relapse-free and overall survival were 43.9% (95% CI 33.4-54.7) and 44.9% (34.2-55.9) in patients with micrometastases, and 62.7% (56.5-68.6) and 65.7% (59.4-71.5) in patients without micrometastases at presentation (p<0.001). For relapse-free survival and overall survival, allowing for tumour size, lymph-node status, and vascular invasion, the effect of micrometastases decreased and was no longer significant, with a hazard ratio of 1.09 (0.74-1.61) for relapse-free survival and 1.21 (0.84-1.75) for overall survival.

INTERPRETATION

The presence of bone-marrow micrometastases in patients with primary breast cancer is associated with a shorter relapse-free survival and overall survival, but is not an independent prognostic factor. This immunocytochemical technique may be of value in patients for whom pathological tumour size and lymph-node status are unavailable (ie, patients receiving primary medical treatment).

Immunohistochemical detection of tumor cells in the bone marrow of breast cancer patients

BACKGROUND

Contamination of bone marrow and peripheral blood stem cells with tumor cells is a problem that may be encountered when autologous hematopoietic stem cell transplantation is conducted concurrently with high-dose chemotherapy.

METHODS

Using monoclonal antibodies to a variety of tumors, the detection of tumor cells in the bone marrow of breast cancer patients was studied by immunohistochemistry.

RESULTS

KL-1 and CAM5.2 were strongly reactive with breast cancer cells, but not with normal bone marrow cells. The reactivity of the tumor cells with EMA was not strong, and DF-3 and 115D8 yielded only slightly positive reactions. These latter antibodies also exhibited some reactivity to normal bone marrow cells. When tumor cells were admixed with normal cells, the sensitivity of CAM5.2 and EMA permitted the detection of one cell in 10(4), but with KL-1, the detection of one in 10(5) cells was possible. When immunohistochemical staining was used in testing 40 patients with advanced or recurrent breast cancer, positive reactions were obtained in four of 27 patients (14.8%) with KL-1, four of 26 (15.4%) with CAM5.2, and nine of 37 (23.7%) with KL-1 + CAM5.2, figures similar to those reported by others who studied stage IV patients.

CONCLUSIONS

Immunohistochemical staining with KL-1 and CAM5.2 is therefore considered to be a useful technique for detecting contamination by tumor cells.

Non-specifically labelled cells that simulate bone marrow metastases in patients with non-metastatic breast cancer

AIMS

To determine whether the presence of disseminated bone marrow tumour cells at diagnosis is a prognostic factor for breast cancer patients at high risk of recurrence or bone metastasis, and to assess their presence as a criterion for evaluation of the potential benefits of adjuvant chemotherapy.

METHODS

Multiple bone marrow aspirates from 72 breast cancer patients free from metastasis were obtained during surgery at the time of diagnosis and were tested immunologically by alkaline phosphatase antialkaline phosphatase technique with a panel of three antiepithelial monoclonal antibodies (MoAb) KL1, EMA, and HMFG2.

RESULTS

In nine of 72 patients, with each MoAb tested, numerous strongly positive cells always isolated were observed. However, it was demonstrated that these cells were non-specifically labelled and could be found in normal controls.

CONCLUSIONS

There was no evidence of marrow tumour cells in 72 operable breast cancer patients. It is suggested that published results may be greatly overestimated and that non-specific labelling may be undetected. More specific MoAb should be found and a correlation with molecular biology should be performed if this criterion is to be considered as a prognostic factor.

Tumour cell detection in the bone marrow of breast cancer patients at primary therapy: results of a 3-year median follow-up

We examined bone marrow aspirates from 100 metastasis-free primary breast cancer patients. In 38/100 patients (38%), tumour cells were detected in the marrow using an immunocytochemical technique with a cocktail of two monoclonal antibodies: anti-EMA and anti-cytokeratin. Median follow-up was 34 months: 15/38 (39%) tumour cell-positive patients have since relapsed, but only 9/62 (15%) tumour cell-negative patients. The median interval between tumour cell detection and relapse was 11.4 months. No statistically significant correlation existed between tumour cell presence and 'established' prognostic factors. However, relapse-free survival was significantly shorter in tumour cell-positive patients. Multivariate analysis showed tumour cell presence as a strong, significant prognostic factor for relapse-free as well as overall survival. We conclude that screening for tumour cells in bone marrow of primary breast cancer patients identifies high-risk patients for early relapse. In particular, patients with node-negative tumours who have tumour cells in their bone marrow may require subsequent systemic therapy.

Tumor markers for breast cancer

Many antigenic and genetic markers have been proposed for breast cancer, with potential utility in identification, screening, prognosis, detection, or monitoring. Of the available markers, those with the greatest promise in 1993 include the yet-to-be-cloned BrCa1, the p53 tumor suppressor gene, tissue-associated prognostic factors such as HER-2/neu, cathepsin-D, and indicators of angiogenesis, and circulating tumor markers that provide an indication of clinical course, such as CA15-3 and CEA. However, the precise clinical utilities of all of these markers have yet to be determined. It is especially important that the relative independence of the markers in relation to other available markers to determined so as to avoid the unnecessary cost and expense of redundancy. Moreover, it is important that the clinician be aware of the limitations in both sensitivity and specificity of each marker so as not to sensitivity and specificity of each marker so as not to over- or under-interpret the predictive value of any test. With these caveats in mind, judicial application of germ-line, tissue, and soluble tumor markers can improve clinical care of patients at risk for and with breast cancer.

Selection of appropriate cellular and molecular biologic diagnostic tests in the evaluation of cancer

In this article, the use of cellular and molecular markers to diagnose and stage tumors is discussed. Their role in the evaluation of tumor prognosis and tumor susceptibility also is covered. The immunologic, cytogenetic, and molecular phenotype is discussed. Traditional markers are compared with newer methodologic approaches including evaluation of oncogenes, tumor suppressor genes, and genes that predict tumor susceptibility. These discussions are presented in relation to specific tumors. Finally, statements one might use to decide which tests to perform are presented.

Prognostic indicators of metastatic bone disease in human breast cancer

The time to detection of metastatic bone disease (MBD) by radiographic examination was studied in 221 patients with advanced breast cancer. None of the patients had bone metastases by radiography or bone marrow carcinosis, evaluated by bilateral iliac crest biopsy. The period of follow-up after first recurrence was 46 months. Fifty-five patients (25%) had MBD; 89 patients died without MBD. The cumulated rate of MBD was 14% and 27% after 1 and 2 years, respectively. The actuarial time to MBD was associated significantly with the presence of positive regional lymph nodes at primary diagnosis, the occurrence of metastases in the mediastinum, and the presence of visceral metastases. Moreover, a positive bone scintigraphic scan at the time of first recurrence and abnormal biochemical analyses from serum also were associated significantly with a shortened time to MBD. Micrometastases in the bone marrow, as detected by monoclonal antibodies against epithelial markers (epithelial membrane antigen and cytokeratin), were present in 18% of the patients. The presence of such tumor cells was not associated with development of radiologic MBD. Cox analyses revealed that the result of bone scintigraphic scanning and the presence of visceral metastases were the most important and independent predictors of the time of MBD. Four distinct prognostic groups were identified based on the status of these two variables. The recognition of these prognostic groups has several implications for clinical and therapeutic management of patients with recurrent breast cancer.

Micrometastatic tumour cells in bone marrow of patients with gastric cancer: methodological aspects of detection and prognostic significance

Monoclonal antibodies (Mab) are potent probes to identify individual tumour cells or small tumour cell clusters in bone marrow. In the present study, various antibodies directed against either cell surface or intracytoplasmic antigens of epithelial cells were assessed for their ability to detect such cells in bone marrow of patients with breast, colorectal and gastric cancer. According to the presented data, monoclonal antibodies against intracellular cytokeratin (CK) components are superior in terms of specificity and sensitivity to antibodies reacting with epitopes of the cell membrane. Using a monoclonal antibody against the cytokeratin polypeptide 18 in connection with the alkaline phosphatase anti-alkaline phosphatase detection system (APAAP), we could detect tumour cells in bone marrow of 34 out of 97 patients with gastric cancer examined at the time of primary surgery. The incidence of positive findings was correlated to established risk factors, such as histological classification and locoregional lymph node involvement. Clinical follow-up studies on 38 patients demonstrated a significantly increased relapse rate in patients presenting with CK-positive cells in their bone marrow at the time of primary surgery. Thus the described technique may help to identify patients with gastric cancer carrying a high risk of early relapse.

Bone marrow trephine interpretation: diagnostic utility and potential pitfalls

Good quality paraffin-embedded sections can be obtained from bone marrow trephines, allowing the routine use of these biopsies in diagnostic histopathology. Trephines are superior to aspirates, especially for the assessment of marrow cellularity, the extent and pattern of tumour infiltration and the cell type. Bone marrow biopsies are useful in several areas, e.g. non-haematological disorders, myelodysplasia, the myeloproliferative group, lymphomas and leukaemias, which are briefly discussed below. Further advances in interpretation are likely with more frequent use of bone marrow trephines.

Micrometastases in breast cancer: long-term follow-up of the first patient cohort

"Micrometastases" can be identified in the bone marrow of patients with apparently localised breast cancer using an immunocytochemical stain for epithelial membrane antigen (EMA). Of 39 women who had marrow samples examined at the time of initial presentation (37), or with locally recurrent disease (2), 13 (33%) had samples which contained small numbers of EMA positive cells. 10 out of 23 (44%) lymph-node positive patients were marrow positive, compared to 1 out of 14 (7%) lymph node negative cases (P = 0.03). Long-term follow-up (median 9.5 years) has shown that 11 out of 13 (85%) patients with micrometastases have developed metastatic disease compared to 8 out of 26 (31%) with negative bone marrow aspirates (P less than 0.05). The small number of EMA positive cells detected in bone marrow samples probably reflects the high metastatic potential of primary or recurrent cancers rather than established microscopic deposits; it is not yet clear whether the finding of such micrometastases will act as an independent variable compared to established prognostic factors.

Biological response modifiers in the management of patients with breast cancer

Despite impressive progress in understanding the biology of breast cancer, mechanisms of host defense, and the pathophysiology of the metastatic process, this burgeoning fact bank has made little impact on the management of patients with breast cancer. There are many interesting ideas for improved diagnosis and therapy in various stages of development, but few have actually translated into improved survival of patients with breast cancer. Potentially useful biological agents include cytokines, monoclonal antibodies, immunotoxins, vaccines, and adoptive cellular therapies. Therapies targetting growth factor receptors and the cellular machinery required for metastasis may become useful, especially when used in combination with other cytotoxic agents. Colony-stimulating factors may allow a test of the hypothesis that augmented dose-intensity of cytotoxic chemotherapy will cure more patients. Though we are not yet sure precisely how to use all of these new tools, there can be little doubt that their application will make a significant impact on the management of patients with breast cancer and other malignancies in the next decade.

Functional immunocytopathology and the diagnosis of bone marrow micrometastases

Immunocytochemical methods offer a new dimension for cytopathology in the diagnosis, prognosis and biology of neoplastic diseases. This concept is illustrated with particular respect to the immunodetection of bone marrow micrometastases and the role of cytologically demonstrable functional parameters in prognosis and therapy planning. A future role for the polymerase chain reaction (PCR) in this diagnostic sphere is proposed.

Critical evaluation of monoclonal antibody staining in breast carcinoma

The immunoperoxidase staining of 84 primary invasive breast carcinomas with four monoclonal antibodies (BRST-1, HMFG1, EMA, B72.3) was evaluated by semiquantitative light microscopical examination and quantitative image analysis. Major differences in the staining of the tumours for each of the monoclonal antibodies was observed. Correlation between monoclonal antibody staining and patient age, survival, histological grade, tumour diameter and cellularity was also carried out. This showed a significant association between histological grade and staining with BRST-1 and EMA.