Epitope specificity of 30 monoclonal antibodies against cytokeratin antigens: the ISOBM TD5-1 Workshop

Lung cancer biomarkers: Raising the clinical value of the classical and the new ones

Blood-based diagnostics for lung cancer support the diagnosis, estimation of prognosis, prediction, and monitoring of therapy response in lung cancer patients. The clinical utility of serum tumor markers has considerably increased due to developments in serum protein tumor markers analytics and clinical biomarker studies, the exploration of preanalytical and influencing conditions, the interpretation of biomarker combinations and individual biomarker kinetics, as well as the implementation of biostatistical models. In addition, circulating tumor DNA (ctDNA) and other liquid biopsy markers are playing an increasingly prominent role in the molecular tumor characterization and the monitoring of tumor evolution over time. Thus, modern lung cancer biomarkers may considerably contribute to an individualized companion diagnostics and provide a sensitive guidance for patients throughout the course of their disease. In this special edition on Tumor Markers in Lung Cancer, experts summarize recent developments in clinical laboratory diagnostics of lung cancer and give an outlook on future challenges and opportunities.

Clinico-Radio-Pathological and Molecular Features of Hepatocellular Carcinomas with Keratin 19 Expression

Hepatocellular carcinoma (HCC) is a heterogeneous neoplasm, both from the molecular and histomorphological aspects. One example of heterogeneity is the expression of keratin 19 (K19) in a subset (4-28%) of HCCs. The presence of K19 expression in HCCs has important clinical implications, as K19-positive HCCs have been associated with aggressive tumor biology and poor prognosis. Histomorphologically, K19-positive HCCs demonstrate a more infiltrative appearance, poor histological differentiation, more frequent vascular invasion, and more intratumoral fibrous stroma than K19-negative conventional HCCs. From the molecular aspect, K19-positive HCCs have been matched with various gene signatures that have been associated with stemness and poor prognosis, including the G1-3 groups, S2 class, cluster A, proliferation signature, and vascular invasion signature. K19-positive HCCs also show upregulated signatures related to transforming growth factor-β pathway and epithelial-to-mesenchymal transition. The main regulators of K19 expression include hepatocyte growth factor-MET paracrine signaling by cancer-associated fibroblast, epidermal growth factor-epidermal growth factor receptor signaling, laminin, and DNA methylation. Clinically, higher serum alpha-fetoprotein levels, frequent association with chronic hepatitis B, more invasive growth, and lymph node metastasis have been shown to be characteristics of K19-positive HCCs. Radiologic features including atypical enhancement patterns, absence of tumor capsules, and irregular tumor margins can be a clue for K19-positive HCCs. From a therapeutic standpoint, K19-positive HCCs have been associated with poor outcomes after curative resection or liver transplantation, and resistance to systemic chemotherapy and locoregional treatment, including transarterial chemoembolization and radiofrequency ablation. In this review, we summarize the currently available knowledge on the clinico-radio-pathological and molecular features of K19-expressing HCCs, including a detailed discussion on the regulation mechanism of these tumors.

Epithelial keratins: Biology and implications as diagnostic markers for liquid biopsies

Keratins are essential elements of the cytoskeleton of normal and malignant epithelial cells. Because carcinomas commonly maintain their specific keratin expression pattern during malignant transformation, keratins are extensively used as tumor markers in cancer diagnosis including the detection of circulating tumor cells in blood of carcinoma patients. Interestingly, recent biological insights demonstrate that epithelial keratins should not only be considered as mere tumor markers. Emerging evidence suggests an active biological role of keratins in tumor cell dissemination and metastasis. In this review, we illustrate the family of keratin proteins, summarize the latest biological insights into keratin function related to cancer metastasis and discuss the current use of keratins for detection of CTCs and other blood biomarkers used in oncology.

TPS Monitoring in Metastatic Breast Cancer

The management of metastatic breast cancer patients reflects the heterogeneous nature of the disease. While patients may benefit from hormonal treatment, in most cases more toxic chemotherapy is applied in the advanced stages. The pretreatment levels of TPS in patients with metastatic breast cancer are correlated with prognosis. Decreasing TPS levels (>50%) during treatment are indicative of response. The fastest decrease in TPS levels is obtained in patients with a favorable prognosis. Increasing TPS levels (>25%) predict disease progression with a considerable lead time (median 8 months). The clinical impact of these observations is discussed in this paper.

Whole blood microRNAs as potential biomarkers in post-operative early breast cancer patients

BACKGROUND

microRNAs (miRNAs) are considered promising cancer biomarkers, showing high reliability, sensitivity and stability. Our study aimed to identify associations between whole blood miRNA profiles, presence of circulating tumor cells (CTCs) and clinical outcome in post-operative early breast cancer patients (EBC) to assess the utility of miRNAs as prognostic markers in this setting.

METHOD

A total of 48 post-operative patients, recruited in frame of the SUCCESS A trial, were included in this retrospective study and tested with a panel of 8 miRNAs (miR-10b, -19a, - 21, - 22, -20a, - 127, - 155, -200b). Additional 17 female healthy donors with no previous history of cancer were included in the study as negative controls. Blood samples were collected at different time points (pre-adjuvant therapy, post-adjuvant therapy, 2 years follow up), total RNA was extracted and the relative concentration of each miRNA was measured by quantitative PCR and compared in patients stratified on blood collection time or CTC detection. Furthermore, we compared miRNA profiles of patients, for each time point separately, and healthy donors. CTCs were visualized and quantified with immunocytochemistry analysis. Data were analyzed using non-parametric statistical tests.

RESULTS

In our experimental system, miR-19a, miR-22 and miR-127 showed the most promising results, differentiating patients at different time points and from healthy controls, while miR-20a, miR-21 and miR-200b did not show any difference among the different groups. miR-10b and miR-155 were never detectable in our experimental system. With respect to patients' clinical characteristics, we found a significant correlation between miR-200b and lymph node status and between miR-20a and tumor type. Furthermore, miR-127 correlated with the presence of CTCs. Finally, we found a borderline significance between Progression Free Survival and miR-19a levels.

CONCLUSIONS

This pilot study suggests that profiling whole blood miRNAs could help to better stratify post-operative EBC patients without any sign of metastasis to prevent later relapse or metastatic events.

Circulating Levels of M30 and M65 Molecules in Transitional Cell Carcinoma of the Bladder and Their Relation to Tumor Progression

BACKGROUND

Various markers are suggested for diagnosis and monitoring of transitional cell carcinoma of the bladder (TCC), including cytokeratins (CKs).

OBJECTIVES

In the present study, the circulating CK18 (M65) and its caspase-cleaved form, ccCK18 (M30), have been investigated in a group of patients with TCC.

PATIENTS AND METHODS

Serum samples were obtained from 60 patients before surgical resection, among which the samples of 26 patients after resection were also included. We measured the levels of soluble M30 and M65 molecules by enzyme-linked immunosorbent assay. The relation between these markers and patients' clinical characteristics was evaluated.

RESULTS

M30 and M65 in total patient sera were 148 ± 16 U/L and 318 ± 34 U/L, respectively. A correlation existed between pre-operative M30 and M65 levels (P < 0.0001, Spearman r = 0.51). M65, but not M30, showed a significant relation to tumor stage and grade. The M65 quantity in patients with T3/T4 tumor stages (350 ± 42 U/L) was higher than that of patients with T1/T2 stages (293 ± 45U/L; P < 0.038). Patients with tumor grades III/IV also showed higher levels of M65 compared to patients with tumor grades I/II (P < 0.04). The M30:M65 ratio in all patients was 0.54 ± 0.04. There was a lower M30:M65 ratio in patients with T3/T4 stage tumors and those with tumor grades III/IV (P < 0.02). The M30 (133 ± 19 U/L) and M65 levels (240 ± 21 U/L) after surgery did not significantly differ compared to their pre-operative values. However, a correlation between the pre- and post-operative M30:M65 ratio in patients ≥ 70 years was seen (P = 0.009).

CONCLUSIONS

These data suggested a relationship of both M65 and the M30:M65 ratio to tumor progression which might imply their importance in TCC monitoring.

Comparison of HER2 Expression in Primary Tumor and Disseminated Tumor Cells in the Bone Marrow of Breast Cancer Patients

OBJECTIVE

The aim of this study was to measure the human epidermal growth factor receptor 2 (HER2) status of disseminated tumor cells (DTCs) from bone marrow (BM) aspirates and to assess correspondence or discrepancy with the primary tumor.

METHODS

DTCs were isolated from the BM of 156 breast cancer patients. Cytokeratin-positive DTCs were further analyzed by the chromogenic in situ hybridization method to detect HER2 gene amplification.

RESULTS

A significant correlation (p = 0.021) was found between the HER2 status of DTCs and the primary tumors. Sixty-one (68.5%) patients had a corresponding status. However, a shift of phenotype between primary tumor and DTCs was found in the remaining patients.

CONCLUSION

This study showed a significant grade of discordance of the HER2 status between primary tumors and DTCs in the BM of a relevant subgroup of patients. Detection of HER2 amplification on DTCs could therefore help to better stratify patients for a more tailored therapy, since they would benefit from a HER2-targeted therapy.

Evaluation of two different analytical methods for circulating tumor cell detection in peripheral blood of patients with primary breast cancer

Background. Evidence is accumulating that circulating tumor cells (CTC) out of peripheral blood can serve as prognostic marker not only in metastatic but also in early breast cancer (BC). Various methods are available to detect CTC. Comparisons between the different techniques, however, are rare. Material and Methods. We evaluate two different methods for CTC enrichment and detection in primary BC patients: the FDA-approved CellSearch System (CSS; Veridex, Warren, USA) and a manual immunocytochemistry (MICC). The cut-off value for positivity was ≥1 CTC. Results. The two different nonoverlapping patient cohorts evaluated with one or the other method were well balanced regarding common clinical parameters. Before adjuvant CHT 21.1% (416 out of 1972) and 20.6% (247 out of 1198) of the patients were CTC-positive, while after CHT 22.5% (359 out of 1598) and 16.6% (177 out of 1066) of the patients were CTC-positive using CSS or MICC, respectively. CTC positivity rate before CHT was thus similar and not significantly different (P = 0.749), while CTC positivity rate immediately after CHT was significantly lower using MICC compared to CSS (P < 0.001). Conclusion. Using CSS or MICC for CTC detection, we found comparable prevalence of CTC before but not after adjuvant CHT.

Clinical significance of disseminated tumour cells in non-small cell lung cancer

Background:

Early-stage non-small cell lung cancer (NSCLC) patients have a high risk of disease relapse despite curatively intended surgical resection, and the detection of tumour cells in the bone marrow could be one method of determining the presence of the disseminated disease in its early stages.

Methods:

Bone marrow aspirates were collected from 296 patients at the time of surgery, and the presence of disseminated tumour cells was determined with the help of immunomagnetic selection (IMS) using the MOC31-antibody recognising EpCAM and with the help of standard immunocytochemistry (ICC) using the anti-cytokeratin (CK) antibodies AE1/AE3.

Results:

Disseminated tumour cells were found in 152 of 252 (59%) bone marrow samples using IMS and in 25 of 234 (11%) samples using ICC. No association between the two detection methods was observed. The presence of EpCAM⁺ cells was not associated with any clinicopathological parameters, whereas a higher frequency of CK⁺ cells was found in patients with an advanced pT status. Disseminated tumour cells, as detected using IMS, had no prognostic impact. Patients with CK⁺ cells in the bone marrow had a reduced relapse-free survival, but the difference was not statistically significant.

Conclusion:

Our findings do not support the further development of DTC detection for clinical use in early-stage NSCLC. Future studies should include the molecular characterisation of DTCs, along with an attempt to identify subpopulations of cells with biological and clinical significance.

Keratins in oral cancer: necessity of mass spectrometry for validation of antibody based identifications

Keratins are intermediate filament family proteins which are predominantly expressed in the epithelial cells. Most of the studies which evaluate the status of keratins in clinical samples of the oral cavity are based on the identification of their presence and localization by immunohistochemistry using monoclonal antibodies. It is very well known that many monoclonal/polyclonal antibodies show cross-reactivity with the other closely related or non-related proteins. This cross-reactivity might be the result of epitope similarity, but it is not always necessary. Therefore studies done with only antibody based techniques can mislead interpretation unless they are validated with additional techniques like mass-spectrometry. In this investigation we have evaluated the status of keratin 18 in cancer of buccal mucosa using 1DE, 2DE and western blotting with monoclonal antibody to keratin 18. The patterns emerging showed aberrant as well as differential expression of K18 in adjacent normal versus tumor tissue samples of buccal mucosa. Mass spectrometry analysis of the immunodetected spots however revealed that it is keratin 13. Thus this study emphasizes the necessity of validation of antibody based findings when dealing with proteins of a large family having similarity/homology in amino acid sequence.

Trastuzumab clears HER2/neu-positive isolated tumor cells from bone marrow in primary breast cancer patients

PURPOSE

Isolated tumor cells (ITC) in the bone marrow of breast cancer patients increase the risk of recurrence and decrease survival, both at primary diagnosis and during follow-up. We tested the efficacy of trastuzumab in clearing HER2/neu-positive ITC from the marrow of patients completing primary treatment.

METHODS

Ten recurrence-free patients with persistent HER2/neu-positive ITC after routine adjuvant treatment received trastuzumab 6 mg/kg q3w for 12 months in a non-randomized pilot phase II interventional study. Bone marrow ITC HER2/neu status was evaluated at baseline, after treatment for 3, 6 and 12 months, and yearly thereafter, in combination with clinical follow-up. Median follow-up was 23 (15-64) months after baseline bone marrow aspiration.

RESULTS

Trastuzumab for 12 months eradicated HER2/neu-positive ITC from bone marrow in all patients (P = 0.002) and significantly reduced the number of ITC-positive patients (P = 0.031). However, HER2/neu-negative ITC persisted in three patients immediately after treatment and were detected at yearly bone marrow aspiration in five patients. Two patients with ITC counts ≥5 at yearly follow-up developed metastases and one died.

CONCLUSION

This is the first evidence that trastuzumab is effective in clearing HER2/neu-positive cells from bone marrow during recurrence-free follow-up in breast cancer patients. It also suggests, thanks to the antigen shift phenomenon, an important prognostic role for HER2/neu expression on marrow ITC as a real-time biopsy. However, treatment was mainly effective in patients with HER2/neu-positive ITC. Given the heterogeneity of minimal residual disease, these patients might benefit from a combination of targeted treatment approaches.

Circulating tumor cells in the management of breast cancer

Most deaths from breast cancer are from metastatic disease. Tests that predict an individual's risk of developing metastatic disease could be useful. There is growing evidence that circulating tumor cells (CTC) could help predict recurrence and effectiveness of therapy. However, there are unresolved issues with CTC detection methods and their implementation in the community. The utility of CTC testing in the management of breast cancer is unclear based on current studies. This article reviews the role of CTC testing in the management of early and metastatic breast cancer.

Circulating tumor cells in metastatic colorectal cancer: efficacy and feasibility of different enrichment methods

Comprehensive in vitro and in vivo studies comparing EpCAM-based methods with other cytometric CTC enrichment technologies in metastatic colorectal cancer (mCRC) patients are lacking. We compare four manual cytometric methods to detect CTCs in vitro and in mCRC patients. The EpCAM-based technology, MACS HEA MicroBeads((R)), showed a significant better tumor cell recovery rate compared to other cytometric methods (p-value<0.0001). CTCs of 38 mCRC patients were enriched with MACS HEA MicroBeads(R). Progression-free survival did significantly differ between mCRC patients without detectable and with >or= 1 CTCs (p=0.007). CTC enrichment with EpCAM coupled antibodies is superior to other cytometric methods and is a feasible method for CTC detection in mCRC patients.

Comparison of bone marrow, disseminated tumour cells and blood-circulating tumour cells in breast cancer patients after primary treatment

The purpose of this study was to determine whether primary breast cancer patients showed evidence of circulating tumour cells (CTCs) during follow-up as an alternative to monitoring disseminated bone marrow tumour cells (DTCs) by immunocytochemistry and reverse transcriptase (RT)–PCR for the detection of micrometastases. We planned to compare CTC and DTC frequency in low-risk and high-risk patients. We identified two cohorts of primary breast cancer patients who were at low (group II, T₁N₀, n=18) or high (group III, >3 nodes positive (with one exception, a patient with two positive nodes) n=33) risk of relapse who were being followed up after primary treatment. We tested each cohort for CTCs using the CellSearch system on 1–7 occasions and for DTCs by immunocytochemistry and RT–PCR on 1–2 occasions over a period of 2 years. We also examined patients with confirmed metastatic disease (group IV, n=12) and 21 control healthy volunteers for CTCs (group I). All group I samples were negative for CTCs. In contrast, 7 out of 18 (39%) group II primary patients and 23 out of 33 (70%) group III patients were positive for CTCs (P=0.042). If we count only samples with >1 cell as positive: 2 out of 18 (11%) group II patients were positive compared with 10 out of 33 (30%) in group III (P=0.174). In the case of DTCs, 1 out of 13 (8%) group II patients were positive compared with 19 out of 27 (70%) in group III (P<0.001). Only 10 out of 33 (30%) patients in group III showed no evidence of CTCs in all tests over the period of testing, compared with 11 out of 18 (61%) in group II (P=0.033). A significant proportion of poor prognosis primary breast cancer patients (group III) have evidence of CTCs on follow-up. Many also have evidence of DTCs, which are more often found in patients who were lymph node positive. As repeat sampling of peripheral blood is more acceptable to patients, the measurement of CTCs warrants further investigation because it enables blood samples to be taken more frequently, thus possibly enabling clinicians to have prior warning of impending overt metastatic disease.

Cytokeratin fragments in the serum: their utility for the management of oral cancer

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy and is a major cause of cancer morbidity and mortality worldwide. Oral cancer is the most predominant malignancy in the Indian subcontinent due to the widespread habits of chewing tobacco and related products. Patients with oral tumours have a high risk of early locoregional relapse. Early detection of disease progression remains a challenging task mainly due to the lack of adequate early prognostic markers. CEA, SCC Ag, CA-125, serum cytokeratin (CK) fragments, Cyfra 21-1 (CK 19), TPS (CK 18), TPA (CK 8, 18, and 19) etc. are being used as serum markers for the prediction of prognosis of various malignancies. This review presents the available literature on serum CK markers in different malignancies evaluates their utility in the management of oral cancer, and identifies the lacunae which need to be addressed to develop sensitive and specific assays for early detection of recurrence, prognosis, and treatment monitoring.

Detection of MAGE-A Transcripts in Bone Marrow Is an Independent Prognostic Factor in Operable Non–Small-Cell Lung Cancer

PURPOSE

MAGE-A gene expression in humans is mostly restricted to tumor cells, and the role of MAGE-A transcripts and peptides as diagnostic markers and therapeutic targets is currently under investigation. Thus far, the clinical relevance of MAGE-A transcripts as marker for disseminated tumor cells in bone marrow of patients with operable lung cancer without overt metastases is still unclear.

EXPERIMENTAL DESIGN

Preoperative bone marrow aspirates from 50 consecutive patients with operable non-small-cell lung cancer free of distant metastases (i.e., pT(1-4) pN(0-2) M(0) R(0)) were admitted to the study. Each bone marrow sample was divided and examined using multimarker MAGE-A reverse transcription-PCR (RT-PCR) and immunocytochemical staining with the anti-pancytokeratin antibody A45-B/B3. Multimarker MAGE-A RT-PCR consisted of multiple subtype-specific nested RT-PCRs with primers for MAGE-A1, MAGE-A2, MAGE-A3/6, MAGE-A4, and MAGE-A12. The median follow-up duration was 92 months (range, 18-110 months).

RESULTS

Twenty-six (52%) lung cancer patients harbored MAGE-A transcripts in their bone marrow, as opposed to none of the 30 healthy controls tested. In all 7 patients with immunocytochemically positive bone marrow, MAGE-A transcripts were also detected. All different MAGE-A subtypes (MAGE-A1, MAGE-A2, MAGE-A3/6, MAGE-A4, and MAGE-A12) were observed. Sixty-five percent of patients with MAGE-A transcripts in bone marrow exhibited only one subtype. Univariate (P = 0.03, log-rank-test) and multivariate survival analysis showed that MAGE-A transcripts in bone marrow were associated with poor outcome in pN(0) patients (P = 0.02; relative risk, 7.6).

CONCLUSIONS

Detection of MAGE-A transcripts in bone marrow predicts an unfavorable outcome in patients with early-stage operable lung cancer. This finding indicates that MAGE-A transcripts are clinically relevant markers of micrometastatic spread in lung cancer and supports further investigation of MAGE-A as potential future therapeutic target.

Intermediate filaments: a historical perspective

Intracellular protein filaments intermediate in size between actin microfilaments and microtubules are composed of a surprising variety of tissue specific proteins commonly interconnected with other filamentous systems for mechanical stability and decorated by a variety of proteins that provide specialized functions. The sequence conservation of the coiled-coil, alpha-helical structure responsible for polymerization into individual 10 nm filaments defines the classification of intermediate filament proteins into a large gene family. Individual filaments further assemble into bundles and branched cytoskeletons visible in the light microscope. However, it is the diversity of the variable terminal domains that likely contributes most to different functions. The search for the functions of intermediate filament proteins has led to discoveries of roles in diseases of the skin, heart, muscle, liver, brain, adipose tissues and even premature aging. The diversity of uses of intermediate filaments as structural elements and scaffolds for organizing the distribution of decorating molecules contrasts with other cytoskeletal elements. This review is an attempt to provide some recollection of how such a diverse field emerged and changed over about 30 years.

HER2 status of bone marrow micrometastasis and their corresponding primary tumours in a pilot study of 27 cases: a possible tool for anti-HER2 therapy management?

Discrepancies have been reported between HER2 status in primary breast cancer and micrometastatic cells in bone marrow. The aim of this study was to assess HER2 gene status in micrometastatic cells in bone marrow and corresponding primary tumour. Micrometastatic cells were detected in bone marrow aspirations in a prospective series of 27 breast cancer patients by immunocytochemistry (pancytokeratin antibody). HER2 status of micrometastatic cells was assessed by fluorescence in situ hybridisation (FISH), respectively in 24 out of 27. Primary tumour HER2 status was assessed by immunohistochemistry (CB11 antibody) and by FISH in 20 out of 27 of the cases. HER2 was amplified or overexpressed in five out of 27 (18.5%) primary tumours and in four out of 27 (15%) micrometastatic cells. In two cases, HER2 was overexpressed and amplified in primary tumour, but not in micrometastatic cells, whereas, in one case, HER2 presented a low amplification rate (six copies) in micrometastatic cells not found in the primary tumour. We demonstrated that negative and positive HER2 status remained, in the majority of the cases, stable between the bone marrow micrometastasis and the primary tumour. Therefore, the efficiency of anti-HER2 adjuvant therapy could be evaluated, in a clinical trial, by sequential detection of HER2-positive micrometastatic cells within the bone marrow, before and after treatment.

A European interlaboratory testing of three well-known procedures for immunocytochemical detection of epithelial cells in bone marrow. Results from analysis of normal bone marrow

BACKGROUND

This investigation intended to study the unspecific background to be expected in normal bone marrow (BM), comparing three well recognized protocols for immunocytochemical detection of disseminated carcinoma cells. The interlaboratory variation in screening and evaluation of stained cells was analyzed and different screening methods were compared.

METHODS

BM mononuclear cells (BM MNC) from 48 normal BMs were immunostained in parallel by three participating laboratories. The protocols, based on three different anti-cytokeratin antibodies, have all been in common use for detection of disseminated carcinoma cells: the A45-B/B3 protocol (Hamburg), the CK2 protocol (Augsburg) and the AE1AE3 protocol (Oslo). For all protocols, the immunostained cells were visualized by the same alkaline-phosphatase (AP) detection system (APAAP) followed by detection of the cells by manual screening and by two different automated screening systems (ACIS from Chromavision and MDS1 from Applied Imaging). Detected AP-visualized cells were morphologically classified into unambiguous hematopoietic (Uhc) and questionable cells (Qc, potentially interpreted as tumor cells).

RESULTS

Seven of 48 BMs (15%) harbored > or = 1 AP-visualized cell(s) among 1 x 10(6) BM MNC, both for the A45-B/B3- and for the AE1AE3 protocol, while for CK2 a higher proportion of BMs (21 BMs; 44%) harbored AP-visualized cells (P < 0.01, McNemar's test). The number of Qc was, for all protocols, 1 log lower than the total number of AP-visualized cells. On average, the frequency of Qc was 0.04, 0.08, and 0.02 per 10(6) BM MNC with A45-B/B3, CK2 and AE1AE3, respectively, and the number of Qc-positive BMs 1, 4, and 1. The MDS1 screening sensitivity was similar to manual screening, while ACIS detected fewer cells (P < 0.001, McNemar's test).

CONCLUSIONS

All protocols resulted in AP-visualization of occasional hematopoietic cells. However, morphological classification brings the specificity to a satisfactory high level. Approximately 10% of AP-visualized cells were categorized "questionable". The CK2 protocol turned out less specific than the A45-B/B3 and AE1AE3 protocols.

Comparison of two methods for enumerating circulating tumor cells in carcinoma patients

BACKGROUND

Monitoring of circulating tumor cells (CTCs) in blood of carcinoma patients treated with novel compounds may be a measurement of treatment effectiveness. Before it can be used clinically, a reliably method is needed to enumerate CTCs. We compared two methods for CTC enumeration, OnkoQuick and the CellSearch system.

METHODS

We drew 22.5 ml of blood into three CellSave tubes from 15 healthy donors and 61 patients with metastatic carcinoma. After pooling, 15 ml was processed with OncoQuick and 7.5 ml with CellSearch.

RESULTS

With both methods no CTCs were found in healthy donors. At least one CTC was detected in 14 of 61 patients (23%) with OncoQuick and 33 of 61 patients (54%) with CellSearch (P < 0.0001). The number of CTCs detected was larger for CellSearch (mean 20 CTCs/7.5 ml of blood) than for OncoQuick (3 CTCs/7.5 ml; P < 0.0001).

CONCLUSION

The CellSearch system is a more accurate and sensitive method to enumerate CTCs. Further studies are warranted to evaluate CTC enumeration by the CellSearch system as a monitoring tool for the evaluation of the efficacy of novel anticancer agents.

Bispecific and human disease-related anti-keratin rabbit monoclonal antibodies

Rabbit antibodies may have favorable properties compared to mouse antibodies, including high affinities and better antigen recognition. We used a biochemical and reverse immunologic approach to generate and characterize rabbit anti-phospho-keratin and anti-keratin monoclonal antibodies (MAb). Human keratins 8 and 18 (K8/K18) were used as immunogens after isolation from cells pretreated with okadaic acid or pervanadate to promote Ser/Thr or Tyr hyperphosphorylation, respectively. Selected rabbit MAb were tested by immunofluorescence staining, immunoprecipitation, and 2-dimensional gels. Keratin phospho and non-phospho-mutants were used for detailed characterization of two unique antibodies. One antibody recognizes a K8 G61-containing epitope, an important epitope given that K8 G61C is a frequent mutation in human liver diseases. This antibody binds K8 that is not phosphorylated on S73, but its binding is ablated by G61 but not S73 mutation. The second antibody is bispecific in that it simultaneously recognizes two epitopes: one phospho (K8 pS431) conformation-independent and one non-phospho conformation-dependent, with both epitopes residing in the K8 tail domain. Therefore, a reverse immunologic and biochemical approach is a viable tool for generating versatile rabbit MAb for a variety of cell biologic applications including the potential identification of physiologic phosphorylation sites.

Newly developed assay measuring cytokeratins 8, 18 and 19 in serum is correlated to survival and tumor volume in patients with esophageal carcinoma

Esophageal carcinoma is the seventh most common cause of cancer-related death in the Western world. In Sweden, approximately 400 new esophageal carcinomas are diagnosed yearly. Cytokeratins (CK) are specific for epithelial cells and the expression profile usually remains unchanged even when the epithelium undergoes malignant transformation. In the present study, MonoTotal, a newly developed RIA-assay detecting circulating CK 8, 18 and 19 fragments, was investigated in sera from patients with esophageal carcinoma. Serum samples from 40 patients with esophageal carcinoma were collected. The median value of circulating CK 8, 18 and 19 measured with MonoTotal was 378 U/L (range 53-6843) and with regard to the defined cut-off (< 75 U/L), 39/40 (98%) patients were shown to have elevated levels of circulating CK 8, 18 and 19. Patients with localized disease had a median value of circulating CK 8, 18 and 19 of 305 U/L (mean: 500 U/L), whereas the corresponding value for metastatic disease was 771 U/L (mean: 1506 U/L). This difference was statistically significant (P = 0.016). Circulating CK 8, 18 and 19, according to cut-off, were not associated with survival in univariate analysis (P = 0.34). However, continuous values of circulating levels of CK 8, 18 and 19 were associated with survival (P = 0.000083) in univariate as well as in the multivariate analysis (P = 0.03). In conclusion, circulating CK 8, 18 and 19 correlates with increased tumor burden and might, in conjunction with other clinical parameters, aid the clinician in estimating the prognosis of the individual patient.

Culture of feline corneal epithelial cells and infection with feline herpesvirus-1 as an investigative tool

OBJECTIVE

To isolate and characterize pure cultures of feline corneal epithelial cells and to assess the extent and nature of feline herpesvirus (FHV)-1 infection in these cells.

SAMPLE POPULATION

Healthy eyes from 23 recently euthanatized cats.

PROCEDURE

Stroma and epithelium of the rostral portion of the cornea were surgically isolated, and epithelial cells were detached from the stroma by enzymatic incubation. Epithelial cells were cultured in hormone-supplemented media. Cells were passaged, and cytokeratin expression was assessed. Cells were then infected with FHV-1, and cytopathic effects were determined.

RESULTS

Cell cultures were readily established from samples obtained from each eye and could be maintained through 6 passages. Cultured cells expressed cytokeratins 3 and 12 but not other cytokeratins. Infection with FHV-1 was rapid and caused widespread cytopathic effects.

CONCLUSIONS AND CLINICAL RELEVANCE

Feline corneal cells cultured in vitro during multiple passages maintain consistent morphologic characteristics and intermediate filament expression. They are susceptible to infection with FHV-1 and may provide a useful in vitro model for investigation of ocular drugs.

Clinical utility of cytokeratins as tumor markers

Cytokeratins, belonging to the intermediate filament (IF) protein family, are particularly useful tools in oncology diagnostics. At present, more than 20 different cytokeratins have been identified, of which cytokeratins 8, 18, and 19 are the most abundant in simple epithelial cells. Upon release from proliferating or apoptotic cells, cytokeratins provide useful markers for epithelial malignancies, distinctly reflecting ongoing cell activity. It appears that motifs in certain cytokeratins make them likely substrates for caspase degradation, and their subsequent release occurs during the intermediate events in apoptosis. The clinical value of determining soluble cytokeratin protein fragments in body fluids lies in the early detection of recurrence and the fast assessment of the efficacy of therapy response in epithelial cell carcinomas. The three most applied cytokeratin markers used in the clinic are tissue polypeptide antigen (TPA), tissue polypeptide specific antigen (TPS), and CYFRA 21-1. TPA is a broad spectrum test that measures cytokeratins 8, 18, and 19. TPS and CYFRA 21-1 assays are more specific and measure cytokeratin 18 and cytokeratin 19, respectively. By following patients with repeated testing during management, the oncologist may obtain critical information regarding the growth activity in symptomatic patients. Although their main use is to monitor treatment and evaluate response to therapy, early prognostic information particularly on tumor progression and metastasis formation is also provided for several types of cancers. Cytokeratin tumor markers can accurately predict disease status before conventional methods and offer a simple, noninvasive, cheap, and reliable tool for more efficient management.

The persistence of isolated tumor cells in bone marrow from patients with breast carcinoma predicts an increased risk for recurrence

BACKGROUND

The prognostic significance of isolated tumor cells (ITCs) in bone marrow (BM) from patients with breast carcinoma at the time of their primary diagnosis recently was been confirmed by a large pooled analysis. If the persistence of ITCs after adjuvant therapy confers a similar risk for recurrence, then it would be an indication to consider secondary adjuvant therapy.

METHODS

The authors analyzed BM aspirates from 228 patients during recurrence-free follow-up at a median interval +/- standard deviation (SD) of 21.3 +/- 29.1 months after a primary diagnosis of breast carcinoma (pathologic T1 [pT1]-pT2, pN0-pN3, pM0). Carcinoma cells were detected using a standardized immunoassay with monoclonal antibody A45-B/B3 directed against cytokeratin (CK). Patients were followed for a median +/- SD of 49.8 +/- 32.1 months after their primary diagnosis.

RESULTS

Persistent ITCs in BM were detected in 12.7% of patients (n=29 patients). Positive BM status was more frequent (15.7%) within the first 21 months after primary diagnosis than after a follow-up > 21 months (9.7%). The Kaplan-Meier estimate for mean recurrence-free survival was 149.7 months (95% confidence interval [95% CI], 139.6-159.8 months) in patients with negative BM status and 86.5 months (95% CI, 65.7-107.4 months; P=0.0003) in patients with positive BM status at the time patients underwent follow-up BM aspiration. Patients who were without evidence of persistent ITCs had a significantly longer overall survival (162.1 months; 95% CI, 152.1-172.0 months) compared with patients who had positive BM status (overall survival, 98.7 months; 95% CI, 79.7-117.9 months; P=0.0008). In multivariate Cox regression analysis that included BM status, tumor size, lymph node status, and histopathologic grade, evidence of ITCs was an independent significant predictor for reduced disease-free survival (relative risk [RR], 4.57; P <0.0001) and overall survival (RR, 5.57; P=0.002). Persistent ITCs had the greatest prognostic relevance when they were detected between 25 months and 42 months after primary diagnosis (RR, 7.68).

CONCLUSIONS

Evidence of persistent ITCs in BM from patients with breast carcinoma indicated an increased risk for subsequent recurrence. Prospective trials should investigate the benefit of secondary adjuvant treatment on the basis of BM marrow status.

Persistence of bone marrow micrometastases in patients receiving adjuvant therapy for breast cancer: Results at 4 years

We have previously developed a quantitative PCR (QPCR) technique for the detection of cytokeratin 19 (CK19) transcripts in blood and bone marrow and compared this to immunocytochemistry (ICC). Together, both have shown promise for monitoring therapeutic efficacy in patients with metastatic breast cancer. The aim of this study was to determine the feasibility and value of these assays for minimal residual disease (MRD) in monitoring efficacy of adjuvant therapy following surgery for primary breast cancer. Bone marrow aspirates and peripheral blood samples were taken at the time of surgery from patients with primary breast cancer and no evidence of metastases on conventional scans. These were tested for the presence of CK19 mRNA transcripts and cytokeratin positive cells. Follow-up bone marrow aspirates were taken at 3, 6, 12, 24, 36 and 48 months. Prior to surgery, 51% of patients displayed evidence of disseminated cancer cells in the bone marrow by either or both QPCR and ICC. Of 91 patients who had repeat samples assayed, 87% and 65% had positive results at some time using QPCR and ICC, respectively. All patients received adjuvant systemic therapy and in 44 cases where there was a positive result in either the pretreatment or 3-month aspirate, 32/44 (73%) showed a fall in CK19:ABL ratio (QPCR) and 15/24 (63%) showed a reduction in the number of cytokeratin-positive cells (ICC) during follow-up. These results indicate that MRD persists despite adjuvant therapy in a majority of patients with primary breast cancer up to 4 years following surgery.

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

PURPOSE

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

EXPERIMENTAL DESIGN

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

RESULTS

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

CONCLUSIONS

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

Minimal residual disease in bone marrow and peripheral blood of patients with metastatic breast cancer

The presence of occult micrometastases in bone marrow (BM) of patients with early breast cancer increases the risk of relapse. Detection of circulation tumor cells in peripheral blood (PB) may also influence the patient's prognosis. Few data are available on the correlation between tumor cell dissemination in BM and PB in solid epithelial tumors. Twenty-milliliter blood samples were collected from PB of 42 patients with advanced breast cancer and centrifuged using the density gradient OncoQuick (OncoQuick Greiner BioOne, Frickenhausen, Germany). The BM aspirates available from 11 of the 42 patients were centrifuged using density centrifugation Ficoll. Tumor cell detection was performed by microscopy after cytospin preparation and immunocytochemical staining with the monoclonal antibody A45-B/B3. Cytokeratin-positive cells were detected in 23 patients (55%) in the PB and in three patients (27%) in the BM. A cohort with bone lesions as the only metastatic side showed a correlation as follows: 7 of the 11 patients (64%) had negative findings in BM and PB, whereas cytokeratin-positive cells in PB were present in 3 of these 11 patients (27%). The presence of visceral metastases was associated with the detection of cytokeratin-positive cells in the PB in 20 of the 31 patients (65%) in this subgroup. The density gradient OncoQuick in combination with immunocytochemical staining allows the detection of cytokeratin-positive cells in PB of patients with advanced breast cancer. The immunocytochemical detection of cytokeratin-positive cells in PB seems to be associated with the site of metastatic manifestation.

Clinical significance of proliferative potential of occult metastatic cells in bone marrow of patients with breast cancer

There is increasing statistical evidence that the presence of tumour cells in bone marrow detected by immunocytochemistry represents an important prognostic indicator in breast cancer, but their individual capacity to become clinical metastases is unknown. The aim of this study was to assess the proliferative capacity of these occult metastatic cells in the bone marrow of patients with various stages of breast cancer. We obtained bone marrow aspirates from 60 patients with breast cancer before treatment with chemotherapy: 17 stage II, 12 stage III and 31 stage IV. After bone marrow culture for 6-34 days (median: 17 days) under specific cell culture conditions, viable epithelial cells were detected by cytokeratin staining in 40 patients (66%). Expansion of tumour cells was poorly correlated with tumour cell detection on primary screening (P=0.06). There was a nonsignificant correlation between the number and the presence of expanded tumour cells and the UICC stage of the patients. On primary screening, tumour cell detection was positive in 56% of patients and was correlated with clinical UICC stage (P=0.01). However, with a median follow-up of 23 months, expansion of tumour cells from bone marrow was associated with decreased patient survival (P=0.04), whereas the survival difference according to detection of CK-positive cells on primary screening was not statistically significant. In conclusion, viable tumour cells can be detected in the bone marrow of breast cancer patients. Their proliferative potential could be predictive of outcome and deserves further investigation.

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

OBJECTIVES

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

Patterns of disease recurrence influenced by hematogenous tumor cell dissemination in patients with cervical carcinoma of the uterus

BACKGROUND

The presence of isolated tumor cells (ITC) in the bone marrow at the time of primary diagnosis indicates an increased risk for subsequent development of distant metastases in various solid tumors. This study evaluates the prevalence and prognostic significance of ITC in patients with primary carcinoma of the cervix uteri.

METHOD

We immunocytochemically analyzed bone marrow aspirates of 130 patients with newly diagnosed carcinoma of the cervix uteri for the presence of cytokeratin(CK)-positive cells from May 1994 to January 2001. We used a quantitative immunoassay with the monoclonal anti-CK antibody A45-B/B3 and evaluated 2 x 10(6) bone marrow cells per patient. Patients were followed prospectively for a median of 43 (range, 1-85) months.

RESULTS

Isolated tumor cells were found in the bone marrow of 38 patients (29%). The presence of ITC did not correlate with the International Federation of Gynecology and Obstetrics (FIGO) tumor stage (P = 0.61), pelvic and paraaortal lymph node involvement (P = 0.41), histopathologic grading (P = 0.67), the histologic type of the carcinoma (P = 0.93), invasion of lymph nodes (P = 0.93) and blood vessels (P = 0.92), or with menopausal status (P = 0.17). The bone marrow status at the time of primary diagnosis did not correlate with the overall survival as estimated by Kaplan-Meier analysis (P = 0.30). However, distant metastases occurred in 5% of the patients (n = 5) with negative bone marrow status and in 15% of the patients (n = 6) with positive bone marrow status (P = 0.054). The median distant disease-free survival period was 78 months (95% confidence interval 73-82) in patients with negative bone marrow status and 72 months (95% CI 61-82) in patients with positive bone marrow status (P = 0.051). Multivariate analysis revealed the presence of ITC as a significant, independent risk factor for the subsequent development of distant metastases (relative risk 3.6, P = 0.046).

CONCLUSION

Despite the locoregional predominance of cervical carcinoma at the time of primary diagnosis, the presence of ITC in the bone marrow indicates an increased risk for the development of distant metastases. This information may prove useful to stratify patients for systemic treatment.

Biospecific interaction analysis: a tool for drug discovery and development

The recent development of surface plasmon resonance (SPR)-based biosensor technologies for biospecific interaction analysis (BIA) enables the monitoring of a variety of molecular reactions in real-time. The biomolecular interactions occur at the surface of a flow cell of a sensor chip between a ligand immobilized on the surface and an injected analyte. SPR-based BIA offers many advantages over most of the other methodologies available for the study of biomolecular interactions, including full automation, no requirement for labeling, and the availability of a large variety of activated sensor chips that allow immobilization of DNA, RNA, proteins, peptides and cells. The assay is rapid and requires only small quantitities of both ligand and analyte in order to obtain informative results. In addition, the sensor chip can be re-used many times, leading to low running costs. Aside from the analysis of all possible combinations of peptide, protein, DNA and RNA interactions, this technology can also be used for screening of monoclonal antibodies and epitope mapping, analysis of interactions between low molecular weight compounds and proteins or nucleic acids, interactions between cells and ligands, and real-time monitoring of gene expression. Applications of SPR-based BIA in medicine include the molecular diagnosis of viral infections and genetic diseases caused by point mutations. Future perspectives include the combinations of SPR-based BIA with mass spectrometry, the use of biosensors in proteomics, and the application of this technology to design and develop efficient drug delivery systems.

Monoclonal antibodies selective for low molecular weight neurofilaments

Neurofilaments are necessary for the maintenance of axonal caliber and structural organization of nerve cells. The low molecular weight form of neurofilament, the neurofilament light protein, which serves as the core of the filament, was used as immunogen for generation of hybridomas with selective reactivity with this form of the filament. Six hybridomas, out of approximately 100 tested clones, were highly discriminatory. All involved epitopes were localized to the rod region of the antigen, as determined by alpha-chymotrypsin digestion of the purified filament and enzymatic peptide mapping. Synthetic peptides (20 mers) covering the entire rod region did not react with the antibodies. A phage display peptide library was used to identify four consensus sequences for the antibodies. The results indicate that all epitopes were of conformational type. Pair-wise BIAcore data furthermore indicated that the epitopes were independent. The access to such specific reagents is a prerequisite for further elucidation of the biology of the low molecular weight form of neurofilaments proteins.

Diagnostic performance of the urinary bladder carcinoma antigen ELISA test and multiparametric DNA/cytokeratin flow cytometry in urine voided samples from patients with bladder carcinoma

BACKGROUND

The objective of the current study was to comparatively analyze the sensitivity and specificity of flow cytometric DNA/cytokeratin 8/18 measurements and the urinary bladder carcinoma antigen (UBC) enzyme linked immunoabsorbent assay (ELISA) test for the detection of bladder carcinoma in voided urine samples.

METHODS

Eighty-one fresh urine voided samples, preserved frozen for a maximum period of 3 months, belonging to patients with an active bladder carcinoma (n = 37), patients who were free of disease as confirmed by cystoscopy (n = 19), patients receiving intravesical therapy (n = 17), and individuals with other benign and malignant conditions (n = 8), were collected. Flow cytometry measurements of thawed samples were based on the detection of cytokeratin (CK) 8+ and CK18+ cells using the 3F3 and 6D7 monoclonal antibodies alone or in combination with the measurement of cell DNA contents, after propidium iodide staining. Urinary bladder carcinoma antigen test was measured by ELISA.

RESULTS

Patients were grouped according to the presence (n = 44) or absence (n = 29) of bladder carcinoma as confirmed by cystoscopy, and taking cutoffs of 9.7 microg/L for UBC-ELISA, 75% for the percentage of 3F3 (+) and 6D7 (+) cells, and 10.6% for the proportion of hyperdiplod cells that suggested a specificity of 83%, the individual sensitivity obtained for each parameter was 77%, 5%, 9%, and 77%, respectively. The presence of DNA aneuploid populations showed a relatively low sensitivity (36%) although it was the most specific parameter (93%). Combining UBC antigen test with the proportion of cells showing DNA content higher than 2n increased to 89% the sensitivity of the UBC antigen alone. However, false-positive results for both techniques were found in individuals with urologic diseases other than bladder carcinoma and in patients receiving intravesical therapy.

CONCLUSIONS

The authors' results suggest that the combined use of the UBC antigen test and DNA/cytokeratin flow cytometry double stainings for the analysis of freshly obtained urine voided samples, cryopreserved to assure cellular integrity, is of great clinical utility for the detection of tumor recurrence in patients with bladder carcinoma.

Transcription of cytokeratins 8, 18, and 19 in bone marrow and limited expression of cytokeratins 7 and 20 by carcinoma cells: inherent limitations for RT-PCR in the detection of isolated tumor cells

The suitability of "real-time" quantitative reverse transcriptase polymerase chain reaction (RT-PCR) for the detection of isolated carcinoma cells in bone marrow was investigated by evaluating the expression of cytokeratin (CK)7, CK8, CK18, CK19, and CK20 in 17 gastrointestinal cancer cell lines, 64 control bone marrow specimens from noncancer patients, and 30 bone marrow specimens from patients with gastric or colorectal cancer. RT-PCR products for CK8 and CK18 were detected in all cancer cell lines, but only 16, 5, and 11 cell lines provided evidence for CK19, CK7, and CK20 transcription. Variable numbers of bone marrow specimens from noncancer patients demonstrated background transcription of CK8 (78.1%), CK18 (95.3%), CK19 (35.9%), CK20 (29.6%), and CK7 (16.7%). Maximal background transcription for CK8, CK18, and CK19 ranged from 52.2 to 56.1 copies/10(3) copies glyceraldehyde-3-phosphate dehydrogenase (GAPDH), the corresponding values of 0.06 and 0.76 copies for CK7 and CK20 being distinctly lower. When maximal background values were used as a threshold value to define positivity in tumor cell dilution experiments, sensitivity levels of one tumor cell in 10(4) bone marrow cells were determined for CK7 and CK20 RT-PCR assays. Maximal background expression values of the different CKs as obtained in the control series were exceeded once (CK20), twice (CK18 and CK19), and 18 times (CK7) in bone marrow specimens from cancer patients, with none of these specimens exceeding the maximal background expression value of CK8. We conclude that RT-PCR for CK8, CK18, and CK19 cannot be recommended for the detection of isolated tumor cells in bone marrow of cancer patients. On the other side, the limited number of gastric and colorectal cancer cell lines expressing CK7 and CK20 indicates that assay sensitivity for these CKs might be limited because of their selective expression by carcinoma cells.

Disseminated cytokeratin positive tumor cells in the bone marrow of patients with prostate cancer: detection and prognostic value

PURPOSE

Previous investigations have shown that cytokeratin 18 positive bone marrow cells in localized and lymphatically spread prostate cancer correlates with neither established prognostic factors nor with the biochemical and clinical course after radical prostatectomy. Since the well-known down-regulation of cytokeratin 18 in tumor cells may lead to false-negative results, we asked whether staining with a pan-cytokeratin antibody recognizing a common epitope of cytokeratins 8, 18 and 19 would result in different data.

MATERIALS AND METHODS

Preoperative bone marrow aspirates of 82 patients with localized (N0) and lymphatically spread (N1) prostate cancer were examined using the monoclonal antibody cytokeratin 2 and the pan-cytokeratin antibody A 45-B/B3, called A 45.

RESULTS

In contrast to findings with the cytokeratin 18 antibody, those with the pan-cytokeratin antibody correlated with the biochemical course. At a median followup of 1,477 days (4 years) patients with pan-cytokeratin positive cells in the preoperative bone marrow aspirate had biochemical progression significantly earlier than those with pan-cytokeratin negative results (mean time to prostate specific antigen relapse 886 versus 1,409 days, p < or =0.004). Compared with other parameters, such as prostate specific antigen, pathological stage and Gleason score, preoperative pan-cytokeratin findings proved to be an independent prognostic factor.

CONCLUSIONS

Cytokeratin positive cells in the bone marrow also have prognostic relevance in prostate cancer. The comprehensive analysis of these cells, studies of the individual course of these findings and sufficiently long followup allow us to discuss whether and under what conditions metastasis may develop from 1 or several cytokeratin positive cells.

The fate and prognostic value of occult metastatic cells in the bone marrow of patients with breast carcinoma between primary treatment and recurrence

BACKGROUND

The current study examines the fate of occult metastatic cells detected in bone marrow (BM) at primary diagnosis and evaluates whether persistently positive findings support the prognostic influence of these cells in patients with Stage I--III (International Union Against Cancer) breast carcinoma.

METHODS

The authors analyzed BM aspirates, at the time of primary diagnosis and after a median interval of 19 months (range, 7--67 months), from 89 patients who were free of recurrence. The presence of cytokeratin (CK) positive cells was assessed with the monoclonal anti-CK antibody A45-B/B3. Patients were observed prospectively for a median of 41 (range, 12--78) months after the first aspiration.

RESULTS

At the time of primary diagnosis, 24 of 89 patients (27%) presented with occult metastatic cells in the BM. Of the same 89 patients, 25 (28%) had a positive BM finding at the time of the second BM analysis. Among those patients with an initially negative BM finding, 15 patients (17%) had occult metastatic cells at time of the second BM aspiration, whereas 10 patients (11%) had a persistently positive BM finding. Patients with a persistently negative BM status (n = 50) had a significantly better overall survival than patients with a positive BM status at the time of the second BM aspiration (n = 25), both by univariate analysis (P = 0.045, log-rank) and multivariate analysis (P = 0.034, Cox regression).

CONCLUSIONS

In many patients with primary breast carcinoma, minimal residual disease can be detected by follow-up examination of the BM. This finding is prognostically relevant and provides reason to include BM monitoring in future clinical trials.

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.

The role of caspase 3 in producing cytokeratin 19 fragment (CYFRA21-1) in human lung cancer cell lines

The CYFRA 21-1 assay, which detects cytokeratin 19 (CK19) fragment, is widely used as a tumor marker for lung cancer, particularly non-small cell lung cancer. However, the reason that some lung cancer cell lines release CYFRA 21-1 in culture supernatants and others do not remains unclear. We hypothesized that the release of CYFRA 21-1 might be related to the expression of CK19 and caspase 3. In order to prove this, the quantities of mRNA for CK19 were evaluated by the competitive reverse transcriptase-polymerase chain reaction (RT-PCR). CK19 protein synthesis was also evaluated by Western blotting and immunohistochemistry, and the levels of CYFRA 21-1 in the culture supernatant were measured by an immunoradiometric assay. The expression of mRNA for caspase 3 was evaluated by the RT-PCR, and caspase 3 protein synthesis was also evaluated by immunohistochemistry. In 13 lung cancer cell lines, the amounts of mRNA for CK19 correlated with the levels of CYFRA 21-1 in culture supernatants, results of Western blotting for CK19, and positivities of immunohistochemistry for CK19. In 5 cell lines that produced a significant amount of CYFRA 21-1, the level of CYFRA 21-1 correlated with the positivity of RT-PCR for caspase 3 and immunohistochmistry for caspase 3. This suggests that caspase 3 played a role in the formation of CYFRA 21-1. In addition, the specific inhibitor of caspase 3 significantly inhibited the release of CYFRA 21-1 in culture supernatants. In conclusion, we demonstrate that caspase 3, which cleaves several intermediate filaments and carries out cell apoptosis, played an important role in producing CYFRA 21-1 in human lung cancer cell lines.

Prognostic significance of the immunocytochemical detection of contaminating tumor cells (CTC) in apheresis products of patients with high-risk breast cancer treated with high-dose chemotherapy and stem cell transplantation

The aim of this study was to determine whether the detection of CTC in the apheresis product contribute significantly to treatment failure of patients with high-risk breast carcinoma treated with high-dose chemotherapy (HDC) and stem cell transplantation (SCT). Patients were with stage II and III adenocarcinoma of the breast with > or = 10 axillary lymph nodes affected after primary surgery (> or = 10 N+) who had received HDC with SCT. We analyzed retrospectively the presence of CTC as assessed by immunocytochemistry (ICC) in the apheresis products obtained after standard adjuvant chemotherapy. We compared the clinical outcome of patients who received HDC and SCT with or without CTC-positive apheresis. One hundred and twenty-seven apheresis products samples were obtained from 51 patients. Fourteen (27.4%) of these samples were CTC positive. After a median follow-up of 4.6 years, 20 patients have relapsed, 14 died from progression of their disease and 30 patients remain alive and free of progression. For the whole group of patients the 5 year probabilities of DFS and OS were 60% (IC 95%, 47-75%) and 71% (IC 95%, 55-83%), respectively. However, the 5 year probabilities of DFS were 23% (IC 95%, 0-46) and 75% (IC 95%, 60-89) for patients with CTC positive and negative, respectively. The 5 year probabilities of OS were 42% (IC 95%, 15-68) and 83% (IC 95%, 70-95) for patients with CTC positive and negative, respectively. Both univariate and multivariate analysis showed that the presence of CTC in the apheresis product was the only prognostic factor associated with a higher incidence of clinically overt disease relapse (P = 0.002) and shorter survival (P = 0.003). The presence of cytokeratin-positive metastatic cells in the apheresis product increases the risk of relapse after HDC and SCT in patients with stage II and III adenocarcinoma of the breast with > or = 10 N+.

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.

Clinical relevance of occult metastatic cells in the bone marrow of patients with different stages of breast cancer

Data are emerging about the prognostic relevance of occult metastatic cells in the bone marrow of patients with various solid tumors. Discrepancies among different studies on the prognostic relevance of isolated tumor cells may be caused by tumor cell heterogeneity and the use of different immunoassays. There is increasing evidence that validated anticytokeratin antibodies (e.g., A45-B/B3) represent the present standard for the detection of isolated tumor cells. This immunocytochemical assay allows the identification of patients with occult tumor cell dissemination that cannot be identified by conventional screening methods in tumor staging. According to recent studies, these patients are at higher risk for subsequent development of distant metastases and might therefore benefit from early systemic therapy. At advanced stages of the disease, the micrometastatic tumor load after adjuvant therapy, or at the time of emerging recurrences, appears to reflect the tumor's ability to progress. Therapeutic monitoring and cell-cycle independent antibody-based therapy are among possible implications of this new, promising diagnostic tool. The present review also focuses on state of the art, reliable detection methods of occult metastatic cells in the bone marrow of breast cancer patients and on the prognostic relevance of these cells at different stages of the disease.

Preliminary report of the clinical performance of a new urinary bladder cancer antigen test: comparison to voided urine cytology in the detection of transitional cell carcinoma of the bladder

We compared the ability of a new urinary bladder cancer antigen (UBC) test with conventional cytology for the detection of transitional cell carcinoma of the bladder using voided urine samples. The UBC was measured and corrected for the creatinine concentration in the urine of 61 patients with transitional cell carcinoma of the bladder (group 1), 23 patients without recurrent bladder tumors during follow-up (group 2), 28 patients with benign prostatic hyperplasia (group 3), nine patients with prostate cancer (group 4), and 90 healthy volunteers free of urological diseases (group 5). The UBC concentrations were 408.8+/-578.5, 18.8+/-26.6, 23.9+/-32.7, 17.5+/-18.6 and 4.6+/-6.7 ngmg(-1) creatinine (mean+/-S. D.) for groups 1-5, respectively. The level for group 1 was significantly higher than for any other group. The sensitivity and specificity, which were optimized using receiver-operating characteristic curves for groups 1 and 2 were 82.0% and 82.6%, respectively, at a threshold value of 39 ngmg(-1) creatinine. The sensitivity and specificity of cytology for these same groups were 60.7% and 86.9%, respectively. The sensitivity of the UBC was significantly higher than that of cytology, not only for total bladder tumors (82.0% vs. 60.7%, P<0.02) but also for grade I transitional cell carcinoma of the bladder (76.5% vs. 11.8%, P<0. 001). While offering a similarly high specificity, the UBC test might have an advantage over cytology in terms of superior sensitivity, particularly for low-grade tumors.

Prognostic significance of an increased number of micrometastatic tumor cells in the bone marrow of patients with first recurrence of breast carcinoma

BACKGROUND

Using cytokeratin (CK) as a histogenetic marker of epithelial tumor cells in the bone marrow of patients with primary breast carcinoma, a subgroup of patients with decreased survival can be identified. This study was designed to evaluate the frequency and prognostic relevance of such cells in patients with recurrent breast carcinoma.

METHODS

Bone marrow aspirates from 65 patients were analyzed immunocytochemically for the presence of CK positive cells. A quantitative immunoassay with monoclonal anti-CK antibody A45-B/B3 was used and 2 x 10(6) bone marrow cells per patient were evaluated. For prognostic evaluation the authors calculated a cutoff value of micrometastatic tumor cells by analogy to classification and regression tree (CART) analysis. Patients were monitored prospectively for a median of 37 months (range, 11-63 months).

RESULTS

Bone marrow micrometastases were present in 5 of 32 patients (16%) with locoregional recurrence and in 24 of 33 patients (73%) with distant recurrence. The bone marrow status yielded no prognostic indication for patients with locoregional recurrence. In contrast, a cutoff value of 2.5 tumor cells per 1 million bone marrow cells analyzed (2.5 x 10(-6) tumor cells) correlated with a significantly different prognosis for women with distant disease. Patients with metastatic disease and a micrometastatic tumor load of > 2.5 x 10(-6) tumor cells survived for a mean of 6 months (95% confidence interval [95% CI], 2.0-9.1) compared with 17 months (95% CI, 11.6-22.0) for patients with < or = 2.5 x 10(-6) tumor cells (P < 0.0001). Multivariate analysis, allowing for hormone receptor status, disease free interval prior to recurrence, manifestation site of metastases, age, and micrometastases in bone marrow, revealed that bone marrow involvement was an independent risk factor, with a hazard ratio of 7.4 (95% CI, 1.6-13.3) for disease-related death.

CONCLUSIONS

An increased number of micrometastases identified in the bone marrow of patients with metastatic breast carcinoma represents an independent prognostic factor that may influence future therapeutic strategies for patients with metastatic breast carcinoma.

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.

Lack of effect of adjuvant chemotherapy on the elimination of single dormant tumor cells in bone marrow of high-risk breast cancer patients

PURPOSE

There is an urgent need for markers that can predict the efficacy of adjuvant chemotherapy in patients with solid tumors. This study was designed to evaluate whether monitoring of micrometastases in bone marrow can predict the response to systemic chemotherapy in breast cancer.

PATIENTS AND METHODS

Bone marrow aspirates of 59 newly diagnosed breast cancer patients with either inflammatory (n = 23) or advanced (> four nodes involved) disease (n = 36) were examined immunocytochemically with the monoclonal anticytokeratin (CK) antibody A45-B/B3 (murine immunoglobulin G(1); Micromet, Munich, Germany) before and after chemotherapy with taxanes and anthracyclines.

RESULTS

Of 59 patients, 29 (49.2%) and 26 (44.1%) presented with CK-positive tumor cells in bone marrow before and after chemotherapy, respectively. After chemotherapy, less than half of the previously CK-positive patients (14 of 29 patients; 48.3%) had a CK-negative bone marrow finding, and 11 (36. 7%) of 30 previously CK-negative patients were CK-positive. At a median follow-up of 19 months (range, 6 to 39 months), Kaplan-Meier analysis of 55 assessable patients revealed a significantly reduced overall survival (P =.011; log-rank test) if CK-positive cells were detected after chemotherapy. In multivariate analysis, the presence of CK-positive tumor cells in bone marrow after chemotherapy was an independent predictor for reduced overall survival (relative risk = 5.0; P =.016).

CONCLUSION

The cytotoxic agents currently used for chemotherapy in high-risk breast cancer patients do not completely eliminate CK-positive tumor cells in bone marrow. The presence of these tumor cells after chemotherapy is associated with poor prognosis. Thus, bone marrow monitoring might help predict the response to systemic chemotherapy.

Survey of the 1998 optical biosensor literature

The utilization of optical biosensors to study molecular interactions continues to expand. In 1998, 384 articles relating to the use of commercial biosensors were published in 130 different journals. While significant strides in new applications and methodology were made, a majority of the biosensor literature is of rather poor quality. Basic information about experimental conditions is often not presented and many publications fail to display the experimental data, bringing into question the credibility of the results. This review provides suggestions on how to collect, analyze and report biosensor data.

Cross-reactive staining of normal bone-marrow cells by monoclonal antibody 2E11

The monoclonal antibody (MAb) 2E11 is commonly used for detection of microdisseminated epithelial cells in bone marrow of cancer patients. Surprisingly, in an earlier report 2E11 was shown to bind to mononuclear cells in bone marrow in 61% of healthy donors. In the present study we tested whether this cross-reaction with non-epithelial bone-marrow cells can be characterized further. In addition, we analyzed the influence of 2E11 concentration on the staining of mononuclear cells. We performed immunocytochemical double stainings of bone-marrow aspirations from breast-cancer patients using 2E11/A45-B/B3 (MAb against cytokeratin 8, 18, 19) and 2E11/CD45 (MAb against CD45-leukocyte common antigen), while tumor cell lines MCF-7 and K526 as well as bone marrow from breast-cancer patients were treated with different concentrations of 2E11. A portion of 2E11-positive cells was characterized as hematopoietic cells by CD-45-binding, while others were identified as epithelial cells by A45-B/B3-binding. We defined a concentration of 2E11 to immunolabel epithelial cells and distinguish hematopoietic cells. Higher concentrations of 2E11 enhance staining of hematopoietic cells, to match that of epithelial cells. We conclude that 2E11 shows cross-reactivity to epitopes displayed by hematopoietic cells. However, specific staining of epithelial cells can be achieved. As long as there is no antibody available which is highly specific for epithelial cells, detection of microdisseminated tumor cells in bone marrow by antigen-antibody reaction should be verified morphological criteria.

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.