Disseminated Tumor Cells In Patients Research Articles

Abstract A011: Detection of disseminated tumor cells in advanced clear cell renal cell carcinoma through research autopsy

Abstract Background: The vast majority of cancer deaths can be attributed to tumor metastases. Disseminated tumor cells (DTCs) are thought to act as a reservoir of tumor clones which can lie dormant before causing overt metastases. Their presence has been shown to be a poor prognostic indicator in several tumor types. Despite their importance, the timing and source of DTCs is unclear across most solid cancers and even less is known about them in late-stage disease. The Posthumous Evaluation of the Advanced Cancer Environment (PEACE) post-mortem study enables extensive sampling of malignant lesions but also normal tissues, thereby allowing study of DTCs in patients with advanced cancer. Methods: We performed research autopsy sampling of macroscopically normal bone, lung and liver in 3 patients with advanced clear cell renal cell carcinoma (RCC). In addition, we performed bone marrow aspiration at autopsy from vertebral bodies and the ilium using an anterior approach. Mechanical disaggregation followed by collagenase digestion was used to generate single cell suspensions. Detection of tumor cells was carried out using antibodies against known tumor or epithelial markers carbonic anhydrase IX (CAIX). Epithelial cell adhesion molecule (EpCAM) was also used for bone marrow samples as native bone marrow cells do not express this marker. These sub-populations were then isolated using fluorescence activated cell sorting and DNA was extracted and amplified from single cells. Results: We performed and optimised collagenase-based digestion on all solid tissues collected. The percentage of viable cells generated varied significantly between subjects and tissues with bone marrow samples more viable than lung and liver. Rare and distinct populations of CAIX+ and EpCAM+ cells were detected in normal tissues between 0.5-2%. DNA amplification was successful on single cells isolated from normal lung and liver but not from bone tissue. Pilot shallow coverage whole genome sequencing revealed genomically aberrant cells ranging from single chromosome arm losses to widespread copy number aberrations. Conclusion: We demonstrate feasibility of sequencing single cells from autopsy study subjects. Rare populations of single cells with markers of clear cell RCC were detected and isolated both in normal tissues of patients with advanced disease. Genomic analyses of these cells will lead to insights into their relationship to the primary tumor and overt metastatic lesions. Citation Format: Haixi Yan, Cristina Cotobal Martin, Christie English, Annelien Verfaillie, Jonas Demeulemeester, Andrew Rowan, Annika Fendler, Anne-Laure Cattin, Sucheta Mahapatra, Lewis Au, Scott Shepherd, Ben Shum, Charlotte Spencer, Zayd Tippu, Ula Mahadeva, Anna Green, Eleanor Carlyle, Cristina Naceur-Lombardelli, PEACE consortium, Mariam Jamal-Hanjani, Charles Swanton, Samra Turajlic, Peter Van Loo. Detection of disseminated tumor cells in advanced clear cell renal cell carcinoma through research autopsy [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr A011.

Prostate cancer dormancy and recurrence.

Prostate cancer can progress rapidly after diagnosis, but can also become undetectable after curative intent radiation or surgery, only to recur years or decades later. This capacity to lie dormant and recur long after a patient was thought to be cured, is relatively unique to prostate cancer, with estrogen receptor positive breast cancer being the other common and well-studied example. Most investigators agree that the bone marrow is an important site for dormant tumor cells, given the frequency of bone metastases and that multiple studies have reported disseminated tumor cells in patients with localized disease. However, while more difficult to study, lymph nodes and the prostate bed are likely to be important reservoirs as well. Dormant tumor cells may be truly quiescent and in the G0 phase of the cell cycle, which is commonly called cellular dormancy. However, tumor growth may also be held in check through a balance of proliferation and cell death (tumor mass dormancy). For induction of cellular dormancy, prostate cancer cells respond to signals from their microenvironment, including TGF-β2, BMP-7, GAS6, and Wnt-5a, which result in signals transduced in part through p38 MAPK and pluripotency associated transcription factors including SOX2 and NANOG, which likely affect the epi-genome through histone modification. Clinical use of adjuvant radiation or androgen deprivation has been modestly successful to prevent recurrence. With the rapid pace of discovery in this field, systemic adjuvant therapy is likely to continue to improve in the future.

Disseminated tumour cells from the bone marrow of early breast cancer patients: Results from an international pooled analysis

PurposePresence of disseminated tumour cells (DTCs) in the bone marrow (BM) has been described as a surrogate of residual disease in patients with early breast cancer (EBC). PADDY (Pooled Analysis of DTC Detection in Early Breast Cancer) is a large international analysis of pooled data that aimed to assess the prognostic impact of DTCs in patients with EBC. Experimental designIndividual patient data were collected from 11 centres. Patients with EBC and available follow-up data in whom BM sampling was performed at the time of primary diagnosis before receiving any anticancer treatment were eligible. DTCs were identified by antibody staining against epithelial cytokeratins. Multivariate Cox regression was used to compare the survival of DTC-positive versus DTC-negative patients. ResultsIn total, 10,307 patients were included. Of these, 2814 (27.3%) were DTC-positive. DTC detection was associated with higher tumour grade, larger tumour size, nodal positivity, oestrogen receptor and progesterone receptor negativity, and HER2 positivity (all p < 0.001). Multivariate analyses showed that DTC detection was an independent prognostic marker for overall survival, disease-free survival and distant disease-free survival with hazard ratios (HR) and 95% confidence intervals (CI) of 1.23 (95% CI: 1.06–1.43, p = 0.006), 1.30 (95% CI: 1.12–1.52, p < 0.001) and 1.30 (95% CI: 1.08–1.56, p = 0.006), respectively. There was no association between locoregional relapse-free survival and DTC detection (HR 1.21; 95% CI 0.68–2.16; p = 0.512). ConclusionsDTCs in the BM represent an independent prognostic marker in patients with EBC. The heterogeneous metastasis-initiating potential of DTCs is consistent with the concept of cancer dormancy.

The prognostic role of circulating tumor cells and disseminated tumor cells in patients with ovarian cancer: a systematic review and meta-analysis

The prognostic role of circulating tumor cells and disseminated tumor cells in patients with ovarian cancer: a systematic review and meta-analysis

Hardware-software complex for diagnostics of breast cancer on the basis of flow cytometry

The method of multicolor flow cytometry makes it possible to quantify the disseminated tumor cells (DTC) in patients with solid tumors. Application of the method multi-color flow cytometry showed its efficiency and accuracy in the detection of DTC in patients with breast cancer.

Prognostic value of circulating tumor cells and disseminated tumor cells in patients with esophageal cancer: a meta-analysis

To explore the correlations of circulating tumor cells (CTCs) and disseminated tumor cells (DTCs) with the clinicopathological characteristics, prognostic events, and survival outcomes in esophageal cancer (EC) patients. The PubMed, Web of Science, Embase database and Cochrane database were searched for studies reporting the outcomes of interest. The studies were selected according to established inclusion/exclusion criteria. Meta-analysis of the studies was performed using Review Manager 5.3 and Stata12.0 software with the odds ratio (OR), risk ratio (RR) , hazard ratio (HR) , and 95% confidence interval (95% CI) as the effect indexes. Nineteen studies involving a total of 1766 patients were included in the analysis. Significant correlations of CTCs and DTCs were found with the clinicopathological parameters including the tumor stage (OR=1.95), depth of invasion (OR=1.99), lymph node metastasis (OR=2.44SEN), distal metastasis (OR=5.98SEN), histological differentiation (OR=1.67) and lymphovascular invasion (OR=4.48). CTCs and DTCs were also correlated with the prognostic events including relapse (RR=6.86SEN) and metastasis (RR=3.22) and with the survival outcomes including the overall survival (OS) overall analysis (HR=3.46) and disease-free survival/progression-free survival (DFS/PFS) overall analysis (HR=3.00). CTCs and DTCs are significantly associated with an advanced tumor stage, depth of tumor invasion, lymph node metastasis, distant metastasis before therapy, differentiation, lymphovascular invasion, relapse and metastasis in patients with EC. They are also significantly correlated with a poorer survival for OS and DFS/PFS to serve as clinical and prognostic predictors in patients with EC.

MiR-615-3p expression level in bone marrow is associated with tumor recurrence in hepatocellular carcinoma.

The significance of disseminated tumor cells (DTCs) in bone marrow (BM) on tumor recurrence has not been investigated in patients with hepatocellular carcinoma (HCC). The aim of te present study was to clarify the molecular characteristics of DTCs that affect postoperative recurrence based on microRNA (miRNA) expression profiles in clinical HCC patients undergoing curative resection. DTCs were prospectively collected from the BM of preoperative HCC patients using immunomagnetic beads and subjected to miRNA microarray analysis. Microarray analysis of nine HCC patients (n=5 patients with postoperative HCC recurrence, n=4 patients without HCC recurrence) demonstrated that miR-615-3p is significantly upregulated in the DTCs of patients with recurrence compared to the DTCs from patients without recurrence. In vitro experiments demonstrated that the miR-615-3p expression level is significantly correlated with malignant characteristics in HCC cells. These data suggest that miR-615-3p in DTCs may play an important role in postoperative HCC recurrence, which suggests that miR-615-3p is a potential target molecule for regulating postoperative HCC recurrence.

Prognostic relevance of induced and spontaneous apoptosis of disseminated tumor cells in primary breast cancer patients.

BackgroundAn imbalance between cell proliferation and programmed cell death can result in tumor growth. Although most systemic cytotoxic agents induce apoptosis in tumor cells, a high apoptotic rate in primary breast cancer correlates with poor prognosis. The aim of this study was to investigate the incidence and the prognostic significance of apoptotic disseminated tumor cells (DTC) in the bone marrow (BM) of breast cancer patients who either underwent primary surgery or primary systemic chemotherapy (PST).MethodsA total of 383 primary breast cancer patients with viable DTC in the BM were included into this study. Eighty-five patients were initially treated with primary systemic chemotherapy whereas 298 patients underwent surgery first. Detection of apoptotic DTC were performed by immunocytochemistry using the M30 antibody which detects a neo-epitope expressed after caspase cleavage of cytokeratin 18 during early apoptosis. The median follow up was 44 months (range 10–88 months).ResultsEighty-two of 298 (27%) primary operated patients and 41 of 85 (48%) patients treated with primary systemic systemic therapy had additional apoptotic DTC (M30 positive). In the neoadjuvant group M30-positive patients were less likely to suffer relapse than those without apoptotic DTC (7% vs. 23% of the events, p = 0.049). In contrast, the detection of apoptotic DTC in patients treated by primary surgery was significantly associated with poor overall survival (5% vs. 12% of the events, p = 0.008).ConclusionsApoptotic DTC can be detected in breast cancer patients before and after systemic treatment. The presence of apoptotic DTC in patients with PST may be induced by the cytotoxic agents. Thus, both spontaneous and chemotherapy-induced apoptosis may have different prognostic significance.

Disseminated Tumor Cells in Bone Marrow of Gastric Cancer Patients: Correlation with Tumor Hypoxia and Clinical Relevance

Aim. The evaluation of the clinical relevance of disseminated tumor cells (DTCs) in bone marrow (BM) of patients with gastric cancer (GC) and their association with primary tumor hypoxia. Patients and Methods. 89 resected specimens were used. DTCs were detected using immunocytochemistry, the level of tumor hypoxia using NMR spectroscopy, CD68, CD34, VEGF, and VEGFR-1 (Flt-1) expression using immunohistochemistry, and MMP-2 and MMP-9 activity using zymography. Results. DTCs were detected in 51.4% of GC patients with M0. There was significant correlation between frequency of DTCs in BM and level of tumor hypoxia (P < 0.024). DTCs presence was accompanied with Flt-1 positivity of BM. The correlation between DTCs and tumor VEGF expression in patients with M0 was shown (P < 0.0248). Activity of MMP-2 and MMP-9 in BM was linked with DTCs in patients with M0 (P < 0.05). Overall survival (OS) of patients with M0 and DTCs was shorter than that of patients without DTCs (patients in both groups were operated only) (P = 0.0497). Conclusion. Appearance of DTCs correlates with hypoxia level in primary tumors. Detection of DTCs in GC patients may be relevant indicator for adjuvant chemotherapy using.

Identification of patients at high risk of recurrent disease development by detection of HER2-positive disseminated tumor cells in bone marrow of patients with HER2-negative tumors.

633 Background: A subpopulation of patients with HER2-negative tumors benefit from HER2 therapy. HER2 expression can be discordant between primary tumors and metastases. We have examined the bone marrow (BM) of early stage breast cancer patients for HER2-expression by disseminated tumor cells (DTCs) and the association with disease recurrence. Methods: BM was collected from clinical stage II-III breast cancer prior to treatment between 2007-2011. Gene expression of ERBB2 was determined by multiplex PCR (Fluidigm Biomark [FB]). Positive expression was defined as at least 1.4 fold above a pool of normal BM. Expression was confirmed by single gene PCR and Nanostring nCounter (NC) assays. Cox proportional model was used to estimate hazard ratios (HR). Results: BM from 74 patients was analyzed. Median follow-up was 3.4 years (range 8 months-84 months). 24% of the patients developed metastatic disease. For ERBB2 detection, there was excellent correlation between NC and the FB assays (kappa=0.87, 95% CI [0.62, 1.00]). Nine patients expressed ERBB2 in their BM. Five of the 9 patients had Her2-positive tumors and were treated with trastuzumab. One of 5 (20%) of these patients relapsed whereas 75% (3 of 4) of the patients with HER2-negative tumors but ERBB2-positive DTCs relapsed. Patients with HER2-negative tumors/ERBB2-positive BM were found to have a greater hazard of recurrence than patients with HER2-negative tumors/ERBB2-negative BM or ERBB2-positive DTCs treated with trastuzumab (p=.0069; Table). Those patients with ERBB2-positive BM who did not receive trastuzumab had a decreased disease free survival (p=.016). Conclusions: We have found discordant expression of HER2/ERBB2 in tumors and BM of stage II-III breast cancer patients. The presence of ERBB2 expressing DTCs in patients with HER2-negative tumors identifies a subset of patients at increased risk of recurrence who may benefit from targeted HER2-therapy. [Table: see text] .

Abstract 804: Disseminated tumor cell heterogeneity and dormancy in prostate cancer.

Abstract Prostate cancer (PCa) can remain in the bone marrow for a prolonged period of time (&amp;gt;5 years) while the patient shows no evidence of disease before the cancer eventually recurs. Dormant cancer cells can be detected in bone, the principal metastatic site of PCa, and these bone-homing cancer cells are known as disseminated tumor cells (DTC). Little information is available on the heterogeneity and dormancy of DTC in PCa. In this study, we isolated and compared the gene expression profile of individual DTC (n=45) from the bone marrow of 4 PCa patients with no evidence of disease and 5 patients with advanced disease. Using principle component analysis and cluster analysis of the 1000 most variable genes, we determined the heterogeneity of the DTC population within each patient. To identify a dormancy signature from DTC in the bone marrow and primary PCa cells, we carried out two gene expression analyses: DTC in patients with no evidence of disease vs. those with advanced disease, and primary PCa tissues from patients with a short vs. long dormancy period post radical prostatectomy (8-86 months). Genes associated in other cancers with cellular senescence, cell-cycle inhibition, and dormancy were analyzed. Candidate genes from both gene expression arrays were validated at the protein level by a tissue microarray consisting of 64 primary PCa cases that recurred after either a short or long dormancy period post radical prostatectomy (6-121 months). The identification of heterogeneous gene signatures in DTC and novel proteins that promote dormancy will guide the development of possible biomarkers and therapeutic targets to prevent PCa recurrence, possibly by either eliminating DTC or inhibiting their escape from dormancy. Citation Format: Hung-Ming Lam, Lisly Chéry, Ilsa Coleman, Bryce Lakely, Sandy Larson, Roger Coleman, Lisha Brown, Kathy Doan, Jennifer Noteboom, Xiaotun Zhang, Lawrence True, Peter Nelson, Bruce Montgomery, Paul Lange, Linda Snyder, Robert Vessella, Colm Morrissey. Disseminated tumor cell heterogeneity and dormancy in prostate cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 804. doi:10.1158/1538-7445.AM2013-804

Metastasis Awakening: Targeting dormant cancer

An important challenge for oncologists is to treat overt metastasis, the major source of cancer-related deaths1. Adjuvant therapy should prevent distant recurrences by targeting residual disseminated tumor cells (DTCs) that give origin to metastasis, as well as existing undetected micrometastasis. Whereas in some cases, such as breast cancer, patients can show delayed metastasis after hormonal therapies (for example, in estrogen receptor–positive tumors) or treatment with trastuzumab, for HER2 (also called ERBB2)-positive tumors2, adjuvant therapy is for the most part ineffective in fully blocking metastasis development and improving overall survival.

Tu2056 Sevofluorane Reduces Liver Damage Secondary to Ischemic/Reperfusion Injury by a Mechanism Not Related to a Preconditioning Effect

Introduction: Recent analyses uncovered genetic variations between paired samples from primary gastrointestinal tumors, lymph node metastases and disseminated tumor cells (DTCs). These findings might help to explain individually variable responses to standard (neo-)adjuvant therapies and further suggest thatmultimodality treatment options in gastrointestinal cancer should be guided by these individual genetic tumor characteristics. Therefore, we assessed the genetic variations in the primary tumor, lymph node metastases and DTCs of patients with esophageal cancer. Patients and Methods: In this translational analysis 86 patients with esophageal cancer undergoing multimodality therapy were included. Initially, we established a protocol for double immunofluorescence labeling for simultaneous visualization of epithelial cell adhesion molecule (EpCAM) expression on cytokeratin positive cells for the detection of DTCs in bone marrow and lymph nodes. After isolation of positively stained cells, their genomic DNA was globally amplified using the MSE-adapter PCR method. Finally, we applied comparative genomic hybridization (CGH) for the genome-wide screening of DNA-gains/-losses on paired samples from primary tumors, lymph node metastases and DTCs of the study patients. Results: DTCs were detected in 25% of the bone marrow and 38% of the lymph node samples. Interestingly, CGH analysis revealed differences between the numbers of chromosal aberrations in DTCs of the bone marrow compared to the lymph node samples with a higher frequency of aberrations in DTCs in the lymph node samples. In addition, genomic analysis revealed differences in the nature of chromosomal aberrations between primary tumors and corresponding lymph node metastases. Moreover, cluster analysis demonstrated similarities of the aberration spectrum between the DTCs and lymph node metastases while primary tumors showed distinct profiles. Conclusion: Chromosal aberration patterns in lymph node metastases and disseminated tumor cells of patients with esophageal cancer undergoing multimodality therapy are very similar while primary tumors show a different genomic aberration pattern. These individual genetic tumor characteristics might guide future multimodality treatment options in esophageal cancer.

Tu2057 Anti-Inflammatory Effects of Hypertonic Saline Solution in Pancreatic Ischemia/Reperfusion Injuries

Introduction: Recent analyses uncovered genetic variations between paired samples from primary gastrointestinal tumors, lymph node metastases and disseminated tumor cells (DTCs). These findings might help to explain individually variable responses to standard (neo-)adjuvant therapies and further suggest thatmultimodality treatment options in gastrointestinal cancer should be guided by these individual genetic tumor characteristics. Therefore, we assessed the genetic variations in the primary tumor, lymph node metastases and DTCs of patients with esophageal cancer. Patients and Methods: In this translational analysis 86 patients with esophageal cancer undergoing multimodality therapy were included. Initially, we established a protocol for double immunofluorescence labeling for simultaneous visualization of epithelial cell adhesion molecule (EpCAM) expression on cytokeratin positive cells for the detection of DTCs in bone marrow and lymph nodes. After isolation of positively stained cells, their genomic DNA was globally amplified using the MSE-adapter PCR method. Finally, we applied comparative genomic hybridization (CGH) for the genome-wide screening of DNA-gains/-losses on paired samples from primary tumors, lymph node metastases and DTCs of the study patients. Results: DTCs were detected in 25% of the bone marrow and 38% of the lymph node samples. Interestingly, CGH analysis revealed differences between the numbers of chromosal aberrations in DTCs of the bone marrow compared to the lymph node samples with a higher frequency of aberrations in DTCs in the lymph node samples. In addition, genomic analysis revealed differences in the nature of chromosomal aberrations between primary tumors and corresponding lymph node metastases. Moreover, cluster analysis demonstrated similarities of the aberration spectrum between the DTCs and lymph node metastases while primary tumors showed distinct profiles. Conclusion: Chromosal aberration patterns in lymph node metastases and disseminated tumor cells of patients with esophageal cancer undergoing multimodality therapy are very similar while primary tumors show a different genomic aberration pattern. These individual genetic tumor characteristics might guide future multimodality treatment options in esophageal cancer.

P4-06-04: Detection of HER2 Gene Amplification in Circulating Tumor Cells and Disseminated Tumor Cells by Fluorescence In Situ Hybridization Using OncoCEE™.

Abstract BACKGROUND: The status of HER2 gene amplification in circulating tumor cells (CTCs) and disseminated tumor cells (DTCs) might provide useful information for monitoring response to trastuzumab therapy, and may provide a basis for consideration of trastuzumab in patients with HER2 negative primary tumors who have HER2 positive CTCs and/or DTCs. The majority of techniques utilized for detection of minimal residual disease are limited in their ability to allow detailed phenotypic and genotypic evaluation of the cells. We report the utility of a microfluidic platform (OncoCEE™,Biocept, San Diego) for detecting HER2 gene amplification in CTCs and DTCs in patients with non-metastatic breast cancer. METHODS: Peripheral blood (10ml) and bone marrow (BM) (1-2ml) were collected from patients with clinical stage I-III breast cancer in acid citrate dextrose solution (BD, Franklin Lakes, NJ) and anti-clumping reagent (OncoCEE-Sure™). Mononuclear cells were recovered using a Percoll density gradient method, incubated with a mixture of 10 primary capture antibodies (Abs), introduced into CEE™ microchannels, stained with fluorescent anti cytokeratin (CK) and CD45 abs and finally processed for fluorescence in situ hybridization (FISH) using probes specific to centromere 17 (spectrum green) and HER2 (spectrum arrange). The ratio of HER2:CEP17 &amp;gt;2.2 in any CK+/CD45- and CK-/CD45- cell was regarded as positive for HER2 gene amplification. RESULTS: Peripheral blood and/or BM from 78 patients (65 BM; 70 blood; 57 matched blood and BM) with T1NO (39), T1N1 (8), T2N0 (12), T2N1 (2), T2N2 (1), T2N3 (3), T3N0 (2), T3N1 (2), T3N2 (1), T4N0(5), T4N1 (3), with HER2+ (n=12) and HER2− (n=58) primary invasive breast tumors were studied. The 12 patients with HER2+ primary tumors had HER2+ DTCs in 3/12 (25%) and HER2+ CTCs in 1/9 (11%) cases respectively. HER2+ DTCs and HER2+ CTCs occurred in 12/55 (24%) and in 4/63 (6%) of the patients with HER2− primary breast tumors. HER2+ CTCs and DTCs occurred simultaneously in only 2 patients and in either blood (3) or BM (13) in the remaining patients. CONCLUSION: 1. The cell enrichment and extraction microfluidic technology (OncoCEE™) provides a sensitive platform for evaluation of HER2 gene amplification of CTCs and DTCs. 2. HER2+ primary tumors were associated with either HER2+ CTCs or DTCs in 25% of the patients. 3. HER2+ CTCs or DTCs occurred in 28% of patients with HER2−primary tumor. 4. Discordant HER2 status was contributed mainly by HER2+ DTCs occurring in HER2 - primary tumors. 5. The clinical significance of evaluating the status of HER2 gene amplification in CTCs and DTCs in the management of patients with breast cancer needs to be evaluated prospectively in larger clinical trials. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-06-04.

Multicenter study on the detection of disseminated tumor cells in primary breast cancer.

Abstract Abstract #5021 Background: Detection of disseminated tumor cells (DTC) in bone marrow (BM) has prognostic value in primary breast cancer (BC) and is currently under investigation for therapy stratification and monitoring. Anti-cytokeratin (CK) antibodies (Abs) have been established as markers for detection of such DTC in patients with BC. Here we present a direct comparison of the two Abs most frequently used for DTC detection over the past 10 years.&amp;#x2028; Material and Methods: We screened BM samples from 391 BC patients of which 64 were node-positive (N+). All patients were free of any signs of overt metastases (stage M0, pT1-3, pN0-3). Tumor cells in BM were enriched by Ficoll-Hypaque gradient and the mononuclear cell (MNC) fraction was spun on slides. For each patient 2*106 MNC were analyzed per Ab, using A45-B/B3 (A45) and AE1/AE3 (AE) Abs in parallel. A45 staining was, however, performed a couple of years later than AE staining, on cytospins stored at -80°C. All samples were screened automatically for the presence of CK-positive cells. By morphological evaluation only TC-compatible cells were scored positive. Median follow-up times ranged from 5 to 118 months.&amp;#x2028; Results: For both Abs, the number of DTC revealed was 5 or less. Of the 391 patients, 24 patients (6.1%) were positive for A45, and 41 patients (10.5%) for AE, respectively. Concordance obtained by cross-analysis for the two Abs was 84.4%, whereas the overlap in positive cases was only 3.2%. Regarding immunohistopathological characteristics AE- and A45-positive BM were found significantly more frequent in tumors of higher nodal status (p=0.003 and p=0.026), and for AE also in hormone receptor negative (HR-) compared to HR+ patients (p=0.006). Positivity for AE and/or A45 staining in BM correlated with high nodal status and large tumor size (p=0.001 and p= 0.016, respectively). Survival analyses revealed shorter relapse-free survival for A45-positive patients (p=0.026). In node-positive patients, a significantly worse prognosis regarding overall and BC specific survival was observed for AE-positive (p=0.0245 and p=0.0125) and for AE- and/or A45-positive patients (p=0.035 and p=0.044, respectively). In node-negative patients, A45-positivity was correlated to a significantly shorter relapse-free survival (p=0.032). Immunocytochemical double staining of BM samples from 26 patients (M+ and M0) revealed subpopulations of DTC labeled with both Abs (in 8/26 cases) and other DTC exclusively stained for either A45 or AE (4/26).&amp;#x2028; Discussion: Our results indicate that the two anti-cytokeratin Abs most frequently used for DTC detection in BM do not give identical results. They appear to identify at least partially different subpopulations of DTC in BC patients. This implies a possible advantage of the combined use of these Abs in future trials using DTC diagnostics. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5021.

Review: Biological relevance of disseminated tumor cells in cancer patients

The prognosis of cancer patients is largely determined by the occurrence of distant metastases. In patients with primary tumors, this relapse is mainly due to clinically occult micrometastasis present in secondary organs at primary diagnosis but not detectable even with high resolution imaging procedures. Sensitive and specific immunocytochemical and molecular assays enable the detection and characterization of disseminated tumor cells (DTC) at the single cell level in bone marrow (BM) as the common homing site of DTC and circulating tumor cells (CTC) in peripheral blood. Because of the high variability of results in DTC and CTC detection, there is an urgent need for standardized methods. In this review, we will focus on BM and present currently available methods for the detection and characterization of DTC. Furthermore, we will discuss data on the biology of DTC and the clinical relevance of DTC detection. While the prognostic impact of DTC in BM has clearly been shown for primary breast cancer patients, less is known about the clinical relevance of DTC in patients with other carcinomas. Current findings suggest that DTC are capable to survive chemotherapy and persist in a dormant nonproliferating state over years. To what extent these DTC have stem cell properties is subject of ongoing investigations. Further characterization is required to understand the biology of DTC and to identify new targets for improved risk prevention and tailoring of therapy. Our review will focus on breast, colon, lung, and prostate cancer as the main tumor entities in Europe and the United States.

Significance of micrometastasis in bone marrow and blood of operable breast cancer patients: research tool or clinical application?

Approximately 25% of breast cancer patients without lymph node metastases develop systemic relapse. A growing body of data supports the notion that hematogenous dissemination of breast cancer cells occurs independently of lymphatic spread of disease; however, current clinical practice does not involve routine analysis of circulating or disseminated cells. Recent studies have documented that both circulating tumor cells (CTCs) within the blood and disseminated tumor cells (DTCs) in bone marrow can be identified using a variety of techniques. It is now clear that the presence of DTCs correlates with subsequent development of clinically evident bone metastases, and a worse outcome from breast cancer. While there are data identifying prognostic significance of CTCs in patients with metastatic breast cancer, there are few data regarding CTCs in operable patients. Factors such as presence of a cancer stem cell phenotype and/or certain microenvironmental conditions are involved in the establishment of distant metastases from a primary breast cancer, emphasizing the need for further studies within this area. The purpose of this report is to review the data regarding CTCs and DTCs in patients with operable breast cancer.

Detection and characterization of circulating and disseminated prostate cancer cells

The dissemination of prostate cancer cells to secondary sites appears to be an intermediate step in the formation of tumor metastases. However, the significance of tumor cell dissemination into the blood and bone marrow as well as the characteristics of these cells remains largely unknown. In attempts to correlate the presence of disseminated tumor cells with disease prognosis, studies have utilized a range of molecular and histologic techniques. The results of this research have been largely inconclusive in terms of clinical utility. Nevertheless, they have demonstrated that these cells are detectable and present much more often than would be expected based on the rate of prostate cancer recurrence. Further research has thus begun to focus on the isolation of individual disseminated tumor cells which can then be analyzed with techniques such as gene expression microarrays and comparative genomic hybridization in order to better characterize the cells. This review paper will examine the various methods of detecting disseminated tumor cells in patients with prostate cancer and the results of studies correlating these cells with clinical variables. Additionally, we discuss the isolation and analysis of disseminated cells and examine their potential value in helping to understand the relationship between these cells and tumor metastasis.

Detection of disseminated tumor cells in patients with gynecological cancers

Aims: The presence of disseminated tumor cells (DTC) in breast cancer patients is associated with poor prognosis. However, there is limited data about the prevalence and prognostic impact of DTC in patients with gynecological tumors.