Immunomagnetic tumor cell enrichment is promising in detecting circulating breast cancer cells

OBJECTIVE: Magnetic-activated cell separation (MACS) for the enrichment of tumor cells was evaluated with immunocytochemistry (ICC) and flow cytometry (FCM). METHODS: Blood (20 ml) was sampled in 36 affected patients before surgery. Nucleated blood cells were obtained with the removal of red blood cells in the buffy coat. Nucleated blood cells (2 x 10(6)) from breast cancer patients were aliquoted before enrichment for direct immunostaining (ICC group), while all remaining cells were enriched and then immunostained (MACS/ICC group). Breast cancer cell lines were spiked serially in normal nucleated blood cells for FCM evaluation of the enrichment efficiency of MACS. RESULTS: The enrichment rate of spiked tumor cells was 37- to 2,300-fold and was negatively correlated with the ratio of tumor cells to normal nucleated cells (p < 0.05). The positive rate was only 5.6% (2/36) in the ICC group and was as high as 38.9% (14/36) in the MACS/ICC group (p < 0.001). The positivity in the enriched fraction was 0% (0/4), 33.3% (8/24), 60% (3/5) and 100% (3/3) for tumors at stages I, II, III and IV, respectively (p < 0.05). CONCLUSION: MACS can enrich circulating tumor cells, and the presence of circulating breast cancer cells correlates with clinical staging.     

Advances in genomic characterization of circulating tumor cells

Molecular characterization of circulating tumor cells (CTCs) found in the blood of cancer patients offers the potential to provide new insights into the biology of cancer metastasis. However, since they are rare and difficult to isolate, the molecular nature of CTCs remains poorly understood. In this paper, we reviewed a decade’s worth of scientific literature (2003–2013) describing efforts on isolation and genomic analysis of CTCs. The limited number of CTC genomic studies we found attested to the infancy of this field of study. These initial reports, however, provide an important framework for future comprehensive exploration of CTC biology. For CTCs to be broadly accepted as therapeutic targets and biomarkers of metastatic spread, further in-depth molecular characterization is warranted.     

Detection rate and prognostic value of circulating tumor cells and circulating tumor DNA in metastatic uveal melanoma

Circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) have been recently investigated in several cancer types, but their respective clinical significance remains to be determined. In our prospective study, we compared the detection rate and the prognostic value of these two circulating biomarkers in patients with metastatic uveal melanoma. GNAQ/GNA11 mutations were characterized in archived tumor tissue. Using a highly sensitive and mutation‐specific bidirectional pyrophosphorolysis‐activated polymerization (bi‐PAP) technique, GNAQ c.626A>T, GNAQ c.626A>C and GNA11 c.626A>T copy numbers were quantified in plasma from 12 mL of blood. CTCs were detected at the same time in 7.5 mL of blood by the CellSearch® technique. Patient characteristics and outcome were prospectively collected. CTCs (≥1) were detected in 12 of the 40 included patients (30%, range 1–20). Among the 26 patients with known detectable mutations, ctDNA was detected and quantified in 22 (84%, range 4–11,421 copies/mL). CTC count and ctDNA levels were associated with the presence of miliary hepatic metastasis (p = 0.004 and 0.03, respectively), with metastasis volume (p = 0.005 and 0.004) and with each other (p < 0.0001). CTC count and ctDNA levels were both strongly associated with progression‐free survival (p = 0.003 and 0.001) and overall survival (p = 0.0009 and <0.0001). In multivariate analyses, ctDNA appeared to be a better prognostic marker than CTC. In conclusion, ctDNA and CTC are correlated and both have poor prognostic significance. CTC detection can be performed in every patient but, in patients with detectable mutations, ctDNA was more frequently detected than CTC and has possibly more prognostic value.     

The prognostic value of circulating tumor cells in patients with melanoma: a systematic review and meta-analysis.

BACKGROUND: The detection of circulating tumor cells (CTC) in patients with melanoma represents an appealing prognostic tool, but no consensus exists on this topic. We aimed to comprehensively and quantitatively summarize the evidence for the use of CTC to predict patients' clinical outcome. METHODS: Fifty-three studies enrolling 5,433 patients were reviewed. Correlation of CTC status with tumor-node-metastasis disease stage and patients' overall (OS) and progression-free (PFS) survival was assessed by means of association statistics and meta-analysis, respectively. RESULTS: CTC status correlated with both tumor-node-metastasis stage (stage I, 32%; stage II, 41.7%; stage III, 41.1%; stage IV, 47.4%; P(trend) < 0.0001) and survival (OS: hazard ratio, 2.42; 95% confidence interval, 1.7-3.45, P < 0.0001; PFS: hazard ratio, 2.45; 95% confidence interval, 1.78-3.38; P < 0.0001). However, statistical heterogeneity was significant for both OS and PFS, likely underscoring the wide variability in study design. Furthermore, CTC positivity rates in early stages were higher and in the metastatic setting were lower than expected, which indicates an unsatisfactory accuracy of currently available CTC detection assays. CONCLUSIONS: Our findings suggest that CTC might have a clinically valuable prognostic power in patients with melanoma. However, the heterogeneity of the studies thus far published warrants caution not to overestimate the favorable results of pooled data.     

The prognostic impact of circulating tumor cells in subtypes of metastatic breast cancer

The detection of circulating tumor cells (CTCs) in the peripheral blood of metastatic breast cancer (MBC) patients is an independent marker of prognosis. This large prospective multicenter study aimed to assess the impact of CTCs on overall survival (OS) and progression free survival (PFS) in patients with predefined molecular subgroups of MBC. To this end, 468 MBC patients were divided into three subgroups based on immunohistochemical staining of the primary tumor: (1) hormone receptor-positive/HER2-negative (HorR+/HER2?), (2) HER2-positive (HER2+), and (3) HorR-negative/HER2-negative (HorR?/HER2?) patients. CTC status (<5 CTCs/7.5 ml blood (CTC-negative) vs. ≥5 CTCs/7.5 ml blood (CTC-positive)) was determined using the CellCearch^® system before patients started a new line of therapy. At baseline, 205 (42 %) patients were CTC-positive. On multivariate analysis, CTC-positivity was an independent prognostic factor for shorter PFS and OS. In HorR+/HER2? patients, median PFS [95 % CI] of CTC-negative versus CTC-positive patients was 8.60 [5.93–11.27] versus 4.33 [3.29–5.38] months (p < 0.001), in HER2+ patients 7.60 [5.40–9.79] versus 6.60 [4.20–9.00] months (p = 0.477) and in HorR?/HER2? patients 5.83 [5.09–6.78] versus 3.05 [1.81–4.29] months (p < 0.001), respectively. Median OS [95 % CI] of CTC-negative versus CTC-positive patients was as follows: not reached by either in the HorR+/HER2? subgroup (p < 0.001), not reached versus 18.07 [11.10–25.05] months (p = 0.001) in the HER2+ subgroup, and not reached versus 8.57 [4.07–13.07] months in the HorR?/HER2? subgroup (p = 0.001). In conclusion, our results strongly confirm the independent prognostic value of CTC enumeration in MBC patients. In contrast to recent reports, there was no association between primary tumor-based molecular subgroups and the impact of CTC status on OS. Hence, CTC status may help to identify patients who require aggressive therapy, especially among those with triple-negative MBC.     

Molecular detection of circulating tumor cells is an independent prognostic factor in patients with high-risk cutaneous melanoma

Detection of circulating tumor cells (CTCs) might improve current staging procedures by identifying a subgroup of patients with minimal residual disease and thus a higher risk of disease recurrence. Forty patients with > or =2-mm-thick cutaneous melanoma with or without lymph node metastasis were enrolled. After standard radical surgery and adjuvant therapy in case of lymph node metastasis, patients were followed up with routine physical and radiologic assessments as well as serial PCR-based analysis of CTCs using 2 melanoma markers (tyrosinase and Melan-A/Mart-1). After a median follow-up of 30 months, 18 patients had disease recurrence and 28 were PCR-positive before the disease became clinically evident. The sensitivity of the molecular test was 83%. Median time to PCR positivity and median PCR-to-relapse time were 12 and 8 months, respectively. At multivariate analysis, PCR positivity was an independent predictor of disease recurrence (hazard ratio=2.06, 95% CI 1.07-3.35; p=0.03). Among high-risk melanoma patients, serial PCR-based analysis of CTCs can identify a subgroup at higher risk of disease recurrence, with clinically significant advance. Therefore, CTC detection might be employed for the selection of patients for adjuvant treatment and during follow-up for early indication of therapeutic failure.     

Towards an optimized platform for the detection,enrichment, and semi-quantitation circulating tumor cells

There is a growing belief that the metabolic program of breast tumor cells could be a therapeutic target. Yet, without detailed information on central carbon metabolism in breast tumors it is impossible to know which metabolic pathways to target, and how their inhibition might influence different stages of breast tumor progression. Here we perform the first comprehensive profiling of central metabolism in the MCF10 model of mammary carcinoma, where the steps of breast tumor progression (transformation, tumorigenicity and metastasis) can all be examined in the context of the same genetic background. The metabolism of [U-(13)C]-glucose by a series of progressively more aggressive MCF10 cell lines was tracked by 2D NMR and mass spectrometry. From this analysis the flux of carbon through distinct metabolic reactions was quantified by isotopomer modeling. The results indicate widespread changes to central metabolism upon cellular transformation including increased carbon flux through the pentose phosphate pathway (PPP), the TCA cycle, as well as increased synthesis of glutamate, glutathione and fatty acids (including elongation and desaturation). The de novo synthesis of glycine increased upon transformation as well as at each subsequent step of breast tumor cell progression. Interestingly, the major metabolic shift in metastatic cells is a large increase in the de novo synthesis of proline. This work provides the first comprehensive view of changes to central metabolism as a result of breast tumor progression.     

一种高通量循环血液富集循环肿瘤细胞的装置

目的:通过具有生物相容性的微滤膜和外周血循环单通道闭合环路装置的结合来有效富集循环肿瘤细胞（circulating tumor cells,CTCs）。方法:使用均匀分布有直径为10 μm大小微孔的派瑞林微滤膜；采用肺癌H1975细胞系，以不同浓度混入健康受试者外周血，体外免疫荧光实验检测微滤膜对肿瘤细胞的捕获率；进一步二代测序实验验证了基于微滤膜捕获肿瘤细胞行基因突变检测的敏感性。体内实验在猪模型中，验证该单通道闭合环路装置的安全性。结果:使用微滤膜可以在肺癌H1975细胞系样本中获得85.00％的捕获率。在一定的细胞浓度下，基于微滤膜捕获的肿瘤细胞可有效实现基因突变的检测，并且通过猪模型初步确定了装置的安全性。结论:基于微滤膜的单通道闭合环路装置是一种可实现高通量、高效的CTCs捕获设备，为后续CTCs的高效富集及基于CTCs的相关分子生物学检测、实时个体化治疗的探索奠定了基础。     

Array-based comparative genomic hybridization of circulating esophageal tumor cells

Esophageal squamous cell carcinoma (ESCC) shows a high frequency of lymphatic and/or systemic metastasis, even when the tumor invades only the submucosa. To investigate the genetic alterations in circulating esophageal tumor cells, we performed array-based comparative genomic hybridization (CGH) analysis of 8 DNA samples of xenografts, which were previously established from the thoracic duct lymph of 13 ESCC patients. A total of 5 loci (or genes), 10q21.3 (EGR2), 11q13.3 (CCND1/CyclinD1, FGF4, and EMS1), 11q14 (PAK1), and 22qtel (ARSA) were found to be candidate amplified loci in the xenograft. In contrast, a total of 24 loci including 9p21 (p16 and MTAP) were found to be homozygously deleted candidates in the xenograft. Both p16 homozygous deletion and CCND1 amplification were detected in 6 (75%) and 5 (62.5%) of the 8 xenografts. Furthermore, by quantitative Southern blot analysis, we found p16 homozygous deletion in 30.8% (8/26) of the primary tumors and in 50% (4/8) of the metastasized lymph nodes. The frequency of CCND1 amplification and p16 homozygous deletion is suggested to be associated with ESCC progression. Matrigel invasion assays of p16-deleted ESCC cells showed that restoring wild-type p16 activity into the cells significantly inhibits tumor-cell invasion, suggesting that p16 inactivation could be involved in ESCC invasion. This is the first report showing the genetic alteration of concealed tumor cells in the thoracic duct lymph. The present gene list should be helpful for identifying new amplified and deleted genes in primary ESCCs as well as in metastasized lymph nodes.     

Phenotypic characterization and prognostic impact of circulating γδ and αβ T‐cells in metastatic malignant melanoma

Human T cells carrying γδ T‐cell receptors (TCRs) represent a minor population relative to those with αβ TCRs. There has been much interest recently in the possibility of using these γδ T‐cells in cancer therapy because they can kill tumor cells in vitro in an MHC‐unrestricted manner, and possess potential regulatory capability and antigen‐presenting capacity. The presence of γδ T‐cells in late‐stage melanoma patients and their relationship with survival has not been extensively explored, although relatively lower percentages of total γδ T‐cells and Vδ2+ cells have been reported. Here, we present a detailed analysis of associations of γδ T‐cell subsets and differentiation stages with survival in Stage IV patients, compared with CD4+ and CD8+ αβ T‐cells. We found an increased Vδ1:Vδ2‐ratio and a decreased CD4:CD8‐ratio in patients compared to healthy controls, on the basis both of relative frequencies and absolute cell counts per μL blood. Nonetheless, Kaplan–Meier analyses showed that a higher than median frequency of Vδ1+ cells was negatively associated with survival, whereas there were no positive or negative associations with frequencies of Vδ2+ cells. Correlations of cell differentiation status with survival revealed a negative association of early‐differentiated Vδ1+ T cells with survival, both on the basis of relative frequencies and absolute counts. There was also a positive correlation between the frequencies of early‐differentiated CD8+ αβ T‐cells and survival. Our findings suggest peripheral blood frequencies of Vδ1+ T‐cells as a potential prognostic marker in melanoma. The mechanisms by which higher abundance of Vδ1+ cells are associated with poorer survival require determination.     

Identification and characterization of circulating prostate carcinoma cells

BACKGROUND: Analysis of prostate carcinoma cells isolated from the peripheral blood suggested a classification based on three categories. METHODS: Centrifugation density gradients and magnetic cell sorting were used to isolate circulating prostate carcinoma cells from peripheral blood. Immunocytochemistry staining and fluorescent in situ hybridization allowed characterization of isolated cancer cells. RESULTS: Terminal cells can be divided into 3 classes: 1) large, buoyant, fragile cells with a large nucleus that were captured in a 1.068 g/mL gradient; 2) enucleate cells (4, 6-diamidino-2-phenylindole [DAPI] negative) that were positive for cytokeratin and PSMA antibodies; and 3) cellular debris exhibiting cytokeratin and PSMA positive staining as well as nuclear debris identified by DAPI staining, which included cytoplasmic debris. Growing cells also exhibited three morphologic characteristics: those possessing stem cell-like morphology and characteristics such as small size, high density, developed cytokeratin systems, PSMA expression, and aneuploidy; those in M phase; and cell clusters. The majority of isolated cells exhibited intermediate characteristics and thus comprised the third group of circulating cancer cells. CONCLUSIONS: Although the significance of the cluster remains undetermined, observation suggests that the cluster has the ability to circulate as a microtumor and subsequently arrest in the small veins and capillaries. It is hypothesized that the clusters could escape certain facets of immune surveillance and possibly gain a selective growth advantage over single cells in a distant site. Further hypothesis proposes that arrested cells recruit growth-promoting nutrients, which would result in the invasion of local blood vessels and vascularization.     

Independent prognostic impact of lymphatic vessel density and presence of low-grade lymphangiogenesis in cutaneous melanoma.

The aim of this study was to determine lymphatic vessel density (LVD) in a series of nodular melanoma and correlate the findings with the expression of several angiogenic factors, including vascular endothelial growth factor-C, basic fibroblast growth factor (bFGF), patient survival, and clinico-pathologic data. Patients with nodular melanoma and complete follow-up information were included. Lymphatic vessels were immunostained with the LYVE-1 and Podoplanin antibodies, and LVD was evaluated in both intra- and peri-tumoral (LVDpt) areas. Median LVD was 6.3 and 12.5 vessels/mm(2) in intra- and peri-tumoral areas, and coexpression of LYVE-1 and Ki-67/MIB-1 in lymphatic endothelial cells within the tumor was demonstrated, indicating active but low-grade lymphangiogenesis. Increased LVDpt was significantly associated with localization on the extremities (P = 0.005), decreased tumor thickness (P = 0.036), absence of vascular invasion (P = 0.004), brisk lymphocytic infiltration (P = 0.018), low proliferative rate by Ki-67 (P = 0.011), increased bFGF expression in tumor cells (P = 0.01) as well as in endothelial cells (P = 0.008), and decreased tumor cell expression of Ephrin-A1 (P = 0.009). Decreased LVD in intra-tumoral areas and LVDpt both predicted improved survival rates in multivariate analyses (for LVDpt, Hazard ratio: 2.1, P = 0.009). We found that decreased LVD was present in thicker and more proliferative tumors (Ki-67) and that increased LVD was significantly associated with improved patient survival in multivariate analysis. In addition, our data suggest the presence of low-grade intra-tumoral lymphangiogenesis in melanoma and a stimulating role of bFGF in lymphangiogenesis.     

Cutaneous melanoma: prognostic factors.

BACKGROUND: Recent data have changed our views of prognostic factors in cutaneous melanoma. While some newer methods have yielded better prognostic information, some insights have evolved as a result of large-scale population-based analyses. METHODS: We review current data on several different prognostic factors and divide these factors according to their application in localized primary melanoma or metastatic melanoma. For each prognostic factor, the level of evidence supporting its use and its applicability to clinical practice are considered. RESULTS: For localized primary melanoma, the dominant predictors of survival include lesion thickness, ulceration, and lymph node involvement. Factors such as age, sex, anatomic location, and satellite/in-transit lesions are important in localized melanoma. Factors currently being investigated are tumor vascularity, vascular invasion, mitotic rate, tumor regression, and tumor-infiltrating lymphocytes. For metastatic melanoma, the most important prognostic factors are site of metastases and the presence of elevated serum lactic dehydrogenase. The value of these prognostic factors to clinicians caring for melanoma patients is discussed. CONCLUSIONS: A better understanding of prognostic factors in cutaneous melanoma has evolved over the last decade, allowing oncologists to provide appropriate treatment for their patients. Many of the prognostic factors are interrelated. In the near future, it is expected that several molecular genetic factors will provide more insight into the prognosis of patients with melanoma.     

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

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

Immunomagnetic enrichment and detection of micrometastases in colorectal cancer: correlation with established clinical parameters.

PURPOSE: Micrometastatic disease in bone marrow is of prognostic significance in colorectal cancer patients. However, detection rates of standard immunocytology are relatively low. We used magnetic activated cell sorting (MACS), a highly sensitive method, to increase detection rates and correlated the presence of cytokeratin (CK)-expressing cells with clinical parameters. PATIENTS AND METHODS: Bone marrow was obtained from 51 consecutive patients with newly diagnosed colorectal adenocarcinoma who underwent primary surgery and 18 control subjects. International Union Against Cancer (UICC) stage I disease was diagnosed in 11 patients, stage II disease was diagnosed in 14 patients, stage III disease was diagnosed in 12 patients, and stage IV disease was diagnosed in 14 patients. CK-positive cells were enriched and stained with magnetically labeled CAM 5.2 antibodies directed to CK 7 and 8. RESULTS: CK-positive cells were found in 33 (65%) patients and were absent in 18 (35%). Four of 11 (36%) patients with UICC stage I disease, nine of 14 (64%) with stage II diease, eight of 12 (67%) with stage III disease, and 12 of 14 (86%) with stage IV disease were CK-positive. Epithelial cells were more frequently found in pT3/4 (72%) than in pT1/2 (36%) tumors (P =.026), but there was no difference for lymph node status. CK-positive patients had a higher chance for elevated carcinoembryonic antigen (85% v 15%, P = NS) and CA 19-9 levels (92% v 8%, P =.019). There were no significant differences in CA 72-4, sex, age, tumor grading, or tumor localization regarding the presence of CK-positive cells. All control subjects were CK-negative. CONCLUSION: In searching for micrometastases in colorectal cancer patients, we have achieved high detection rates by using MACS. The presence of these cells correlated significantly with tumor stage, tumor extension, and the tumor marker CA 19-9.     

Visualization of circulating melanoma cells in peripheral blood of patients with primary uveal melanoma

PURPOSE: In patients with uveal melanoma, tumor cell dissemination and subsequent formation of metastases are confined mainly to the hematogenous route. Here, we sought to isolate circulating melanoma cells in peripheral blood of patients with primary uveal melanoma and clinically localized disease. EXPERIMENTAL DESIGN: Blood samples from 52 patients with clinically localized uveal melanoma and from 20 control individuals were prospectively collected before therapy of the primary tumor. Tumor cells expressing the melanoma-associated chondroitin sulfate proteoglycan were enriched by immunomagnetic cell sorting and visualized by immunocytologic staining. Results were compared with clinical data at presentation. RESULTS: In 10 of 52 patients [19%; 95% confidence interval (95% CI), 10-33%], between 1 and 5 circulating melanoma cells were detected in 50 mL peripheral blood. No melanoma-associated chondroitin sulfate proteoglycan-positive cells were detected in any of the 20 controls examined. The presence of tumor cells in peripheral blood was associated with ciliary body invasion [odds ratio (OR), 20.0; 95% CI, 3.0-131.7], advanced local tumor stage (OR, 6.7; 95% CI, 1.8-25.4), and anterior tumor localization (OR, 4.0; 95% CI, 1.2-12.7), all established factors for uveal melanoma progression. CONCLUSIONS: Immunomagnetic enrichment enables detection of intact melanoma cells in peripheral blood of patients with clinically localized ocular disease. Visualization and capturing of these cells provide a unique tool for characterizing potentially metastasizing tumor cells from a primary melanoma at an early stage of the disease.