The detection of circulating breast cancer cells in blood

An automated centrifugal microfluidic assay for whole blood fractionation and isolation of multiple cell populations using an aqueous two-phase system

Fractionating whole blood and separating its constituent components one from another is an essential step in many clinical applications. Currently blood sample handling and fractionation processes remain a predominantly manual task that require well-trained operators to produce reliable and reproducible results. Herein, we demonstrate an advanced on-chip whole human blood fractionation and cell isolation process combining (i) an aqueous two-phase system (ATPS) to create complex separation layers with (ii) a centrifugal microfluidic platform (PowerBlade) with active pneumatic pumping to control and automate the assay. We use a polyethylene glycol (PEG) and dextran (DEX) mixture as the two-phase density gradient media and our automated centrifugal microfluidic platform to fractionate blood samples. Different densities of precisely tuned PEG-DEX solutions were tested to match each of the cell types typically targeted during blood fractionation applications. By employing specially designed microfluidic devices, we demonstrate the automation of the following steps: loading of a whole blood sample on-chip, layering of the blood on the ATPS solution, blood fractionation, precise radial repositioning of the fractionated layers, and finally extraction of multiple, selected fractionated components. Fractionation of up to six distinct layers is shown: platelet-rich plasma, buffy coat, PEG, DEX with neutrophils, red blood cells (RBCs) and high density gradient media (HDGM). Furthermore, through controlled dispensing of HDGM to the fractionation chamber, we show that each of the fractionated layers can be repositioned radially, on-the-fly, without disturbing the interfaces, allowing precise transfer of target fractions and cell types into external vials via a chip-to-world interface. Cell counting analysis and cell viability studies showed equivalence to traditional, manual methods. An overall cell viability greater than 90% of extracted cells demonstrates that the proposed approach is suitable for cell isolation applications. This proof-of-principle demonstration highlights the utility of the proposed system for automated whole blood fractionation and isolation for blood cell applications. We anticipate that the proposed approach will be a useful tool for many clinical applications such as standard cell isolation procedures and other bioanalytical assays (e.g., circulating tumor cells, and cell and gene therapy).

Mid-infrared spectral classification of endometrial cancer compared to benign controls in serum or plasma samples

This study demonstrates a discrimination of endometrial cancer versus (non-cancerous) benign controls based on mid-infrared (MIR) spectroscopy of dried plasma or serum liquid samples. A detailed evaluation was performed using four discriminant methods (LDA, QDA, kNN or SVM) to execute the classification task. The discriminant methods used in the study comprised methods that are widely used in the statistics (LDA and QDA) and machine learning literature (kNN and SVM). Of particular interest, is the impact of discrimination when presented with spectral data from a section of the bio-fingerprint region (1430 cm-1 to 900 cm-1) in contrast to the more extended bio-fingerprint region used here (1800 cm-1 to 900 cm-1). Quality metrics used were the misclassification rate, sensitivity, specificity, and Matthew's correlation coefficient (MCC). For plasma (with spectral data ranging from 1430 cm-1 to 900 cm-1), the best performing classifier was kNN, which achieved a sensitivity, specificity and MCC of 0.865 ± 0.043, 0.865 ± 0.023 and 0.762 ± 0.034, respectively. For serum (in the same wavenumber range), the best performing classifier was LDA, achieving a sensitivity, specificity and MCC of 0.899 ± 0.023, 0.763 ± 0.048 and 0.664 ± 0.067, respectively. For plasma (with spectral data ranging from 1800 cm-1 to 900 cm-1), the best performing classifier was SVM, with a sensitivity, specificity and MCC of 0.993 ± 0.010, 0.815 ± 0.000 and 0.815 ± 0.010, respectively. For serum (in the same wavenumber range), QDA performed best achieving a sensitivity, specificity and MCC of 0.852 ± 0.023, 0.700 ± 0.162 and 0.557 ± 0.012, respectively. Our findings demonstrate that even when a section of the bio-fingerprint region has been removed, good classification of endometrial cancer versus non-cancerous controls is still maintained. These findings suggest the potential of a MIR screening tool for endometrial cancer screening.

Selection of a new peptide homing SK-BR-3 breast cancer cells

Breast cancer diagnosis remains a challenge, mostly due to its heterogeneity. This reality translates in delayed treatments, increasing treatment aggressiveness and lower chances of overall survival. The conventional detection techniques, although becoming increasingly sophisticated each year, still lack the ability to provide reliable conclusions without being time consuming, expensive, and uncomfortable for the patients. The identification of novel biomarkers for breast cancer research is therefore of utmost relevance for an early diagnosis. Moreover, breast cancer-specific peptide moieties can be used to develop novel targeted drug delivery systems. In this work, we used phage display to identify a novel peptide with specificity to the SK-BR-3 breast cancer cell line. Cytometry assays confirmed its specificity, while bioinformatics and docking studies predicted the potential biomarkers at the SK-BR-3 cells' surface. These findings can be potentially useful in the clinical context, contributing to more specific and targeted therapeutic solutions against HER2-positive breast cancer subtypes.

Characteristic of Five Subpopulation Leukocytes in Single-Cell Levels Based on Partial Principal Component Analysis Coupled with Raman Spectroscopy

Characteristics of five subpopulation leukocytes in single-cell levels based on partial principal component analysis coupled with Raman spectroscopy were proposed to recognize the biochemical features of five subpopulation leukocytes. Using wavelet transform, the reconstructed spectra of the low-frequency wavelet coefficients were used to perform multiple principal component analysis based on segmented spectral data wreathing cover at 720-800 cm^-1, 840-994 cm^-1, and 1010-1070 cm^-1 wavenumbers, respectively. Our approach is promising since it enables to establish a better understanding of the underlying molecular difference between the subtypes of leukocytes in a label-free manner and to estimate the source of infection.

Efficacy of Emu Oil Transfersomes for Local Transdermal Delivery of 4-OH Tamoxifen in the Treatment of Breast Cancer

Oral tamoxifen used in the prevention and treatment of ductal carcinoma in situ (DCIS) (estrogen-positive) patients has limited acceptance, due to its adverse side effects. The efficacy of tamoxifen is related to its major metabolite, 4-hydroxytamoxifen. Local transdermal therapy of 4-hydroxytamoxifen to the breast might avert the toxicity of oral tamoxifen, while maintaining efficacy. We aim to study the skin irritancy, as well as to evaluate the efficacy of the developed transfersome formulations, with/without emu oil, using a syngeneic mouse model of breast cancer. We also quantified tamoxifen/4-hydroxytamoxifen concentrations in blood plasma and performed histopathology. The skin irritancy test showed that the pure emu oil and transfersome formulations with or without the emu oil did not cause skin irritancy in the animals studied. A sensitive and specific LC–MS/MS method for the quantification of tamoxifen and 4-hydroxytamoxifen was developed and validated. Studies on tumor volume and necrosis (histopathology) using the breast cancer mouse model showed that the 4-OHT transfersomal formulations, with and without emu oil, showed comparable efficacy with that of orally administered tamoxifen. However, the transfersomal formulations, with and without emu oil, resulted in significantly lower (10.24 ± 0.07 and 32.45 ± 0.48 ng/mL, respectively) plasma concentrations of 4-hydroxytamoxifen, compared to the oral tamoxifen (TAMX) group (634.42 ± 7.54 ng/mL). This study demonstrated the potential use of emu oil in a local transdermal formulation for the treatment of breast cancer and its reduced adverse effects.

Remodelling of the bone marrow microenvironment by stromal hyaluronan modulates the malignancy of breast cancer cells

Background

Hyaluronan (HA) is an abundant component of the bone marrow (BM) extracellular matrix. Here, we investigated the abnormal deposition of HA in the BM microenvironment and its remodelling in mediating the malignancy of breast cancer cells (BCCs).

Methods

BCCs were transplanted into nude mice by intracardiac injection. The BCCs were cocultured with BM-derived stromal HS5 cells. Then, the abnormal metabolism of HA and its correlation with the malignant growth and the intracellular signalling pathways of the BCCs were investigated. After knockdown/out of the HA receptor CD44 in cancer cells by shRNA and CRISPR/Cas9, the mechanism was investigated in vivo through intratibial inoculation and in vitro by coculture with HS5 cells.

Results

The malignancy of cancer cells was highly related to the degree of accumulation of HA in the BM. Further, stromal cell-derived HA, especially the mixed complex, significantly promoted the growth of BCCs and osteolysis by binding to the CD44 receptor. Additionally, the investigation of the underlying mechanism revealed that the PI3K, Cyclin D1, and CDK4 pathways were involved in the effect of bone stromal cell-derived HA on the BCC activities.

Conclusion

These data suggested that HA in abnormal BM stroma might be a therapeutic candidate for bone metastasis of breast cancer.

CYP19A1 gene expression in the peripheral blood of Brazilian women with breast cancer relapse

Background

The CYP19A1 gene, which encodes the enzyme responsible for androgen aromatization into estrogens, may play an important role in breast cancer aggressiveness. However, no study has evaluated CYP19A1 gene expression in the peripheral blood of women with relapsed breast cancer.

Methods

In this cross-sectional study, CYP19A1 gene expression was quantified by RT-PCR in the peripheral blood of 146 women with breast cancer who were first divided into two groups according to the expression of CYP19A1 (low and high); each group had 73 patients. Subsequently, women were divided into two groups: those without recurrence (control, n = 85) and those with recurrence (study, n = 61). Statistical analysis of the data was performed using ANOVA, the Mann-Whitney, Chi-square or Fisher’s exact test (p <  0.05).

Results

There were no significant differences between the relative expression of CYP19A1 mRNA in the low expression group and the high expression group according to the variables studied. There were no significant differences in CYP19A1 gene expression in the study and control groups (p = 0.8461). In the relapse group, CYP19A1 gene expression was significantly higher in the hybrid luminal subtype than in the triple-negative subtype (p = 0.0321), whereas it was significantly lower in HER2-negative cases than in HER2-positive cases (p <  0.0376). Women with locoregional recurrence showed higher expression than women with distant recurrence (p <  0.0001).

Conclusions

The present study found no significant differences between women with high and low expression of the CYP19A1 gene mRNA or between those in the study group and the control group. However, in women with recurrence, there was increased expression of CYP19A1 mRNA in those who had the luminal hybrid subtype and locoregional relapse and decreased expression in those negative for HER2.

Circulating Tumor Cells in Breast Cancer

With active screening for early detection and advancements in treatment, there has been a significant decrease in mortality from breast cancer. However, a significant proportion of patients with non-metastatic breast cancer at time of diagnosis will relapse. Therefore, it is suggested that the dissemination of bloodstream tumor cells (circulating tumor cells, CTCs) undetectable by currently available diagnostic tools occurs during the early stages of breast cancer progression, and may be the potential source of micrometastases responsible for treatment failures. Here, we review the clinical significance of CTCs, as detected by the FDA-approved CellSearch^® System, in both metastatic and non-metastatic breast cancer patients. Studies so far suggest that CTCs are prognostic of poorer outcomes in breast cancer patients; however, there is currently insufficient data to support use of CTC data to guide treatment. Therefore, there are ongoing studies to evaluate the utility of assessing CTC phenotypes to develop personalized breast cancer treatment, which will be reviewed in this chapter.

Role of some circulating MiRNAs on breast cancer diagnosis

Aberrant expression of miRNAs has a link with tumorgenesis and their deregulation is reported in biological fluids of cancer patients. Authors aimed to investigate the diagnostic role of miRNA-17-5p, miR-155 and miRNA-222 in serum samples from breast cancer patients (n = 80), benign breast patients (n = 40) and healthy individuals (n = 30) using quantitative real-time PCR technique. Median levels of investigated markers revealed significant increase in primary breast cancer followed by benign and control groups. Investigated miRNAs reported significant relation with clinical stages and histological grading, while only miRNA-17-5p showed significant relation with hormone receptors. When considering investigated miRNAs as compared to tumor marker, their sensitivities were superior over tumor markers for early diagnosis of breast cancer, detection of early stages and low grades breast cancer patients. In conclusion, detection of the miRNA-17-5p, miR-155 and miRNA-222 expression levels in serum samples is significant promising molecular markers for early breast cancer diagnosis.

Comparative Study of Blood, Tissue and Serum Levels of Carcinoembryonic Antigen (CEA) Detection in Breast Cancer

Background:

Carcinoembryonic antigen (CEA) detection was evaluated in breast cancer (BC). The statistical correlation between the CEA mRNA and clinico-pathological features in the peripheral blood (PB) and tissue samples of BC was assessed.

Materials and Methods:

RT-PCR (Reverse transcription-polymerase chain reaction) analysis was applied to study the expression of CEA in PB of 30 healthy females and 30 patients with operable BC before receiving any therapy, as well as in the tissue of 30 BC patients.

Results:

CEA was observed in a number of normal subjects, but there was a significant difference between the patients and controls. The detected CEA mRNA from tissue samples were the same as PB of patients and a correlation was observed between the CEA mRNA in PB and tissue samples (Pearson chi-square = 8.62, P=0.003). In the PB, CEA mRNA was significantly different in HER-2 (-)/HR (+) compare with HER-2(+)/HR (-) tumor group (p=0.026). Finally, CEA in serum was also significantly different in HER-2(-)/HR (+) compared with HER-2(+)/HR (+) and HER-2(+)/HR (-) subtypes (p=0.008 and p=0.043, respectively).

Conclusion:

CEA mRNA evaluation is diagnostically valuable as a breast cancer marker. Additionally, CEA can significantly improve the sensitivity of diagnosis.

Combination of miR-21 with Circulating Tumor Cells Markers Improve Diagnostic Specificity of Metastatic Breast Cancer

Circulating miR-21 is upregulated in breast cancer. However, correlation of miR-21 expression with clinic pathologic characteristics remains questionable. In this study, we investigate whether combination of circulation miR-21 with circulating tumor cells (CTCs) marker (EpCAM, MUS1, HER2) could improve diagnostic specificity of metastatic breast cancer. Total 223 breast cancer patients were included. 89 % patients were associated with upregulation of miR-21 compared with health control. 20 % patients were detected for CTCs marker positive. For higher specificity purpose, triple marker positive samples were selected as true CTCs positive, which only occupied 59.5 % of total metastatic breast cancer patients. Specificity of detection of CTCs was 96.7 %. Furthermore, 59.5 % metastatic breast cancer patients were shown both abnormal miR-21 and true CTCs positive according to distribution of true CTCs positive and abnormal miR-21; Combination of miR-21 and CTCs was increased specificity of metastatic detection to 100 %. Our findings suggested that combination of miR-21 with CTCs marker could be used for better diagnosis of metastatic breast cancer in the future.

Relationship between erb-B2 mRNA Expression in Blood and Tissue of Invasive Ductal Carcinoma Breast Cancer Patients and Clinicopathological Characteristics of the Tumors

Molecular detection methods such as RT-PCR for detecting breast cancer-associated gene expression in the peripheral blood have the potential to modify breast cancer (BC) staging and therapy. In this regard, we evaluated the potential of erb-B2 molecular marker in BC detection and analyzed the expression of erb-B2 mRNA in the peripheral blood and fresh tissue samples of 50 pretreated female BC patients and 50 healthy females by reverse transcription-PCR (RT-PCR) method. We also assessed the correlation of erb-B2 mRNA marker positivity in peripheral blood and tumor tissue samples with clinical and pathological factors in BC patients in order to evaluate its prognostic value. It was shown that there is a significant difference between healthy females and BC patients with expression of the erb-B2 molecular marker (p<0.01). A significant difference between the expression of erb-B2 in the peripheral blood and tissue samples of BC patients (p<0.01) and the frequency of circulating erb-B2 mRNA expression in peripheral blood and in tissue was detected by RT-PCR. No correlation was found between erb-B2 mRNA expression in blood or tumor tissue samples and lymph node, tumor grade, tumor stage, tumor size, patient's age, ki67, estrogen receptor (ER), progesterone receptor (PGR), P53, and HER-2 status. However, in a small subset of 31 BC patients we found that expression of erb-B2 in peripheral blood or in both peripheral blood and tumor tissue was directly correlated with lympho-vascular invasion and perineural invasion as poor prognostic features. The highest rates of erb-B2 expression in peripheral blood or tumor tissue were in the ER and PR negative and HER-2 positive group. This study suggests that the application of the RT-PCR and immunohistochemical methods for erb-B2 molecular marker detection would provide a higher detection rate, especially in early stage BC.

Single cell analysis of cancer cells using an improved RT-MLPA method has potential for cancer diagnosis and monitoring

Single cell analysis techniques have great potential in the cancer genomics field. The detection and characterization of circulating tumour cells are important for identifying metastatic disease at an early stage and monitoring it. This protocol is based on transcript profiling using Reverse Transcriptase Multiplex Ligation-dependent Probe Amplification (RT-MLPA), which is a specific method for simultaneous detection of multiple mRNA transcripts. Because of the small amount of (circulating) tumour cells, a pre-amplification reaction is performed after reverse transcription to generate a sufficient number of target molecules for the MLPA reaction. We designed a highly sensitive method for detecting and quantifying a panel of seven genes whose expression patterns are associated with breast cancer, and optimized the method for single cell analysis. For detection we used a fluorescence-dependent semi-quantitative method involving hybridization of unique barcodes to an array. We evaluated the method using three human breast cancer cell lines and identified specific gene expression profiles for each line. Furthermore, we applied the method to single cells and confirmed the heterogeneity of a cell population. Successful gene detection from cancer cells in human blood from metastatic breast cancer patients supports the use of RT-MLPA as a diagnostic tool for cancer genomics.

Discrimination of circulating tumor cells of breast cancer and colorectal cancer from normal human mononuclear cells using Raman spectroscopy

Circulating tumor cells present an important marker of the progress of several cancer diseases including breast and colorectal cancer, and enables an interesting prognosis and diagnostic options that can complement convenient diagnostic techniques based on several imaging methods. Based on its relevance, the analysis of such kinds of cells is within the scope of many research and clinical institutes; however, it still presents a difficult task. Here we used a state-of-the-art micro-Raman microscopic technique to enhance possibilities in the study of circulating tumor cells and their further differentiation. As cytospins present a convenient form of sample collection and preparation, we used this form of sampling as the initial point. Raman presents a non-destructive form of sample analysis and thus the samples can be further used for a method validation. We have considered the influence of fixation methods of the cells, where we found out that the ability of Raman spectroscopy to differentiate between three cell lines strictly depends upon the sample preparation method used. Namely breast (BT 549) and colorectal (HCT 116) circulating tumor cell lines and human mononuclear cells were compared. Methanol and paraformaldehyde methods of fixation were compared to simple drying out of the sample. It has been shown that drying out of the cells enables the best performance to be obtained in cell differentiation and this is demonstrated by the use of principal component analysis, where all three given cell lines were differentiated with a high level of confidence. Next, the cells were also scanned using 1 μm spatial resolution. The acquired data were visualized using both chemigrams and hierarchical clustering analysis.

Circulating tumor cells as predictors of response and failure in breast cancer patients treated with preoperative chemotherapy

AIM

To explore the significance of circulating tumor cells (CTCs) detection in the course of preoperative chemotherapy (PC) and their effect on the outcomes.


METHODS

Fifty-five patients with stage II/III invasive breast cancer were enrolled into a preoperative clinical trial. Patients were given PC with sequential single-agent doxorubicin and paclitaxel vs paclitaxel followed by doxorubicin. Blood samples (8 mL) were collected from patients before PC, after each phase, and at 6 months intervals during follow-up. Peripheral blood mononuclear cells were isolated and enriched for epithelial cells. Quantitative RT-PCR was used to determine the presence of cytokeratin 19 (CK19) mRNA. Samples were considered positive when the PCR curve crossed the standard threshold curve.


RESULTS

After the first phase of chemotherapy, there was a 59% overall reduction in the median tumor volume. The percentage of volume reduction did not differ between patients who presented with detectable CTCs at baseline and those who did not (p=0.89). After the second phase of chemotherapy, there was a further decrease in the median tumor volume to 93% from baseline. There was no correlation between the lack of response and the presence of CTCs either after the first (p=0.36) or second (p=0.5391) phases of PC. The presence of CTCs was a predictor of local or distant relapse (p=0.0411). The detection of CTCs did not affect overall survival (p=0.2569).


CONCLUSION

CTCs can be used as predictors of relapse after definitive treatment of locally advanced breast cancer; however, CTCs detection in peripheral blood during the course of PC does not implicate a particular pattern of response to treatment.

Photoacoustic Imaging for Cancer Detection and Staging

Cancer is one of the leading causes of death in the world. Diagnosing a cancer at its early stages of development can decrease the mortality rate significantly and reduce healthcare costs. Over the past two decades, photoacoustic imaging has seen steady growth and has demonstrated notable capabilities to detect cancerous cells and stage cancer. Furthermore, photoacoustic imaging combined with ultrasound imaging and augmented with molecular targeted contrast agents is capable of imaging cancer at the cellular and molecular level, thus opening diverse opportunities to improve diagnosis of tumors, detect circulating tumor cells and identify metastatic lymph nodes. In this paper we introduce the principles of photoacoustic imaging, and review recent developments in photoacoustic imagingas an emerging imaging modality for cancer diagnosis and staging.

Molecular markers in peripheral blood of Iranian women with breast cancer

A biomarker is a quantifiable laboratory measure of a disease specific biologically relevant molecule that can act as an indicator of a current or future disease state. The purpose of this study is to detect the expression of RNA biomarkers using Cytokeratin 19 (CK-19), Mammaglobin (MAM), Carcinoembryonic antigen (CEA), Mucin (MUC), C-Myc, erb-B2, a proliferation marker (Ki-67), Epidermal growth factor receptor (Her2/neu) and Estrogen receptor (ER) in Iranian women who were diagnosed with breast cancer. In this study, 90 samples; 60 cancer patients and 30 healthy controls were considered. 73.4 % patients were in stage I/II and 26.6 % were in stage III/IV. Patients were selected prior to the administration of any adjuvant systemic therapy. Total RNA extraction was obtained from peripheral blood of each patient and healthy control. Reverse transcription polymerase chain reaction (RT-PCR) method was used for detection of mRNA of the selected biomarkers of circulating breast cancer cells in blood. Molecular characterization is assessed as a method for early detection of breast cancer. For this purpose, eleven specific primers were selected and RT-PCR was used. The data of RT-PCR revealed that expression of MUC1, CK19, CEA, MAM, erbB-2, Ki67 and C-Myc biomarkers were significantly different between breast cancer patients and healthy controls. On the other hand, ERα, ERβ and Her2 markers were not significantly different between the two mentioned groups. Biomarkers detection of breast cancer patients could be assessed as a diagnostic factor and its potential for conveying as a prognostic factor require further studies, with a larger number of patients.

Detection of prolactin inducible protein mRNA, a biomarker for breast cancer metastasis, using a molecular beacon-based assay

Mortality due to breast cancer is increasingly linked to early, undetected metastasis, making methods for earlier detection acutely necessary. We describe the development of an assay based on molecular beacon (MB) chemistry with fluorescence detection to monitor a breast cancer biomarker for the analysis of breast cancer metastasis. The MB assay is based on the complementary base-pairing interactions of the MB nucleic acid with mRNA indicative of breast cancer metastasis. The presence of mRNA is characterized by an increase in the fluorescence intensity of the molecular beacon. The assay gives a linear, reproducible response to prolactin inducible protein mRNA, with a limit of detection in the high picomolar range. This method sensitively and specifically identifies a biomarker directly in serum samples in minimal time and with a straightforward procedure, dramatically reducing the total time for sample analysis over current methods from days to hours. The potential impact of this work in detection and understanding of breast cancer metastasis lies in improvements in simplicity, accuracy, and speed over current methods, which could allow for improved patient treatment and prognoses. Ultimately, additional sample throughput will result in better understanding of disease progression.

Bone metastasis: mechanisms and therapeutic opportunities

The skeleton is one of the most common sites for metastatic cancer, and tumors arising from the breast or prostate possess an increased propensity to spread to this site. The growth of disseminated tumor cells in the skeleton requires tumor cells to inhabit the bone marrow, from which they stimulate local bone cell activity. Crosstalk between tumor cells and resident bone and bone marrow cells disrupts normal bone homeostasis, which leads to tumor growth in bone. The metastatic tumor cells have the ability to elicit responses that stimulate bone resorption, bone formation or both. The net result of these activities is profound skeletal destruction that can have dire consequences for patients. The molecular mechanisms that underlie these painful and often incurable consequences of tumor metastasis to bone are beginning to be recognized, and they represent promising new molecular targets for therapy.

Tissue factor as a novel marker for detection of circulating cancer cells

Tissue factor (TF) is a molecular marker that is up-regulated in cancer cells and aids tumoral dissemination. Our purpose was to develop a nested RT-PCR strategy against TF for detecting blood-borne tumour cells. Our method detected TF expression in a minimum of 1.5 pg total RNA from MCF7 cells. A preliminary study in blood samples from 16 advanced breast carcinoma patients showed that 80% of patients with high TF load progressed and died, while only 18% with low TF load showed the same behaviour. Kaplan-Meier analysis confirmed worse overall survival in patients with high TF load.

Identification and differentiation of single cells from peripheral blood by Raman spectroscopic imaging

Medical diagnosis can be improved significantly by fast, highly sensitive and quantitative cell identification from easily accessible body fluids. Prominent examples are disseminated tumor cells circulating in the peripheral blood of cancer patients. These cells are extremely rare and therefore difficult to detect. In this contribution we present the Raman spectroscopic characterization of different cells that can be found in peripheral blood such as leukocytes, leukemic cells and solid tumor cells. Leukocytes were isolated from the peripheral blood from healthy donors. Breast carcinoma derived tumor cells (MCF-7, BT-20) and myeloid leukaemia cells (OCI-AML3) were prepared from cell cultures. Raman images were collected from dried cells on calcium fluoride slides using 785 nm laser excitation. Unsupervised statistical methods (hierarchical cluster analysis and principal component analysis) were used to visualize spectral differences and cluster formation according to the cell type. With the help of supervised statistical methods (support vector machines) a classification model with 99.7% accuracy rates for the differentiation of the cells was built. The model was successfully applied to identify single cells from an independent mixture of cells based on their vibrational spectra. The classification was confirmed by fluorescence staining of the cells after the Raman measurement.

Detection of melanoma cells in vitro using an optical detector of photoacoustic waves

BACKGROUND AND OBJECTIVE

Circulating tumor cells have been shown to correlate positively with metastatic disease state in patients with advanced cancer. We have demonstrated the ability to detect melanoma cells in a flow system by generating and detecting photoacoustic waves in melanoma cells. This method is similar to flow cytometry, although using photoacoustics rather than fluorescence. Previously, we used piezoelectric films as our acoustic sensors. However, such films have indicated false-positive signals due to unwanted direct interactions between photons from the high laser fluence in the flow system and the film itself. We have adapted an optical detection scheme that obviates the need for piezoelectric films.

STUDY DESIGN/MATERIALS AND METHODS

Our photoacoustic system comprised a tunable laser system with an output of 410-710 nm with a pulse duration of 5 nanoseconds. The light was delivered by optical fiber to a glass microcuvette that contained saline buffer suspensions of melanoma and white blood cells. We used a continuous HeNe laser to provide a probe beam that reflected off of a glass and water interface in close proximity to the microcuvette. The beam was detected by a high-speed photodiode. When a photoacoustic wave was generated in the microcuvette, the wave propagated and changed the reflectance of the beam due to index of refraction change in the water. This perturbation was used to detect the presence of melanoma cells.

RESULTS

We determined a detection threshold of about one individual melanoma cell with no pyroelectric noise indicated in the signals.

CONCLUSIONS

The optical reflectance method provides sensitivity to detect small numbers of melanoma cells without created false-positive signals from pyroelectric interference, showing promise as a means to perform tests for circulating melanoma cells in blood samples.

Relevance of circulating tumor cells, extracellular nucleic acids, and exosomes in breast cancer

Early detection of cancer is vital to improved overall survival rates. At present, evidence is accumulating for the clinical value of detecting occult tumor cells in peripheral blood, plasma, and serum specimens from cancer patients. Both molecular and cellular approaches, which differ in sensitivity and specificity, have been used for such means. Circulating tumor cells and extracellular nucleic acids have been detected within blood, plasma, and sera of cancer patients. As the presence of malignant tumors are clinically determined and/or confirmed upon biopsy procurement-which in itself may have detrimental effects in terms of stimulating cancer progression/metastases-minimally invasive methods would be highly advantageous to the diagnosis and prognosis of breast cancer and the subsequent tailoring of targeted treatments for individuals, if reliable panels of biomarkers suitable for such an approach exist. Herein, we review the current advances made in the detection of such circulating tumor cells and nucleic acids, with particular emphasis on extracellular nucleic acids, specifically extracellular mRNAs and discuss their clinical relevance.

Disseminated and circulating tumor cells: Role in effective cancer management

Dissemination of tumor cells from primary tumors in the circulatory system is an early event in carcinogenesis. The presence of these single disseminated tumor cells (DTC) in peripheral blood, bone marrow and distant organs is the rationale for adjuvant systemic treatment. Detection of DTC in bone marrow aspirates from breast cancer patients and other solid tumors at the primary diagnosis impacts the prognosis of disease. In peripheral blood these cells are termed as circulating tumor cells (CTC). Due to technical difficulties the clinical significance of CTC detection at early stages is less established. This review focuses on available techniques for detection of DTC and CTC, recent technical advances in development of more sensitive microfluidic methods for capture of DTC and CTC and possibilities for further detection and their potential molecular characterization. Not only the clinical significance of DTC but also the presence of cancer stem cells in dissemination clearly demonstrates the need for development of sensitive technologies allowing for definition of biomarkers and molecular targets on cells in dissemination, thus eventually leading to optimization of systemic therapies.

Optical Photoacoustic Detection of Circulating Melanoma Cells In Vitro

The purpose of this research was to investigate the sensitivity of a system for the detection of circulating melanoma cells based on the thermoelastic properties of melanoma. The method employs photoacoustic (PA) excitation coupled with an optical transducer capable of determining the presence of cells within the circulating system in vitro. The transducer is based on stress wave-induced changes of the optical reflectance of a glass-water interface, probed with a continuous laser beam that is incident at an angle close to the critical angle of total internal reflection. A frequency tripled Nd:YAG laser pumping an optical parametric oscillator was employed to provide 532 nm and 620 nm laser light with a pulse duration of 10 ns. A custom-made flow chamber was used as an excitation and acoustic wave collection device. The targets were a human melanoma cell line HS 936 with an average diameter of about 15 μm. Melanoma cells were suspended in 10 mL of two types of media. The first one was Tyrode's buffer in concentrations ranging from 10 to 50 cells per μL, and the second one included 10(6) healthy white blood cells per mL of Tyrode's buffer. PA pressure waves were detected by an optical stress transducer. Detection trials resulted in a detection threshold of the order of one individual cell, indicating the effectiveness of the proposed mechanism. Results imply the potential to assay simple blood samples, from healthy and metastatic patients, to test the presence of cancerous melanoma providing an unprecedented method for screening metastatic disease.

Small breast epithelial mucin (SBEM) has the potential to be a marker for predicting hematogenous micrometastasis and response to neoadjuvant chemotherapy in breast cancer

To investigate the potential role of small breast epithelial mucin (SBEM) as a marker for detecting hematogenous micrometastasis in breast cancer and explore its clinical significance in neoadjuvant chemotherapy. SBEM protein expression in 82 tissue specimens of primary breast cancer was detected using immunohistochemistry (IHC), and SBEM expression in peripheral blood (PB) samples of 109 primary breast cancer patients (94 cases at stage I-III, 15 cases at stage IV) was detected by flow cytometry (FCM) and reverse transcription polymerase chain reaction (RT-PCR). Moreover, SBEM mRNA expression was monitored by quantification real-time PCR (QPCR) before and after 3 cycles' neoadjuvant chemotherapy. SBEM expression correlated with tumor node metastasis (TNM) staging and lymph node metastasis at both mRNA and protein levels. SBEM expression in PB of breast cancer patients was markedly higher than that of healthy donors and other cancer patients. SBEM was found expressed in PB of 50 cases among 94 cases at stage I-III and expressed in PB of 11 cases among 15 cases at stage IV. After 3 cycles' neoadjuvant chemotherapy, SBEM expression levels were significantly down-regulated in up to 58% breast cancer patients. SBEM has the potential to be a specific marker for predicting hematogenous micrometastasis and response to neoadjuvant chemotherapy in breast cancer.

Derlin-1 and stanniocalcin-1 are differentially regulated in metastasizing canine mammary adenocarcinomas

Derlin-1, stanniocalcin-1, epithelial glycoprotein-2 (EGP-2) and maspin are associated with the metastasis of human breast cancer cells. This study reports the potential role of these molecules in metastasis of canine mammary tumours. Laser microdissected tissue samples were prepared from normal canine mammary gland and from simple adenomas, adenocarcinomas and their lymph node metastases. The expression of genes encoding the molecules of interest in these tissues was determined by real-time quantitative reverse transcriptase polymerase chain reaction (RT-PCR). Most adenomas displayed reduced expression of derlin-1 mRNA. Few adenocarcinomas overexpressed derlin-1 mRNA, but all lymph node metastases overexpressed this gene product. Stanniocalcin-1 mRNA was not expressed within adenomas and was reduced in adenocarcinomas and their lymph node metastases. EGP-2 gene expression did not differ between normal, benign and malignant neoplastic tissues. Maspin gene expression varied markedly among the tumours with reduced or increased expression compared with normal mammary gland. Taken together, these results suggest that malignant behaviour of canine mammary adenocarcinoma is associated with reduced transcription of the stanniocalcin-1 gene and overexpression of the derlin-1 gene.

Flow cytometric analysis of CK19 expression in the peripheral blood of breast carcinoma patients: relevance for circulating tumor cell detection

Background

Immunocytochemistry and RT-PCR have been widely used for the detection of circulating tumor cells in patients with breast cancer but their specificity is limited. Our purpose is to utilize a convenient and specific technology to detect circulating tumor cells in breast cancer patients.

Methods

To determine the sensitivity and specificity of our method, A431 cells were serially diluted with human peripheral blood leukocytes and stained with CK19. A total of 73 blood specimens including 25 healthy volunteers and 48 patients with breast carcinoma and benign tumor were tested by flow cytometry to quantify the expression of CK19.

Results

The detectable upper limit of A431 cells was 1 cancer cell among 10⁴ human white blood cells. CK19 was detected in 27% of breast cancer patients but none control gives positive result. The number of cancer cells increased gradually along with the disease stages for it was the least in stage I (0%) and the most in stage IV (1.29%). Fifteen patients were observed during three month chemotherapy after surgery, and most of their CK19 expression levels declined after treatment.

Conclusion

Our research convinces that the detection of CK19 in peripheral blood by flow cytometry is also a specific and feasible method to monitor circulating tumor cells in breast cancer.

Intramammary lymph node metastasis predicts poorer survival in breast cancer patients

Involvement of an intramammary lymph node with metastatic breast cancer is an uncommon clinical or radiological presentation. Previously reported series of patients are small in number and the clinical advice is unclear. We identified 100 patients on our pathology database with intramammary lymph nodes in association with a primary breast cancer. Ten were identified pre-operatively on breast imaging and 90 were first discovered on pathological assessment of excised breast tissue. Twenty one contained metastasis. Factors that predicted for intramammary node metastasis were increasing age (p=0.017), lymphovascular invasion (p=0.002) and grade of tumour (p=0.012). The presence of metastasis within the intramammary lymph node was associated with a poorer disease free survival (p=0.007) and reduced overall survival (p=0.035). Sixty seven percent of patients with intramammary node metastasis had further axillary metastases. One patient had an intramammary node metastasis but uninvolved axillary sentinel node. She presented 19 months later with an axillary nodal recurrence. The presence of intramammary lymph node metastasis is associated with poorer outcome in breast cancer patients. Pre-operative detection of intramammary lymph node metastasis is helpful to guide breast and axillary surgeries. Intramammary lymph node metastasis predicts strongly for axillary metastatic disease and axillary node clearance is recommended.

Molecular characterization of circulating tumor cells in large quantities of contaminating leukocytes by a multiplex real-time PCR

Detection of circulating tumor cells (CTCs) in whole blood from metastatic cancer patients by the CellSearch CTC Test (Veridex LLC, Warren, NJ, USA) has been shown to have clinical relevance. In addition to enumeration, there is great interest in molecular characterization of these CTCs. We aimed to establish a robust method to perform mRNA expression analysis of multiple genes by a real-time reverse transcriptase (RT)-PCR on small numbers of CTCs enriched from whole blood by the CellSearch system. Despite the 4 log depletion of leukocytes after CellSearch enrichment, the CTC-enriched fractions still contained leukocytes, in particular B-lymphocytes, which severely interfered with our CTC-specific gene expression profiling. After extensive washing and leukocyte-specific depletion by anti-CD45 coated magnetic beads prior to CellSearch enrichment, the number of leukocytes present in the enriched fraction was still high (range 60-929). However, by using a set of genes with no or minor expression by leukocytes, we succeeded to perform quantitative gene expression profiling specific for as little as one breast cancer CTC present in a CTC-enriched environment typically containing over 800 contaminating leukocytes. Our method allows molecular characterization specific for as little as one CTC, and can be used to expand the understanding of the biology of metastasis and, potentially, to improve patient management.

The detection of circulating tumor cells of breast cancer patients by using multimarker (Survivin, hTERT and hMAM) quantitative real-time PCR

OBJECTIVES

To develop a specific, reliable assay for detecting circulating tumor cells (CTC) in peripheral blood of breast cancer patients.

DESIGN AND METHODS

94 breast cancer patients, 35 patients with benign breast tumor, 40 healthy individuals, and 25 patients with other solid tumors were evaluated by quantitative real-time reverse transcription-PCR (qRT-PCR) for detecting Survivin, hTERT, and hMAM mRNA in peripheral blood (PB) of breast cancer patients. In addition, analyses were carried out for their correlation with patients' clinicopathologic features.

RESULTS

The sensitivity of Survivin, hTERT, and hMAM mRNA in the PB of breast cancer patients was 36.2%, 59.6% and 33.0%, respectively. Survivin and hTERT were detected in the PB patients with solid tumors other than breast cancer, but hMAM mRNA was only detected in breast cancer patients. The sensitivity of three combined markers in the parallel test was 70.2%.Compared to that of single marker detection, the three combined markers' percentage was significantly higher. However, the specificity of three combined markers of serial test was 100%. The expression of the three mRNAs significantly correlated with TNM stage, and lymph node metastasis.

CONCLUSIONS

Survivin, hTERT and hMAM mRNA assays are powerful methods for detection of CTC of breast cancer patients. With combination of the three markers for detection of CTC of breast cancer, the parallel test increases the sensitivity. This analysis can offer a simple, noninvasive, and promising adjuvant tool for the early detection of micrometastatic tumor cells in breast cancer patients.

Spectral discrimination of live prostate and bladder cancer cell lines using Raman optical tweezers

An investigation into the use of Raman optical tweezers to study urological cell lines is reported, with the ultimate aim of determining the presence of malignant CaP cells in urine and peripheral fluids. To this end, we trapped and analyzed live CaP cells (PC-3) and bladder cells (MGH-U1), because both prostate and bladder cells are likely to be present in urine. The laser excitation wavelength of 514.5 nm was used, with Raman light collected both in back- and forward-scattering geometric configurations. For the backscattering configuration the same laser was used for trapping and excitation, while for forward scattering a 1064 nm laser provided the trapping beam. Analysis of cell-diameter distributions for cells analyzed suggested normal distribution of cell sizes, indicating an unbiased cell-selection criterion. Principal components analysis afforded discrimination of MGH-U1 and PC-3 spectra collected in either configuration, demonstrating that it is possible to trap, analyze, and differentiate PC-3 from MGH-U1 cells using a 514.5 nm laser. By loading plot analysis, possible biomolecules responsible for discrimination in both configurations were determined. Finally, the effect of cell size on discrimination was investigated, with results indicating that separation is based predominantly on cell type rather than cell size.

Clinical significance of detecting survivin-expressing circulating cancer cells in patients with non-small cell lung cancer

We previously demonstrated that the detection of circulating cancer cells (CCC) expressing survivin mRNA could provide valuable information for predicting metastasis and recurrence in breast cancer. The objective of this study was to investigate the significance of detecting survivin-expressing CCC on the clinical outcomes of patients with non-small cell lung cancer (NSCLC). Peripheral blood samples collected from 143 NSCLC patients and 177 healthy volunteers were quantitatively evaluated using a technique developed in our laboratory that detected reverse transcription-polymerase chain reaction (RT-PCR) products based on a hybridisation-enzyme linked immunosorbant essay (ELISA), which we called RT-PCR ELISA. The presence of survivin-expressing CCC was detected in 63 cancer patients (44.1%) and was significantly associated with pathological T classification, nodal status, and disease stages (all P<0.001). During a follow-up period of 36 months, patients who had positive survivin expressions at the time of the initial assay test had a higher relapse rate and shorter survival time when compared to those who had negative survivin expressions (all P<0.001). Through multivariate analysis, the detection of survivin-expressing CCC was found to be an independent predictor for cancer recurrence (HR=43.5; 95% CI=2.67-70.9; P=0.008) and survival (HR=1.35; 95% CI=1.02-4.31; P=0.049). Thus, detection of survivin-expressing CCC could be used in the prediction of disease recurrence as well as in the prognosis of NSCLC.

Detection and quantification of mammaglobin in the blood of breast cancer patients: can it be useful as a potential clinical marker? Preliminary results of a GOIM (Gruppo Oncologico dell'Italia Meridionale) prospective study

BACKGROUND

Mammaglobin is expressed mainly in mammary tissue, overexpressed in breast cancer (BC) and rarely in other tissue. The aim of this study was to assess the sensitivity and specificity of transcript MGB1 detection and to evaluate the role of MGB1 as potential clinical marker for the detection of disseminated cancer cells in the blood of BC patients.

PATIENTS AND METHODS

A consecutive series of 23 BC tissues, 36 peripheral blood BC samples and 35 healthy peripheral blood samples was prospectively recruited to investigate MGB1 expression by means of a quantitative Real Time RT-PCR assay.

RESULTS

MGB1 overexpression in tissue samples of BC patients is significantly associated only with high level of Ki67 (P <0.05). None of the samples from peripheral blood of 35 healthy female individuals were positive for MGB1 transcript. In contrast MGB1 mRNA expression was detected in three of 36 (8%) peripheral blood of BC patients.

CONCLUSIONS

Our preliminary results demonstrate that the detection of MGB1 transcript in peripheral blood of BC patients was specific but with low sensitivity. MGB1 overexpression by itself or in combination with Ki67 might be considered an index of BC progression.

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

Metastasis describes the process of migration of a frequently clinically occult circulating tumor cell (CTC) from the primary lesion to a new location and the subsequent formation of an overt growth. We and others have shown that the detection and quantitation of these cells has significant prognostic value, however there still remains no consensus as to the optimal methods to achieve this. The work described herein therefore considered various techniques, from storage and sample processing to data acquisition and analysis, to find an optimal combination of methods for an effective and practical platform for the detection of CTCs in peripheral blood. A dual-antigen epithelial cell enrichment procedure followed by a multi-marker QPCR analysis demonstrated the highest sensitivity and specificity, with the ability to detect as few as 10 tumor cells from a background of 10(6) peripheral blood mononuclear cells. Using these techniques in conjunction with a quadratic linear discriminant analysis (QDA) resulted in a platform able to generate this data and then combine it a single score for each patient, in which positivity reflected tumor cell presence, and negativity represented tumor cell absence. This assay was able to correctly determine tumor cell presence or absence in 100% of healthy controls and 84% of metastatic patients in a validation cohort of 39 individuals. This platform represents a highly sensitive and specific assay which could augment current routine assays for CTCs in the clinic.

Detection of circulating tumor cells in early-stage breast cancer metastasis to axillary lymph nodes

PURPOSE

Clinical and pathologic prognostic factors do not always accurately predict disease outcome. Patients with early-stage breast cancer may harbor clinically significant but undetected systemic disease. We hypothesized that a multimarker quantitative real-time reverse transcription-PCR (qRT) assay could detect circulating tumor cells (CTC) in patients with early-stage breast cancer and correlate with sentinel lymph node (SLN) and non-SLN metastasis status.

EXPERIMENTAL DESIGN

Blood samples from 90 women with the American Joint Committee on Cancer stages I to III breast cancer and 39 age-matched normal healthy volunteers were assessed by qRT for mRNA expression of three markers: stanniocalcin-1 (STC-1), N-acetylgalactosaminyltransferase (GalNacT), and melanoma antigen gene family-A3 (MAGE-A3). CTC biomarker detection was correlated with overall axillary LN (ALN), SLN, and non-SLN histopathology status.

RESULTS

CTCs were detected in 39 of 90 (43%) patients, but not in normal volunteers. At least one CTC biomarker was detected in 10 of 35 (29%) stage I patients, 19 of 42 (45%) stage II patients, and 10 of 13 (77%) stage III patients. In multivariate analysis, only lymphovascular invasion and >or=2 CTC biomarkers detected significantly correlated with ALN metastasis [odds ratio (OR), 12.42; 95% confidence interval (95% CI), 3.52-43.77, P<0.0001; and OR, 3.88; 95% CI, 1.69-8.89, P=0.001, respectively]. The number of CTC biomarkers detected similarly correlated with SLN and non-SLN metastasis status (P=0.0004). At least one CTC biomarker was detected in 10 of 11 (91%) patients with non-SLN metastases.

CONCLUSION

The detection of CTCs offers a novel means to assess the presence of systemic disease spreading relative to SLN and ALN histopathology status.

CYP17 gene polymorphism and its association with high-risk north Indian breast cancer patients

A single T > C change at the 5' promoter region of the CYP17 gene is reported to be associated with increased risk of breast cancer. This study evaluates the influence of genetic polymorphism of CYP17 on breast cancer susceptibility. Two hundred and forty-two patients with histopathologically confirmed breast cancer and 212 age-matched controls were included in the present study. Information relating to age at onset of the disease, family history and estrogen receptor status was elicited. Investigation for CYP17 polymorphism was carried out in 106 early onset, 80 late onset and 56 familial cases. The frequencies of two CYP17 alleles were also analyzed in 116 (47.9%) cases with known estrogen receptor (ER) status confirmed immunohistochemically. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used to detect the polymorphism, and the genotypes identified were assigned as homozygous wild type (A1A1), heterozygous variant (A1A2), and homozygous variant (A2A2). Associations between the various genotypes in patients and controls were investigated with Fisher's exact test. All the tests were two tailed. The results showed that the frequency of heterozygous and homozygous CYP17 genotype was higher in early onset breast cancer patients (94.3%) than in controls (80.3%), and the difference was significant (P = 0.001). A highly statistically significant increased risk in carriers of homozygous A2 allele was found in young patients (P < or = 0.001) in comparison with patients having late onset condition (P = 0.260). However, no significant association between the genotype and breast cancer risk was observed among women with strong family history. Further, data had showed that patients (80.6%) with at least one A2 allele tended to exhibit ER-independent cell proliferation, although statistical significance could not be established (P = 0.160). The present findings suggest that CYP17 A2 allele gene polymorphism might play a significant role in breast cancer development in young Indian women.

Detection of Survivin-expressing circulating cancer cells in the peripheral blood of breast cancer patients by a RT-PCR ELISA

Survivin mRNA expression was detected in 69.2%-93.8% of primary breast carcinomas, but is rarely expressed in normal breast tissues and hematopoietic cells. The objective of this study was to investigate the significance that the detection of Survinin-expressing circulating breast cancer cells in the peripheral blood has on clinical outcomes. The detection method was based on a RT-PCR ELISA technique developed in our laboratory. Sixty-seven breast cancer patients in various stages and 135 normal healthy women were investigated. Survivin-expressing circulating cancer cells were detected in the peripheral blood samples from 34 (50.7%) out of 67 breast cancer patients, but not in the healthy women that were used as controls. The presence of Survivin-expressing circulating breast cancer cells was found to be significantly associated with various clinicopathological parameters such as vessel infiltration, histological grade, tumor size, nodal status, ER/PgR status, Her-2 status and clinical stages of the disease (P < 0.01). During a follow-up period of 36 months, 9 out of 11 (81.8%) breast cancer patients that had a positive Survivin-expressing at the time of the initial assay test suffered a relapse of the disease, whereas recurrence was only found in 2 out of 6 (33.3%) breast cancer patients that had a negative Survivin-expression. Thus, the detection of circulating cancer cells expressing Survivin mRNA could provide valuable information for the prediction of metastasis and recurrence of breast cancer.

Microarray-based identification and RT-PCR test screening for epithelial-specific mRNAs in peripheral blood of patients with colon cancer

BACKGROUND

The efficacy of screening for colorectal cancer using a simple blood-based assay for the detection of tumor cells disseminated in the circulation at an early stage of the disease is gaining positive feedback from several lines of research. This method seems able to reduce colorectal cancer mortality and may replace colonoscopy as the most effective means of detecting colonic lesions.

METHODS

In this work, we present a new microarray-based high-throughput screening method to identifying candidate marker mRNAs for the early detection of epithelial cells diluted in peripheral blood cells. This method includes 1. direct comparison of different samples of colonic mucosa and of blood cells to identify consistent epithelial-specific mRNAs from among 20,000 cDNA assayed by microarray slides; 2. identification of candidate marker mRNAs by data analysis, which allowed selection of only 10 putative differentially expressed genes; 3. Selection of some of the most suitable mRNAs (TMEM69, RANBP3 and PRSS22) that were assayed in blood samples from normal subjects and patients with colon cancer as possible markers for the presence of epithelial cells in the blood, using reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Our present results seem to provide an indication, for the first time obtained by genome-scale screening, that a suitable and consistent colon epithelium mRNA marker may be difficult to identify.

CONCLUSION

The design of new approaches to identify such markers is warranted.

Photoacoustic detection of metastatic melanoma cells in the human circulatory system

Detection of disseminating tumor cells among patients suffering from various types and stages of cancer can function as an early warning system, alerting the physician of the metastatic spread or recurrence of the disease. Early detection of such cells can result in preventative treatment of the disease, while late stage detection can serve as an indicator of the effectiveness of chemotherapeutics. The prognostic value of exposing disseminating tumor cells poses an urgent need for an efficient, accurate screening method for metastatic cells. We propose a system for the detection of metastatic circulating tumor cells based on the thermoelastic properties of melanoma. The method employs photoacoustic excitation coupled with a detection system capable of determining the presence of disseminating cells within the circulatory system in vitro. Detection trials consisting of tissue phantoms and a human melanoma cell line resulted in a detection threshold of the order of ten individual cells, thus validating the effectiveness of the proposed mechanism. Results imply the potential to assay simple blood draws, from healthy and metastatic patients, for the presence of cancerous melanoma providing an unprecedented method for routine cancer screening.

Specific detection of cytokeratin 20-positive cells in blood of colorectal and breast cancer patients by a high sensitivity real-time reverse transcriptase-polymerase chain reaction method

A real-time reverse transcriptase-polymerase chain reaction (RT-PCR) method for detection of cytokeratin 20-positive cells in blood characterized by two novel features was developed and tested on 99 patients with colorectal cancer, 110 with breast cancer, and 150 healthy subjects. To optimize the specificity and sensitivity of the method, two novel features were used. First, a primer overlapping two adjacent exons was generated to inhibit nonspecific amplification both in healthy donors and cancer patients; second, a non-end-point first-round amplification was used to increase sensitivity. The number of first-round cycles was chosen to reach the highest level of sensitivity while conserving quantitative characteristics. PCR efficiency increased from 88.9% in single-round RT-PCR to 99.0% in nested real-time RT-PCR. To establish sensitivity and specificity of the method, HT29 cells were serially diluted with normal blood. Detection limit improved from 100 HT29 cells (single-round RT-PCR) to 1 to 10 cells (nested real-time RT-PCR) per 3 ml of whole blood. None of the healthy subjects was positive, whereas 22 and 29% of all colorectal and breast cancer patients, respectively, had cytokeratin 20 cell equivalents in blood. The association between cytokeratin 20 cell equivalents and metastasis was statistically significant for breast (P = 0.026) but not colorectal cancer patients (P = 0.361). Negativity of all 150 healthy controls examined confers diagnostic potential to the method.

Breast cancer biomarkers

Substantial progress has been made over the past three decades in our understanding of the epidemiology, clinical course and basic biology of breast cancer. This chapter considers the existing ancillary tests and emerging molecular markers in breast cancer prognosis assessment and the prediction of response of breast cancer to treatment of the disease.

A combinatorial approach to the selective capture of circulating malignant epithelial cells by peptide ligands

Early detection is critical in the administration of definitive and curative therapy of cancer. However, current detection methods are ineffective at identifying the presence of circulating metastatic cancer cells in the blood because they typically sample only a relatively small volume of blood. One strategy for sampling larger blood volumes would be to capture circulating cells in vivo over an extended period of time. The development of such a method would be substantially facilitated by the identification of peptide ligands that bind selectively to metastatic cancer cells in the blood with high affinity. To identify such ligands a combinatorial peptide library was synthesized on polyethylene acrylamide (PEGA) resin and screened for binding to malignant epithelial cells. Using Biacore, cell binding assays were performed to demonstrate that peptides selected from PEGA bead screen can bind selectively to malignant epithelial cancer cells and not to circulating leukocytes under physiologic shear stress conditions. One peptide, with the sequence QMARIPKRLARH, was used to demonstrate selective labeling of malignant epithelial cells spiked in whole blood. When immobilized on appropriate surfaces, these peptides could be used in both in vivo and ex vivo cell separation devices to efficiently and selectively capture metastatic epithelial cancer cells from flowing blood.