Direct Comparison of Metastasis-Related miRNAs Expression Levels in Circulating Tumor Cells, Corresponding Plasma, and Primary Tumors of Breast Cancer Patients.

BACKGROUND: Circulating tumor cells (CTCs) and microRNAs (miRNAs) are important in liquid biopsies in which peripheral blood is used to characterize the evolution of solid tumors. We evaluated the expression levels of miR-21, miR-146a, miR-200c, and miR-210 in CTCs of breast cancer patients with verified metastasis and compared their expression levels in corresponding plasma and primary tumors. METHODS: Expression levels of the miRNAs were quantified by quantitative reverse transcription PCR (RT-qPCR) in (a) 89 primary breast tumors and 30 noncancerous breast tissues and (b) CTCs and corresponding plasma of 55 patients with metastatic breast cancer and 20 healthy donors. For 30 of these patients, CTCs, corresponding plasma, and primary tumor tissues were available. RESULTS: In formalin-fixed, paraffin-embedded tissues, these miRNAs were differentially expressed between primary breast tumors and noncancerous breast tissues. miR-21 (P < 0.001) and miR-146a (P = 0.001) were overexpressed, whereas miR-200c (P = 0.004) and miR-210 (P = 0.002) were underexpressed. In multivariate analysis, miR-146a overexpression was significantly [hazard ratio 2.969 (1.231-7.157), P = 0.015] associated with progression-free survival. In peripheral blood, all miRNAs studied were overexpressed in both CTC and corresponding plasma. There was a significant association between miR-21 expression levels in CTCs and plasma for 36 of 55 samples (P = 0.008). In plasma, ROC curve analysis revealed that miR-21, miR-146a, and miR-210 could discriminate patients from healthy individuals. CONCLUSIONS: Metastasis-related miRNAs are overexpressed in CTCs and corresponding plasma; miR-21 expression levels highly correlate in CTCs and plasma; and miR-21, miR-146a, and miR-210 are valuable plasma biomarkers for discriminating patients from healthy individuals.

SOX17 promoter methylation in circulating tumor cells and matched cell-free DNA isolated from plasma of patients with breast cancer.

INTRODUCTION: Detection of circulating tumor cells (CTCs) and cell-free DNA (cfDNA) in the peripheral blood of patients with solid tumors has been widely studied for the early detection of metastatic spread. We evaluated whether there was an association between the origin of cfDNA and CTCs. We investigated whether SRY (sex determining region Y)-box 17 (SOX17) promoter methylation in CTCs was associated with the methylation pattern of this gene in matched cfDNA isolated from plasma of patients with breast cancer. METHODS: We examined SOX17 methylation in 79 primary breast tumors, in 114 paired samples of DNA isolated from CTCs and cfDNA, and in 60 healthy individuals. Isolated DNA was modified by sodium bisulfite and subjected to methylation specific PCR. RESULTS: The SOX17 promoter was methylated in 68 (86.0%) of 79 of primary breast tumors. In CTCs, SOX17 was methylated in 19 (34.5%) of 55 patients with early breast cancer, 27 (45.8%) of 59 patients with metastatic cancer, and 1 (4.3%) of 23 healthy individuals, whereas in matched cfDNA SOX17 was methylated in 19 (34.5%) of 55, 24 (40.7%) of 59, and 1 (2.0%) of 49 of these same groups, respectively. There was a significant correlation between SOX17 methylation in cfDNA and CTCs in patients with early breast cancer (P = 0.008), but not in patients with verified metastasis (P = 0.283). CONCLUSIONS: The SOX17 promoter is highly methylated in primary breast tumors, in CTCs isolated from patients with breast cancer, and in corresponding cfDNA samples. Our findings indicate a direct connection between the presence of CTCs and cfDNA in patients with operable breast cancer, after surgical removal of the primary tumor.

Molecular characterization of circulating tumor cells in breast cancer by a liquid bead array hybridization assay.

BACKGROUND: Molecular characterization of circulating tumor cells (CTCs) is crucial to identify novel diagnostic and therapeutic targets for individualized therapies. We developed a multiplexed PCR-coupled liquid bead array to detect the expression of multiple genes in CTCs. METHODS: mRNA isolated from immunomagnetically enriched CTCs was subjected to multiplex PCR for KRT19 (keratin 19; also known as CK19), ERBB2 [v-erb-b2 erythroblastic leukemia viral oncogene homolog 2, neuro/glioblastoma derived oncogene homolog (avian); also known as HER2], SCGB2A2 (secretoglobin, family 2A, member 2; also known as MGB1, mammaglobin A), MAGEA3 (melanoma antigen family A, 3), TWIST-1 [twist homolog 1 (Drosophila)], and HMBS (hydroxymethylbilane synthase; also known as PBGD). Biotinylated amplicons were hybridized against fluorescent microspheres carrying gene-specific capture probes and incubated with streptavidin-phycoerythrin. We quantified the captured labeled amplicons and decoded the beads by Luminex flow cytometry. The assay was validated for limit of detection, specificity, and comparison with reverse-transcription quantitative PCR (RT-qPCR), and its clinical performance was evaluated in 64 patients with operable breast cancer, 20 patients with metastasis, and 17 healthy individuals. RESULTS: The assay was specific for each gene in complex multiplexed formats and could detect the expression of each gene at the level of a single SK-BR-3 cell. The assay produced results comparable to those for RT-qPCR for each gene. None of the genes tested was detected in the CTC fraction of healthy donors. We detected KRT19, ERBB2, MAGEA3, SCGB2A2, and TWIST1 in 26.6%, 12.5%, 18.7%, 10.9%, and 31.2% of operable breast cancer patients, respectively, and detected the corresponding genes in 65%, 20%, 30%, 20%, and 20% of patients with verified metastasis, respectively. CONCLUSIONS: The expression of 6 genes in CTCs can be measured simultaneously and reliably, thereby saving precious sample and reducing the costs and time of analysis.

DNA methylation of tumor suppressor and metastasis suppressor genes in circulating tumor cells.

BACKGROUND: Circulating tumor cells (CTCs) are associated with prognosis in a variety of human cancers and have been proposed as a liquid biopsy for follow-up examinations. We show that tumor suppressor and metastasis suppressor genes are epigenetically silenced in CTCs isolated from peripheral blood of breast cancer patients. METHODS: We obtained peripheral blood from 56 patients with operable breast cancer, 27 patients with verified metastasis, and 23 healthy individuals. We tested DNA extracted from the EpCAM-positive immunomagnetically selected CTC fraction for the presence of methylated and unmethylated CST6, BRMS1, and SOX17 promoter sequences by methylation-specific PCR (MSP). All samples were checked for KRT19 (keratin 19, formerly CK-19) expression by reverse-transcription quantitative PCR. RESULTS: In CTCs of patients with operable breast cancer, promoter methylation of CST6 was observed in 17.9%, BRMS1 in 32.1%, and SOX17 in 53.6% of patients. In CTCs of patients with verified metastasis, promoter methylation of CST6 was observed in 37.0%, BRMS1 in 44.4%, and SOX17 in 74.1%. In healthy individuals, promoter methylation of CST6 was observed in 4.3%, BRMS1 in 8.7%, and SOX17 in 4.3%. DNA methylation of these genes for both operable and metastatic breast cancer was significantly different from that of the control population. CONCLUSIONS: DNA methylation of tumor suppressor and metastasis suppressor genes is a hallmark of CTCs and confirms their heterogeneity. Our findings add a new dimension to the molecular characterization of CTCs and may underlie the acquisition of malignant properties, including their stem-like phenotype.

Personal growth and psychological distress in advanced breast cancer.

AIMS: The experience of posttraumatic growth following breast cancer, its association with psychological distress and the predictive value of psychological distress, sociodemographic and clinical characteristics of cancer patients in their personal growth. METHODS: The Posttraumatic Growth Inventory and the Greek version of the Hospital Depression and Anxiety Scale (G-HADS) were administered to 100 breast cancer patients. Sociodemographic and clinical characteristics were recorded. RESULTS: The analysis showed that significant associations were found between PTGI-Total patients' age (p=0.001), and being married (p=0.007). Moreover, significant negative association was observed between PTGI-II ("New Possibilities") and HADS-Depression (r=-0.314, p<0.05). Multiple regression analyses showed that age is a significant predictor of PTGI-II ("New Possibilities") (p=0.005), PTGI-V ("Appreciation of Life") (p=0.0005) and PTGI-Total (p=0.037), while marital status is a significant predictor of PTGI-Total (p=0.009). CONCLUSION: Specific patients' characteristics, such as young age and being with a partner, influence the experience of posttraumatic growth in breast cancer patients.

Direct comparison study of DNA methylation markers in EpCAM-positive circulating tumour cells, corresponding circulating tumour DNA, and paired primary tumours in breast cancer.

Circulating Tumour Cells (CTCs) and circulating tumour DNA (ctDNA) represent a non-invasive liquid biopsy approach for the follow-up and therapy management of cancer patients. We evaluated whether DNA methylation status in CTCs and ctDNA is comparable and whether it reflects the status of primary tumours. We compared the methylation status of three genes, SOX17, CST6 and BRMS1 in primary tumours, corresponding CTCs and ctDNA in 153 breast cancer patients and healthy individuals, by using real time methylation specific PCR. We report a clear association between the EpCAM-positive CTC-fraction and ctDNA for SOX17 promoter methylation both for patients with early (P = 0.001) and metastatic breast cancer (P = 0.046) but not for CST6 and BRMS1. In early breast cancer, SOX17 promoter methylation in the EpCAM-positive CTC-fraction was associated with CK-19 mRNA expression (P = 0.006) and worse overall survival (OS) (P = 0.044). In the metastatic setting SOX17 promoter methylation in ctDNA was highly correlated with CK-19 (P = 0.04) and worse OS (Ρ = 0.016). SOX17 methylation status in CTCs and ctDNA was comparable and was associated with CK-19 expression but was not reflecting the status of primary tumours in breast cancer. DNA methylation analysis of SOX17 in CTCs and matched ctDNA provides significant prognostic value.

Detection of Mammaglobin A-mRNA-positive circulating tumor cells in peripheral blood of patients with operable breast cancer with nested RT-PCR.

OBJECTIVES: The development and validation of a nested RT-PCR methodology for the detection of Mammaglobin A-mRNA-positive circulating tumor cells in peripheral blood of patients with operable breast cancer and evaluation of its prognostic significance. DESIGN AND METHODS: Different combinations of specific primers were in silico designed and selected, so that false positive results due to genomic DNA contamination were avoided. The specificity of the primers used was evaluated in 30 healthy individuals, 20 patients with colorectal cancer and 20 patients with non-small cell lung cancer. The method was applied in 101 patients with operable breast cancer before the administration of adjuvant chemotherapy and 39 patients with metastatic breast cancer. RESULTS: Mammaglobin A-mRNA-positive cells were detected in 14/101 (13.9%) of early breast cancer patients but not in the control population studied (0%); 9 of them (64.3%) relapsed during the follow-up period. Mammaglobin A was detected in 7/39 (17.9%) of patients with verified metastasis. Multivariate analysis revealed the detection of Mammaglobin A-mRNA-positive cells, as an independent risk factor for reduced DFI. CONCLUSIONS: Mammaglobin A is a highly specific molecular marker for the detection of circulating tumor cells in operable breast cancer, with important prognostic applications.

Phase II trial of biweekly administration of vinorelbine and gemcitabine in pretreated advanced breast cancer.

PURPOSE: To determine the efficacy of gemcitabine (GEM) plus vinorelbine (VRL) administered biweekly in pretreated patients with advanced breast cancer. PATIENTS AND METHODS: Advanced breast cancer patients without response, with stable disease, or with recurrence within 6 months of prior treatment were given GEM 1,000 mg/m(2) and VRL 25 mg/m(2), once every 2 weeks for at least six cycles. RESULTS: Of the 51 patients enrolled, 50 (median, age 58 years; range, 34 to 76 years) were assessable. All patients had prior chemotherapy with an anthracycline-related regimen that included taxanes in 50% of the cases. Four patients (8%) had a complete response (CR) and 23 (46%) had a partial response (PR), for an overall response rate of 54%; 16 (32%) had stable disease and 7 (14%) experienced disease progression. Response occurred mainly in patients with soft tissue (83.3%) and lung metastasis (66.7%). Response duration was 4 to 8+, 4 to 9+, and 4 to 9 months for those with CR, PR, and stable disease, respectively. The regimen was well tolerated, with grade 1 to 2 myelotoxicity and asthenia reported. No patient required a dose reduction. Gastrointestinal side effects were negligible. Patients received 99.7% (range, 93.0% to 100.0%) of the planned dose-intensity of each drug. CONCLUSION: GEM in combination with VRL is an active regimen for advanced breast cancer patients, and biweekly administration significantly reduces myelotoxicity.

Real-time quantification of CK-19 mRNA-positive cells in peripheral blood of breast cancer patients using the lightcycler system.

PURPOSE: The purpose of this research was to develop a quantitative real-time reverse transcription-PCR (RT-PCR) for CK19-mRNA and evaluate its clinical potential for the molecular detection of occult carcinoma cells in the peripheral blood of breast cancer patients. EXPERIMENTAL DESIGN: The method is based on real-time monitoring during PCR of fluorescently labeled specific hybridization probes for CK19-mRNA. The breast cancer cell line MCF-7 was used for the development and analytical evaluation of the assay. We analyzed blood samples from 89 healthy blood donors, 77 patients with early breast cancer (stage I-II) postoperatively, and 47 patients with previously untreated metastatic disease (stage IV) before and after chemotherapy. All of the samples were also analyzed by nested RT-PCR. RESULTS: The method is highly sensitive and specific, because only 2 of 89 (2.2%) of the healthy control subjects had detectable CK19-mRNA+ cells. In 77 patients with early breast cancer, CK19-mRNA+ cells were detected in 24 (31.2%) before and 5 (6.5%) after adjuvant chemotherapy, and their levels differed significantly (P < 0.001, Wilcoxon test). In 47 patients with verified metastases 19 (40.4%) and 20 (42.6%) were found positive before and after chemotherapy, and no significant difference in CK19-mRNA+ cell levels was observed (P = 0.96, Wilcoxon test). Results obtained by the proposed real-time RT-PCR method correlated well with those obtained for the same samples by nested RT-PCR [concordance in 312 of 337 (92.6%); P = 0.69, McNemar test]. CONCLUSIONS: The developed method is highly sensitive and specific, and can be used for high-throughput continuous monitoring and quantification of circulating epithelial cells in the peripheral blood of breast cancer patients.

A rapid and accurate closed-tube Methylation-Sensitive High Resolution Melting Analysis assay for the semi-quantitative determination of SOX17 promoter methylation in clinical samples.

INTRODUCTION: SOX17 promoter methylation can provide important prognostic information in cancer. We developed a novel semi-quantitative MS-HRMA assay for SOX17 promoter methylation. METHODS: The assay was optimized by using synthetic control samples and validated by analyzing 165 clinical samples: a) 107 formalin fixed paraffin embedded (FFPEs) samples of patients with early breast cancer, b) 27 FFPE samples of patients with metastatic breast cancer, c) 15 reduction mammoplasty specimens obtained from healthy women and d) 16 genomic DNA samples isolated from healthy blood donors. Comparison with real time MSP was also performed. RESULTS: The assay is highly specific and sensitive and provides a semi-quantitative estimation of SOX17 promoter methylation. SOX17 promoter was found methylated in 96/134 (71.6%) breast cancer samples, while none of the 31 non-cancerous samples tested was positive (0%). SOX17 promoter methylation levels varied significantly among samples. When 165 clinical samples were analyzed both by MS-HRMA and real time MSP results were significantly comparable (concordance: 146/165, 88.5%). CONCLUSIONS: This novel MS-HRMA assay for SOX17 promoter methylation is closed-tube, highly sensitive, specific, cost-effective, rapid and easy-to-perform. It gives comparable results to Real-Time MSP in less time, while it offers the advantage of additionally providing an estimation of SOX17 promoter methylation levels.

Weekly administration of topotecan and paclitaxel in pretreated advanced cancer patients: a phase I/II study.

PURPOSE: This study was a phase I/II, cohort, dose-escalation trial of topotecan and paclitaxel. Its aim was to determine the dose-limiting toxicity (DLT) of the combination and to define the maximum tolerated dose (MTD), as a recommended dose for phase II, as well as to get preliminary data on the efficacy (activity) of the drug in pretreated patients with ovarian cancer, small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC). METHODS: Included in the study were 52 pretreated patients, 19 with ovarian cancer, 20 with SCLC and 13 with NSCLC. The doses of topotecan were escalated from 1.25 to 2 mg/m2 and of paclitaxel from 60 to 80 mg/m2. A minimum of four patients were included at each of the six levels of dose escalation. RESULTS: We found that DLT due to grade 3 and 4 myelotoxicity was at levels 5 and 6 at doses of 1.75 and 80 mg/m2 (level 5) and 2 and 80 mg/m2 (level 6) for topotecan and paclitaxel, respectively. The MTD and recommended accepted doses are 1.75 mg/m2 for topotecan and 70 mg/m2 for paclitaxel. Of the 52 patients, 17 (33%) showed a response: 1 complete response (1.92%) and 16 partial responses (30.77%). CONCLUSIONS: Topotecan combined with paclitaxel administered once weekly for three consecutive weeks repeated for every 28 days resulted in well-tolerated toxicity at doses of 1.75 and 70 mg/m2, respectively, and a response rate of 33% in pretreated cancer patients.

Development of a highly sensitive RT-PCR luminometric hybridization assay for human telomerase reverse-transcriptase beta-plus transcript.

BACKGROUND: Telomerase is a general diagnostic and prognostic molecular tumor marker since it is expressed in the majority of human tumors in contrast to most healthy tissues. Alternate splicing of human telomerase reverse transcriptase (hTERT) has been shown to affect telomerase activity. PATIENTS AND METHODS: We have developed a hybridization assay that selectively detects the hTERT beta-plus transcript. Biotinylated PCR products were captured on streptavidin-coated microtiter wells, hybridized with digoxigenin-labeled probes and detected by a highly sensitive luminometric reaction. RESULTS: The method was applied in ten colorectal tumor forceps biopsies and their corresponding normal tissues. Six out of ten tumors were positive for hTERT beta plus transcript whereas none of the corresponding normal tissues were found positive. There was a complete concordance between the hybridization assay and real-time PCR. When the method was applied in peripheral blood of 20 breast cancer patients with metastatic disease and 21 healthy blood donors, 14 patients (70%) were found positive while all 21 healthy blood donors were negative. CONCLUSION: The developed hybridization assay is highly sensitive and specific for the detection of hTERT beta-plus transcript in clinical samples.

PIK3CA mutational status in circulating tumor cells can change during disease recurrence or progression in patients with breast cancer.

PURPOSE: Molecular characterization of circulating tumor cells (CTC) is crucial for the investigation of molecular-targeted therapies while PIK3CA somatic mutations play a crucial role in therapy response. We investigated the presence of PIK3CA mutations in CTC and whether this is associated with clinical outcome. EXPERIMENTAL DESIGN: We developed and validated an ultrasensitive methodology for the detection of PIK3CA mutations that is based on a combination of allele-specific, asymmetric rapid PCR and melting analysis. We analyzed PIK3CA hotspot mutations in: (i) a training group consisting of EpCAM-positive CTC fraction from 37 patients with clinically confirmed metastasis, and 26 healthy female volunteers and 15 primary breast tumor tissues and (ii) an independent group consisting of EpCAM-positive CTC fraction from 57 metastatic and 118 operable breast cancer patients and 76 corresponding primary tumors. RESULTS: The assay could detect 0.05% of mutated dsDNA in the presence of 99.95% wtDNA for both exons (9 and 20) and was highly specific (0/26 healthy donors). PIK3CA mutations were identified in EpCAM-positive CTC in 20 of 57(35.1%) and in 23 of 118 (19.5%) patients with metastatic and operable breast cancer, and in 45 of 76(59.2%) corresponding FFPEs. Our data indicate that PIK3CA mutational status in CTCs can change during disease progression and is associated with worse survival (P = 0.047). CONCLUSIONS: PIK3CA hotspot mutations are present at a relatively high frequency in CTCs and their presence is associated with worse survival in patients with breast cancer with metastasis. Evaluation of PIK3CA mutational status in CTCs is a strategy with potential clinical application.

CST6 promoter methylation in circulating cell-free DNA of breast cancer patients.

OBJECTIVES: We have recently shown that detection of CST6 promoter methylation in primary breast tumors can provide important prognostic information in patients with operable breast cancer and that CST6 promoter is also methylated in Circulating Tumor Cells (CTC). In this study we evaluated the presence of CST6 promoter methylation in cell-free DNA (cfDNA) circulating in plasma of breast cancer patients. DESIGN AND METHODS: Our study material consisted of: a) a pilot testing group of 27 patients with stage I-III operable breast cancer, 46 patients with verified metastasis and 37 healthy donors and b) an independent cohort of 123 consecutive stage I-III operable breast cancer patients. Methylated and unmethylated CST6 promoter sequences were detected by using methylation-specific PCR (MSP). CST6 immunohistochemical detection was performed in 20 corresponding primary tumor tissues. RESULTS: In the pilot testing group, CST6 promoter was methylated in 8/27 (29.6%) operable breast cancer patients, in 6/46 (13.0%) patients with verified metastasis but none of 37 healthy individuals (0%). In the independent cohort, 49/123 (39.8%) operable breast cancer patients were found positive. During the follow up period, 25/123 (20.3%) patients relapsed and 9/123 (7.3%) died. CST6 was methylated in cfDNA of 13/25 (52%) patients that relapsed and in 3/9 (33.3%) patients that died. CONCLUSIONS: CST6 promoter is highly methylated in cfDNA of breast cancer patients, but not in healthy individuals. CST6 promoter methylation in cfDNA, should be prospectively validated as a novel plasma tumor biomarker for breast cancer in a large cohort of breast cancer patients.

A highly specific real-time RT-PCR method for the quantitative determination of CK-19 mRNA positive cells in peripheral blood of patients with operable breast cancer.

The aim of the present study was to decrease the incidence of false positives and to better characterize marginally cytokeratin-19 (CK-19) mRNA positive peripheral blood samples from patients with early stage breast cancer. A new set of highly specific primers for CK-19, which avoids amplification of contaminating genomic DNA, was designed and evaluated to improve the specificity and sensitivity of the previously described methodology. The primers were specifically designed to avoid amplification of contaminating genomic DNA and CK-19 pseudogenes. The breast cancer cell line MCF-7 was used as positive control for the development and analytical evaluation of the assay, while peripheral blood samples from 62 healthy female individuals and 160 patients with early breast cancer were used for the evaluation of the sensitivity and specificity of the new primer pair. The novel designed primer pair was highly sensitive, as it detects up to 1 MCF-7 cell, and specific as none of the healthy individuals had detectable CK-19 mRNA positive cells in their peripheral blood. CK-19 mRNA positive cells were detected in 33 out of 160 (20.6%) patients with early breast cancer. Results obtained by the proposed optimized real-time RT-PCR protocol correlated well with those obtained in the same samples by our previously reported quantitative real-time RT-PCR [concordance in 198/222 (89.2%), p = 0.0022, McNemar test]. The improved method eliminates the incidence of false positives and is highly sensitive and specific. The method could be used in a clinical setting in the near future for continuous monitoring and quantification of circulating epithelial cells in the peripheral blood of patients with operable breast cancer, provided that a quite larger number of clinical samples with a known follow-up will be analyzed.