Prognostic Role of Circulating Tumor Cell Trajectories in Metastatic Colorectal Cancer.

BACKGROUND: A large amount of evidence from clinical studies has demonstrated that circulating tumor cells are strong predictors of outcomes in many cancers. However, the clinical significance of CTC enumeration in metastatic colorectal cancer is still questioned. The aim of this study was to evaluate the clinical value of CTC dynamics in mCRC patients receiving first-line treatments. MATERIALS AND METHODS: Serial CTC data from 218 patients were used to identify CTC trajectory patterns during the course of treatment. CTCs were evaluated at baseline, at a first-time point check and at the radiological progression of the disease. CTC dynamics were correlated with clinical endpoints. RESULTS: Using a cut-off of ≥1 CTC/7.5 mL, four prognostic trajectories were outlined. The best prognosis was obtained for patients with no evidence of CTCs at any timepoints, with a significant difference compared to all other groups. Lower PFS and OS were recognized in group 4 (CTCs always positive) at 7 and 16 months, respectively. CONCLUSIONS: We confirmed the clinical value of CTC positivity, even with only one cell detected. CTC trajectories are better prognostic indicators than CTC enumeration at baseline. The reported prognostic groups might help to improve risk stratification, providing potential biomarkers to monitor first-line treatments.

A multidisciplinary approach for the differential diagnosis between multiple primary lung adenocarcinomas and intrapulmonary metastases.

PURPOSE: The distinction between multiple primary lung cancers (MPLCs) and intrapulmonary metastases has a significant impact on tumor staging and therapeutic choices. Several criteria have been proposed to solve this diagnostic issue, but a definitive consensus is still missing. We tested the efficacy of a combined clinical, histopathological and molecular ("real world") approach for the correct classification of multiple lung tumors in a selected cohort of patients. METHODS: 24 multiple lung tumors with a diagnosis of adenocarcinoma from 10 patients were retrospectively reviewed. Radiological, pathological and clinical information, including follow-up, were integrated with molecular profiling via a routine multigene panel sequencing. RESULTS: Comprehensive histologic assessment revealed readily distinguishable histologic patterns between multiple tumors suggesting unrelated lesions in 7 cases, in agreement with clinical, radiological and molecular data, thus leading to final diagnosis of MPLCs. In the remaining 3 cases, the differential diagnosis between MPLCs and intrapulmonary metastases was challenging, since the histologic features of the lesions were similar or identical. The final interpretation (2 MPLCs and 1 most likely intrapulmonary metastases) was reached thanks to the integration of all available data, and was confirmed by follow-up. CONCLUSIONS: A multidisciplinary approach including a routinely affordable multigene panel sequencing is a useful tool to discriminate MPLCs from intrapulmonary metastases in multiple lung nodules sharing the adenocarcinoma histotype.

Circulating Methylated DNA to Monitor the Dynamics of RAS Mutation Clearance in Plasma from Metastatic Colorectal Cancer Patients.

The clearance of RAS mutations in plasma circulating tumor DNA (ctDNA) from originally RAS-mutant metastatic colorectal cancer (mCRC) has been recently demonstrated. Clinical trials investigating whether RAS mutant mCRC who "convert" to wild-type in plasma might benefit from EGFR blockade are ongoing. Detection of tumor-specific DNA methylation alterations in ctDNA has been suggested as a specific tool to confirm the tumoral origin of cell-free DNA. We monitored RAS clearance in plasma from patients with RAS-mutant mCRC at baseline (pre-treatment) (T0); after 4 months of first-line therapy (T1); at the time of first (T2) and second (T3) progression. A five-gene methylation panel was used to confirm the presence of ctDNA in samples in which RAS mutation clearance was detected. At T1, ctDNA analysis revealed wild-type RAS status in 83% of samples, all not methylated, suggesting at this time point the lack of ctDNA shedding. At T2, ctDNA analysis revealed wild-type RAS status in 83% of samples, of which 62.5% were found methylated. At T3, 50% of wild-type RAS samples were found methylated. Non-methylated samples were found in patients with lung or brain metastases. This five-gene methylation test might be useful to confirm the presence of ctDNA in RAS wild-type plasma samples.

Baseline CD44v6-positive circulating tumor cells to predict first-line treatment failure in patients with metastatic colorectal cancer.

CD44v6, the CD44 isoform mostly involved in cancer cell migration and invasion, has been identified as a functional biomarker and therapeutic target in colon cancer stem cells. We here provide evidence that baseline CD44v6-positive CTC predict treatment failure in patients with metastatic colorectal cancer undergoing first-line chemotherapy. We suggest that CD44v6-positive CTC can be used to early detect intrinsic drug resistance in this cancer type.

Detection of circulating tumor cells in patients with laryngeal cancer using ScreenCell: Comparative pre- and post-operative analysis and association with prognosis.

The presence of circulating tumor cells (CTCs) in the blood of patients with metastatic breast, colorectal and prostate cancer have been widely investigated; however, few studies have examined CTCs in patients with laryngeal cancer. The present pilot study aimed to detect pre- and postoperative CTCs in the blood of patients with laryngeal cancer and evaluate the association with prognosis. Eight patients with laryngeal squamous cell carcinoma (LSCC) at stage III were included in the present study and underwent total or subtotal laryngectomy and radical bilateral neck lymph node dissection. Blood samples were collected from all patients before and after surgery at different time-points. The following processing steps were followed; preoperative blood sampling, surgery, postoperative blood sampling at 3, 6 and 12 month follow-ups, and prognostic association analysis. CTCs were retained on ScreenCell filters for cytological characterization. The presence of CTCs was associated with a less favorable prognosis, whereas a decrease of CTCs in the postoperative sampling was observed in patients who exhibited an improved therapeutic response. The results of the present pilot study revealed a possible association between the presence of CTCs and a less favorable prognosis in patients with LSCC; therefore, these preliminary findings may encourage further research into the incorporation of a liquid biopsy in the management of LSCC, as this may help identify patients with occult metastatic disease earlier and in a non-invasive manner. In addition, this approach may represent novel independent prognostic factor for use in the clinical evaluation of patients with LSCC.

Clinical Multigene Panel Sequencing Identifies Distinct Mutational Association Patterns in Metastatic Colorectal Cancer.

Extensive molecular characterization of human colorectal cancer (CRC) via Next Generation Sequencing (NGS) indicated that genetic or epigenetic dysregulation of a relevant, but limited, number of molecular pathways typically occurs in this tumor. The molecular picture of the disease is significantly complicated by the frequent occurrence of individually rare genetic aberrations, which expand tumor heterogeneity. Inter- and intratumor molecular heterogeneity is very likely responsible for the remarkable individual variability in the response to conventional and target-driven first-line therapies, in metastatic CRC (mCRC) patients, whose median overall survival remains unsatisfactory. Implementation of an extensive molecular characterization of mCRC in the clinical routine does not yet appear feasible on a large scale, while multigene panel sequencing of most commonly mutated oncogene/oncosuppressor hotspots is more easily achievable. Here, we report that clinical multigene panel sequencing performed for anti-EGFR therapy predictive purposes in 639 formalin-fixed paraffin-embedded (FFPE) mCRC specimens revealed previously unknown pairwise mutation associations and a high proportion of cases carrying actionable gene mutations. Most importantly, a simple principal component analysis directed the delineation of a new molecular stratification of mCRC patients in eight groups characterized by non-random, specific mutational association patterns (MAPs), aggregating samples with similar biology. These data were validated on a The Cancer Genome Atlas (TCGA) CRC dataset. The proposed stratification may provide great opportunities to direct more informed therapeutic decisions in the majority of mCRC cases.

Identification of novel BRCA1 large genomic rearrangements by a computational algorithm of amplicon-based Next-Generation Sequencing data.

BACKGROUND: Genetic testing for BRCA1/2 germline mutations in hereditary breast/ovarian cancer patients requires screening for single nucleotide variants, small insertions/deletions and large genomic rearrangements (LGRs). These studies have long been run by Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA). The recent introduction of next-generation sequencing (NGS) platforms dramatically improved the speed and the efficiency of DNA testing for nucleotide variants, while the possibility to correctly detect LGRs by this mean is still debated. The purpose of this study was to establish whether and to which extent the development of an analytical algorithm could help us translating NGS sequencing via an Ion Torrent PGM platform into a tool suitable to identify LGRs in hereditary breast-ovarian cancer patients. METHODS: We first used NGS data of a group of three patients (training set), previously screened in our laboratory by conventional methods, to develop an algorithm for the calculation of the dosage quotient (DQ) to be compared with the Ion Reporter (IR) analysis. Then, we tested the optimized pipeline with a consecutive cohort of 85 uncharacterized probands (validation set) also subjected to MLPA analysis. Characterization of the breakpoints of three novel BRCA1 LGRs was obtained via long-range PCR and direct sequencing of the DNA products. RESULTS: In our cohort, the newly defined DQ-based algorithm detected 3/3 BRCA1 LGRs, demonstrating 100% sensitivity and 100% negative predictive value (NPV) (95% CI [87.6-99.9]) compared to 2/3 cases detected by IR (66.7% sensitivity and 98.2% NPV (95% CI [85.6-99.9])). Interestingly, DQ and IR shared 12 positive results, but exons deletion calls matched only in five cases, two of which confirmed by MLPA. The breakpoints of the 3 novel BRCA1 deletions, involving exons 16-17, 21-22 and 20, have been characterized. CONCLUSIONS: Our study defined a DQ-based algorithm to identify BRCA1 LGRs using NGS data. Whether confirmed on larger data sets, this tool could guide the selection of samples to be subjected to MLPA analysis, leading to significant savings in time and money.

EpCAMlow Circulating Tumor Cells: Gold in the Waste.

The CellSearch® system which is still considered the gold standard for the enumeration of circulating tumor cells (CTC) utilizes antibodies against the epithelial cell adhesion molecule (EpCAM) for CTC enrichment. Recently, CTC discarded by the CellSearch® system due to their low EpCAM expression have been isolated and analyzed. We here sought to discuss technical and biological issues concerning the isolation and characterization of EpCAMlow CTC, highlighting the enormous potential of this subpopulation discarded by CellSearch®, which might instead reveal an unexpected clinical significance in tumor types where CTC enumeration has never been validated for prognostic and predictive purpose.

Circulating Tumor Cells in Right- and Left-Sided Colorectal Cancer.

Molecular alterations are not randomly distributed in colorectal cancer (CRC), but rather clustered on the basis of primary tumor location underlying the importance of colorectal cancer sidedness. We aimed to investigate whether circulating tumor cells (CTC) characterization might help clarify how different the patterns of dissemination might be relative to the behavior of left- (LCC) compared to right-sided (RCC) cancers. We retrospectively analyzed patients with metastatic CRC who had undergone standard baseline CTC evaluation before starting any first-line systemic treatment. Enumeration of CTC in left- and right-sided tumors were compared. The highest prognostic impact was exerted by CTC in left-sided primary cancer patients, even though the lowest median number of cells was detected in this subgroup of patients. CTC exhibit phenotypic heterogeneity, with a predominant mesenchymal phenotype found in CTC from distal compared to proximal primary tumors. Most CTC in RCC patients exhibited an apoptotic pattern. CTC in left-sided colon cancer patients exhibit a predominant mesenchymal phenotype. This might imply a substantial difference in the biology of proximal and distal cancers, associated with different patterns of tumor cells dissemination. The poor prognosis of right-sided CRC is not determined by the hematogenous dissemination of tumor cells, which appears to be predominantly a passive shedding of non-viable cells. Conversely, the subgroup of poor-prognosis left-sided CRC is reliably identified by the presence of mesenchymal CTC.

Circulating Tumor Cells Identify Patients with Super-High-Risk Non-Muscle-Invasive Bladder Cancer: Updated Outcome Analysis of a Prospective Single-Center Trial.

BACKGROUND: Clinical behavior of non-muscle-invasive bladder cancer (NMIBC) is largely unpredictable, and even patients treated according to European Association of Urology recommendations have a heterogeneous prognosis. High-grade T1 (HGT1) bladder cancer is the highest-risk subtype of NMIBC, with an almost 40% rate of recurrence and 20% of progression at 5 years. Nomograms predicting risk of recurrence, progression, and cancer-specific survival (CSS) are not available specifically within HGT1 bladder cancer, and the identification of robust prognostic biomarkers to better guide therapeutic strategies in this subgroup of patients is of paramount importance. Strategies to identify putative biomarkers in liquid biopsies from blood and urine collected from patients with bladder cancer have been intensively studied in the last few years. SUBJECTS, MATERIALS, AND METHODS: We here report the final analysis of a single-center prospective study aimed to investigate the impact of circulating tumor cells (CTCs) on CSS and overall survival (OS) in 102 patients with HGT1 bladder cancer, in a median follow-up of 63 months. RESULTS: We here demonstrate that the presence of even a single CTC is predictive of shorter CSS and OS, as compared with the standard predictive variables. Points of attention in this multivariable analysis are the long-term follow-up and the adequate number of outcome events. CONCLUSION: The accurate risk stratification provided by CTCs might be essential for determining the best surveillance strategy for patients after diagnosis. A closer follow-up, an early radical surgery, or even a systemic treatment might be recommended in patients with super-high-risk non-muscle-invasive bladder cancer. IMPLICATIONS FOR PRACTICE: Circulating tumor cells identify patients with super-high-risk non-muscle-invasive bladder cancer who require closer monitoring for local recurrence and/or progression of disease. This super-high-risk subgroup of patients might also require more aggressive treatment interventions, which should be evaluated in large prospective cohorts.

Transient Disappearance of RAS Mutant Clones in Plasma: A Counterintuitive Clinical Use of EGFR Inhibitors in RAS Mutant Metastatic Colorectal Cancer.

Genomic studies performed through liquid biopsies widely elucidated the evolutionary trajectory of RAS mutant clones under the selective pressure of EGFR inhibitors in patients with wild type RAS primary colorectal tumors. Similarly, the disappearance of RAS mutant clones in plasma has been more recently reported in some patients with primary RAS mutant cancers, supporting for the first time an unexpected negative selection of RAS mutations during the clonal evolution of mCRC. To date, the extent of conversion to RAS wild type disease at the time of progression has not been clarified yet. As a proof of concept, we prospectively enrolled mCRC patients progressing under anti-VEGF based treatments. Idylla™ system was used to screen RAS mutations in plasma and the wild type status of RAS was further confirmed through IT-PGM (Ion Torrent Personal Genome Machine) sequencing. RAS was found mutant in 55% of cases, retaining the same plasma mutation as in the primary tumor at diagnosis, while it was found wild-type in 45%. Four patients testing negative for RAS mutations in plasma at the time of progression of disease (PD) were considered eligible for treatment with EGFR inhibitors and treated accordingly, achieving a clinical benefit. We here propose a hypothetical algorithm that accounts for the transient disappearance of RAS mutant clones over time, which might extend the continuum of care of mutant RAS colorectal cancer patients through the delivery of a further line of therapy.

Molecular Characterization of Circulating Tumor Cells to Study Cancer Immunoevasion.

Cancer cells leaving the primary tumor immunosuppressive microenvironment become vulnerable to active immune surveillance and require mechanisms of immunoevasion to survive in the circulation. Studies have identified several pathways by which circulating tumor cells (CTCs) might escape the immune system/immunotherapy attack. The PD-1/PD-L1 axis is an immune checkpoint regulator, playing a major role in maintaining self-tolerance. It is now well recognized that tumor cells co-opt the PD-1/PD-L1 axis of immune regulation to interfere with cytotoxic T lymphocyte function. Transcriptional changes in CTCs, leading to the upregulation of PD-L1, might enable them to survive in circulation. Very recent data revealed a previously unappreciated role of epithelial-mesenchymal transition (EMT) in reprogramming the immune response in the local tumor microenvironment and a mutual regulation between EMT and immunoevasion is becoming apparent. In this chapter, we will describe in detail both EpCAM-dependent and -independent approaches that allow the identification of PD-L1 expression and EMT-like features in circulating tumor cells.

Coexistence of three EGFR mutations in an NSCLC patient: A brief report.

BACKGROUND: The epidermal growth factor receptor (EGFR) represents a molecular target for tyrosine kinase inhibitors for non-small cell lung cancer (NSCLC) patients with a mutation in the EGFR gene. Mutations of the EGFR gene that occur at a single position in NSCLC tissue are found as single, whereas two or more mutations on the same allele are poorly detected and investigated. PATIENT AND METHODS: We investigated the presence of the EGFR gene mutations in tumor tissue by Sanger sequencing and ion torrent sequencing in an NSCLC patient at Stage IV of disease. RESULTS: We found the presence of three coexisting mutations on the EGFR gene-two of which on exon 21 are present on the same allele, and the third, on exon 20, was analyzed by Sanger sequencing of the peripheral blood lymphocytes. The patient staged as cT4N0M1c (Stage IV) and started afatinib 40 mg daily 8 months ago, showing a clinical benefit. CONCLUSION: In this report we describe the case of an NSCLC patient harboring three coexisting mutations on the EGFR gene, two of which are present on the same allele. This mutation pattern may represent, for patient progeny, a genetic risk of cancer development. Therefore it should be possible to obtain screening guidelines to improve the risk calculation for lung cancer susceptibility in the future.

Liquid Biopsy in Rare Cancers: Lessons from Hemangiopericytoma.

Hemangiopericytoma (HPT) is a rare mesenchymal tumor of fibroblastic type and for its rarity is poorly studied. The most common sites of metastatic disease in patients with intracranial HPT are the bone, liver, and lung, suggestive for an hematogenous dissemination; for this reason, we investigated, for the first time, the presence of circulating tumor cells (CTCs) in hemangiopericytoma patient by CellSearch® and SceenCell® devices. Peripheral blood samples were drawn and processed by CellSearch, an EpCAM-dependent device, and ScreenCell®, a device size based. We found nontypical CTCs by CellSearch system and the immunofluorescence analysis performed on CTCs isolate by ScreenCell demonstrated the presence of single CTCs and CTC clusters. The molecular characterization of single CTCs and CTC clusters, using antibodies directed against EpCAM, CD34, cytokeratins (8, 18, and 19), and CD45, showed a great heterogeneity in CTC clusters. We believe that the present study may open a new scenario in the rare tumors: the introduction of the liquid biopsy and the molecular characterization of circulating tumor cells could lead to personalized targeted treatments and also for rare tumors.

PD-L1 and epithelial-mesenchymal transition in circulating tumor cells from non-small cell lung cancer patients: A molecular shield to evade immune system?

The programmed cell death 1 (PD-1)/PD-1 ligand 1 (PD-L1) pathway has emerged as a critical inhibitory pathway regulating T-cell response in non-small-cell lung cancer (NSCLC), and the development of PD-1/PD-L1 inhibitors has changed the landscape of NSCLC therapy. Nevertheless, the high degree of non-responders demonstrates that we are still far from completely understanding the events underlying tumor immune resistance. Although the expression of PD-L1 in tumor tissue has been correlated with clinical response to anti PD-1 inhibitors, the ability of this marker to discriminate the subgroup of patients who derive benefit from immunotherapy is suboptimal. Circulating tumor cells (CTCs), as an accessible source of tumor for biologic characterization that can be serially obtained with minimally invasive procedure, hold significant promise to facilitate treatment-specific biomarkers discovery. We recently demonstrated that the presence of PD-L1 on CTCs apparently predicts resistance to the anti-PD-1 Nivolumab in metastatic NSCLC patients and that PD-L1 positive CTCs usually have an elongated morphology that can be ascribed to epithelial-mesenchymal transition (EMT). We here demonstrate for the first time that PD-L1 positive CTCs isolated from NSCLC patients are characterized by partial EMT phenotype, and hypothesize that the co-expression of PD-L1 and EMT markers might represent for these cells a possible molecular background for immune escape.

EpCAM-expressing circulating tumor cells in colorectal cancer.

BACKGROUND: Several studies have raised the issue of the inadequacy of CellSearch® to detect the entire pool of circulating tumor cells (CTCs) from blood of cancer patients, suggesting that cells expressing low levels of epithelial cell adhesion molecule (EpCAM) are not recognized by the capture reagent. In this exploratory study, we aimed to evaluate the status of EpCAM in CTCs isolated from a group of metastatic colorectal cancer patients, in 40% of whom, CTC had been found to be undetected by the CellSearch® system. METHODS: CTCs were analyzed using both a microfiltration method (ScreenCell) and CellSearch® in parallel. Furthermore, since EpCAM exists in 2 different variants, we investigated the presence of both its intracellular domain (EpICD) and extracellular domain (EpEX) through immunofluorescence staining of CTCs on filters. RESULTS: Results from immunofluorescence experiments demonstrated that, overall, EpICD and/or EpEX was expressed in 176 CTCs detected by ScreenCell, while the CellSearch® system was able to capture only 10 CTCs. CONCLUSIONS: This is the first demonstration that the low sensitivity of CellSearch® to detect CTCs in colorectal cancer patients is not due to the lack of EpCAM.

Letter to the Editor: "Circulating Cell-Free DNA and Circulating Tumor Cells as Prognostic and Predictive Biomarkers in Advanced Non-Small Cell Lung Cancer Patients Treated with First-Line Chemotherapy".

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The long-term prognostic value of survivin expressing circulating tumor cells in patients with high-risk non-muscle invasive bladder cancer (NMIBC).

OBJECTIVES: Long-term follow-up study to evaluate the impact on disease-free survival and cancer-specific survival of survivin expression in tissue and CTCs from T1G3 bladder cancer patients. PATIENTS AND METHODS: The study was conducted using tumor tissue and blood samples from 54 patients with a primary diagnosis of T1G3 NMIBC. Survivin was evaluated by reverse transcription-polymerase chain reaction in tumor tissues. CTCs were isolated from blood by CELLection™ Dynabeads (Invitrogen, Carlsbad, CA, USA). Cells were lysed and cDNA was synthesized and analysed for the expression of CD45, CK8 and survivin. The endpoints of this long-termanalysis were disease-free survival, DFS and cancer-specific survival, CSS. RESULTS: Here, we report that, at 9 years of median follow-up, disease-free survival and cancer-specific survival are both significantly influenced by the expression of survivin in tumor tissue (p = 0.006), by the presence of CTCs (p < 0.0001) and by the expression of survivin in CTCs (p < 0.0001). CONCLUSION: The statistically significant impact of survivin expressing CTCs on cancer-specific survival that we observed might be interpreted as the result of the persistence of a subpopulation of highlander cells in the blood of T1G3 bladder patients over time.