Synergic activity of FGFR2 and MEK inhibitors in the treatment of FGFR2-amplified cancers of unknown primary.

Patients with cancer of unknown primary (CUP) carry the double burden of an aggressive disease and reduced access to therapies. Experimental models are pivotal for CUP biology investigation and drug testing. We derived two CUP cell lines (CUP#55 and #96) and corresponding patient-derived xenografts (PDXs), from ascites tumor cells. CUP cell lines and PDXs underwent histological, immune-phenotypical, molecular, and genomic characterization confirming the features of the original tumor. The tissue-of-origin prediction was obtained from the tumor microRNA expression profile and confirmed by single-cell transcriptomics. Genomic testing and fluorescence in situ hybridization analysis identified FGFR2 gene amplification in both models, in the form of homogeneously staining region (HSR) in CUP#55 and double minutes in CUP#96. FGFR2 was recognized as the main oncogenic driver and therapeutic target. FGFR2-targeting drug BGJ398 (infigratinib) in combination with the MEK inhibitor trametinib proved to be synergic and exceptionally active, both in vitro and in vivo. The effects of the combined treatment by single-cell gene expression analysis revealed a remarkable plasticity of tumor cells and the greater sensitivity of cells with epithelial phenotype. This study brings personalized therapy closer to CUP patients and provides the rationale for FGFR2 and MEK targeting in metastatic tumors with FGFR2 pathway activation.

Extracellular Vesicles, Circulating Tumor Cells, and Immune Checkpoint Inhibitors: Hints and Promises.

Immune checkpoint inhibitor (ICI) therapy has revolutionized the treatment of cancer, in particular lung cancer, while the introduction of predictive biomarkers from liquid biopsies has emerged as a promising tool to achieve an effective and personalized therapy response. Important progress has also been made in the molecular characterization of extracellular vesicles (EVs) and circulating tumor cells (CTCs), highlighting their tremendous potential in modulating the tumor microenvironment, acting on immunomodulatory pathways, and setting up the pre-metastatic niche. Surface antigens on EVs and CTCs have proved to be particularly useful in the case of the characterization of potential immune escape mechanisms through the expression of immunosuppressive ligands or the transport of cargos that may mitigate the antitumor immune function. On the other hand, novel approaches, to increase the expression of immunostimulatory molecules or cargo contents that can enhance the immune response, offer premium options in combinatorial clinical strategies for precision immunotherapy. In this review, we discuss recent advances in the identification of immune checkpoints using EVs and CTCs, their potential applications as predictive biomarkers for ICI therapy, and their prospective use as innovative clinical tools, considering that CTCs have already been approved by the Food and Drug Administration (FDA) for clinical use, but providing good reasons to intensify the research on both.

Circulating Tumour Cells: Detection and Application in Advanced Non-Small Cell Lung Cancer.

Non-small cell lung cancer (NSCLC) is one of the deadliest diseases worldwide. Tissue biopsy is the current gold standard for the diagnosis and molecular profiling of NSCLC. However, this approach presents some limitations due to inadequate tissue sampling, and intra- and intertumour heterogenicity. Liquid biopsy is a noninvasive method to determine cancer-related biomarkers in peripheral blood, and can be repeated at multiple timepoints. One of the most studied approaches to liquid biopsies is represented by circulating tumour cells (CTCs). Several studies have evaluated the prognostic and predictive role of CTCs in advanced NSCLC. Despite the limitations of these studies, the results of the majority of studies seem to be concordant regarding the correlation between high CTC count and poor prognosis in patients with NSCLC. Similarly, the decrease of CTC count during treatment may represent an important predictive marker of sensitivity to therapy in advanced NSCLC. Furthermore, molecular characterization of CTCs can be used to provide information on tumour biology, and on the mechanisms involved in resistance to targeted treatment. This review will discuss the current status of the clinical utility of CTCs in patients with advanced NSCLC, highlighting their potential application to prognosis and to treatment decision making.

Settling the uncertainty about unconventional circulating tumor cells: Epithelial-to-mesenchymal transition, cell fusion and trogocytosis.

Circulating tumor cells (CTCs) were first described 150 years ago. The so-called "classical" CTC populations (EpCAM+/CK+/CD45-) have been fully characterized and proposed as the most representative CTC subset, with clinical relevance. Nonetheless, other "atypical" or "unconventional" CTCs have also been identified, and their critical role in metastasis formation was demonstrated. In this chapter we illustrate the studies that led to the discovery of unconventional CTCs, defined as CTCs that display both epithelial and mesenchymal markers, or both cancer and immune markers, also in the form of hybrid cancer-immune cells. We also present biological explanations for the origin of these unconventional CTCs: epithelial to mesenchymal transition, cell-cell fusion and trogocytosis. We believe that a deeper knowledge on the biology of CTCs is needed to fully elucidate their role in cancer progression and their use as cancer biomarkers.

A Novel FLCN Variant in a Suspected Birt-Hogg-Dubè Syndrome Patient.

Subjects with pathogenic (PV) and likely pathogenic (LPV) FLCN variants have an increased risk of manifesting benign and malignant disorders that are related to Birt-Hogg-Dubé syndrome (BHDS): an autosomal dominantly inherited disorder whose severity can vary significantly. Renal cell carcinoma (RCC) development in BHD (Birt-Hogg-Dubé) patients has a very high incidence; thus, identifying this rare syndrome at early stages and preventing metastatic spread is crucial. Over the last decade, the advancement of Next Generation Sequencing (NGS) and the implementation of multigene panels for hereditary cancer syndromes (HCS) have led to a subsequent focus on additional genes and variants, including those of uncertain significance (VUS). Here, we describe a novel FLCN variant observed in a subject manifesting disorders that were suspected to be related to BHDS and with a family history of multiple cancers.

Analysis of EVs from patients with advanced pancreatic cancer identifies antigens and miRNAs with predictive value.

The identification of predictive factors for treatment of pancreatic cancer (PC) is an unmet clinical need. In the present work, we analyzed blood-derived extracellular vesicles (EVs) from patients with advanced PC in order to find a molecular signature predictive of response to therapy. We analyzed samples from 21 patients with advanced PC, all receiving first-line treatment with gemcitabine + nab-paclitaxel. Isolated EVs have been analyzed, and the results of laboratory have been matched with clinical data in order to investigate possible predictive factors. EV concentration and size were similar between responder and non-responder patients. Analysis of 37 EV surface epitopes showed a decreased expression of SSEA4 and CD81 in responder patients. We detected more than 450 expressed miRNAs in EVs. A comparative survey between responder and non-responder patients showed that at least 44 miRNAs were differently expressed. Some of these miRNAs have already been observed in relation to the survival and gemcitabine sensitivity of tumor cells. In conclusion, we showed the ability of our approach to identify EV-derived biomarkers with predictive value for therapy response in PC. Our findings are worthy of further investigation, including the analysis of samples from patients treated with different schedules and in different settings.

From phenotypical investigation to RNA-sequencing for gene expression analysis: A workflow for single and pooled rare cells.

Combining phenotypical and molecular characterization of rare cells is challenging due to their scarcity and difficult handling. In oncology, circulating tumor cells (CTCs) are considered among the most important rare cell populations. Their phenotypic and molecular characterization is necessary to define the molecular mechanisms underlying their metastatic potential. Several approaches that require cell fixation make difficult downstream molecular investigations on RNA. Conversely, the DEPArray technology allows phenotypic analysis and handling of both fixed and unfixed cells, enabling a wider range of applications. Here, we describe an experimental workflow that allows the transcriptomic investigation of single and pooled OE33 cells undergone to DEPArray analysis and recovery. In addition, cells were tested at different conditions (unfixed, CellSearch fixative (CSF)- and ethanol (EtOH)-fixed cells). In a forward-looking perspective, this workflow will pave the way for novel strategies to characterize gene expression profiles of rare cells, both single-cell and low-resolution input.

Dissecting Molecular Heterogeneity of Circulating Tumor Cells (CTCs) from Metastatic Breast Cancer Patients through Copy Number Aberration (CNA) and Single Nucleotide Variant (SNV) Single Cell Analysis.

Circulating tumor cells' (CTCs) heterogeneity contributes to counteract their introduction in clinical practice. Through single-cell sequencing we aim at exploring CTC heterogeneity in metastatic breast cancer (MBC) patients. Single CTCs were isolated using DEPArray NxT. After whole genome amplification, libraries were prepared for copy number aberration (CNA) and single nucleotide variant (SNV) analysis and sequenced using Ion GeneStudio S5 and Illumina MiSeq, respectively. CTCs demonstrate distinctive mutational signatures but retain molecular traces of their common origin. CNA profiling identifies frequent aberrations involving critical genes in pathogenesis: gains of 1q (CCND1) and 11q (WNT3A), loss of 22q (CHEK2). The longitudinal single-CTC analysis allows tracking of clonal selection and the emergence of resistance-associated aberrations, such as gain of a region in 12q (CDK4). A group composed of CTCs from different patients sharing common traits emerges. Further analyses identify losses of 15q and enrichment of terms associated with pseudopodium formation as frequent and exclusive events. CTCs from MBC patients are heterogeneous, especially concerning their mutational status. The single-cell analysis allows the identification of aberrations associated with resistance, and is a candidate tool to better address treatment strategy. The translational significance of the group populated by similar CTCs should be elucidated.

Case Report: Analysis of Plasma Extracellular Vesicles in a Triple Negative Spindle-Cell Metaplastic Breast Cancer Patient.

Metaplastic breast cancer (MpBC) is a rare tumor representing 1% of all breast malignancies. The prognosis of this histologic subtype is actually poor and there are no current clear-cut therapeutic guidelines. Hence, despite its uniqueness, its aggressive prognostic profile strongly encourages further studies to identify new markers and therapeutic targets. Herein, we report a case of 32-years-old patient affected with of triple negative spindle-shaped MpBC. The research of molecular targets on the primary tumor did not allow performing an effective therapeutic choice. Extracellular Vesicles (EVs) are under intense study as new potential pathophysiological markers and targets for therapeutic applications, in different tumors for their role in tumor onset, progression and aggressiveness. Here, we examined the involvement of EVs in this case, to look into the MpBC microenvironment willing to identify new potential molecular targets, pathways of aggressiveness, and markers of prognosis and therapeutic efficacy. Firstly, we characterized MpBC patient EV dimensions and surface proteins. Moreover, we analyzed the EV RNA cargo supposed to be delivered to nearby and distant recipient cells. Interestingly, we observed a dysregulation EV-contained miRNAs, which could determine an increased expression of oncogenes in the tumor microenvironment, probably enabling cancer progression. These data suggest that the characterization of miRNA cargo of EVs could be important for the identification of new markers and for the application of future new target therapies.

Appropriateness and Economic Analysis of Conventional Circulating Biomarkers Assessment in Early Breast Cancer: A Real-World Experience from the E.Pic.A Study.

The risk of relapse for early breast cancer (BC) patients persists even after decades and to date, no specific and sensitive effective circulating biomarker for recurrence prediction has been identified yet. The international guidelines do not recommend the assessment of the serum tumor markers CEA and CA15-3 in the follow-up of asymptomatic early BC patients. In our institute, IRCCS Istituto Romagnolo per lo Studio dei Tumori (IRST) "Dino Amadori", as part of the E.Pic.A study, which was designed to assess the economic appropriateness of integrated care pathways in early BC, the use of CEA and CA15-3 as circulating tumor biomarkers in early BC patients was evaluated in 1502 patients one year after surgery, from 2015 to 2018, with an overall expense of EUR 51,764. A total of EUR 47,780 (92%) was used for execution of circulating tumor markers in early BC patients with stage 0, I and II tumors, neglecting the current guidelines and considered inappropriate by our professional board. We found that no patients with stage I BC experienced relapse in the 365 days after surgery, and in any case examination of the circulating markers CEA and CA15-3 was considered crucial for diagnosis of relapse. Our findings suggest that this inadequacy is a low-value area, supporting the reallocation of economic resources for interventions of a higher value for patients.

CNA Profiling of Single CTCs in Locally Advanced Esophageal Cancer Patients during Therapy Highlights Unexplored Molecular Pathways.

BACKGROUND: Here, we monitored the evolution of CTCs spread in 11 patients affected by locally advanced EC who were undergoing therapy. METHODS: In this perspective study, we designed multiple blood biopsies from individual patients: before and after neoadjuvant chemo-radio therapy and after surgery. We developed a multi-target array, named Grab-all assay, to estimate CTCs for their epithelial (EpCAM/E-Cadherin/Cytokeratins) and mesenchymal/stem (N-Cadherin/CD44v6/ABCG2) phenotypes. Identified CTCs were isolated as single cells by DEPArray, subjected to whole genome amplification, and copy number aberration (CNA) profiles were determined. Through bioinformatic analysis, we assessed the genomic imbalance of single CTCs, investigated specific focal copy number changes previously reported in EC and aberrant pathways using enrichment analysis. RESULTS: Longitudinal monitoring allowed the identification of CTCs in at least one time-point per patient. Through single cell CNA analysis, we revealed that CTCs showed significantly dynamic genomic imbalance during treatment. Individual CTCs from relapsed patients displayed a higher degree of genomic imbalance relative to disease-free patients' groups. Genomic aberrations previously reported in EC occurred mostly in post-neoadjuvant therapy CTCs. In-depth analysis showed that networks enrichment in all time-point CTCs were inherent to innate immune system. Transcription/gene regulation, post-transcriptional and epigenetic modifications were uniquely affected in CTCs of relapsed patients. CONCLUSIONS: Our data add clues to the comprehension of the role of CTCs in EC aggressiveness: chromosomal aberrations on genes related to innate immune system behave as relevant to the onset of CTC-status, whilst pathways of transcription/gene regulation, post-transcriptional and epigenetic modifications seem linked to patients' outcome.

Early Detection and Investigation of Extracellular Vesicles Biomarkers in Breast Cancer.

Breast cancer (BC) is the most commonly diagnosed malignant tumor in women worldwide, and the leading cause of cancer death in the female population. The percentage of patients experiencing poor prognosis along with the risk of developing metastasis remains high, also affecting the resistance to current main therapies. Cancer progression and metastatic development are no longer due entirely to their intrinsic characteristics, but also regulated by signals derived from cells of the tumor microenvironment. Extracellular vesicles (EVs) packed with DNA, RNA, and proteins, are the most attractive targets for both diagnostic and therapeutic applications, and represent a decisive challenge as liquid biopsy-based markers. Here we performed a study based on a multiplexed phenotyping flow cytometric approach to characterize BC-derived EVs from BC patients and cell lines, through the detection of multiple antigens. Our data reveal the expression of EVs-related biomarkers derived from BC patient plasma and cell line supernatants, suggesting that EVs could be exploited for characterizing and monitoring disease progression.

Circulating Tumor Cells as a Tool to Untangle the Breast Cancer Heterogeneity Issue.

Breast cancer (BC) is a disease characterized by high degrees of heterogeneity at morphologic, genomic, and genetic levels, even within the same tumor mass or among patients. As a consequence, different subpopulations coexist and less represented clones may have a selective advantage, significantly influencing the outcome of BC patients. Circulating tumor cells (CTCs) represent a rare population of cells with a crucial role in metastatic cascade, and in recent years have represented a fascinating alternative to overcome the heterogeneity issue as a "liquid biopsy". However, besides the raw enumeration of these cells in advanced epithelial tumors, there are no CTC-based assays applied in the clinical practice to improve personalized medicine. In this review, we report the latest findings in the field of CTCs for intra-tumoral heterogeneity unmasking in BC, supporting the need to deepen their analysis to investigate their role in metastatic process and include the molecular characterization in the clinical practice. In the future, CTCs will be helpful in monitoring patients during treatment, as well as to better address therapeutic strategies.

Case Report: Analysis of Circulating Tumor Cells in a Triple Negative Spindle-Cell Metaplastic Breast Cancer Patient.

Circulating tumor cells (CTCs) are a rare population of cells found in the bloodstream and represent key players in the metastatic cascade. Their analysis has proved to provide further core information concerning the tumor. Herein, we aim at investigating CTCs isolated from a 32-year-old patient diagnosed with triple negative spindle-shaped metaplastic breast cancer (MpBC), a rare tumor poorly responsive to therapies and with a dismal prognosis. The molecular analysis performed on the primary tumor failed to underline effective actionable targets to address the therapeutic strategy. Besides the presence of round-shaped CTCs, cells with a spindle shape were present as well, and through molecular analysis, we confirmed their malignant nature. This aspect was coherent with the primary tumor histology, proving that CTCs are released regardless of their morphology. Copy number aberration (CNA) profiling and variant analysis using next-generation sequencing (NGS) showed that these cells did not harbor the alterations exhibited by the primary tumor (PIK3CA G1049A mutation, MYC copy number gain). However, despite the great heterogeneity observed, the amplification of regions involved in metastasis emerged (8q24.22-8q24.23). Our findings support the investigation of CTCs to identify alterations that could have a role in the metastatic process. To the best of our knowledge, this is the first examination of CTCs in an MpBC patient.

miR-9-5p as a Regulator of the Androgen Receptor Pathway in Breast Cancer Cell Lines.

Breast cancer (BC) is the most diagnosed carcinoma and the leading cause of cancer death in female over 100 countries. Thanks to the advance in therapeutic strategies, patients' survival has improved. However, the lack of response to treatments and drug resistance are still a main concern, demanding for new therapeutic approaches, in particular for the advanced stages of the disease. Androgen receptor (AR) is gaining increasing interest as a fourth targetable receptor in BC, however, its regulation in BC cells is still poorly understood. MicroRNAs (miRNAs) regulate gene expression post-transcriptionally. Here, we identified miR-9-5p as an inhibitor of AR expression, we validated the inverse correlation between miR-9-5p and AR in primary BC samples and we further identified a feedback loop in which androgen agonists of AR up-regulate miR-9-5p. We also provided evidence that miR-9-5p elicits anti-proliferative effects in BC cell lines regardless of their estrogen receptor status. Finally, we showed that miR-9-5p can revert AR-downstream signaling even in presence of AR-agonists, highlighting the role of this miR in the hormonal response of BC. In conclusion, this study supports the role of miR-9-5p as an anti-proliferative miR in BC and as a central modulator of AR-signaling response to circulating androgens in BC.

Single-Cell NGS-Based Analysis of Copy Number Alterations Reveals New Insights in Circulating Tumor Cells Persistence in Early-Stage Breast Cancer.

Circulating tumor cells (CTCs) are a rare population of cells representing a key player in the metastatic cascade. They are recognized as a validated tool for the identification of patients with a higher risk of relapse, including those diagnosed with breast cancer (BC). However, CTCs are characterized by high levels of heterogeneity that also involve copy number alterations (CNAs), structural variations associated with gene dosage changes. In this study, single CTCs were isolated from the peripheral blood of 11 early-stage BC patients at different time points. A label-free enrichment of CTCs was performed using OncoQuick, and single CTCs were isolated using DEPArray. Libraries were prepared from single CTCs and DNA extracted from matched tumor tissues for a whole-genome low-coverage next-generation sequencing (NGS) analysis using the Ion Torrent S5 System. The analysis of the CNA burden highlighted that CTCs had different degrees of aberration based on the time point and subtype. CTCs were found even six months after surgery and shared CNAs with matched tumor tissue. Tumor-associated CNAs that were recurrent in CTCs were patient-specific, and some alterations involved regions associated with BC and survival (i.e., gains at 1q21-23 and 5p15.33). The enrichment analysis emphasized the involvement of aberrations of terms, associated in particular with interferon (IFN) signaling. Collectively, our findings reveal that these aberrations may contribute to understanding the molecular mechanisms involving CTC-related processes and their survival ability in occult niches, supporting the goal of exploiting their application in patients' surveillance and follow-up.

Microbiota-Derived Metabolites in Tumor Progression and Metastasis.

Microbial communities and human cells, through a dynamic crosstalk, maintain a mutualistic relationship that contributes to the maintenance of cellular metabolism and of the immune and neuronal systems. This dialogue normally occurs through the production and regulation of hormonal intermediates, metabolites, secondary metabolites, proteins, and toxins. When the balance between host and microbiota is compromised, the dynamics of this relationship change, creating favorable conditions for the development of diseases, including cancers. Microbiome metabolites can be important modulators of the tumor microenvironment contributing to regulate inflammation, proliferation, and cell death, in either a positive or negative way. Recent studies also highlight the involvement of microbiota metabolites in inducing epithelial-mesenchymal transition, thus favoring the setup of the metastatic niche. An investigation of microbe-derived metabolites in "liquid" human samples, such as plasma, serum, and urine, provide further information to clarify the relationship between host and microbiota.

Adipocytes and microRNAs Crosstalk: A Key Tile in the Mosaic of Breast Cancer Microenvironment.

Breast cancer (BC) is a disease characterized by a high grade of heterogeneity. Consequently, despite the great achievements obtained in the last decades, most of the current therapeutic regimens still fail. The identification of new molecular mechanisms that will increase the knowledge of all steps of tumor initiation and growth is mandatory in finding new clinical strategies. The BC microenvironment, consisting of endothelial cells, fibroblasts, immune cells and adipocytes, plays an essential role in regulating BC development, and recently it has gained great attention in the scientific community. In particular, adipose tissue is emerging as an important target to investigate among mammary gland components. The mechanisms underlying BC progression driven by adipocytes are predominantly unexplored, especially that involving the switch from normal adipocytes to the so-called cancer-associated adipocytes (CAAs). MicroRNAs (miRNAs), a class of gene expression modulators, have emerged as the regulators of key oncogenes and tumor suppressor genes that affect multiple pathways of the tumor microenvironment and adipose tissue. This review concerns a presentation of the role of adipocytes in breast tissue, and describes the most recent discoveries about the interplay between adipocytes and miRNAs, which collaborate in the arrangement of a pro-inflammatory and cancerous microenvironment, laying the foundations for new concepts in the prevention and treatment of BC.

E-cadherin Downregulation and microRNAs in Sporadic Intestinal-Type Gastric Cancer.

CDH1 gene, encoding E-cadherin, is a tumor suppressor gene frequently altered in gastric cancers (GCs) of both diffuse (DGC) and intestinal (IGC) histotypes, albeit through different mechanisms. The study aimed to characterize CDH1 expression in sporadic IGC and to investigate whether microRNAs (miRs) are involved in its transcriptional control. We evaluated CDH1 expression by quantitative real-time PCR (RT-qPCR) in 33 IGC patients and found a significant downregulation in tumor tissues compared to normal counterparts (p-value = 0.025). Moreover, 14 miRs, predicted to be involved in CDH1 regulation in both a direct and indirect manner, were selected and analyzed by RT-qPCR in an independent case series of 17 IGCs and matched normal tissues. miR-101, miR-26b, and miR-200c emerged as significantly downregulated and were confirmed in the case series of 33 patients (p-value < 0.001). Finally, we evaluated EZH2 expression, a target of both miR-101 and miR-26b, which showed significant upregulation in IGCs (p-value = 0.005). A significant inverse correlation was observed between EZH2 overexpression and CDH1, miR-101, and miR-26b levels (p-value < 0.001). Our results reinforce the link between CDH1 and IGC, highlighting the role of miRs in its transcriptional control and improving our understanding of GC subtypes and biomarkers.