Detecting circulating tumor material and digital pathology imaging during pancreatic cancer progression

A Comprehensive Review of the Potential Role of Liquid Biopsy as a Diagnostic, Prognostic, and Predictive Biomarker in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma is one of the most lethal malignant diseases, with a mortality rate being close to incidence. Due to its heterogeneity and plasticity, as well as the lack of distinct symptoms in the early phases, it is very often diagnosed at an advanced stage, resulting in poor prognosis. Traditional tissue biopsies remain the gold standard for making a diagnosis, but have an obvious disadvantage in their inapplicability for frequent sampling. Blood-based biopsies represent a non-invasive method which potentially offers easy and repeated sampling, leading to the early detection and real-time monitoring of the disease and hopefully an accurate prognosis. Given the urgent need for a reliable biomarker that can estimate a patient's condition and response to an assigned treatment, blood-based biopsies are emerging as a potential new tool for improving patients' survival and surveillance. In this article, we discuss the current advances and challenges in using liquid biopsies for pancreatic cancer, focusing on circulating tumour DNA (ctDNA), extracellular vesicles (EVs), and circulating tumour cells (CTCs), and compare the performance and reliability of different biomarkers and combinations of biomarkers.

Lectins as potential tools for cancer biomarker discovery from extracellular vesicles

Extracellular vesicles (EVs) have considerable potential as diagnostic, prognostic, and therapeutic agents, in large part because molecular patterns on the EV surface betray the cell of origin and may also be used to "target" EVs to specific cells. Cancer is associated with alterations to cellular and EV glycosylation patterns, and the surface of EVs is enriched with glycan moieties. Glycoconjugates of EVs play versatile roles in cancer including modulating immune response, affecting tumor cell behavior and site of metastasis and as such, paving the way for the development of innovative diagnostic tools and novel therapies. Entities that recognize specific glycans, such as lectins, may thus be powerful tools to discover and detect novel cancer biomarkers. Indeed, the past decade has seen a constant increase in the number of published articles on lectin-based strategies for the detection of EV glycans. This review explores the roles of EV glycosylation in cancer and cancer-related applications. Furthermore, this review summarizes the potential of lectins and lectin-based methods for screening, targeting, separation, and possible identification of improved biomarkers from the surface of EVs.

Cell-free DNA as a prognostic and predictive biomarker in resectable distal common bile duct cancer

BACKGROUND

Cell-free DNA (cfDNA) as an oncological biomarker has drawn much attention in recent years, but very limited effort has been made to investigate the prognostic values of cfDNA in distal common bile duct (CBD) cancer.

METHODS

Plasma cfDNA was measured in 67 patients with resectable distal CBD cancer. Survival outcomes and the correlation of cfDNA with other conventional prognostic factors were determined.

RESULTS

cfDNA levels were significantly higher in female patients, and those with poor tumor differentiation, abnormal serum carcinoembryonic antigen (CEA) level, and stage III cancer. The significant prognostic factors included a high cfDNA level (>8955 copies/mL), abnormal serum CEA level, stage III cancer, and positive resection margins. Compared with patients with high cfDNA level, those with lower cfDNA level (≤8955 copies/mL) had significantly better overall survival outcomes (74.4% vs 100% and 19.2% vs 52.6%, for 1- and 5-year survival rates, respectively, p = 0.001). The cfDNA level, perineural invasion, CEA level, and radicality were identified as independent prognostic factors for distal CBD cancer after multivariate analysis.

CONCLUSION

Circulating cfDNA levels play a significant role in predicting the prognosis and survival outcome for resectable distal CBD cancer. Furthermore, acting as a promising liquid biopsy, cfDNA could serve as a prognostic and predictive biomarker in combination with current conventional markers to improve diagnostic and prognostic efficacy.

Systematic exploration of the underlying mechanism of gemcitabine resistance in pancreatic adenocarcinoma

Resistance to gemcitabine is the main challenge of chemotherapy for pancreatic ductal adenocarcinoma (PDAC). Hence, the development of a response signature to gemcitabine is essential for precision therapy of PDAC. However, existing quantitative signatures of gemcitabine are susceptible to batch effects and variations in sequencing platforms. Therefore, based on within-sample relative expression ordering of pairwise genes, we developed a transcriptome-based gemcitabine signature consisting of 28 gene pairs (28-GPS) that could predict response to gemcitabine for PDAC at the individual level. The 28-GPS was superior to previous quantitative signatures in terms of classification accuracy and prognostic performance. Resistant samples classified by 28-GPS showed poorer overall survival, higher genomic instability, lower immune infiltration, higher metabolic level and higher-fidelity DNA damage repair compared with sensitive samples. In addition, we found that gemcitabine combined with phosphoinositide 3-kinase (PI3K) inhibitor may be an alternative treatment strategy for PDAC. Single-cell analysis revealed that cancer cells in the same PDAC sample showed both the characteristics of sensitivity and resistance to gemcitabine, and the activation of the TGFβ signalling pathway could promote progression of PDAC. In brief, 28-GPS could robustly determine whether PDAC is resistant or sensitive to gemcitabine, and may be an auxiliary tool for clinical treatment.

Detection of Pancreatic Ductal Adenocarcinoma by Ex Vivo Magnetic Levitation of Plasma Protein-Coated Nanoparticles

Pancreatic Ductal Adeno Carcinoma (PDAC) is one of the most lethal malignancies worldwide, and the development of sensitive and specific technologies for its early diagnosis is vital to reduce morbidity and mortality rates. In this proof-of-concept study, we demonstrate the diagnostic ability of magnetic levitation (MagLev) to detect PDAC by using levitation of graphene oxide (GO) nanoparticles (NPs) decorated by a biomolecular corona of human plasma proteins collected from PDAC and non-oncological patients (NOP). Levitation profiles of corona-coated GO NPs injected in a MagLev device filled with a paramagnetic solution of dysprosium(III) nitrate hydrate in water enables to distinguish PDAC patients from NOP with 80% specificity, 100% sensitivity, and global classification accuracy of 90%. Our findings indicate that Maglev could be a robust and instrumental tool for the early detection of PDAC and other cancers.

Circulating Cell-Free DNA as a Prognostic Biomarker in Resectable Ampullary Cancer

Simple Summary

Circulating cell-free DNA (cfDNA) in patients with ampullary cancer was measured to clarify the correlation between cfDNA and clinicopathological factors and the impact of cfDNA on survival outcomes. The level of cfDNA was significantly higher in patients with lymph node involvement, lymphovascular invasion, abnormal serum carcinoembryonic antigen level, and stage II and III cancer. The 1- and 5-year survival rates were 92.0% and 66.5%, respectively, for patients with low cfDNA levels ≤ 6687 copies/mL as compared with 84.0% and 49.9%, respectively, for patients with high cfDNA levels > 6687 copies/mL (p < 0.001). After multivariate analysis, only the cfDNA level and cancer stage were independent factors in determining the prognosis of the ampullary cancer. The cfDNA level could act as a surrogate marker of both disease extent and biological aggressiveness of ampullary cancer. Moreover, cfDNA plays a significant role in determining the prognosis of resectable ampullary cancer.

Abstract

Circulating cell-free DNA (cfDNA) in ampullary cancer patients was measured to clarify the correlation between cfDNA and clinicopathological factors and the impact of cfDNA on survival outcomes. Patients with ampullary cancer undergoing pancreaticoduodenectomy were included. Correlations between cfDNA and clinicopathological and prognostic factors were determined. The cfDNA levels in patients ranged from 1282 to 21,674 copies/mL, with a median of 6687 copies/mL. The cfDNA level was significantly higher in patients with lymph node involvement, lymphovascular invasion, abnormal serum carcinoembryonic antigen (CEA) level, and stage II and III cancer. Poor prognostic factors for ampullary cancer included high cfDNA > 6687 copies/mL, lymph node involvement, abnormal serum CEA > 5 ng/mL, and advanced stage II and III cancer. The 1- and 5-year survival rates were 92.0% and 66.5%, respectively, for patients with low cfDNA < 6687 copies/mL and 84.0% and 49.9%, respectively, for patients with high cfDNA > 6687 copies/mL (p < 0.001). After multivariate analysis, only the cfDNA level and stage were independent prognostic factors of ampullary cancer. Thus, the cfDNA level could act as a surrogate marker of both disease extent and biological aggressiveness of ampullary cancer. Moreover, cfDNA plays a significant role in the prognosis of resectable ampullary cancer.

Circulating Cell-Free DNA in Pancreatic Head Adenocarcinoma Undergoing Pancreaticoduodenectomy

OBJECTIVE

Circulating cell-free DNA (cfDNA) analysis is recently reported as a promising prognostic biomarker in various types of cancer. This study aimed to evaluate the role of cfDNA in pancreatic head adenocarcinoma.

METHODS

Data for pancreatic head adenocarcinoma undergoing pancreaticoduodenectomy were studied for cfDNA. Prognostic factors were determined, and their correlation with cfDNA level was evaluated.

RESULTS

The median of cfDNA for 97 cases was 7724 copies/mL, with a mean of 10,467, and ranging from 1856 to 44,203. Cell-free DNA was significantly higher in positive lymph node involvement and advanced stage III. Poor prognostic factors included high cfDNA level (>7724 copies/mL), abnormal carbohydrate antigen 19-9, abnormal carcinoembryonic antigen, and advanced stage. The 1- and 5-year survivals for those with high cfDNA were poorer, 70.2% and 21.2%, respectively, as compared with 93.4% and 23.7% for those with low cfDNA level. Only cfDNA level and stage were independent prognostic factors after multivariate analysis.

CONCLUSIONS

The level of cfDNA was correlated with tumor burden. Therefore, it could be an emerging survival predictor for resectable pancreatic head adenocarcinoma, and its detection might be a promising liquid biopsy to monitor both tumor progression and treatment response.

Synergistic Analysis of Protein Corona and Haemoglobin Levels Detects Pancreatic Cancer

Simultaneous detection of multiple analytes from a single biological sample is gaining more attention in the development of more reliable and point-of-care diagnostic devices. We developed a multiplexed strategy that combined outcomes of clinical biomarkers with analysis of the protein corona that forms around graphene oxide sheets upon exposure to patient's plasma. As a paradigmatic case study, we selected pancreatic ductal adenocarcinoma (PDAC), mainly because of the absence of effective detection strategies that resulted in an extremely low five-year survival rate after diagnosis (<10%). Association of protein corona analysis and haemoglobin levels discriminated PDAC patients from healthy volunteers in up to 90% of cases. If further confirmed in larger-cohort studies, this approach may be used in the detection of PDAC.

Extracellular Vesicle-Dependent Cross-Talk in Cancer-Focus on Pancreatic Cancer

Extracellular vesicles (EVs) like exosomes and shed microvesicles are generated by many different cells. However, among all the cells, cancer cells are now recognized to secrete more EVs than healthy cells. Tumor-derived EVs can be isolated from biofluids such as blood, urine, ascitic fluid, and saliva. Their numerous components (nucleic acids, proteins, and lipids) possess many pleiotropic functions involved in cancer progression. The tumor-derived EVs generated under the influence of tumor microenvironment play distant roles and promote cellular communication by directly interacting with different cells. Moreover, they modulate extracellular matrix remodeling and tumor progression. Tumor-derived EVs are involved in pre-metastatic niche formation, dependent on the EV-associated protein receptors, and in cancer chemoresistance as they transfer drug-resistance-related genes to recipient cells. Recent advances in preclinical and clinical fields suggest their potential use as biomarkers for diagnosis and prognosis as well as for drug delivery in cancer. In this Review, we discuss EV characteristics and pro-tumor capacities, and highlight the future crucial impact of tumor-derived EVs in pancreatic cancer diagnosis and prognosis.

Application of liquid biopsy for surgical management of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest forms of cancer. Although drug development over the past decade has gradually improved the prognosis of PDAC, the prognosis remains extremely poor. The predominant determinant of a poor prognosis is that patients are already at the advanced stage when they are diagnosed. Therefore, it is essential to detect early-stage PDAC to ensure a good prognosis. However, in general, being asymptomatic at the early stage makes the detection of early-stage PDAC very difficult. Recently, much attention has been focused on the utility of a liquid biopsy as a biomarker. Theoretically, early-stage tumors can be detected even under asymptomatic conditions. A number of studies on liquid biopsies have been reported so far. Several biomarkers, including circulating tumor DNA (ctDNA), circulating tumor cells (CTCS), and exosomes, are used in liquid biopsies, with the potential to be applied to the clinical setting. Each biomarker is reported to have different utilities, such as the detection of early-stage disease, the differential diagnosis of PDAC from other types of pancreatic tumors, the prediction of the prognosis or risk of recurrence, and monitoring the treatment response. In this review, we focus on ctDNA, CTCS, and exosomes as representative liquid biopsy biomarkers and describe the specific functions of each biomarker in the treatment of PDAC. Furthermore, we discuss the application of liquid biopsies, especially for the surgical management of PDAC.

Detection of Circulating Tumor-Related Materials by Aptamer Capturing and Endogenous Enzyme-Signal Amplification

Circulating tumor-related materials (CTRMs) shed from original or metastatic tumors, carry a lot of tumor information and are considered as important markers for cancer diagnosis and metastasis prognosis. Herein, we report a colorimetric detection strategy for CTRMs based on aptamer-based magnetic isolation and endogenous alkaline phosphatase (AP)-signal amplification. This strategy exhibited high sensitivity and selectivity toward the CTRMs that express AP heterodimers (the target of aptamer, a potential tumor marker). For clinical samples, this CTRM assay significantly discriminated colorectal cancer patients (n = 50) from healthy individuals (n = 39, p < 0.0001). The receiver operating characteristic (ROC) analysis indicated the sensitivity and specificity reached 92% and 82%, respectively, at the optimal cutoff point, the area under the curve of ROC reached 0.93, suggesting great potential for colorectal cancer diagnosis and therapeutic monitoring. Compared with CTC assays, this strategy is simple and has the potential for point-of-care testing.

Fluids and their mechanics in tumour transit: shaping metastasis

Metastasis is a dynamic succession of events involving the dissemination of tumour cells to distant sites within the body, ultimately reducing the survival of patients with cancer. To colonize distant organs and, therefore, systemically disseminate within the organism, cancer cells and associated factors exploit several bodily fluid systems, which provide a natural transportation route. Indeed, the flow mechanics of the blood and lymphatic circulatory systems can be co-opted to improve the efficiency of cancer cell transit from the primary tumour, extravasation and metastatic seeding. Flow rates, vessel size and shear stress can all influence the survival of cancer cells in the circulation and control organotropic seeding patterns. Thus, in addition to using these fluids as a means to travel throughout the body, cancer cells exploit the underlying physical forces within these fluids to successfully seed distant metastases. In this Review, we describe how circulating tumour cells and tumour-associated factors leverage bodily fluids, their underlying forces and imposed stresses during metastasis. As the contribution of bodily fluids and their mechanics raises interesting questions about the biology of the metastatic cascade, an improved understanding of this process might provide a new avenue for targeting cancer cells in transit.

Liquid Biopsy as Surrogate for Tissue for Molecular Profiling in Pancreatic Cancer: A Meta-Analysis Towards Precision Medicine

Liquid biopsy (LB) is a non-invasive approach representing a promising tool for new precision medicine strategies for cancer treatment. However, a comprehensive analysis of its reliability for pancreatic cancer (PC) is lacking. To this aim, we performed the first meta-analysis on this topic. We calculated the pooled sensitivity, specificity, positive (LR+) and negative (LR−) likelihood ratio, and diagnostic odds ratio (DOR). A summary receiver operating characteristic curve (SROC) and area under curve (AUC) were used to evaluate the overall accuracy. We finally assessed the concordance rate of all mutations detected by multi-genes panels. Fourteen eligible studies involving 369 patients were included. The overall pooled sensitivity and specificity were 0.70 and 0.86, respectively. The LR+ was 3.85, the LR- was 0.34 and DOR was 15.84. The SROC curve with an AUC of 0.88 indicated a relatively high accuracy of LB for molecular characterization of PC. The concordance rate of all mutations detected by multi-genes panels was 31.9%. LB can serve as surrogate for tissue in the molecular profiling of PC, because of its relatively high sensitivity, specificity and accuracy. It represents a unique opportunity to be further explored towards its introduction in clinical practice and for developing new precision medicine approaches against PC.

Label-free characterization of exosome via surface enhanced Raman spectroscopy for the early detection of pancreatic cancer

Pancreatic cancer is a highly lethal malignancy. Lack of early diagnostic markers makes timely detection of pancreatic cancer a highly challenging endeavor. Exosomes have emerged as information-rich cancer specific biomarkers. However, characterization of tumor-specific exosomes has been challenging. This study investigated the proof of principle that exosomes could be used for the detection of pancreatic cancer. Label-free analysis of exosomes purified from normal and pancreatic cancer cell lines was performed using surface enhanced Raman Spectroscopy (SERS) and principal component differential function analysis (PC-DFA), to identify tumor-specific spectral signatures. This method differentiated exosomes originating from pancreatic cancer or normal pancreatic epithelial cell lines with 90% accuracy. The cell line trained PC-DFA algorithm was next applied to SERS spectra of serum-purified exosomes. This method exhibited up to 87% and 90% predictive accuracy for HC and EPC individual samples, respectively. Overall, our study identified utility of SERS spectral signature for deciphering exosomal surface signature.

Functions and clinical implications of exosomes in pancreatic cancer

Pancreatic cancer is one of the most aggressive human malignancies and is associated with a dismal prognosis, which can be contributed to its atypical symptoms, metastatic propensity, and significant chemoresistance. Emerging evidence shows that pancreatic cancer cell-derived exosomes (PEXs) play critical roles in tumorigenesis and tumor development, as they are involved in drug resistance, immune evasion and metabolic reprograming, and distant metastasis of pancreatic cancer. Their numerous differentially expressed and functional contents make PEXs promising screening tools and therapeutic targets, which require further exploration. In this review, we focus on the functions of PEX contents and their clinical implications in pancreatic cancer.

Liquid biopsies for management of pancreatic cancer

Pancreatic cancer is one of the main causes of cancer-related deaths worldwide. It is asymptomatic at an early stage, and most diagnosis occurs when the disease is already at a late stage, by which time the tumor is nonresectable. In order to increase the overall survival of patients with pancreatic cancer, as well as to decrease the cancer burden, it is necessary to perform early diagnosis, prognosis stratifications and cancer monitoring using accurate, minimally invasive, and cost-effective methods. Liquid biopsies seek to detect tumor-associated biomarkers in a variety of extractable body fluids and can help to monitor treatment response and disease progression, and even predict patient outcome. In patients with pancreatic cancer, tumor-derived materials, primarily circulating tumor DNA, circulating tumor cells and exosomes, are being studied for inclusion in the management of the disease. This review focuses on describing the biology of these biomarkers, methods for their enrichment and detection, as well as their potential for clinical application. Moreover, we discuss the future direction of liquid biopsies and introduce how they can be exploited toward point of care personalized medicine for the management of pancreatic cancer.

Improving the accuracy of pancreatic cancer clinical staging by exploitation of nanoparticle-blood interactions: A pilot study

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) early diagnosis is  crucial  and new, cheap and user-friendly techniques for biomarker identification  are  needed. "Protein corona" (PC) is emerging a new bio-interface potentially useful in tumor early diagnosis. In a previous investigation, we showed that relevant differences between the  protein patterns of  PCs formed on lipid NPs after exposure to PDAC and non-cancer plasma  samples exist. To extend that research, We performed this pilot study to investigate the effect of PDAC tumor size and distant metastases on PC composition.

METHODS

Twenty PDACs were clinically staged according to the UICC TNM staging system 8 t h Edition. Collected plasma samples were let to interact with lipid NPs; resulting PCs were characterized by SDS-PAGE. To properly evaluate changes in the PC, the protein intensity profiles were reduced to four regions of molecular weight: < 25 kDa, 25-50 kDa, 50-120 kDa, > 120 kDa.  RESULTS: Data analysis allowed to distinguish T1-T2 cases from T3 and above all from metastatic ones (p < 0.05). Discrimination power was particularly due to a subset of plasma proteins with molecular  weight comprised between 25-50 kDa  and 50-120 kDa.

CONCLUSIONS

PC composition is critically influenced by tumor size and presence of distant metastases in PDAC. If our findings will be further confirmed, we envision that future developments of cheap and user-friendly PC-based tools will allow to improve the accuracy of PDAC clinical staging, identifying among resectable  PDACs with potentially better prognosis (i.e. T1 and T2) those at higher risk of occult distant metastases.

Reshaping the Tumor Stroma for Treatment of Pancreatic Cancer

Pancreatic cancer is accompanied by a fibrotic reaction that alters interactions between tumor cells and the stroma to promote tumor progression. Consequently, strategies to target the tumor stroma might be used to treat patients with pancreatic cancer. We review recently developed approaches for reshaping the pancreatic tumor stroma and discuss how these might improve patient outcomes. We also describe relationships between the pancreatic tumor extracellular matrix, the vasculature, the immune system, and metabolism, and discuss the implications for the development of stromal compartment-specific therapies.