Circulating Tumor Cells in Pancreatic Cancer: Current Perspectives

The role of chloride intracellular channel 4 in tumors

Tumors are among the most predominant health problems in the world, and the annual incidence of cancer is increasing globally; therefore, there is an urgent need to identify effective therapeutic targets. Chloride intracellular channel 4 (CLIC4) belongs to the family of chloride intracellular channels (CLICs), which are widely expressed in various tissues and organs, such as the brain, lung, pancreas, colorectum, and ovary, and play important roles in promoting apoptosis, promoting angiogenesis, maintaining normal proliferation of endothelial cells, and regulating the assembly and reconstruction of the cytoskeleton. The expression and function of CLIC4 in tumors varies. It has been reported that CLIC4 is low expressed in gastric cancer, skin cancer and prostate cancer, suggesting a tumor suppressor role. Interestingly, CLIC4 is overexpressed in pancreatic, ovarian and breast cancers, indicating a cancer-promoting role. CLIC4 expression is dysregulated in some solid tumors, which may be because CLIC4 is involved in the growth, migration or invasion of some cancer cells through various mechanisms. Regulation of CLIC4 expression may be a potential therapeutic strategy for some tumors. CLIC4 may be a promising therapeutic target and a biomarker for some cancers. In this study, we review the role of CLIC4 in several cancers and its value in the diagnosis and treatment of tumors.

Plasma treatment can efficiently increase the attachment of pancreatic circulatory tumor cells to the surface

Pancreatic cancer ranks as the fourth most common cause of cancer-related fatalities globally, with a notably low 5-year relative survival rate. We need to immediately develop fast, dependable, and noninvasive diagnostic techniques that can accurately identify pancreatic cancer at an early stage. The research project created a straightforward but effective method for detecting and increasing the amount of tumor cells that could bind to polystyrene (PS) well plates. To significantly improve the adhesion of the pancreatic cancer cell line PANC-1 on PS well plates, a 5-min exposure to high-power oxygen plasma was implemented. This treatment caused a significant increase in surface energy and roughness. Surface characterization was assessed by utilizing an atomic force microscope and X-ray photoelectron spectroscopy. Water contact angle measurement is used to assess the level of wettability present on the treated surface. To determine how well the circulatory tumor cells (CTCs) model adheres to a plasma-treated surface (PTS), appropriate amounts of mCherry-labeled PANC-1 cells are mixed into a sample of blood cells to mimic clinical conditions. After applying plasma treatment, the experiment achieved a 96% success rate in binding at 2 h, specifically for the PANC-1 cell type. Moreover, the platform demonstrated a considerable ability to attach to cancerous cells compared to non-cancerous cells found in blood. To summarize, this study has shown that non-thermal plasma treatment could be a novel and efficient method for the better adhesion of pancreatic cancer cells, with the benefits of being cost-effective and quick. It is necessary for additional research to be conducted to confirm the clinical efficacy of the method.

Patient-derived xenografts from circulating cancer stem cells as a preclinical model for personalized pancreatic cancer research

Patient-derived xenografts (PDXs) provide biologically relevant models and potential platforms for the development of treatment strategies for precision medicine in pancreatic cancer. Furthermore, circulating epithelial tumor cells (CETCs/CTCs) are released into the bloodstream by solid tumors and a rare subpopulation-circulating cancer stem cells (cCSCs) - is considered to be responsible for recurrence and plays a key role in metastasis. For the identification of cCSCs, an innovative in vitro assay to generate tumorspheres was established in this study. The number of tumorspheres and CETCs/CTCs was analyzed perioperatively in 25 pancreatic cancer patients. Additionally, an individual in vivo chorioallantoic membrane (CAM) culture system was used to generate PDXs from these tumorspheres. While overall correlations of CETCs/CTCs with clinicopathological parameters did not reach statistical significance, a significant difference in the number of tumorspheres was observed between patient subgroups with lower and higher UICC stages. This finding underscores their potential as biomarkers, providing valuable insights into clinical decision-making and tumor progression. The application of tumorspheres on the CAM successfully established PDXs within 7 days. These xenografts closely resembled the histological features of the primary tumor. Hence, this model represents a novel and fast option for individualized testing of new therapies for PDAC.

Nanomaterial-based detection of circulating tumor cells and circulating cancer stem cells for cancer immunotherapy

Nanomaterials have emerged as transformative tools for detecting circulating tumor cells (CTCs) and circulating cancer stem cells (CCSCs), significantly enhancing cancer diagnostics and immunotherapy. Nanomaterials, including those composed of gold, magnetic materials, and silica, have enhanced the sensitivity, specificity, and efficiency of isolating these rare cells from blood. These developments are of paramount importance for the early detection of cancer and for providing real-time insights into metastasis and treatment resistance, which are essential for the development of personalized immunotherapies. The combination of nanomaterial-based platforms with phenotyping techniques, such as Raman spectroscopy and microfluidics, enables researchers to enhance immunotherapy protocols targeting specific CTC and CCSC markers. Nanomaterials also facilitate the targeted delivery of immunotherapeutic agents, including immune checkpoint inhibitors and therapeutic antibodies, directly to tumor cells. This synergistic approach has the potential to enhance therapeutic efficacy and mitigate the risk of metastasis and relapse. In conclusion, this review critically examines the use of nanomaterial-driven detection systems for detecting CTCs and CCSCs, their application in immunotherapy, and suggests future directions, highlighting their potential to transform the integration of diagnostics and treatment, thereby paving the way for more precise and personalized cancer therapies.

[The concept of the liquid biopsy in the treatment of malignant eye tumours]

The liquid biopsy is a cutting-edge technique that involves analysing non-solid biological tissues, primarily blood but also ocular fluids, for the presence of cancer cells or fragments of tumour DNA. Unlike traditional biopsies, liquid biopsies are usually minimally invasive and can be performed more frequently, enabling continuous monitoring of disease progression and treatment efficacy. This article (and the associated series of articles) outlines the key developments in liquid biopsy, which include the analysis of circulating tumor DNA (ctDNA), circulating tumor cells (CTC) and exosomal RNA and protein biomarkers. Techniques, such as digital droplet PCR and next-generation sequencing (NGS) have made it possible to detect even very low levels of ctDNA, which is crucial for early cancer detection and monitoring minimal residual disease. The detection of rare CTCs is enhanced by techniques, such as microfluidic devices and immunomagnetic separation. Multiomic approaches, whereby exosomal RNA, protein and ctDNA analyses are combined, help to create a more comprehensive picture of tumour biology, including insights into tumour heterogeneity, potentially leading to better diagnostic and prognostic tools and helping to predict treatment response and resistance. The challenges of liquid biopsy application, which will be described in the following article, include (a) standardization, (b) cost and accessibility, (c) validation and clinical utility. However, the liquid biopsy represents a promising frontier in the application of precision ocular oncology, with ongoing research likely to expand its applications and improve its effectiveness in the coming years.

Circulating Neoplastic-Immune Hybrid Cells Are Biomarkers of Occult Metastasis and Treatment Response in Pancreatic Cancer

BACKGROUND/OBJECTIVES

Pancreatic ductal adenocarcinoma (PDAC) presents significant diagnostic and prognostic challenges, as current biomarkers frequently fail to accurately stage disease, predict rapid metastatic recurrence (rPDAC), or assess response to neoadjuvant therapy (NAT). We investigated the potential for circulating neoplastic-immune hybrid cells (CHCs) as a non-invasive, multifunctional biomarker for PDAC.

METHODS

Peripheral blood specimens were obtained from patients diagnosed with PDAC. CHCs were detected by co-expression of pan-cytokeratin and CD45, normalized to 50,000 peripheral blood mononuclear cells. rPDAC was defined as metastatic recurrence within six months of margin-negative pancreatectomy. Cyclic immunofluorescence (CyCIF) analyses compared hybrid phenotypes in blood and tumors.

RESULTS

Blood samples were collected from 42 patients with PDAC prior to resection. Those with radiographically occult metastatic disease and rPDAC had higher preoperative CHC numbers compared to patients who did not (65.0 and 74.4, vs. 11.52 CHCs; p < 0.001). Patients with complete or near-complete pathologic responses to NAT had lower preoperative CHC numbers than partial and/or non-responders (1.7 vs. 13.1 CHCs; p = 0.008). When assessed longitudinally, those with partial pathologic response saw CHC levels become undetectable while on treatment but increase in the interval between NAT completion and resection. In contrast, patients with poor responses or development of metastatic disease experienced persistent CHC detection during therapy or rising levels prior to radiographic evidence of metastases. Further, in metastatic PDAC patients, treatment-induced phenotypic changes in hybrid cells mirrored those in paired metastatic tumor samples.

CONCLUSIONS

CHC enumeration and phenotyping display promise as a real-time indicator of disease burden, recurrence risk, and treatment response in PDAC. CHCs have great potential as tumor-derived biomarkers to optimize therapeutic strategies and improve survival in patients with PDAC.

Circulating tumor cells in pancreatic cancer: more than liquid biopsy

Circulating tumor cells (CTCs) are tumor cells that slough off the primary lesions and extravasate into the bloodstream. By forming CTC clusters and interacting with other circulating cells (platelets, NK cells, macrophage, etc.), CTCs are able to survive in the circulatory system of tumor patients and colonize to metastatic organs. In recent years, the potential of CTCs in diagnosis, prognostic assessment, and individualized therapy of various types of tumors has been gradually explored, while advances in biotechnology have made it possible to extract CTCs from patient blood samples. These biological features of CTCs provide us with new insights into cancer vulnerabilities. With the advent of new immunotherapies and personalized medicines, disrupting the heterotypical interaction between CTCs and circulatory cells as well as direct CTCs targeting hold great promise. Pancreatic cancer (PC) is one of the most malignant cancers, in part because of early metastasis, difficult diagnosis, and limited treatment options. Although there is significant potential for CTCs as a biomarker to impact PC from diagnosis to therapy, there still remain a number of challenges to the routine implementation of CTCs in the clinical management of PC. In this review, we summed up the progress made in understanding biological characteristics and exceptional technological advances of CTCs and provided insight into exploiting these developments to design future clinical tools for improving the diagnosis and treatment of PC.

Early detection of pancreatic cancer in the era of precision medicine

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer-related mortality and it is often diagnosed at advanced stages due to non-specific clinical presentation. Disease detection at localized disease stage followed by surgical resection remains the only potentially curative treatment. In this era of precision medicine, a multifaceted approach to early detection of PDAC includes targeted screening in high-risk populations, serum biomarkers and "liquid biopsies", and artificial intelligence augmented tumor detection from radiologic examinations. In this review, we will review these emerging techniques in the early detection of PDAC.

Prospects of liquid biopsy in the prognosis and clinical management of gastrointestinal cancers

Gastrointestinal (GI) cancers account for one-fourth of the global cancer incidence and are incriminated to cause one-third of cancer-related deaths. GI cancer includes esophageal, gastric, liver, pancreatic, and colorectal cancers, mostly diagnosed at advanced stages due to a lack of accurate markers for early stages. The invasiveness of diagnostic methods like colonoscopy for solid biopsy reduces patient compliance as it cannot be frequently used to screen patients. Therefore, minimally invasive approaches like liquid biopsy may be explored for screening and early identification of gastrointestinal cancers. Liquid biopsy involves the qualitative and quantitative determination of certain cancer-specific biomarkers in body fluids such as blood, serum, saliva, and urine to predict disease progression, therapeutic tolerance, toxicities, and recurrence by evaluating minimal residual disease and its correlation with other clinical features. In this review, we deliberate upon various tumor-specific cellular and molecular entities such as circulating tumor cells (CTCs), tumor-educated platelets (TEPs), circulating tumor DNA (ctDNA), cell-free DNA (cfDNA), exosomes, and exosome-derived biomolecules and cite recent advances pertaining to their use in predicting disease progression, therapy response, or risk of relapse. We also discuss the technical challenges associated with translating liquid biopsy into clinical settings for various clinical applications in gastrointestinal cancers.

Combined Therapy of Chemotherapy and Radiofrequency Ablation for Pancreatic Cancer Patients With Metachronous Hepatic Metastatic Lesions After Radical Pancreatic Resection

PURPOSE

Hepatic metastasis frequently occurs in patients who have undergone radical pancreatic resection for pancreatic cancer. Besides chemotherapy, various local treatment approaches targeting hepatic lesions have been explored. However, research on radiofrequency ablation (RFA) as a localized therapy for hepatic metastasis is limited. Therefore, we conducted this retrospective study to provide clinical evidence.

METHODS

This is a single-center, retrospective, cohort study. After radical pancreaticoduodenectomy, 32 patients developed metachronous hepatic metastasis with fewer than 3 lesions, the largest of which was less than 3 cm in diameter. These patients underwent combined treatment with chemotherapy and RFA. After 8 weeks of chemotherapy, patients received RFA for hepatic lesions. Additional chemotherapy was administered, and the patients' tumor status and survival were monitored. The primary endpoint of this study was overall survival (OS). Factors affecting OS were analyzed using the Cox risk model.

RESULTS

Among the 32 patients, the mean OS was 28.4 months. Univariate and multivariate Cox regression analysis revealed that the time (in months) of liver metastasis (HR = 0.04, 95% CI: 0.01 to 0.19; P < 0.001), the number of liver metastases (HR = 7.08, 95% CI: 1.85 to 27.08, P = 0.004), and PD (progressive disease) response to the second round of chemotherapy (HR = 29.50, 95% CI: 1.46 to 597.27; P = 0.027) were independent predictors of poorer survival.

CONCLUSION

Combined therapy with RFA and chemotherapy is safe in patients with hepatic metastasis after radical pancreaticoduodenectomy. Early recurrence (≤12 months), three liver metastatic lesions, and a poor response to the second round of chemotherapy were associated with poor survival.

Liquid biopsy techniques and pancreatic cancer: diagnosis, monitoring, and evaluation

Pancreatic cancer (PC) is one of the most common malignancies. Surgical resection is a potential curative approach for PC, but most patients are unsuitable for operations when at the time of diagnosis. Even with surgery, some patients may still experience tumour metastasis during the operation or shortly after surgery, as precise prognosis evaluation is not always possible. If patients miss the opportunity for surgery and resort to chemotherapy, they may face the challenging issue of chemotherapy resistance. In recent years, liquid biopsy has shown promising prospects in disease diagnosis, treatment monitoring, and prognosis assessment. As a noninvasive detection method, liquid biopsy offers advantages over traditional diagnostic procedures, such as tissue biopsy, in terms of both cost-effectiveness and convenience. The information provided by liquid biopsy helps clinical practitioners understand the molecular mechanisms underlying tumour occurrence and development, enabling the formulation of more precise and personalized treatment decisions for each patient. This review introduces molecular biomarkers and detection methods in liquid biopsy for PC, including circulating tumour cells (CTCs), circulating tumour DNA (ctDNA), noncoding RNAs (ncRNAs), and extracellular vesicles (EVs) or exosomes. Additionally, we summarize the applications of liquid biopsy in the early diagnosis, treatment response, resistance assessment, and prognostic evaluation of PC.

Witek M, Soper SA. Circulating Tumor Cell Subpopulations Predict Treatment Outcome in Pancreatic Ductal Adenocarcinoma (PDAC) Patients

There is a high clinical unmet need to improve outcomes for pancreatic ductal adenocarcinoma (PDAC) patients, either with the discovery of new therapies or biomarkers that can track response to treatment more efficiently than imaging. We report an innovative approach that will generate renewed interest in using circulating tumor cells (CTCs) to monitor treatment efficacy, which, in this case, used PDAC patients receiving an exploratory new therapy, poly ADP-ribose polymerase inhibitor (PARPi)-niraparib-as a case study. CTCs were enumerated from whole blood using a microfluidic approach that affinity captures epithelial and mesenchymal CTCs using anti-EpCAM and anti-FAPα monoclonal antibodies, respectively. These antibodies were poised on the surface of two separate microfluidic devices to discretely capture each subpopulation for interrogation. The isolated CTCs were enumerated using immunophenotyping to produce a numerical ratio consisting of the number of mesenchymal to epithelial CTCs (denoted "Φ"), which was used as an indicator of response to therapy, as determined using computed tomography (CT). A decreasing value of Φ during treatment was indicative of tumor response to the PARPi and was observed in 88% of the enrolled patients (n = 31). Changes in Φ during longitudinal testing were a better predictor of treatment response than the current standard CA19-9. We were able to differentiate between responders and non-responders using ΔΦ (p = 0.0093) with higher confidence than CA19-9 (p = 0.033). For CA19-9 non-producers, ΔΦ correctly predicted the outcome in 72% of the PDAC patients. Sequencing of the gDNA extracted from affinity-selected CTC subpopulations provided information that could be used for patient enrollment into the clinical trial based on their tumor mutational status in DNA repair genes.

Advancement of single-cell sequencing for clinical diagnosis and treatment of pancreatic cancer

Single-cell sequencing is a high-throughput technique that enables detection of genomic, transcriptomic, and epigenomic information at the individual cell level, offering significant advantages in detecting cellular heterogeneity, precise cell classification, and identifying rare subpopulations. The technique holds tremendous potential in improving the diagnosis and treatment of pancreatic cancer. Moreover, single-cell sequencing provides unique insights into the mechanisms of pancreatic cancer metastasis and cachexia, paving the way for developing novel preventive strategies. Overall, single-cell sequencing has immense potential in promoting early diagnosis, guiding personalized treatment, and preventing complications of pancreatic cancer. Emerging single-cell sequencing technologies will undoubtedly enhance our understanding of the complex biology of pancreatic cancer and pave the way for new directions in its clinical diagnosis and treatment.

Graphene Sensor Arrays for Rapid and Accurate Detection of Pancreatic Cancer Exosomes in Patients' Blood Plasma Samples

Biosensors based on graphene field effect transistors (GFETs) have the potential to enable the development of point-of-care diagnostic tools for early stage disease detection. However, issues with reproducibility and manufacturing yields of graphene sensors, but also with Debye screening and unwanted detection of nonspecific species, have prevented the wider clinical use of graphene technology. Here, we demonstrate that our wafer-scalable GFETs array platform enables meaningful clinical results. As a case study of high clinical relevance, we demonstrate an accurate and robust portable GFET array biosensor platform for the detection of pancreatic ductal adenocarcinoma (PDAC) in patients' plasma through specific exosomes (GPC-1 expression) within 45 min. In order to facilitate reproducible detection in blood plasma, we optimized the analytical performance of GFET biosensors via the application of an internal control channel and the development of an optimized test protocol. Based on samples from 18 PDAC patients and 8 healthy controls, the GFET biosensor arrays could accurately discriminate between the two groups while being able to detect early cancer stages including stages 1 and 2. Furthermore, we confirmed the higher expression of GPC-1 and found that the concentration in PDAC plasma was on average more than 1 order of magnitude higher than in healthy samples. We found that these characteristics of GPC-1 cancerous exosomes are responsible for an increase in the number of target exosomes on the surface of graphene, leading to an improved signal response of the GFET biosensors. This GFET biosensor platform holds great promise for the development of an accurate tool for the rapid diagnosis of pancreatic cancer.

Evolving utility of exosomes in pancreatic cancer management

Despite the development of newer oncological treatment, the survival of patients with pancreatic cancer (PC) remains poor. Recent studies have identified exosomes as essential mediators of intercellular communications and play a vital role in tumor initiation, metastasis and chemoresistance. Thus, the utility of liquid biopsies using exosomes in PC management can be used for early detection, diagnosis, monitoring as well as drug delivery vehicles for cancer therapy. This review summarizes the function, and clinical applications of exosomes in cancers as minimally invasive liquid biomarker in diagnostic, prognostic and therapeutic roles.

Clinical implications and perspectives of portal venous circulating tumor cells in pancreatic cancer

Despite recent improvements in the diagnosis and treatment of pancreatic cancer (PC), clinical outcomes remain dismal. Moreover, there are no effective prognostic or predictive biomarkers or options beyond carbohydrate antigen 19-9 for personalized and precise treatment. Circulating tumor cells (CTCs), as a member of the liquid biopsy family, could be a promising biomarker; however, the rarity of CTCs in peripheral venous blood limits their clinical use. Because the first venous drainage of PC is portal circulation, the portal vein can be a more suitable location for the detection of CTCs. Endoscopic ultrasound-guided portal venous sampling of CTCs is both feasible and safe. Several studies have suggested that the detection rate and number of CTCs may be higher in the portal blood than in the peripheral blood. CTC counts in the portal blood are highly associated with hepatic metastasis, recurrence after surgery, and survival. The phenotypic and genotypic properties measured in the captured portal CTCs can help us to understand tumor heterogeneity and predict the prognosis of PC. Small sample sizes and heterogeneous CTC detection methods limit the studies to date. Therefore, a large number of prospective studies are needed to corroborate portal CTCs as a valid biomarker in PC.

A Paradigm Shifts: Neoadjuvant Therapy for Clearly Resectable Pancreatic Cancer

Over the past decade, neoadjuvant therapy has become the standard of care for patients with borderline resectable and locally advanced pancreatic cancer. The surgical community remains divided regarding the value of neoadjuvant therapy for patients who present with clearly resectable disease. Thus far, randomized controlled trials comparing neoadjuvant therapy with conventional upfront surgical strategies for patients with clearly resectable pancreatic cancer have been plagued by poor accrual, and are often underpowered. Nonetheless, meta-analyses of the results of these trials suggest that neoadjuvant therapy can be offered as an acceptable standard of care for patients with clearly resectable pancreatic cancer. Previous trials used neoadjuvant gemcitabine, but more recent studies have demonstrated superior survival for patients who were able to tolerate neoadjuvant FOLFIRINOX (leucovorin, 5-fluorouracil, irinotecan hydrochloride, and oxaliplatin). The increased utilization of FOLFIRINOX may be shifting the treatment paradigm in favor of neoadjuvant therapy among patients with clearly resectable disease. Randomized controlled trials assessing the value of neoadjuvant FOLFIRINOX in clearly resectable pancreatic cancer, which are expected to provide more conclusive recommendations, are still ongoing. This review outlines the rationale, considerations, and current level of evidence for the use of neoadjuvant therapy in patients with clearly resectable pancreatic cancer.

Multiplexed analysis of EV reveals specific biomarker composition with diagnostic impact

Exosomes and extracellular vesicles (EV) are increasingly being explored as circulating biomarkers, but their heterogenous composition will likely mandate the development of multiplexed EV technologies. Iteratively multiplexed analyses of near single EVs have been challenging to implement beyond a few colors during spectral sensing. Here we developed a multiplexed analysis of EV technique (MASEV) to interrogate thousands of individual EVs during 5 cycles of multi-channel fluorescence staining for 15 EV biomarkers. Contrary to the common belief, we show that: several markers proposed to be ubiquitous are less prevalent than believed; multiple biomarkers concur in single vesicles but only in small fractions; affinity purification can lead to loss of rare EV subtypes; and deep profiling allows detailed analysis of EV, potentially improving the diagnostic content. These findings establish the potential of MASEV for uncovering fundamental EV biology and heterogeneity and increasing diagnostic specificity.

Circulating Cancer Associated Macrophage-like Cells as a Potential New Prognostic Marker in Pancreatic Ductal Adenocarcinoma

BACKGROUND

Circulating Cancer Associated Macrophage-like cells (CAMLs) have been described as novel liquid biopsy analytes and unfavorable prognostic markers in some tumor entities, with scarce data for Pancreatic Ductal Adenocarcinomas (PDAC).

METHODS

Baseline and follow-up blood was drawn from resected curative (n = 36) and palliative (n = 19) PDAC patients. A microfluidic size-based cell enrichment approach (Parsortix^TM) was used for CAML detection, followed by immunofluorescence staining using pan-keratin, CD14, and CD45 antibodies to differentiate between CAMLs, circulating tumor cells (CTCs), and leukocytes.

RESULTS

CAMLs were detectable at baseline in 36.1% of resected patients and 47.4% of palliative PDAC patients. CAML detection was tumor stage independent. Follow-up data indicated that detection of CAMLs (in 45.5% of curative patients) was an independent prognostic factor for shorter recurrence-free survival (RFS) (HR: 4.3, p = 0.023). Furthermore, a combined analysis with CTCs showed the detectability of at least one of these cell populations in 68.2% of resected patients at follow-up. The combined detection of CAMLs and CTCs was also significantly associated with short RFS (HR: 8.7, p = 0.003).

CONCLUSIONS

This pilot study shows that detection of CAMLs in PDAC patients can provide prognostic information, either alone or even more pronounced in combination with CTCs, which indicates the power of liquid biopsy marker analyses.

Folate receptor-positive circulating tumor cells predict survival and recurrence patterns in patients undergoing resection for pancreatic cancer

Objective

To evaluate the prognostic impact of folate receptor (FR)-positive circulating tumor cells (FR⁺ CTCs) for patients with pancreatic cancer (PC).

Background

Risk stratification before surgery for PC patients remains challenging as there are no reliable prognostic markers currently. FR⁺ CTCs, detected by ligand-targeted polymerase chain reaction (LT-PCR), have shown excellent diagnostic value for PC in our previous study and prognostic value in a variety of cancer types.

Methods

Peripheral blood samples from 44 consecutive patients diagnosed with PC were analyzed for FR⁺ CTCs. 25 patients underwent tumor resection and were assigned to the surgical group. 19 patients failed to undergo radical resection because of local advance or distant metastasis and were assigned to the non-surgical group. The impact of CTCs on relapse and survival were explored.

Results

For the prognostic stratification, the optimal cut-off value of CTCs analyzed by receiver operating characteristic (ROC) curve was 14.49 folate units (FU)/3 ml. High CTC levels (> 14.49 FU/3 ml) were detected in 52.0% (13/25) of the patients in the surgical group and 63.2% (12/19) in the non-surgical group. In the surgical group, median disease-free survival (DFS) for patients with high CTC levels versus low CTC levels (< 14.49 FU/3 ml) was 8.0 versus 26.0 months (P = 0.008). In multivariable analysis, CTCs were an independent risk factor for DFS (HR: 4.589, P = 0.012). Concerning the recurrence patterns, patients with high CTC levels showed a significantly frequent rate of distant and early recurrence (P = 0.017 and P = 0.011). CTC levels remained an independent predictor for both distant (OR: 8.375, P = 0.014) and early recurrence (OR: 8.412, P = 0.013) confirmed by multivariable logistic regression. However, CTCs did not predict survival in the non-surgical group (P = 0.220).

Conclusion

FR⁺ CTCs in resected PC patients could predict impaired survival and recurrence patterns after surgery. Preoperative CTC levels detected by LT-PCR may help guide treatment strategies and further studies in a larger cohort are warranted.

Characterization of RARRES1 Expression on Circulating Tumor Cells as Unfavorable Prognostic Marker in Resected Pancreatic Ductal Adenocarcinoma Patients

Simple Summary

Our explorative study used a microfluidic-based approach for circulating tumor cell (CTC) detection in 55 pancreatic ductal adenocarcinoma (PDAC) patients before treatment initiation (baseline) and during follow-up (FUP). For the first time, we assessed the expression of retinoic acid receptor responder 1 (RARRES1) on CTCs. CTCs were detected in 25.5% of patients at baseline, while the detection rate during FUP was higher (45.5%). Especially high CTC counts during FUP in resected patients were associated with early tumor relapse (p = 0.02). Combining CTC detection and RARRES1 protein expression showed that RARRES1-positive patients with high CTCs counts after curative operation during FUP had a worse prognosis (p = 0.001). In conclusion, RARRES1 is a new marker of interest for further research investigations on subtypes of CTCs in PDAC.

Abstract

Background: In pancreatic ductal adenocarcinoma (PDAC), the characterization of circulating tumor cells (CTCs) opens new insights into cancer metastasis as the leading cause of cancer-related death. Here, we focused on the expression of retinoic acid receptor responder 1 (RARRES1) on CTCs as a novel marker for treatment failure and early relapse. Methods: The stable isotope labeling of amino acids in cell culture (SILAC)—approach was applied for identifying and quantifying new biomarker proteins in PDAC cell lines HPDE and its chemoresistant counterpart, L3.6pl-Res. Fifty-five baseline and 36 follow-up (FUP) peripheral blood samples were processed via a marker-independent microfluidic-based CTC detection approach using RARRES1 as an additional marker. Results: SILAC-based proteomics identified RARRES1 as an abundantly expressed protein in more aggressive chemoresistant PDAC cells. At baseline, CTCs were detected in 25.5% of all PDAC patients, while FUP analysis (median: 11 months FUP) showed CTC detection in 45.5% of the resected patients. CTC positivity (≥3 CTC) at FUP was significantly associated with short recurrence-free survival (p = 0.002). Furthermore, detection of RARRES1 positive CTCs was indicative of an even earlier relapse after surgery (p = 0.001). Conclusions: CTC detection in resected PDAC patients during FUP is associated with a worse prognosis, and RARRES1 expression might identify an aggressive subtype of CTCs that deserves further investigation.

ALCAM: A Novel Surface Marker on EpCAMlow Circulating Tumor Cells

Background: Current strategies in circulating tumor cell (CTC) isolation in pancreatic cancer heavily rely on the EpCAM and cytokeratin cell status. EpCAM is generally not considered a good marker given its transitory change during Epithelial to Mesenchymal Transition (EMT) or reverse EMT. There is a need to identify other surface markers to capture the complete repertoire of PDAC CTCs. The primary objective of the study is to characterize alternate surface biomarkers to EpCAM on CTCs that express low or negligible levels of surface EpCAM in pancreatic cancer patients. Methods: Flow cytometry and surface mass spectrometry were used to identify proteins expressed on the surface of PDAC CTCs in culture. CTCs were grown under conditions of attachment and in co-culture with naïve neutrophils. Putative biomarkers were then validated in GEMMs and patient samples. Results: Surface proteomic profiling of CTCs identified several novel protein biomarkers. ALCAM was identified as a novel robust marker in GEMM models and in patient samples. Conclusions: We identified several novel surface biomarkers on CTCs expressed under differing conditions of culture. ALCAM was validated and identified as a novel alternate surface marker on EpCAMlow CTCs.

Disassembly of α6β4-mediated hemidesmosomal adhesions promotes tumorigenesis in PTEN-negative prostate cancer by targeting plectin to focal adhesions

Loss of α6β4-dependent hemidesmosomal adhesions has been observed during prostate cancer progression. However, the significance and underlying mechanisms by which aberrant hemidesmosome assembly may modulate tumorigenesis remain elusive. Using an extensive CRISPR/Cas9-mediated genetic engineering approaches in different prostate cancer cell lines combined with in vivo tumorigenesis studies in mice, bone marrow-on-chip assays and bioinformatics, as well as histological analysis of prostate cancer patient cohorts, we demonstrated that simultaneous loss of PTEN and hemidesmosomal adhesions induced several tumorigenic properties including proliferation, migration, resistance to anoikis, apoptosis, and drug treatment in vitro, and increased metastatic capacity in vivo. These effects were plectin-depended and plectin was associated with actin-rich adhesions upon hemidesmosome disruption in PTEN-negative prostate cancer cells leading to activation of EGFR/PI3K/Akt- and FAK/Src-pathways. These results suggest that analysis of PTEN and hemidesmosomal proteins may have diagnostic value helping to stratify prostate cancer patients with high risk for development of aggressive disease and highlight actin-associated plectin as a potential therapeutic target specifically in PTEN/hemidesmosome dual-negative prostate cancer.

Tumor-Stroma Interaction in PDAC as a New Approach for Liquid Biopsy and its Potential Clinical Implications

The extremely poor prognosis for patients with pancreatic ductal adenocarcinoma (PDAC) has remained unchanged for decades. As a hallmark of PDAC histology, the distinct desmoplastic response in the tumor microenvironment is considered a key factor exerting pro- and antitumor effects. Increasing emphasis has been placed on cancer-associated fibroblasts (CAFs), whose heterogeneity and functional diversity is reflected in the numerous subtypes. The myofibroblastic CAFs (myCAFs), inflammatory CAFs (iCAFs) and antigen presenting CAFs (apCAFs) are functionally divergent CAF subtypes with tumor promoting as well as repressing effects. Precise knowledge of the underlying interactions is the basis for a variety of treatment approaches, which are subsumed under the term antistromal therapy. Clinical implementation is still pending due to the lack of benefit-as well as paradoxical preclinical findings. While the prominent significance of CAFs in the immediate environment of the tumor is becoming clear, less is known about the circulating (c)CAFs. cCAFs are of particular interest as they seem not only to be potential new liquid biopsy biomarkers but also to support the survival of circulating tumor cells (CTC) in the bloodstream. In PDAC, CTCs correlate with an unfavorable outcome and can also be employed to monitor treatment response, but the current clinical relevance is limited. In this review, we discuss CTCs, cCAFs, secretomes that include EVs or fragments of collagen turnover as liquid biopsy biomarkers, and clinical approaches to target tumor stroma in PDAC.

Prognostic Implications of Portal Venous Circulating Tumor Cells in Resectable Pancreatic Cancer

Circulating tumor cells (CTCs) are a promising prognostic biomarker for cancers. However, the paucity of CTCs in peripheral blood in early-stage cancer is a major challenge. Our study aimed to investigate whether portal venous CTCs can be a biomarker for early recurrence and poor prognosis in pancreatic cancer. Patients who underwent upfront curative surgery for resectable pancreatic cancer were consecutively enrolled in this prospective study. Intraoperatively, 7.5 mL of portal and peripheral blood was collected, and CTC detection and identification were performed using immunofluorescence staining. Peripheral blood CTC sampling was performed in 33 patients, of which portal vein CTC sampling was performed in 28. The median portal venous CTCs (2.5, interquartile ranges (IQR) 1−7.75) were significantly higher than the median peripheral venous CTCs (1, IQR 0−2, p < 0.001). Higher stage and regional lymph node metastasis were related with a larger number of CTCs (≥3) in portal venous blood. Patients with low portal venous CTCs (≤2) showed better overall (p = 0.002) and recurrence-free (p = 0.007) survival than those with high portal venous CTCs (≥3). If validated, portal CTCs can be used as a prognostic biomarker in patients with resectable pancreatic cancer.

The implication of liquid biopsies to predict chemoresistance in pancreatic cancer

Pancreatic cancer is one of the most aggressive diseases among solid tumors. Most patients are diagnosed with advanced or metastatic disease and are characterized by poor chemosensitivity. Therefore, earlier diagnosis and novel therapeutic possibilities for pancreatic cancer patients are urgently needed. Liquid biopsy is an emerging technology that allows the noninvasive sampling of tumor material. Nowadays, liquid biopsy has shown promising results as diagnostic, prognostic and predictive biomarkers, but it has not yet been universally adopted into regular use by clinicians. In this review, we describe different components of liquid biopsy, especially circulating tumor cells, circulating tumor DNA and exosomes and their potential clinical utility for pancreatic cancer patients.

A combination of circulating tumor cells and CA199 improves the diagnosis of pancreatic cancer

BACKGROUND

Early diagnosis of pancreatic ductal adenocarcinoma (PDAC) is difficult due to the lack of effective screening tests. CA199, the standard biomarker for PDAC management, is not sufficiently reliable for early diagnosis. This prospective study aimed to evaluate whether circulating tumor cells (CTCs) could complement or perform better than CA199 in determining PDAC.

METHODS

A total of 168 blood samples were collected from 80 patients with PDAC, 32 patients with acute pancreatitis, 22 patients with benign pancreatic masses, and 34 healthy donors. CTCs were detected by a novel system combining negative enrichment with immunostaining and fluorescence in situ hybridization (NE-imFISH). Next, ROC curves and AUC analyses were conducted to assess diagnostic abilities of CA199, CTCs, and the combination of the two biomarkers in PDAC.

RESULTS

CTCs were stained as CD45-/DAPI+/CEP8 ≥3. With 2 CTCs/3.2 ml as the cut-off value, the sensitivity/specificity of the CTC number was 0.76/0.94, which was comparable to that of CA199 (0.78/0.83; Delong test p = 0.3360). Improved performance was achieved through a logistic regression model integrating CA199 and CTC number (AUCCTC+CA199  = 0.95, AUCCA199  = 0.80, AUCCTC number  = 0.85; Delong test p vs . CA199  < 0.0001 and p vs . CTC number  = 0.0002). CTC subtype was inferior to CTC number as a diagnostic marker (AUCCTC subtype  = 0.73; Delong test p vs . CTC number  < 0.0001).

CONCLUSION

The dual-marker panel consisting of CA199 and CTC number can significantly improve upon the diagnostic performance of CA199 alone, highlighting the promising clinical utilization as an effective strategy for PDAC surveillance.

Correlation between drug sensitivity profiles of circulating tumour cell-derived organoids and clinical treatment response in patients with pancreatic ductal adenocarcinoma

INTRODUCTION

Pancreatic ductal adenocarcinoma (PDAC) is highly aggressive and has poor prognosis. There are few biomarkers to inform treatment decisions, and collecting tumour samples for testing is challenging.

METHODS

Circulating tumour cells (CTCs) from patients with PDAC liquid biopsies were expanded ex vivo to form CTC-derived organoid cultures, using a laboratory-developed biomimetic cell culture system. CTC-derived organoids were tested for sensitivity to a PDAC panel of nine drugs, with tests conducted in triplicate, and a weighted cytotoxicity score (CTS) was calculated from the results. Clinical response to treatment in patients was evaluated using Response Evaluation Criteria in Solid Tumours (RECIST) version 1.1 criteria at the time of blood sampling and 3 months later. The correlation between CTS and clinical response was then assessed.

RESULTS

A total of 41 liquid biopsies (87.8% from patients with Stage 4 disease) were collected from 31 patients. The CTC-derived organoid expansion was achieved in 3 weeks, with 87.8% culture efficiency. CTC-derived organoid cultures were positive for EpCAM staining and negative for CD45 staining in the surface marker analysis. All patients had received a median of two lines of treatment prior to enrolment and prospective utility analysis indicated significant correlation of CTS with clinical treatment response. Two representative case studies are also presented to illustrate the relevant clinical contexts.

CONCLUSIONS

CTCs were expanded from patients with PDAC liquid biopsies with a high success rate. Drug sensitivity profiles from CTC-derived organoid cultures correlated meaningfully with treatment response. Further studies are warranted to validate the predictive potential for this approach.

Clinical Validation of a Circulating Tumor Cell Assay Using Density Centrifugation and Automated Immunofluorescence Microscopy

OBJECTIVES

The US Food and Drug Administration (FDA)-approved CELLSEARCH assay (Menarini Silicon Biosystems) for circulating tumor cells (CTCs) relies on expression of an epithelial cell adhesion molecule to enrich for CTCs. We sought to validate a CTC assay (RareCyte) for clinical use that instead collects a buffy coat preparation enriched for CTCs.

METHODS

Normal peripheral blood specimens spiked with cultured breast and prostate cancer cells and 47 clinical samples were used to validate assay performance. Specimens were enriched for buffy coat cells and applied onto 8 glass slides. The slides were immunofluorescently stained and imaged by automated microscopy and computer-aided image analysis.

RESULTS

The assay was 100% specific for detecting spiked tumor cells. For samples spiked with 25, 50, and 125 cells, the percentage coefficients of variation were 42%, 21%, and 3.7%, respectively. Linearity studies demonstrated a slope of 0.99, an intercept of 1.6, and R2 of 0.96. Recoveries at the 25-, 50-, and 125-cell levels were 92%, 111%, and 100%, respectively. Clinical samples run on both CELLSEARCH and RareCyte correlated with an R2 of 0.8 after log-transformation and demonstrated 87.5% concordance using the CELLSEARCH criteria for predicting adverse outcomes.

CONCLUSIONS

The RareCyte CTC assay has comparable performance to the FDA-cleared method and is ready for further clinical validation studies.

Single-EV analysis (sEVA) of mutated proteins allows detection of stage 1 pancreatic cancer

Tumor cell-derived extracellular vesicles (EVs) are being explored as circulating biomarkers, but it is unclear whether bulk measurements will allow early cancer detection. We hypothesized that a single-EV analysis (sEVA) technique could potentially improve diagnostic accuracy. Using pancreatic cancer (PDAC), we analyzed the composition of putative cancer markers in 11 model lines. In parental PDAC cells positive for KRASmut and/or P53mut proteins, only ~40% of EVs were also positive. In a blinded study involving 16 patients with surgically proven stage 1 PDAC, KRASmut and P53mut protein was detectable at much lower levels, generally in <0.1% of vesicles. These vesicles were detectable by the new sEVA approach in 15 of the 16 patients. Using a modeling approach, we estimate that the current PDAC detection limit is at ~0.1-cm3 tumor volume, below clinical imaging capabilities. These findings establish the potential for sEVA for early cancer detection.

The clinical significance of circulating tumor cells and T lymphocyte subtypes in pancreatic cancer patients

Circulating tumor cells (CTCs) are sensitive and reliable biomarkers for tracing relapsed and metastatic cancer. Here, we explore the clinical significance of CTCs and T lymphocyte subtypes in patients with pancreatic cancer. A total of 106 patients with the pancreatic cancer were enrolled in this study. The enrichment and identification of CTCs were achieved before treatment by a PatrolCTC detection technique. Flow cytometry (FACS) was used to characterize CD4, CD8, natural killer (NK) cells, and Tregulatory (Treg) lymphocyte subtypes. Interleukin-2 (IL-2), Interleukin-4 (IL-4), Interleukin-17A (IL-17A), Interleukin-10 (IL-10), and Interferon γ (IFN-γ) were measured by meso-scale discovery (MSD) assay. Among these patients, 44 (41.5%) patients with pancreatic ductal adenocarcinoma (PDAC) were female and 62 (58.5%) cases were male. Case numbers with II-IV tumor-node-metastasis (TNM) stages were 32 (30.2%), 50 (47.2%), and 24 (22.6%), respectively. The positive rate of CTCs before surgery was 37.5% (12/32), 88.0% (44/50) and 100% (24/24) in stage II, III, and IV patients, respectively. Total CTCs, mixed CTCs, and mesenchymal CTCs (MCTCs) were strongly relevant to shorter progression-free survival (PFS) of the patients. In addition, total CTCs (≥6) and positive MCTCs were also significantly correlated with recurrence and metastasis. The patients with high CTCs also had low levels of CD4, CD4/CD8 ratio, NK cells, IL-2, and IFNγ. In contrast, Treg cells had significant elevation in PDAC patients. These results indicated that CTCs number in PDAC patients was an independent indicator for worse PFS. High CTCs also had strong correlation with weak cellular immunity functions.

Exploring the Clinical Utility of Pancreatic Cancer Circulating Tumor Cells

Pancreatic ductal adenocarcinoma (PDAC) is the most frequent pancreatic cancer type, characterized by a dismal prognosis due to late diagnosis, frequent metastases, and limited therapeutic response to standard chemotherapy. Circulating tumor cells (CTCs) are a rare subset of tumor cells found in the blood of cancer patients. CTCs has the potential utility for screening, early and definitive diagnosis, prognostic and predictive assessment, and offers the potential for personalized management. However, a gold-standard CTC detection and enrichment method remains elusive, hindering comprehensive comparisons between studies. In this review, we summarize data regarding the utility of CTCs at different stages of PDAC from early to metastatic disease and discuss the molecular profiling and culture of CTCs. The characterization of CTCs brings us closer to defining the specific CTC subpopulation responsible for metastasis with the potential to uncover new therapies and more effective management options for PDAC.

Liquid Biopsy as a Prognostic and Theranostic Tool for the Management of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinomas (PDAC) represent one of the deadliest cancers worldwide. Survival is still low due to diagnosis at an advanced stage and resistance to treatment. Herein, we review the main types of liquid biopsy able to help in both prognosis and adaptation of treatments.

Deconstructing Pancreatic Cancer Using Next Generation-Omic Technologies-From Discovery to Knowledge-Guided Platforms for Better Patient Management

Comprehensive molecular landscaping studies reveal a potentially brighter future for pancreatic ductal adenocarcinoma (PDAC) patients. Blood-borne biomarkers obtained from minimally invasive "liquid biopsies" are now being trialled for early disease detection and to track responses to therapy. Integrated genomic and transcriptomic studies using resectable tumour material have defined intrinsic patient subtypes and actionable genomic segments that promise a shift towards genome-guided patient management. Multimodal mapping of PDAC using spatially resolved single cell transcriptomics and imaging techniques has identified new potentially therapeutically actionable cellular targets and is providing new insights into PDAC tumour heterogeneity. Despite these rapid advances, defining biomarkers for patient selection remain limited. This review examines the current PDAC cancer biomarker ecosystem (identified in tumour and blood) and explores how advances in single cell sequencing and spatially resolved imaging modalities are being used to uncover new targets for therapeutic intervention and are transforming our understanding of this difficult to treat disease.

Synergistic Analysis of Circulating Tumor Cells Reveals Prognostic Signatures in Pilot Study of Treatment-Naïve Metastatic Pancreatic Cancer Patients

Simple Summary

Pancreatic cancer is one of the most deadly cancer types because it usually is not diagnosed until the cancer has spread throughout the body. In this study, we isolate cancer cells found in the blood of pancreatic cancer patients called circulating tumor cells (CTCs) to study their mutation and gene expression profiles. Comparing patients with better and worse survival duration revealed signatures found in these cancer cells. Characterizing these signatures may help improve patient care by using alternative treatment options.

Abstract

Pancreatic ductal adenocarcinoma is typically diagnosed at late stages and has one of the lowest five-year survival rates of all malignancies. In this pilot study, we identify signatures related to survival and treatment response found in circulating tumor cells (CTCs). Patients with poor survival had increased mutant KRAS expression and deregulation of connected pathways such as PI3K-AKT and MAPK signaling. Further, in a subset of these patients, expression patterns of gemcitabine resistance mechanisms were observed, even prior to initiating treatment. This work highlights the need for identifying patients with these resistance profiles and designing treatment regimens to circumvent these mechanisms.

Current trends in the diagnosis of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a dreaded malignancy with a dismal 5-year survival rate despite maximal efforts on optimizing treatment strategies. Currently, early detection is considered to be the most effective way to improve survival as radical resection is the only potential cure. PDAC is often divided into four categories based on the extent of disease: resectable, borderline resectable, locally advanced, and metastatic. Unfortunately, the majority of patients are diagnosed with locally advanced or metastatic disease, which renders them ineligible for curative resection. This is mainly due to the lack of or vague symptoms while the disease is still localized, although appropriate utilization and prompt availability of adequate diagnostic tools is also critical given the aggressive nature of the disease. A cost-effective biomarker with high specificity and sensitivity allowing early detection of PDAC without the need for advanced or invasive methods is still not available. This leaves the diagnosis dependent on radiodiagnostic methods or endoscopic ultrasound. Here we summarize the latest epidemiological data, risk factors, clinical manifestation, and current diagnostic trends and implications of PDAC focusing on serum biomarkers and imaging modalities. Additionally, up-to-date management and therapeutic algorithms are outlined.

Effects of Red Blood Cell Transfusions on Distant Metastases of Oral Squamous Cell Carcinomas

Simple Summary

Patients with distant metastasis of oral squamous cell carcinoma should be identified at an early stage of disease. In this study, we investigated if patients who received red blood cell transfusions are at risk for the development of distant metastasis. A positive correlation was found between RBC transfusion (HR = 2.42) and the occurrence of M+ in a multivariate regression model. Therefore, the administration of RBC can be considered as an independent prognostic factor and special attention should be paid to its detrimental effects in the perioperative management of OSCC patients.

Abstract

There is no consensus on the effect of red blood cell (RBC) transfusions on patients with oral squamous cell carcinoma (OSCC). The aim of this study was to investigate the association between RBC administration and the occurrence of distant metastases (M+) after surgical treatment of OSCC. All medical records of patients who underwent primary surgery for OSCC in our department (2003–2019) were analyzed retrospectively (n = 609). Chi and Cox regression models were used to analyze the influence of transfusion on the development of M+, and survival rates. Kaplan–Meier curves were used for graphical presentation. A multitude of patient-specific factors showed a statistical impact in univariate analysis (transfusion, age, gender, diabetes, pT, pN, L, V, Pn, G, UICC, adjuvant therapy, free microvascular transplant, preoperative hemoglobin level). Transfusion status and pN stage were the only variables that showed a significant correlation to M+ in the multivariate Cox model. The hazard ratios for the occurrence of M+ were 2.42 for RBC transfusions and 2.99 for pN+. Administration of RBC transfusions was identified as a significant prognostic parameter for the occurrence of distant metastases after surgical treatment of OSCC. Hence, the administration of RBC transfusions should be considered carefully in the perioperative management.

Clinical significance of circulating tumor cells after chemotherapy in unresectable pancreatic ductal adenocarcinoma

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CTCs can be reliably captured with a microfluidic disc in unresectable PDAC patients.

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EpCAM/CK and additional Plectin-1 can effectively identify PDAC CTCs.

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Decreased number of CTCs after chemotherapy is associated with longer survival.

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The relative change of CTCs after chemotherapy can be a surrogate marker for survival.

Circulating tumor cells (CTCs) have emerged as liquid biopsy biomarker providing non-invasive assessment of cancer progression and biology. We investigated whether longitudinal analysis of CTCs could monitor disease progression, response to chemotherapy, and survival in patients with unresectable pancreatic ductal adenocarcinoma (PDAC). A total of 52 patients with PDAC were prospectively enrolled in this study. Peripheral blood samples were serially collected at the time of diagnosis and after chemotherapy with clinical assessments. CTCs were isolated through a centrifugal microfluidic disc, enumerated with immunostaining against Epithelial cell adhesion molecule (EpCAM), Cytokeratin (CK), Plectin-1 and CD45, and identified by an automated imaging system. One or more CTCs were detected in 84.62% patients with unresectable PDAC at the time of diagnosis. CTC numbers were not statistically different across tumor sizes, location and metastatic sites. The absolute number of CTCs after chemotherapy was inversely related to overall survival (OS), and the decreased number of CTCs after chemotherapy was significantly associated with longer OS in patients with PDAC. Identifying CTCs and monitoring CTC changes after chemotherapy could be a useful prognostic marker for survival in patients with unresectable PDACs.

Targeting Tumor-Stromal Interactions in Pancreatic Cancer: Impact of Collagens and Mechanical Traits

Pancreatic ductal adenocarcinoma (PDAC) has one of the worst outcomes among cancers with a 5-years survival rate of below 10%. This is a result of late diagnosis and the lack of effective treatments. The tumor is characterized by a highly fibrotic stroma containing distinct cellular components, embedded within an extracellular matrix (ECM). This ECM-abundant tumor microenvironment (TME) in PDAC plays a pivotal role in tumor progression and resistance to treatment. Cancer-associated fibroblasts (CAFs), being a dominant cell type of the stroma, are in fact functionally heterogeneous populations of cells within the TME. Certain subtypes of CAFs are the main producer of the ECM components of the stroma, with the most abundant one being the collagen family of proteins. Collagens are large macromolecules that upon deposition into the ECM form supramolecular fibrillar structures which provide a mechanical framework to the TME. They not only bring structure to the tissue by being the main structural proteins but also contain binding domains that interact with surface receptors on the cancer cells. These interactions can induce various responses in the cancer cells and activate signaling pathways leading to epithelial-to-mesenchymal transition (EMT) and ultimately metastasis. In addition, collagens are one of the main contributors to building up mechanical forces in the tumor. These forces influence the signaling pathways that are involved in cell motility and tumor progression and affect tumor microstructure and tissue stiffness by exerting solid stress and interstitial fluid pressure on the cells. Taken together, the TME is subjected to various types of mechanical forces and interactions that affect tumor progression, metastasis, and drug response. In this review article, we aim to summarize and contextualize the recent knowledge of components of the PDAC stroma, especially the role of different collagens and mechanical traits on tumor progression. We furthermore discuss different experimental models available for studying tumor-stromal interactions and finally discuss potential therapeutic targets within the stroma.

Engineered multifunctional metal-phenolic nanocoatings for label-free capture and "self-release" of heterogeneous circulating tumor cells

Immunomagnetic beads have been widely explored as an important analytical tool for the rapid and sensitive detection of circulating tumor cells (CTCs). However, their clinical application is seriously hindered by the tedious preparation procedures and heterogeneous nature of CTCs. To this end, a designed multifunctional platform named Fe₃O₄@TA/Cu^II superparamagnetic nanoparticles (SPMNPs) is expected to have the following features: (i) the formation of a tannic acid-copper (II) ion (TA/Cu^II) coating which could be accomplished by a one-step method is very simple; (ii) the TA/Cu^II coating shows high affinity for heterogeneous CTCs and good resistance to nonspecific adhesion of blood cells; (iii) "self-release" of the captured cells could be achieved as the TA/Cu^II coating gradually degrades in the cell culture environment without any additional interventions. Therefore, the resulting Fe₃O₄@TA/Cu^II SPMNPs could capture various CTCs (MCF-7, HepG2 and HeLa cells) with different expression levels of the epithelial cell adhesion molecule (EpCAM). And the capture efficiency and cell purity can reach 88% and 87%, respectively. In addition, 68% of the captured cells are self-released after 6 h of incubation and most of the released cells show high cell proliferation activity. In particular, Fe₃O₄@TA/Cu^II SPMNPs can successfully detect 1-13 CTCs from 1 mL of blood of 14 patients with 6 types of cancers. Hence, we expect that the as-prepared Fe₃O₄@TA/Cu^II SPMNPs with simple, efficient, and universal yet cost-efficient characteristics could act as a promising analytical tool for clinical CTC detection.

Label-free enrichment of rare unconventional circulating neoplastic cells using a microfluidic dielectrophoretic sorting device

Cellular circulating biomarkers from the primary tumor such as circulating tumor cells (CTCs) and circulating hybrid cells (CHCs) have been described to harbor tumor-like phenotype and genotype. CHCs are present in higher numbers than CTCs supporting their translational potential. Methods for isolation of CHCs do not exist and are restricted to low-throughput, time consuming, and biased methodologies. We report the development of a label-free dielectrophoretic microfluidic platform facilitating enrichment of CHCs in a high-throughput and rapid fashion by depleting healthy peripheral blood mononuclear cells (PBMCs). We demonstrated up to 96.5% depletion of PBMCs resulting in 18.6-fold enrichment of cancer cells. In PBMCs from pancreatic adenocarcinoma patients, the platform enriched neoplastic cells identified by their KRAS mutant status using droplet digital PCR with one hour of processing. Enrichment was achieved in 75% of the clinical samples analyzed, establishing this approach as a promising way to non-invasively analyze tumor cells from patients.

Clinical prognostic value of circulating tumor cells in the treatment of pancreatic cancer with gemcitabine chemotherapy

Pancreatic cancer (PC) is a highly malignant tumor type with a high early metastasis rate and no obvious symptoms. Gemcitabine is a first-line chemotherapeutic drug for PC. Since there is no distinct method to determine the efficacy of chemotherapy with gemcitabine in patients with PC, the purpose of the present study was to determine whether positivity for circulating tumor cells (CTCs) in patients with advanced PC is associated with response to gemcitabine chemotherapy and to explore whether CTCs may be used as a predictor of prognosis of patients with advanced PC undergoing chemotherapy. First, immunomagnetic microspheres (magnetic beads; MIL) were prepared to detect CTCs. The patients' clinical characteristics and survival data, as well as efficacy and adverse effects of chemotherapy, were prospectively obtained and their association with CTCs was analyzed. The results indicated that CTC-positive patients with advanced PC had a higher probability of developing resistance to gemcitabine chemotherapy than CTC-negative patients. Survival in the CTC-negative group was significantly higher than in the CTC-positive group (χ²=14.58, P<0.001). CTC-positive patients with advanced PC also had shorter progression-free survival (PFS) after chemotherapy with gemcitabine (P=0.01). In conclusion, CTC-positive patients with PC are more likely to develop gemcitabine resistance, have poor PFS and low incidence of thrombocytopenia. CTCs are expected to become a prognostic indicator for chemotherapy response in patients with PC.

Adjuvant Treatment in Pancreatic Cancer: Shaping the Future of the Curative Setting

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease even in the early stages, despite progresses in surgical and pharmacological treatment in recent years. High potential for metastases is the main cause of therapeutic failure in localized disease, highlighting the current limited knowledge of underlying pathological processes. However, nowadays research is focusing on the search for personalized approaches also in the adjuvant setting for PDAC, by implementing the use of biomarkers and investigating new therapeutic targets. In this context, the aim of this narrative review is to summarize the current treatment scenario and new potential therapeutic approaches in early stage PDAC, from both a preclinical and clinical point of view. Additionally, the review examines the role of target therapies in localized PDAC and the influence of neoadjuvant treatments on survival outcomes.

Circulating Immunological Biomarkers: Prognosis of Pancreatic Cancer Patients Reflected by the Immune System

ABSTRACT

To date, little advances have been made toward new and more effective therapies for pancreatic ductal adenocarcinoma (PDAC). Discovery of prognostic and predictive biomarkers is needed to stratify patients for available treatments and to elucidate how new therapies could be developed. Recent studies have made clear that the immune system is not only affected in the microenvironment of the primary tumor and it is also systemically disrupted in PDAC patients. Under normal circumstances, the immune system is in perfect balance with both proinflammatory and anti-inflammatory components present. In this review, we focus on circulating immunological characteristics including immune cells and their subtypes, cytokines, and immune checkpoints in the peripheral blood not only to understand the poor prognosis of PDAC patients but also to find new leads for new innovative therapies.

The molecular biology of pancreatic adenocarcinoma: translational challenges and clinical perspectives

Pancreatic cancer is an increasingly common cause of cancer mortality with a tight correspondence between disease mortality and incidence. Furthermore, it is usually diagnosed at an advanced stage with a very dismal prognosis. Due to the high heterogeneity, metabolic reprogramming, and dense stromal environment associated with pancreatic cancer, patients benefit little from current conventional therapy. Recent insight into the biology and genetics of pancreatic cancer has supported its molecular classification, thus expanding clinical therapeutic options. In this review, we summarize how the biological features of pancreatic cancer and its metabolic reprogramming as well as the tumor microenvironment regulate its development and progression. We further discuss potential biomarkers for pancreatic cancer diagnosis, prediction, and surveillance based on novel liquid biopsies. We also outline recent advances in defining pancreatic cancer subtypes and subtype-specific therapeutic responses and current preclinical therapeutic models. Finally, we discuss prospects and challenges in the clinical development of pancreatic cancer therapeutics.

Early detection of pancreatic cancer using DNA-based molecular approaches

Due to its poor prognosis and the late stage at which it is typically diagnosed, early detection of pancreatic cancer is a pressing clinical problem. Advances in genomic analysis of human pancreatic tissue and other biospecimens such as pancreatic cyst fluid, pancreatic juice and blood have opened the possibility of DNA-based molecular approaches for early detection of pancreatic cancer. In this Review, we discuss and focus on the pathological and molecular features of precancerous lesions of the pancreas, including pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasm and mucinous cystic neoplasm, which are target lesions of early detection approaches. We also discuss the most prevalent genetic alterations in these precancerous lesions, including somatic mutations in the oncogenes KRAS and GNAS as well as tumour suppressor genes CDKN2A, TP53 and SMAD4. We highlight the latest discoveries related to genetic heterogeneity and multifocal neoplasia in precancerous lesions. In addition, we review specific approaches, challenges and clinically available assays for early detection of pancreatic cancer using DNA-based molecular techniques. Although detection and risk stratification of precancerous pancreatic neoplasms are difficult problems, progress in this field highlights the promise of molecular approaches for improving survival of patients with this disease.

Distribution and Clinical Analysis of EpCAM+/Vimentin+ Circulating Tumor Cells in High-Risk Population and Cancer Patients

Circulating Tumor Cells (CTCs) are already present in the peripheral blood of patients with early tumors and even precancerous lesions. The objective of this study was to determine the count of CTCs in peripheral blood from high-risk population(HRP), healthy subjects and patients with Pan-cancer. The CTCs in the peripheral blood from HRP and cancer patients were enriched and identified based on the positive sorting method by epithelial cell adhesion molecular (EpCAM) liposome magnetic bead (Ep-LMB) and Vimentin liposome magnetic bead (Vi-LMB). Simultaneously, further analysis was carried out focusing on the clinical characteristics of patients by collecting the peripheral blood samples from healthy subjects as the parallel control. According to the results, the prepared LMBs had high specificity and stability, resulting in an average (Av) proliferation rate of over 90% for each cell line, and the average capture rate of higher than 80%. In terms of CTCs count detection in clinical blood samples, the average count was 0.9 (Ep: Av=0.6, Vi: Av=0.3), 2.4 (Ep: Av=1.4, Vi: Av=0.8) and 7.3 (Ep: Av=4.0, Vi: Av=3.3) in healthy subjects, HRP and total cancer patients, respectively. Besides, there was no obvious difference in the average count of CTCs among patients with different cancer types. While count of CTCs in the aforementioned cancer patients was statistically different from that in healthy subjects and patients with HRP. The survival time of cancer patients whose number of CTCs is greater than the average is significantly increased. Collectively, the study confirmed that CTCs can achieve early tumor detection and auxiliary diagnosis, and its number is related to the occurrence and development of tumors, and CTCs can be detected in HRP and sub-health population.

Blood biomarkers for differential diagnosis and early detection of pancreatic cancer

Pancreatic cancer is currently the most lethal tumor entity and case numbers are rising. It will soon be the second most frequent cause of cancer-related death in the Western world. Mortality is close to incidence and patient survival after diagnosis stands at about five months. Blood-based diagnostics could be one crucial factor for improving this dismal situation and is at a stage that could make this possible. Here, we are reviewing the current state of affairs with its problems and promises, looking at various molecule types. Reported results are evaluated in the overall context. Also, we are proposing steps toward clinical utility that should advance the development toward clinical application by improving biomarker quality but also by defining distinct clinical objectives and the respective diagnostic accuracies required to achieve them. Many of the discussed points and conclusions are highly relevant to other solid tumors, too.

Small Cell Size Circulating Aneuploid Cells as a Biomarker of Prognosis in Resectable Non-Small Cell Lung Cancer

Objective

The size distribution of circulating aneuploid cells (CACs) and its clinical significance were investigated in resectable non-small cell lung cancer (NSCLC).

Patients and Methods

A total of 50 patients with resectable NSCLC were enrolled in this study. Blood samples (50 pre-surgery and 35 post-surgery) were collected and used for the detection of CAC chromosome 8 heteroploidy through the subtraction enrichment and immunostaining fluorescence in situ hybridization (SE-iFISH) method.

Results

Less than 20% small cell size and more than 80% large cell size CACs were detected. Karyotypes, including triploid, tetraploid, and multiploid, had varying distributions. The triploid subtype accounted for the majority of small cell size CACs, whereas the multiploid subtype accounted for the majority of large cell size CACs. We found that total small cell size and triploid small cell size CACs, but not large cell size CACs, derived from pre-surgery samples, were associated with shorter disease-free survival. Moreover, total small cell size and triploid small cell size CACs were associated with higher TNM stage and recurrence. Nevertheless, the variation between pre- and post-surgery CACs was not related to survival among patients with resectable NSCLC.

Conclusions

Pre-surgery small cell size CACs, especially the triploid subtype, could be regarded as a potential prognostic biomarker for patients with resectable NSCLC.

Diagnostic, Predictive and Prognostic Molecular Biomarkers in Pancreatic Cancer: An Overview for Clinicians

Simple Summary

Pancreatic cancer is the fourth most common cancer-related cause of death in the United States and is usually asymptomatic in early stages. There is a scarcity of tests that facilitate early diagnosis or accurately predict the disease progression. To this end, biomarkers have been identified as important tools in the diagnosis and management of pancreatic cancer. Despite the increasing number of biomarkers described in the literature, most of them have demonstrated moderate sensitivity and/or specificity and are far from being considered as screening tests. More efficient non-invasive biomarkers are needed to facilitate early-stage diagnosis and interventions. Multi-disciplinary collaboration might be required to facilitate the identification of such markers.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is the most common pancreatic malignancy and is associated with aggressive tumor behavior and poor prognosis. Most patients with PDAC present with an advanced disease stage and treatment-resistant tumors. The lack of noninvasive tests for PDAC diagnosis and survival prediction mandates the identification of novel biomarkers. The early identification of high-risk patients and patients with PDAC is of utmost importance. In addition, the identification of molecules that are associated with tumor biology, aggressiveness, and metastatic potential is crucial to predict survival and to provide patients with personalized treatment regimens. In this review, we summarize the current literature and focus on newer biomarkers, which are continuously added to the armamentarium of PDAC screening, predictive tools, and prognostic tools.