Circulating Tumor Cell Phenotype Predicts Recurrence and Survival in Pancreatic Adenocarcinoma

Stem cell-like circulating tumor cells identified by Pep@MNP and their clinical significance in pancreatic cancer metastasis

Objective

The circulating tumor cells (CTCs) could be captured by the peptide functionalized magnetic nanoparticles (Pep@MNP) detection system in pancreatic ductal adenocarcinoma (PDAC). CTCs and the CXCR4 expression were detected to explore their clinical significance. The CXCR4+ CTCs, this is highly metastatic-prone stem cell-like subsets of CTCs (HM-CTCs), were found to be associated with the early recurrence and metastasis of PDAC.

Methods

CTCs were captured by Pep@MNP. CTCs were identified via immunofluorescence with CD45, cytokeratin antibodies, and the CXCR4 positive CTCs were assigned to be HM-CTCs.

Results

The over-expression of CXCR4 could promote the migration of pancreatic cancer cell in vitro and in vivo. In peripheral blood (PB), CTCs were detected positive in 79.0% of all patients (49/62, 9 (0-71)/2mL), among which 63.3% patients (31/49, 3 (0-23)/2mL) were HM-CTCs positive. In portal vein blood (PVB), CTCs were positive in 77.5% of patients (31/40, 10 (0-40)/2mL), and 67.7% of which (21/31, 4 (0-15)/2mL) were HM-CTCs positive CTCs enumeration could be used as diagnostic biomarker of pancreatic cancer (AUC = 0.862), and the combination of CTCs positive and CA19-9 increase shows improved diagnostic accuracy (AUC = 0.963). in addition, PVB HM-CTCs were more accurate to predict the early recurrence and liver metastasis than PB HM-CTCs (AUC 0.825 vs. 0.787 and 0.827 vs. 0.809, respectively).

Conclusions

The CTCs identified by Pep@MNP detection system could be used as diagnostic and prognostic biomarkers of PDAC patients. We identified and defined the CXCR4 over-expressed CTC subpopulation as highly metastatic-prone CTCs, which was proved to identify patients who were prone to suffering from early recurrence and metastasis.

Cancer-related cells and oncosomes in the liquid biopsy of pancreatic cancer patients undergoing surgery

Pancreatic ductal adenocarcinoma (PDAC) has a five-year survival rate of less than 10% due to its late diagnosis, rapid metastasis, and chemotherapeutic resistance. For a small proportion (10-20%) of early-stage patients however, surgical resection of the pancreatic tumor offers the best chance for survival but the effect of surgery on disease dissemination is unknown. The primary objective of this study was to characterize cellular and acellular blood-based analytes in portal and peripheral blood before pancreatic manipulation, during tumor dissection and immediately after surgical resection to determine the effects of the surgery. This study used the non-enriching third generation High-Definition Single Cell Assay (HDSCA3.0) workflow to investigate heterogeneous circulating rare cell population in the blood. Blood from both sites taken before surgical manipulation of the pancreas had significantly greater incidence of total rare cellular and acellular analytes than normal donor samples. Post-surgery portal and peripheral blood had significantly greater incidence of specific cellular and acellular subtypes compared to the matched pre- and during-surgery samples. Our results reveal that in patients with PDAC liquid biopsy analytes are increased in both the portal and peripheral blood; portal blood contains a higher frequency of analytes than in the peripheral blood; total analytes in the portal and peripheral blood samples were significantly associated with the tumor volume and pathological T stage; and the surgical procedure increased the blood levels of circulating cellular and acellular analytes, but not Epi.CTCs or Mes.CTCs. This study demonstrates liquid biopsy's utility in monitoring patients with PDAC with surgically resectable disease.

Circulating Tumor Cells are an Independent Risk Factor for Poor Prognosis in Patients with Gallbladder Adenocarcinoma

BACKGROUND

The study aimed to evaluate the prognostic impact of circulating tumor cells (CTCs) in patients with gallbladder adenocarcinoma after resection.

MATERIALS AND METHODS

Between January 2018 and January 2021, 101 consecutive patients with gallbladder adenocarcinoma were included. CTCs were detected and enumerated using the CanPatrol® technique. The follow-up period ended in January 2023. The cancer-specific survival (CSS) and disease-free survival (DFS) were calculated using log-rank and Cox regression analyses.

RESULTS

CTCs were detected positively in 61.54% (8/13) of the patients in the non-operation group and 13.64% (12/88) in the operation group. In the operation group, the median CSS for CTCs-positive and CTCs-negative patients was 5.0 and 9.5 months (P < 0.001), respectively, and DFS was 2.8 and 5.0 months at stage III (P < 0.001), respectively. In the non-operation group, the median CSS for CTCs-positive and CTCs-negative patients was 3.5 and 6.5 months (P = 0.0031), respectively. The median CSS for CTCs-positive patients in the operation group was similar to that in the non-operation group (P = 0.67). Multivariate analyses showed that positive CTCs was an independent risk factor for poor CSS (HR 0.066, 95% CI 0.021-0.206, P < 0.001) as well as lymph infiltration (HR 0.320, 95% CI 0.110-0.930, P = 0.036), without R0 curative resection (HR 7.520, 95% CI 2.100-26.931, P = 0.002), and without adjuvant chemotherapy (HR 7.730, 95% CI 2.416-24.731, P < 0.001).

CONCLUSION

Positive CTCs was an independent predictor of poor prognosis after resection in patients with gallbladder adenocarcinoma. Preoperative detection of CTCs may play an important guiding role in formulating treatment strategies for these patients.

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.

Phenotypic characteristics of circulating tumor cells and predictive impact for efficacy of chemotherapy in patients with pancreatic cancer: a prospective study

Objective

Early chemoresistance and tumor mass progression are associated with poor prognosis in pancreatic ductal adenocarcinoma (PDAC). Circulating tumor cells (CTCs) have been studied as potential predictors of treatment response and prognosis in PDAC; however, this approach has yet to be applied in clinical practice. The aim of our study was to investigate the phenotypic characteristics of CTCs and determine their predictive value for PDAC progression.

Methods

We prospectively enrolled 40 patients who were pathologically diagnosed with PDAC and collected blood samples at diagnosis, 2 months after diagnosis, and during disease progression or recurrence. We used a microfabricated filter-based enrichment system to retrieve and analyze CTCs, which were classified using immunofluorescence staining (CD45, EpCAM, and vimentin).

Results

Our study included 20 women and 20 men (median age, 66 years). Overall, 45% of the patients (18/40) had disseminated disease, and 77.5% (31/40) received chemotherapy. Multivariate analysis revealed that the total CTC count and carbohydrate antigen 19-9 level at 2 months after diagnosis were associated with disease progression (P<0.05). Linear mixed model analysis revealed that the total CTC count and vimentin-positive CTCs were significantly correlated with treatment response during chemotherapy (P=0.024 and 0.017, respectively). Kaplan-Meier analysis showed that total CTC positivity at 2 months was significantly associated with poor progression-free survival (P=0.038).

Conclusion

Our study's findings suggest that CTCs can serve as predictive biomarkers of clinical outcomes in patients with PDAC receiving palliative chemotherapy. In particular, the total CTC count and vimentin-positive CTCs showed changes associated with the chemotherapy response.

Persistent Circulating Tumor Cells at 1 Year After Oncologic Resection Predict Late Recurrence in Pancreatic Cancer

OBJECTIVE

The aim of the study was to assess the association between persistent circulating tumor cells (CTCs) and subsequent recurrence in patients who were clinically recurrence free ~12 months postoperatively.

BACKGROUND

Circulating tumor cells have been proposed as biomarkers to predict survival in pancreatic cancer. Some patients demonstrate persistent CTCs postoperatively, which could represent minimal residual disease.

METHODS

Patients from previously published prospective circulating tumor cell in pancreatic cancer trial without clinical evidence of recurrence 12 months postoperatively and CTC testing performed 9 to 15 months postoperatively were included. The presence of epithelial and transitional CTCs (trCTCs) was evaluated as predictor of recurrence. Kaplan-Meier curve, log-rank test, and Cox model were used for survival analysis.

RESULTS

Thirty-three of 129 eligible patients (circulating tumor cell in pancreatic cancer trial) were included. The trCTC-positive and negative patients were well balanced in clinicopathologic features. Patients with trCTCs had a recurrence rate per-person-month of 10.3% compared with 3.1% in trCTCs-negative patients with a median time to recurrence of 3.9 versus 27.1 months, respectively. On multivariable analysis, trCTCs positivity was associated with higher risk of late recurrence (hazard ratio: 4.7, 95% CI, 1.2-18.3, P =0.024). Fourteen (42.4%) patients recurred during the second postoperative year. One-year postoperative trCTCs positivity was associated with a higher rate of recurrence during the second year (odds ratio:13.1, 95% CI, 1.6-1953.4, P =0.028, area under curve=0.72). Integrating clinicopathologic features with trCTCs increased the area under curve to 0.80. A majority of trCTCs-positive patients (N=5, 62.5%) had multisite recurrence, followed by local-only (N=2, 25.0%) and liver-only (N=1, 12.5%) recurrence. This was in striking contrast to trCTCs-negative patients, where a majority (N=6, 66.7%) had a local-only recurrence, followed by liver-only (N=2, 22.2%) and multisite (N=1, 11.1%) recurrence.

CONCLUSIONS

In patients deemed to be clinically disease-free 12 months postoperatively, trCTCs positivity is associated with higher rates of subsequent recurrence with distinct patterns of recurrence. CTCs could be used a putative biomarker to guide patient prognostication and management in pancreatic cancer.

A Delay in Adjuvant Therapy Is Associated With Worse Prognosis Only in Patients With Transitional Circulating Tumor Cells After Resection of Pancreatic Ductal Adenocarcinoma

OBJECTIVES

The aim of the study was to assess the association of circulating tumor cells (CTCs) with survival as a biomarker in pancreatic ductal adenocarcinoma (PDAC) within the context of a delay in the initiation of adjuvant therapy.

BACKGROUND

Outcomes in patients with PDAC remain poor and are driven by aggressive systemic disease. Although systemic therapies improve survival in resected patients, factors such as a delay in the initiation of adjuvant therapy are associated with worse outcomes. CTCs have previously been shown to be predictive of survival.

METHODS

A retrospective study was performed on PDAC patients enrolled in the prospective CircuLating tUmor cellS in pancreaTic cancER trial (NCT02974764) on CTC-dynamics at the Johns Hopkins Hospital. CTCs were isolated based on size (isolation by size of epithelial tumor cells; Rarecells) and counted and characterized by subtype using immunofluorescence. The preoperative and postoperative blood samples were used to identify 2 CTC types: epithelial CTCs (eCTCs), expressing pancytokeratin, and transitional CTCs (trCTCs), expressing both pancytokeratin and vimentin. Patients who received adjuvant therapy were compared with those who did not. A delay in the receipt of adjuvant therapy was defined as the initiation of therapy ≥8 weeks after surgical resection. Clinicopathologic features, CTCs characteristics, and outcomes were analyzed.

RESULTS

Of 101 patients included in the study, 43 (42.5%) experienced a delay in initiation and 20 (19.8%) did not receive adjuvant therapy. On multivariable analysis, the presence of trCTCs ( P =0.002) and the absence of adjuvant therapy ( P =0.032) were associated with worse recurrence-free survival (RFS). Postoperative trCTC were associated with poorer RFS, both in patients with a delay in initiation (12.4 vs 17.9 mo, P =0.004) or no administration of adjuvant chemotherapy (3.4 vs NR, P =0.016). However, it was not associated with RFS in patients with timely initiation of adjuvant chemotherapy ( P =0.293).

CONCLUSIONS

Postoperative trCTCs positivity is associated with poorer RFS only in patients who either experience a delay in initiation or no receipt of adjuvant therapy. This study suggests that a delay in the initiation of adjuvant therapy could potentially provide residual systemic disease (trCTCs) a window of opportunity to recover from the surgical insult. Future studies are required to validate these findings and explore the underlying mechanisms involved.

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.

Contemporary practice and perception of autologous blood salvage in hepato-pancreatico-biliary operations: an international survey

BACKGROUND

This study aimed to assess contemporary knowledge, attitudes and behaviors around transfusion of intraoperative salvaged blood (sRBCt) during hepato-pancreatico-biliary (HPB) operations. Findings are meant to inform the design of future studies that address provider concerns to change behaviors and improve patient outcomes.

METHODS

A survey was designed and assessed for relevance, readability and content, and distributed to an international audience of surgeons performing HPB operations.

RESULTS

The 237 respondents were predominantly distributed across North America (37.55%), Europe (27.43%) and Asia (19.83%). Roughly one-half (52.74%) of respondents had used sRBCt in HPB surgery before. Transplantation surgeons were more likely than HPB surgeons to have previously used sRBCt [odds ratio = 5.18 (95% CI 1.89-14.20)]. More respondents believed sRBCt was safe for non-cancer versus cancer operations (68.57% vs. 24.17%, p < 0.0001). Less than half (45.71%) of respondents believed that sRBCt was safe in clean-contaminated fields. Most did not utilize preoperative strategies to avoid donor transfusion.

CONCLUSION

Practices related to sRBCt in HPB operations vary widely and there is no consensus on its use. Concerns seem primarily related to cancer-specific and infectious outcomes. While further studies are pursued, surgeons may increase their utilization of preoperative strategies to boost hemoglobin levels for at risk patients.

μ-opioid receptor agonist facilitates circulating tumor cell formation in bladder cancer via the MOR/AKT/Slug pathway: a comprehensive study including randomized controlled trial

BACKGROUND

μ-opioid receptor agonists (MORAs) are indispensable for analgesia in bladder cancer (BC) patients, both during surgery and for chronic pain treatment. Whether MORAs affect BC progression and metastasis remains largely unknown. This study focused on the effects of MORAs on the formation of circulating tumor cells (CTCs) in BC and aimed to provide potential therapeutic targets, which would retain the pain-relieving effects of MORAs in BC patients without sacrificing their long-term prognosis.

METHODS

Different preclinical models were used to identify the effects of MORAs on the progression of BC. A novel immunocapture microfluidic chip was utilized to analyze whether MORAs affected the number of CTCs in mouse models and clinical BC patients. Bioinformatic analyses, total transcriptome sequencing, and molecular biology methods were then used to investigate the underlying mechanisms in these models and in BC cell lines.

RESULTS

Mouse models of hematogenous metastasis and in situ BC demonstrated that tumor metastasis was significantly increased after MORA treatment. A significant increase in the number of mesenchymal and/or epithelial CTCs was detected after MORA treatment in both the mouse models and clinical trial patients. Mechanistically, MORAs facilitated the formation of CTCs by activating the MOR/PI3K/AKT/Slug signaling pathway, hereby promoting the epithelial-mesenchymal transition (EMT) of BC cells, as knockdown of MOR, Slug or blockade of PI3K inhibited the EMT process and CTC formation.

CONCLUSION

MORAs promoted BC metastasis by facilitating CTC formation. The EMT-CTC axis could be targeted for preventive measures during MORA treatment to inhibit the associated tumor metastasis or recurrence in BC patients.

Importance of triple tumor markers as biomarkers in patients with pancreatic ductal adenocarcinoma

Aim

There is an urgent need to establish biomarkers for the treatment of pancreatic ductal adenocarcinoma (PDAC). The aim of this study was to investigate the usefulness of the combined assessment of carbohydrate antigen 19-9 (CA19-9), carcinoembryonic antigen (CEA), and duke pancreatic monoclonal antigen type 2 (DUPAN-2) in PDAC.

Methods

We retrospectively investigated the impact of three tumor markers on overall survival (OS) and recurrence-free survival (RFS). Patients were classified into two groups: upfront surgery (US) and neoadjuvant chemoradiation (NACRT) groups.

Results

In total, 310 patients were evaluated. In the US group, patients who had all three elevated markers showed a significantly worse prognosis than the others (median: 16.4 months, P = .005). In the NACRT group, patients who had elevated CA 19-9 and CEA levels after NACRT had significantly worse prognosis than the others (median: 26.2 months, P < .001). The elevated DUPAN-2 levels before NACRT were associated with significantly worse prognosis than normal levels (median: 44.0 vs 59.2 months, P = .030). Patients who had elevated DUPAN-2 levels before NACRT with elevated CA 19-9 and CEA levels after NACRT showed extremely poor RFS (median: 5.9 months). Multivariate analysis revealed that a modified triple-positive tumor marker indicating elevated DUPAN-2 levels before NACRT and elevated CA19-9 and CEA levels after NACRT was an independent prognostic factor of OS (hazard ratio: 2.49, P = .007) and RFS (hazard ration: 2.47, P = .007).

Conclusions

The combined evaluation of three tumor markers may provide useful information for the treatment of patients with PDAC.

Coadaptation fostered by the SLIT2-ROBO1 axis facilitates liver metastasis of pancreatic ductal adenocarcinoma

To explore the mechanism of coadaptation and the potential drivers of pancreatic ductal adenocarcinoma (PDAC) metastasis to the liver, we study key molecules involved in this process and their translational value. Premetastatic niche (PMN) and macrometastatic niche (MMN) formation in a mouse model is observed via CT combined with 3D organ reconstruction bioluminescence imaging, and then we screen slit guidance ligand 2 (SLIT2) and its receptor roundabout guidance receptor 1 (ROBO1) as important factors. After we confirm the expression and distribution of SLIT2 and ROBO1 in samples from PDAC patients and several mouse models, we discover that SLIT2-ROBO1-mediated coadaptation facilitated the implantation and outgrowth of PDAC disseminated tumour cells (DTCs) in the liver. We also demonstrate the dependence receptor (DR) characteristics of ROBO1 in a follow-up mechanistic study. A neutralizing antibody targeting ROBO1 significantly attenuate liver metastasis of PDAC by preventing the coadaptation effect. Thus, we demonstrate that coadaptation is supported by the DR characteristics in the PMN and MMN.

Liquid biopsy leads to a paradigm shift in the treatment of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most cancers. Its 5-year survival rate is very low. The recent induction of neoadjuvant chemotherapy and improvements in chemotherapy for patients with pancreatic cancer have resulted in improved survival outcomes. However, the prognosis of pancreatic cancer is still poor. To dramatically improve the prognosis, we need to develop more tools for early diagnosis, treatment selection, disease monitoring, and response rate evaluation. Recently, liquid biopsy (circulating free DNA, circulating tumor DNA, circulating tumor cells, exosomes, and microRNAs) has caught the attention of many researchers as a new biomarker that is minimally invasive, confers low-risk, and displays an overall state of the tumor. Thus, liquid biopsy does not employ the traditional difficulties of obtaining tumor samples from patients with advanced PDAC to investigate their molecular biological status. In addition, it allows for long-term monitoring of the molecular profile of tumor progression. These could help in identifying tumor-specific alterations that use the target structure for tailor-made therapy. Through this review, we highlighted the latest discoveries and advances in liquid biopsy technology in pancreatic cancer research and showed how it can be applied in clinical practice.

Epithelial to Mesenchymal Transition as Mechanism of Progression of Pancreatic Cancer: From Mice to Men

Owed to its aggressive yet subtle nature, pancreatic cancer remains unnoticed till an advanced stage so that in most cases the diagnosis is made when the cancer has already spread to other organs with deadly efficiency. The progression from primary tumor to metastasis involves an intricate cascade of events comprising the pleiotropic process of epithelial to mesenchymal transition (EMT) facilitating cancer spread. The elucidation of this pivotal phenotypic change in cancer cell morphology, initially heretic, moved from basic studies dissecting the progression of pancreatic cancer in animal models to move towards human disease, although no clinical translation of the concept emerged yet. Despite this transition, a full-blown mesenchymal phenotype may not be accomplished; rather, the plasticity of the program and its dependency on heterotopic signals implies a series of fluctuating modifications of cancer cells encompassing mesenchymal and epithelial features. Despite the evidence supporting the activation of EMT and MET during cancer progression, our understanding of the relationship between tumor microenvironment and EMT is not yet mature for a clinical application. In this review, we attempt to resume the knowledge on EMT and pancreatic cancer, aiming to include the EMT among the hallmarks of cancer that could potentially modify our clinical thinking with the purpose of filling the gap between the results pursued in basic research by animal models and those achieved in translational research by surrogate biomarkers, as well as their application for prognostic and predictive purposes.

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.

Circulating Cells with Macrophage-like Characteristics in Cancer: The Importance of Circulating Neoplastic-Immune Hybrid Cells in Cancer

Simple Summary

In cancer, disseminated neoplastic cells circulating in blood are a source of tumor DNA, RNA, and protein, which can be harnessed to diagnose, monitor, and better understand the biology of the tumor from which they are derived. Historically, circulating tumor cells (CTCs) have dominated this field of study. While CTCs are shed directly into circulation from a primary tumor, they remain relatively rare, particularly in early stages of disease, and thus are difficult to utilize as a reliable cancer biomarker. Neoplastic-immune hybrid cells represent a novel subpopulation of circulating cells that are more reliably attainable as compared to their CTC counterparts. Here, we review two recently identified circulating cell populations in cancer—cancer-associated macrophage-like cells and circulating hybrid cells—and discuss the future impact for the exciting area of disseminated hybrid cells.

Abstract

Cancer remains a significant cause of mortality in developed countries, due in part to difficulties in early detection, understanding disease biology, and assessing treatment response. If effectively harnessed, circulating biomarkers promise to fulfill these needs through non-invasive “liquid” biopsy. While tumors disseminate genetic material and cellular debris into circulation, identifying clinically relevant information from these analytes has proven difficult. In contrast, cell-based circulating biomarkers have multiple advantages, including a source for tumor DNA and protein, and as a cellular reflection of the evolving tumor. While circulating tumor cells (CTCs) have dominated the circulating cell biomarker field, their clinical utility beyond that of prognostication has remained elusive, due to their rarity. Recently, two novel populations of circulating tumor-immune hybrid cells in cancer have been characterized: cancer-associated macrophage-like cells (CAMLs) and circulating hybrid cells (CHCs). CAMLs are macrophage-like cells containing phagocytosed tumor material, while CHCs can result from cell fusion between cancer and immune cells and play a role in the metastatic cascade. Both are detected in higher numbers than CTCs in peripheral blood and demonstrate utility in prognostication and assessing treatment response. Additionally, both cell populations are heterogeneous in their genetic, transcriptomic, and proteomic signatures, and thus have the potential to inform on heterogeneity within tumors. Herein, we review the advances in this exciting field.

Diagnostic and prognostic biomarkers in colorectal cancer and the potential role of exosomes in drug delivery

Colorectal cancer (CRC) is third most common cancer with second most common cause of death worldwide. One fourth to one fifth of the CRC cases are detected at advance stage. Early detection of colorectal cancer might help in decreasing mortality and morbidity worldwide. CRC being a heterogeneous disease, new non-invasive approaches are needed to complement and improve the screening and management of CRC. Reliable and early detectable biomarkers would improve diagnosis, prognosis, therapeutic responses, and will enable the prediction of drug response and recurrence risk. Over the past decades molecular research has demonstrated the potentials of CTCs, ctDNAs, circulating mRNA, ncRNAs, and exosomes as tumor biomarkers. Non-invasive screening approaches using fecal samples for identification of altered gut microbes in CRC is also gaining attention. Exosomes can be potential candidates that can be employed in the drug delivery system. Further, the integration of in vitro, in vivo and in silico models that involve CRC biomarkers will help to understand the interactions occurring at the cellular level. This review summarizes recent update on CRC biomarkers and their application along with the nanoparticles followed by the application of organoid culture in CRC.

Association of Matrix Metalloproteinase 7 Expression With Pathologic Response After Neoadjuvant Treatment in Patients With Resected Pancreatic Ductal Adenocarcinoma

Importance

The use of neoadjuvant therapy (NAT) in resectable pancreatic ductal adenocarcinoma (PDAC) remains controversial. A favorable pathologic response (complete or marked tumor regression) to NAT is associated with better outcomes in patients with resected PDAC. The role of NAT for early systemic control compared with immediate surgical resection for PDAC is under investigation. In the era of precision medicine, biomarkers for patient selection and prediction of therapy response are crucial.

Objective

To evaluate the use of assessment for protein expression on fine-needle aspiration (FNA) biopsy specimens in predicting pathologic response to NAT in treatment-naive patients.

Design, Setting, and Participants

This was a single-institution prognostic study from a high-volume center for pancreatic cancer. All specimens were obtained between January 1, 2009, and December 31, 2018, with a median (SE) follow-up of 20.2 (1.4) months. Analysis of the data was performed from October 1, 2019, to April 30, 2021. Targeted RNA sequencing of frozen FNA biopsy specimens from a discovery cohort of 23 patients was performed to identify genes with aberrant expression that was associated with patients' pathologic response to NAT. Immunohistochemical staining was performed on an additional 80 FNA biopsy specimens to assess expression of matrix metalloproteinase 7 (MMP-7) and its association with pathologic response. Receiver operating characteristic curves for prediction of favorable pathologic response were determined.

Results

In the discovery cohort (12 [52.1%] male; 3 [13.0%] Black and 20 [86.9%] White), RNA sequencing showed that lower MMP-7 expression was associated with favorable pathologic response (College of American Pathologists system scores of 0 [complete response] and 1 [marked response]). In the validation cohort (40 [50.0%] female; 9 [11.3%] Black and 71 [88.7%] White), patients with negative MMP-7 expression were significantly more likely to have a favorable pathologic response (odds ratio, 21.25; 95% CI, 6.19-72.95; P = .001). Receiver operating characteristic curves for prediction of favorable pathologic response from multivariable Cox proportional hazards regression modeling showed that MMP-7 expression increased the area under the curve from 0.726 to 0.906 (P < .001) even after stratifying by resectability status. The positive predictive value and negative predictive value of MMP-7 protein expression on FNA biopsy specimens in predicting unfavorable pathologic response (scores of 2 [partial response] or 3 [poor or no response]) were 88.2% and 73.9%, respectively.

Conclusions and Relevance

Assessment of MMP-7 expression on FNA biopsy specimens at the time of diagnosis may help identify patients who would benefit the most from NAT.

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.

Clinical Applications of Classical and Novel Biological Markers of Pancreatic Cancer

The incidence and prevalence of pancreatic adenocarcinoma have increased in recent years. Pancreatic cancer is the seventh leading cause of cancer death, but it is projected to become the second leading cause of cancer-related mortality by 2040. Most patients are diagnosed in an advanced stage of the disease, with very limited 5-year survival. The discovery of different tissue markers has elucidated the underlying pathophysiology of pancreatic adenocarcinoma and allowed stratification of patient risk at different stages and assessment of tumour recurrence. Due to the invasive capacity of this tumour and the absence of screening markers, new immunohistochemical and serological markers may be used as prognostic markers for recurrence and in the study of possible new therapeutic targets because the survival of these patients is low in most cases. The present article reviews the currently used main histopathological and serological markers and discusses the main characteristics of markers under development.

Recurrence and Prognostic Value of Circulating Tumor Cells in Resectable Pancreatic Head Cancer: A Single Center Retrospective Study

Background and Aim

To investigate the effect of preoperative circulation tumor cells (CTCs) on postoperative recurrence and overall survival prognosis of pancreatic head cancer after pancreaticoduodenectomy (PD).

Methods

From March 2014 to January 2018, 73 patients with pancreatic head cancer underwent radical resection (R0) in Zhongshan People's Hospital. CTCs in peripheral blood of patients with pancreatic head cancer were detected by “Cyttel” method before PD. Seventy-three patients were divided into positive and negative groups according to the positive criteria. To explore the relationship between the clinical data of CTCs and disease-free survival (DFS) and overall survival (OS). Cox proportional hazards model was used to analyzing the risk factors affecting the postoperative recurrence and the survival prognosis of patients.

Results

41 patients (56.2%) were in the CTC-positive group. Preoperative CTCs were correlated with tumor vascular invasion, CA199 level and postoperative liver metastasis (P < 0.05). Preoperative CTC-positive, lymph node metastasis, vascular invasion, and nerve invasion were independent risk factors for DFS (P < 0.05). Preoperative CTC-positive, tumor diameter > 2 cm and vascular invasion were independent risk factors for OS of patients (P < 0.05).

Conclusion

The detection of CTCs before PD is an important factor affecting the DFS and OS of pancreatic head cancer, which is significant in guiding clinical work.

Cell Salvage in Oncological Surgery, Peripartum Haemorrhage and Trauma

Oncological surgery, obstetric haemorrhage and severe trauma are the most challenging conditions for establishing clinical recommendations for the use of cell salvage. When the likelihood of allogeneic transfusion is high, the intraoperative use of this blood-saving technique would be justified, but specific patient selection criteria are needed. The main concerns in the case of oncological surgery are the reinfusion of tumour cells, thereby increasing the risk of metastasis. This threat could be minimized, which may help to rationalize its indication. In severe peripartum haemorrhage, cell salvage has not proven cost-effective, damage control techniques have been developed, and, given the risk of fetomaternal alloimmunization and amniotic fluid embolism, it is increasingly out of use. In trauma, bleeding may originate from multiple sites, coagulopathy may develop, and it should be evaluated whether re-transfusion of autologous blood collected from uncontaminated organ cavities would be feasible. General safety measures include washing recovered blood and its passage through leukocyte depletion filters. To date, no well-defined indications for cell salvage have been established for these pathologies, but with accurate case selection and selective implementation, it could become safe and effective. Randomized clinical trials are urgently needed.

A Combination of Biochemical and Pathological Parameters Improves Prediction of Postresection Survival After Preoperative Chemotherapy in Pancreatic Cancer: The PANAMA-score

OBJECTIVE

To build a prognostic score for patients with primary chemotherapy undergoing surgery for pancreatic cancer based on pathological parameters and preoperative Carbohydrate antigen 19-9 (CA19-9) levels.

BACKGROUND

Prognostic stratification after primary chemotherapy for pancreatic cancer is challenging and prediction models, such as the AJCC staging system, lack validation in the setting of preoperative chemotherapy.

METHODS

Patients with primary chemotherapy resected at the Massachusetts General Hospital between 2007 and 2017 were analyzed. Tumor characteristics independently associated with overall survival were identified and weighted by Cox-proportional regression. The pancreatic neoadjuvant Massachusetts-score (PANAMA-score) was computed from these variables and its performance assessed by Harrel concordance index and area under the receiving characteristics curves analysis. Comparisons were made with the AJCC staging system and external validation was performed in an independent cohort with primary chemotherapy from Heidelberg, Germany.

RESULTS

A total of 216 patients constituted the training cohort. The multivariate analysis demonstrated tumor size, number of positive lymph-nodes, R-status, and high CA19-9 to be independently associated with overall survival. Kaplan-Meier analysis according to low, intermediate, and high PANAMA-score showed good discriminatory power of the new metrics (P < 0.001). The median overall survival for the three risk-groups was 45, 27, and 12 months, respectively. External validation in 258 patients confirmed the prognostic ability of the score and demonstrated better accuracy compared with the AJCC staging system.

CONCLUSION

The proposed PANAMA-score, based on independent predictors of postresection survival, including pathologic variables and CA19-9, not only provides better discrimination compared to the AJCC staging system, but also identifies patients at high-risk for early death.

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.

MIR-203A-3P AND MMP-2 PROTEINS ARE HIGHLY EXPRESSED IN CIRCULATING TUMOR CELLS FROM PATIENTS WITH PANCREATIC CARCINOMA

OBJECTIVES

Ductal adenocarcinoma of the pancreas is the fourth most common cancer-associated cause of death in the Western world. The presence of circulating tumor cells (CTCs) can be considered a potential prognostic factor, as these cells represent tumor progression, allowing monitoring of therapeutic efficacy. The objectives of this study were to explore the morphological, molecular, and phenotypic characteristics of CTCs from the blood of patients with pancreatic carcinoma and to correlate the findings with response to treatment, progression-free survival, overall survival (OS), and deep vein thrombosis (DVT).

METHODS

Peripheral blood (10 mL) was analyzed before the beginning of treatment after 60 and 120 days. CTCs were detected by using ISET® and characterized by immunocytochemistry. For microRNAs (miRNAs) analysis, peripheral leukocytes from the same patients and healthy individuals (controls) were collected in parallel at baseline. The expression of miRNAs was evaluated (in pool) using TaqMan® Array Human MicroRNA Cards v2.0.

RESULTS

Only nine patients were included. The proteins, namely, matrix metalloproteinase-2 (MMP2) and TGFβ-RI, were highly expressed (77.7%) in CTCs at baseline; at the first follow-up, MMP2 was predominant (80%) and, at the second follow-up, MMP2 and vimentin were predominant (50%). Circulating tumor microemboli (CTMs) were found in two patients and both presented DVT. The miR-203a-3p was highly expressed in CTCs. The miR-203a-3p is involved in the stimulation of epithelial-to-mesenchymal transition (EMT) and is related to worse OS in pancreatic cancer (TCGA data).

CONCLUSION

Due to the low number of patients and short follow-up, we did not observe a correlation between CTCs and response to treatment. However, there was a correlation between CTM and DVT and also miR-203a-3p was highly expressed in CTCs, corroborating the findings of EMT proteins. This study opens the perspectives concerning the dynamic change in the pattern of proteins expressed along with treatment and the use of miRNAs as new targets in pancreatic carcinoma.

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.

Favorable tumor biology in locally advanced pancreatic cancer-beyond CA19-9

Patients with pancreatic ductal adenocarcinoma (PDAC) are frequently staged as unresectable locally advanced pancreatic cancer (LAPC) at the time of diagnosis. Recently, the administration of multi-agent induction chemotherapy has resulted in treatment response in up to 60% of these patients rendering their tumors technically resectable. Operative strategies have evolved to allow for successful oncologic resection of LAPC. These technically complex procedures involving vascular resections and reconstructions are now being performed with increasing safety at high-volume centers. However, even after induction therapy and successful resection, disease recurrence sometimes occurs early on, limiting the benefit of resecting the local tumor. Therefore, selection of surgical candidates should factor in each patient's tumor biology which could result in accurate treatment guidance to improve patient outcomes while avoiding overtreatment. Well-informed patient selection is critical to improve outcomes in LAPC. Multidisciplinary teams have to determine the appropriate care for LAPC patients at the time of reevaluation after administration of induction chemotherapy. At this point the concept of favorable vs. unfavorable tumor biology becomes highly relevant and having access to biomarkers that are predictive of tumor behavior are of paramount importance. Currently, CA19-9 remains the only clinically utilized biomarker for PDAC, however, its use is limited by factors discussed in this review. While CA19-9 holds value in patient assessment, additional biomarkers are required that could supplement and improve the current ability to classify tumor biology and predict behavior in individual patients. Recent investigations on the use of circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs) using liquid biopsies, as well as patient-derived organoids to characterize tumor biology have shown promise in achieving precise tumor biology-based patient stratification. Serial assessment of these biomarkers throughout therapy could supplement or even replace the anatomic criteria for resectability in the future.

Comprehensive Analysis of Somatic Mutations in Driver Genes of Resected Pancreatic Ductal Adenocarcinoma Reveals KRAS G12D and Mutant TP53 Combination as an Independent Predictor of Clinical Outcome

BACKGROUND

Prognosis in pancreatic ductal adenocarcinoma (PDAC) remains poor despite improved systemic therapies and surgical techniques. The identification of biomarkers to advance insight in tumor biology and achieve better individualized prognostication could help improve outcomes. Our aim was to elucidate the prognostic role of the four main driver mutations (KRAS, TP53, SMAD4, CDKN2A) and their combinations in resected PDAC.

PATIENTS AND METHODS

A retrospective analysis was conducted utilizing the cBioPortal database and National Cancer Institute's Cancer Genomic Atlas (TCGA) on patients in whom next-generation sequencing was performed on upfront resected PDAC from 2012 to 2020. Multivariable Cox regression was implemented to elucidate risk-adjusted predictors of overall (OS) and recurrence-free survival (RFS). Results were validated employing a Johns Hopkins Hospital (JHH) cohort.'

RESULTS

In the discovery cohort (n = 587), increased number of mutated driver genes was associated with worse OS (p = 0.047). Specifically, patients with mutations in ≥ 2 driver genes had worse OS than ≤ 1 mutated gene (18.2 versus 32.3 months, p = 0.033). Co-occurrence of mutant (mt)KRAS p.G12D with mtTP53 (median OS, 25.9 months) conferred better prognosis than co-occurrence of other mtKRAS variants (p.G12V/R/other) with mtTP53 (median OS, 16.9 months, p = 0.038). The findings were validated using a JHH cohort. Multivariable risk-adjustment found co-occurrence of mtKRAS p.G12D with mtTP53 to be an independent predictor of beneficial OS and RFS [HR (95% CI): 0.18 (0.03-0.81) and 0.31 (0.11-0.89) respectively].

CONCLUSION

In chemo-naïve resected PDAC, combinations of mutations in the four driver genes are associated with prognosis. In patients with combined mtKRAS and mtTP53, KRAS p.G12D variant confers a better OS and RFS.

Epithelial to Mesenchymal Transition: A Challenging Playground for Translational Research. Current Models and Focus on TWIST1 Relevance and Gastrointestinal Cancers

Resembling the development of cancer by multistep carcinogenesis, the evolution towards metastasis involves several passages, from local invasion and intravasation, encompassing surviving anoikis into the circulation, landing at distant sites and therein establishing colonization, possibly followed by the outgrowth of macroscopic lesions. Within this cascade, epithelial to mesenchymal transition (EMT) works as a pleiotropic program enabling cancer cells to overcome local, systemic, and distant barriers against diffusion by replacing traits and functions of the epithelial signature with mesenchymal-like ones. Along the transition, a full-blown mesenchymal phenotype may not be accomplished. Rather, the plasticity of the program and its dependency on heterotopic signals implies a pendulum with oscillations towards its reversal, that is mesenchymal to epithelial transition. Cells in intermixed E⇔M states can also display stemness, enabling their replication together with the epithelial reversion next to successful distant colonization. If we aim to include the EMT among the hallmarks of cancer that could modify clinical practice, the gap between the results pursued in basic research by animal models and those achieved in translational research by surrogate biomarkers needs to be filled. We review the knowledge on EMT, derived from models and mechanistic studies as well as from translational studies, with an emphasis on gastrointestinal cancers (GI).

Circulating Tumor Cell Clusters Are Cloaked with Platelets and Correlate with Poor Prognosis in Unresectable Pancreatic Cancer

Circulating tumor cells (CTCs) are known to be heterogeneous and clustered with tumor-associated cells, such as macrophages, neutrophils, fibroblasts, and platelets. However, their molecular profile and clinical significance remain largely unknown. Thus, we aimed to perform a comprehensive gene expression analysis of single CTCs and CTC clusters in patients with pancreatic cancer and to identify their potential clinical relevance to provide personalized medicine. Epitope-independent, rapid (>3 mL of whole blood/min) isolation of single CTCs and CTC clusters was achieved from a prospective cohort of 16 patients with unresectable pancreatic cancer using a centrifugal microfluidic device. Forty-eight mRNA expressions of individual CTCs and CTC clusters were analyzed to identify pancreatic CTC phenotype. CTC clusters had a larger proportion of mesenchymal expression than single CTCs (p = 0.0004). The presence of CTC clusters positively correlated with poor prognosis (progression-free survival, p = 0.0159; overall survival, p = 0.0186). Furthermore, we found that most CTCs in these patients (90.7%) were cloaked with platelets and found the presence of a positive correlation between the increase in CTC clusters and rapid disease progression during follow-ups. Efficient CTC cluster isolation and analysis techniques will enhance the understanding of complex tumor metastasis processes and can facilitate personalized disease management.

Comparison of hormonal receptor expression and HER2 status between circulating tumor cells and breast cancer metastases

OBJECTIVES

Breast cancer (BC) is the most common neoplasm in women. Biopsy of metastatic lesions is recommended to confirm estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) status as there are discrepancies in these patterns between primary tumors and metastases in up to 40% of the cases. Circulating tumor cells (CTCs) are related to BC outcomes and could potentially be an alternative to the invasive procedures of metastasis rebiopsy. ISET® technology is not currently employed to detect CTCs in patients with BC. Emerging data support that the characterization of CTC protein expression can refine its prognostic value. Transforming growth factor (TGF)-β plays a role in BC progression and invasiveness. Thus, in this study, we aimed to compare ER, PR, and HER2 expression in primary tumors, CTCs, and metastases and evaluate TGF-β type 1 receptor (TGF-β RI) expression in CTCs as prognostic factor for progression free survival (PFS) and overall survival (OS).

METHODS

This prospective study was conducted at the A.C. Camargo Cancer Center, Brazil. Blood samples were processed in ISET® (Isolation by SizE of Tumors, Rarecells, France) before computed tomography-guided biopsy of suspected metastatic lesions. Protein expression levels in CTCs were compared to those in primary tumors/metastases (medical records).

RESULTS

Of the 39 patients initially included, 27 underwent both biopsies of metastases and blood collection and were considered for analysis. The concordance rates for ER, PR, and HER2 expression between primary tumors and metastases were high. No loss of HER2 expression at any metastasis site and retention of the same pattern of protein expression in all triple-negative (TN) tumors (92.5%, 81.5% and 96.2% respectively) (p<0.0001) was observed. When metastases/CTCs were classified as TN/non-TN, CTCs showed high specificity (93%), accuracy (84.2%), and negative predictive value (88%). The median OS of patients without TGF-β RI expression in CTCs was 42.6 versus 20.8 months for TGF-β RI expression-positive ones (p>0.05).

CONCLUSION

The role of CTCs detected by ISET has not yet been established in BC. Here, we suggest that this methodology may be useful to evaluate metastasis in non-TN cases as well as TGF-β RI expression in CTCs, which may impact patient survival. Due to sample limitations, future studies must focus on specific BC subtypes and an expansion of the cohort.

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.

HGF/c-Met Inhibition as Adjuvant Therapy Improves Outcomes in an Orthotopic Mouse Model of Pancreatic Cancer

BACKGROUND

Inhibition of hepatocyte growth factor (HGF)/c-MET pathway, a major mediator of pancreatic stellate cell (PSC)-PC cell interactions, retards local and distant cancer progression. This study examines the use of this treatment in preventing PC progression after resection. We further investigate the postulated existence of circulating PSCs (cPSCs) as a mediator of metastatic PC.

METHODS

Two orthotopic PC mouse models, produced by implantation of a mixture of luciferase-tagged human pancreatic cancer cells (AsPC-1), and human PSCs were used. Model 1 mice underwent distal pancreatectomy 3-weeks post-implantation (n = 62). One-week post-resection, mice were randomised to four treatments of 8 weeks: (i) IgG, (ii) gemcitabine (G), (iii) HGF/c-MET inhibition (HiCi) and (iv) HiCi + G. Tumour burden was assessed longitudinally by bioluminescence. Circulating tumour cells and cPSCs were enriched by filtration. Tumours of Model 2 mice progressed for 8 weeks prior to the collection of primary tumour, metastases and blood for single-cell RNA-sequencing (scRNA-seq).

RESULTS

HiCi treatments: (1) reduced both the risk and rate of disease progression after resection; (2) demonstrated an anti-angiogenic effect on immunohistochemistry; (3) reduced cPSC counts. cPSCs were identified using immunocytochemistry (α-smooth muscle actin+, pan-cytokeratin-, CD45-), and by specific PSC markers. scRNA-seq confirmed the existence of cPSCs and identified potential genes associated with development into cPSCs.

CONCLUSIONS

This study is the first to demonstrate the efficacy of adjuvant HGF/c-Met inhibition for PC and provides the first confirmation of the existence of circulating PSCs.

CD44+ Circulating Tumor Endothelial Cells Indicate Poor Prognosis in Pancreatic Ductal Adenocarcinoma After Radical Surgery: A Pilot Study

Background

Circulating tumor endothelial cells (CTECs) are cells that originate from tumor endothelial cells (TECs) of blood vessels and are shed into peripheral blood. Some studies have shown that CTECs are associated with tumor angiogenesis, growth and indicate prognosis in patients with malignant solid tumor. However, the role of CTECs especially the phenotype of CTECs in pancreatic adenocarcinoma (PDAC) is still not clear. We investigated the relationship between CTECs and patients’ prognosis.

Methods

A total of 73 patients with resectable PDAC were enrolled in our research and underwent radical surgery. Peripheral venous blood samples were collected before surgery, on postoperative day (POD) 7 and on postoperative month (POM) 1, respectively. We used integrated subtraction enrichment and immunostaining-fluorescence in situ hybridization (SE-iFISH) platform to identify and enumerate CTECs. Immunofluorescence was used to identify CTECs expressing CD44 and vimentin.

Results

In patients with early tumor recurrence (DFS< 6 months), the preoperative CD44+ CTEC levels showed significantly higher (P = 0.023). Univariate and multivariate analysis showed that history of diabetes [HR 2.656 (1.194–5.908), P = 0.017], numbers of positive lymph nodes [HR 1.871 (1.388–2.522), P < 0.001], preoperative numbers of CD44+ CTECs [HR 1.216 (1.064–1.390), P = 0.004], and POM1 CA19-9 level [HR 1.002 (1.001–1.002), P < 0.001] were independent prognostic factors for DFS.

Conclusion

The detection of CD44+CTECs in patients with resectable PDAC preoperatively could be an independent predictor of shorter DFS after radical surgery.

Management of Locally Advanced Pancreatic Cancer: Results of an International Survey of Current Practice

OBJECTIVE

The aim of this study was to investigate surgeon preferences for the management of patients with locally advanced pancreatic cancer (LAPC).

BACKGROUND

Select patients with LAPC may become candidates for curative resection following neoadjuvant therapy, and recent reports of survival are encouraging. Yet the optimal management approach remains unclear.

METHODS

An extensive electronic survey was systematically distributed by email to an international cohort of pancreas surgeons. Data collected included practice characteristics, management preferences, attitudes regarding contraindications to surgery, and 6 clinical vignettes of patients that ultimately received a margin negative resection (with detailed videos of post-neoadjuvant imaging) to assess propensity for surgical exploration if resection status is not known.

RESULTS

A total of 153 eligible responses were received from 4 continents. Median duration of practice is 12 years (interquartile range 6-20) and 77% work in a university setting. Most surgeons (86%) are considered high volume (>10 resections/yr), 33% offer a minimally-invasive approach, and 50% offer arterial resections in select patients. Most (72%) always recommend neoadjuvant chemotherapy, and 65% prefer FOLFIRINOX. Preferences for the duration of chemotherapy varied widely: 39% prefer ≥2 months, 43% prefer ≥4 months, and 11% prefer ≥6 months. Forty-one percent frequently recommend neoadjuvant radiotherapy, and 53% prefer 5 to 6 weeks of chemoradiation. The proportion of surgeons favoring exploration following neoadjuvant varied extensively across 5 vignettes of LAPC, from 14% to 53%. In a vignette of oligometastatic liver metastases, 31% would offer exploration if a favorable therapy response is observed.

CONCLUSIONS

In an international cohort of pancreas surgeons, there is substantial variation in management preferences, perceived contraindications to surgery, and the propensity to consider exploration in LAPC. These results emphasize the importance of a robust and nuanced multidisciplinary discussion for each patient, and suggest an evolving concept of "resectability."

Circulating tumor-cell-targeting Au-nanocage-mediated bimodal phototherapeutic properties enriched by magnetic nanocores

Metastasis resulting from circulating tumor cells (CTCs) is associated with 90% of all cancer mortality. To disrupt cancer dissemination, therapeutic targeting of CTCs by extracorporeal photodynamic therapy (PDT) has emerged; however, it still remains impractical due to its limited therapeutic window. Herein, we developed a photosensitive and magnetic targeted core-satellite nanomedicine (TCSN) to augment the light-induced damage to the targeted cells. The magnetic nanocore (MNC) with multiple iron oxide nanoparticles stabilized using thiolated polyvinyl alcohol can magnetize the CTCs to achieve magnetic enrichment under a magnetic field. Multiple gold nanocage (AuNC) satellites were conjugated on the MNC to facilitate bimodal photothermal therapy and PDT. Adjusting the thiol content in the MNC allows manipulating the AuNC density on TCSNs, which has been found to demonstrate a density-dependent bimodal phototherapeutic effect under laser irradiation at 808 and 940 nm. Moreover, with the immobilization of anti-epithelial cell adhesion molecule (anti-EpCAM), TCSN exhibited an enhanced affinity toward EpCAM-expressing 4T1 cells. We demonstrate that TCSN-labeled 4T1 cells can be isolated and photo-eradicated in a microfluidic channel with a dynamic flow. Our studies showed that TCSN with the complementary properties of MNC and AuNCs can largely augment the therapeutic window by magnetic enrichment and bimodal phototherapy, serving as an advanced extracorporeal strategy to remove CTCs.

Perioperative Predictors of Early Recurrence for Resectable and Borderline-Resectable Pancreatic Cancer

Simple Summary

Most patients with a pancreatic ductal adenocarcinoma develop a recurrence after surgery. Predictive factors may therefore guide therapeutic decision-making. We aimed to identify perioperative predictors of the early recurrence of pancreatic ductal adenocarcinomas. We found that preoperative (>52 U/mL) and postoperative (>37 U/mL) elevated carbohydrate antigen 19-9 levels as well as a tumor size >3.0 cm were independently associated with an early recurrence after a pancreatectomy. Furthermore, an early recurrence resulted in a more frequent liver metastasis than a late recurrence, suggesting that patients experiencing a recurrence within 12 months had undetectable micrometastases. Further studies are needed to identify new biomarkers for the detection of clinically occult micrometastases during surgery as current preoperative risk factors are inadequate to accurately identify patients susceptible to an early recurrence of pancreatic ductal adenocarcinomas.

Abstract

We aimed to identify the perioperative predictors of the early recurrence (ER) of resectable and borderline-resectable pancreatic ductal adenocarcinomas (PDACs). After surgery for a PDAC, most patients develop a recurrence. Predictive factors may therefore guide therapeutic decision-making. Patients (n = 234) who underwent a pancreatectomy for a PDAC between 2006 and 2019 were included. The postrecurrence survival (PRS) was estimated using Kaplan–Meier curves. Predictive factors for an ER were assessed using logistic regression analyses; 93 patients (39.7%) were recurrence-free at the last follow-up. Patients with an ER (n = 85, 36.3%), defined as a recurrence within the first 12 months after surgery, had 1- and 2-year PRS rates of 38.7% and 9.5%, respectively, compared with 66.9% and 37.2% for those with a late recurrence (n = 56, 23.9%; both p < 0.001). The most common site of an ER was the liver (55.3%) with a significantly shorter median overall survival time than that with either a local or a lung recurrence (14.5 months; p < 0.001). Preoperative and postoperative risk factors for an ER included a tumor size >3.0 cm (odds ratio (OR): 3.11, 95% confidence interval (CI): 1.35–7.14) and preoperative carbohydrate antigen 19-9 (CA19-9) levels >52 U/mL (OR: 3.25, 95% CI: 1.67–6.30) and a pathological tumor size >3.0 cm (OR: 2.00, 95% CI: 1.03–3.90) and postoperative carbohydrate antigen 19-9 levels >37 U/mL (OR: 2.11, 95% CI: 1.02–4.36), respectively. Preoperatively (>52 U/mL) and postoperatively (>37 U/mL) elevated CA19-9 and a tumor size >3.0 cm were independent predictors for an ER after a pancreatectomy for a PDAC.

An Immunocompetent Model of Pancreatic Cancer Resection and Recurrence

BACKGROUND

Even after surgical resection, most patients with localized pancreatic ductal adenocarcinoma (PDAC) succumb to disease recurrence. Current animal models do not recapitulate this pattern of disease recurrence. Our goal was to develop a clinically relevant, immunocompetent model of PDAC resection to study recurrence and evaluate therapy.

METHODS

Pancreatic cancer cells derived from tumors arising in KPC (LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx-1-Cre) mice were co-injected with stromal cells (pancreatic stellate cells) into the pancreas of immunocompetent mice to simulate the stroma-rich tumors seen in human PDAC. After allowing tumors to form, we resected these localized tumors and followed the mice for tumor recurrence. Circulating tumor cells (CTCs) were isolated, and systemic chemotherapy or immunotherapy was administered following tumor resection.

RESULTS

Tumors formed by co-injection of KPC cells and stromal cells demonstrated a dense desmoplastic reaction similar to that seen in human disease. Resection at days 15 and 21 after implantation revealed uniform tumor volumes of 92 ± 19 mm3 on day 15 and 444 ± 54 mm3 on day 21. Histology of resected tumors showed negative margins. Resembling human PDAC, mice that underwent resection showed improved median survival (58 vs 47 days) but most animals developed intra-abdominal recurrence on follow-up. Adjuvant chemotherapy (median survival 69 vs 58 days), but not immunotherapy (median survival 69 vs 65 days) tended towards improved survival as seen in human disease. Circulating tumor cells were reliably identified from mice with and without resection, suggesting utility of this model in studying tumor metastases and recurrence.

CONCLUSION

We describe an immunocompetent animal model that recapitulates human disease in morphology and recurrence patterns. We show that it can be used to evaluate therapy in clinical scenarios associated with surgical resection and may help characterize factors responsible for disease recurrence.

Liquid Biopsy in Pancreatic Cancer: Are We Ready to Apply It in the Clinical Practice?

Pancreatic ductal adenocarcinoma (PDAC) exhibits the poorest prognosis of all solid tumors, with a 5-year survival of less than 10%. To improve the prognosis, it is necessary to advance in the development of tools that help us in the early diagnosis, treatment selection, disease monitoring, evaluation of the response and prognosis. Liquid biopsy (LB), in its different modalities, represents a particularly interesting tool for these purposes, since it is a minimally invasive and risk-free procedure that can detect both the presence of genetic material from the tumor and circulating tumor cells (CTCs) in the blood and therefore distantly reflect the global status of the disease. In this work we review the current status of the main LB modalities (ctDNA, exosomes, CTCs and cfRNAs) for detecting and monitoring PDAC.

Characterisation of circulating tumour cell phenotypes identifies a partial-EMT sub-population for clinical stratification of pancreatic cancer

BACKGROUND

Limited accessibility of the tumour precludes longitudinal characterisation for therapy guidance in pancreatic ductal adenocarcinoma (PDAC).

METHODS

We utilised dielectrophoresis-field flow fractionation (DEP-FFF) to isolate circulating tumour cells (CTCs) in 272 blood draws from 74 PDAC patients (41 localised, 33 metastatic) to non-invasively monitor disease progression.

RESULTS

Analysis using multiplex imaging flow cytometry revealed four distinct sub-populations of CTCs: epithelial (E-CTC), mesenchymal (M-CTC), partial epithelial-mesenchymal transition (pEMT-CTC) and stem cell-like (SC-CTC). Overall, CTC detection rate was 76.8% (209/272 draws) and total CTC counts did not correlate with any clinicopathological variables. However, the proportion of pEMT-CTCs (prop-pEMT) was correlated with advanced disease, worse progression-free and overall survival in all patients, and earlier recurrence after resection.

CONCLUSION

Our results underscore the importance of immunophenotyping and quantifying specific CTC sub-populations in PDAC.

Expression and analysis of PD-L1 in peripheral blood circulating tumor cells of lung cancer

Aim: PD-L1 is an important immune intervention target for lung cancer treatment; however, its clinical significance and biological function in circulating tumor cells (CTCs) of lung cancer need to be explored in depth. Materials & methods: In this study, the CanPatrol method was used to detect three types of CTCs and PD-L1 in 271 lung cancer patients from December 2015 to October 2019. Results: Smoking index, pathological diagnosis and clinical stage are independent influencing factors of PD-L1 expression. The methods that affect the count of CTCs are first-line chemotherapy and targeted therapy; however, there is no difference in the expression of PD-L1 with different treatments. Conclusions: The detection of CTCs and PD-L1 in peripheral blood is helpful for the diagnosis of lung cancer patients.

Preoperative CTC-Detection by CellSearch® Is Associated with Early Distant Metastasis and Impaired Survival in Resected Pancreatic Cancer

In patients with presumed pancreatic ductal adenocarcinoma (PDAC), biomarkers that may open for personalised, risk-adapted treatment are lacking. The study analysed the impact of CTCs-presence on the patterns of recurrence and survival in 98 patients resected for PDAC with 5-10 years of follow-up. Preoperative samples were analysed by the CellSearch^® system for EpCAM+/DAPI+/CK+/CD45-CTCs. CTCs were detected in 7 of the 98 patients. CTCs predicted a significantly shorter median disease-free survival (DFS) of 3.3 vs. 9.2 months and a median cancer specific survival (CSS)of 6.3 vs. 18.5 months. Relapse status was confirmed by imaging for 87 patients. Of these, 58 patients developed distant metastases (DM) and 29 developed isolated local recurrence (ILR) as the first sign of cancer relapse. All patients with CTCs experienced DM. pN-status and histological grade >2 were other independent risk factors for DM, but only CTCs predicted significantly shorter cancer-specific, disease-free and post-recurrence survival. Preoperative parameters did not affect clinical outcome. We conclude that CTC presence in resected PDAC patients predicted early distant metastasis and impaired survival. Preoperative CTCs alone or in combination with histopathological factors may guide initial treatment decisions in patients with resectable PDAC in the future.

Essential updates 2018/2019: Current topics in the surgical treatment of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is highly malignant. While cancers in other organs have shown clear improvements in 5-year survival, the 5-year survival rate of pancreatic cancer is approximately 10%. Early relapse and metastasis are not uncommon, making it difficult to achieve an acceptable prognosis even after complete surgical resection of the pancreas. Studies have been performed on various treatments to improve the prognosis of PDAC, and multidisciplinary approaches including non-surgical treatments have led to gradual improvement. In the present literature review, we have described the significance of anatomical and biological resectability criteria, the concept of R0 resection in surgical treatment, the feasibility of minimally invasive surgery, the remarkable development of perioperative chemotherapy, the effectiveness of conversion surgery for unresectable PDAC, and ongoing challenges in PDAC treatment. We also provide an essential update on these subjects by focusing on recent trends and topics.

Circulating tumour cells in pancreatic cancer: A systematic review and meta-analysis of clinicopathological implications

BACKGROUND

The detection and quantification of circulating tumour cells (CTCs) in pancreatic cancer (PC) has the potential to provide prognostic information. The aim of this review was to provide an overview of the literature surrounding CTCs in PC.

METHODS

A systematic literature review on CTCs in PC between 2005-2020 was performed. Data based on peripheral vein samples were used to determine the positivity rate of CTCs, their prognostic significance and their relative numbers compared to portal vein (PV) samples.

RESULTS

The overall CTC detection rate in forty-four articles was 65% (95%CI: 55-75%). Detection rate for CellSearch was 26% (95%CI: 14-38%), which was lower than for both filtration and microfluidic techniques. In nine studies with >50 patients, overall survival was worse with CTC positivity (HR 1.82; 95%CI: 1.61-2.05). Five of seven studies which described PV CTC collection provided patient-level data. PV CTC yield was 7.7-fold (95%CI 1.35-43.9) that of peripheral blood.

CONCLUSIONS

CTCs were detected in the peripheral circulation of most patients with PC and may be related to prognosis and disease stage. PV blood contains more CTCs than peripheral blood sampling. This review points to the maturation of techniques of CTC enrichment, and its evidence base for eventual clinical deployment.

Mysteries, Epistemological Modesty, and Artificial Intelligence in Surgery

Life is filled with puzzles and mysteries, and we often fail to recognize the difference. As described by Gregory Treverton and Malcolm Gladwell, puzzles are solved by gathering and assimilating all relevant data in a logical, linear fashion, as in deciding which antibiotic to prescribe for an infection. In contrast, mysteries remain unsolved until all relevant data are analyzed and interpreted in a way that appreciates their depth and complexity, as in determining how to best modulate the host immune response to infection. When investigating mysteries, we often fail to appreciate their depth and complexity. Instead, we gather and assimilate more data, treating the mystery like a puzzle. This strategy is often unsuccessful. Traditional approaches to predictive analytics and phenotyping in surgery use this strategy.

Beyond just a tight fortress: contribution of stroma to epithelial-mesenchymal transition in pancreatic cancer

Novel effective treatment is direly needed for patients with pancreatic ductal adenocarcinoma (PDAC). Therapeutics that target the driver mutations, especially the KRAS oncoprotein and its effector cascades, have been ineffective. It is increasing clear that the extensive fibro-inflammatory stroma (or desmoplasia) of PDAC plays an active role in the progression and therapeutic resistance of PDAC. The desmoplastic stroma is composed of dense extracellular matrix (ECM) deposited mainly by the cancer-associated-fibroblasts (CAFs) and infiltrated with various types of immune cells. The dense ECM functions as a physical barrier that limits tumor vasculatures and distribution of therapeutics to PDAC cells. In addition, mounting evidence have demonstrated that both CAFs and ECM promote PDAC cells aggressiveness through multiple mechanisms, particularly engagement of the epithelial-mesenchymal transition (EMT) program. Acquisition of a mesenchymal-like phenotype renders PDAC cells more invasive and resistant to therapy-induced apoptosis. Here, we critically review seminal and recent articles on the signaling mechanisms by which each stromal element promotes EMT in PDAC. We discussed the experimental models that are currently employed and best suited to study EMT in PDAC, which are instrumental in increasing the chance of successful clinical translation.