Programmed cell death 1 inhibitor sintilimab plus S-1 and gemcitabine for liver metastatic pancreatic ductal adenocarcinoma

BACKGROUND Pancreatic ductal adenocarcinoma(PDAC)is a highly aggressive cancer with poor prognosis.When it metastasizes to the liver,treatment options become particularly limited and challenging.Current treatment options for liver metastatic PDAC are limited,and chemotherapy alone often proves insufficient.Immunotherapy,particularly programmed cell death 1(PD-1)inhibitors like sintilimab,shows potential efficacy for various cancers but has limited reports on PDAC.This study compares the efficacy and safety of sintilimab plus S-1 and gemcitabine vs S-1 and gemcitabine alone in liver metastatic PDAC.AIM To explore the feasibility and effectiveness of combined PD-1 inhibitor sintilimab and S-1 and gemcitabine(combination group)vs S-1 and gemcitabine used alone(chemotherapy group)for treating liver metastatic pancreatic adenocarcinoma.METHODS Eligible patients were those with only liver metastatic PDAC,an Eastern Cooperative Oncology Group performance status of 0-1,adequate organ and marrow functions,and no prior anticancer therapy.Participants in the combination group received intravenous sintilimab 200 mg every 3 weeks,oral S-140 mg/m²twice daily on days 1-14 of a 21-day cycle,and intravenous gemcitabine 1000 mg/m²on days 1 and 8 of the same cycle for up to eight cycles or until disease progression,death,or unacceptable toxicity.Participants in the chemotherapy group received oral S-140 mg/m²twice daily on days 1-14 of a 21-day cycle and intravenous gemcitabine 1000 mg/m²on days 1 and 8 of the same cycle for up to eight cycles.Between June 2020 and December 2021,66 participants were enrolled,with 32 receiving the combination treatment and 34 receiving chemotherapy alone.RESULTS The group receiving the combined therapy exhibited a markedly prolonged median overall survival(18.8 months compared to 10.3 months,P<0.05)and progression-free survival(9.6 months vs 5.4 months,P<0.05).compared to the chemotherapy group.The incidence of severe adverse events did not differ significantly between the two groups(P>0.05).CONCLUSION The combination of PD-1 inhibitor sintilimab with S-1 and gemcitabine demonstrated effectiveness and safety for treating liver metastatic PDAC,meriting further investigation.

Combining prognostic value of serum carbohydrate antigen 19-9 and tumor size reduction ratio in pancreatic ductal adenocarcinoma

BACKGROUND Pancreatic ductal adenocarcinoma(PDAC)is a common cancer with increasing morbidity and mortality due to changes of social environment.AIM To evaluate the significance of serum carbohydrate antigen 19-9(CA19-9)and tumor size changes pre-and post-neoadjuvant therapy(NAT).METHODS This retrospective study was conducted at the Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment,Chongqing University Cancer Hospital.This study specifically assessed CA19-9 levels and tumor size before and after NAT.RESULTS A total of 156 patients who completed NAT and subsequently underwent tumor resection were included in this study.The average age was 65.4±10.6 years and 72(46.2%)patients were female.Before survival analysis,we defined the post-NAT serum CA19-9 level/pre-NAT serum CA19-9 level as the CA19-9 ratio(CR).The patients were divided into three groups:CR<0.5,CR>0.5 and<1 and CR>1.With regard to tumor size measured by both computed tomography and magnetic resonance imaging,we defined the post-NAT tumor size/pre-NAT tumor size as the tumor size ratio(TR).The patients were then divided into three groups:TR<0.5,TR>0.5 and<1 and TR>1.Based on these groups divided according to CR and TR,we performed both overall survival(OS)and disease-free survival(DFS)analyses.Log-rank tests showed that both OS and DFS were significantly different among the groups according to CR and TR(P<0.05).CR and TR after NAT were associated with increased odds of achieving a complete or near-complete pathologic response.Moreover,CR(hazard ratio:1.721,95%CI:1.373-3.762;P=0.006),and TR(hazard ratio:1.435,95%CI:1.275-4.363;P=0.014)were identified as independent factors associated with OS.CONCLUSION This study demonstrated that post-NAT serum CA19-9 level/pre-NAT serum CA19-9 level and post-NAT tumor size/pre-NAT tumor size were independent factors associated with OS in patients with PDAC who received NAT and subsequent surgical resection.

Postoperative serum tumor markers-based nomogram predicting early recurrence for patients undergoing radical resections of pancreatic ductal adenocarcinoma

BACKGROUND Early recurrence(ER)is associated with dismal outcomes in patients undergoing radical resection for pancreatic ductal adenocarcinoma(PDAC).Approaches for predicting ER will help clinicians in implementing individualized adjuvant therapies.Postoperative serum tumor markers(STMs)are indicators of tumor progression and may improve current systems for predicting ER.AIM To establish an improved nomogram based on postoperative STMs to predict ER in PDAC.METHODS We retrospectively enrolled 282 patients who underwent radical resection for PDAC at our institute between 2019 and 2021.Univariate and multivariate Cox regression analyses of variables with or without postoperative STMs,were performed to identify independent risk factors for ER.A nomogram was constructed based on the independent postoperative STMs.Receiver operating characteristic curve analysis was used to evaluate the area under the curve(AUC)of the nomogram.Survival analysis was performed using Kaplan-Meier survival plot and log-rank test.RESULTS Postoperative carbohydrate antigen 19-9 and carcinoembryonic antigen levels,preoperative carbohydrate antigen 125 levels,perineural invasion,and pTNM stage III were independent risk factors for ER in PDAC.The postoperative STMs-based nomogram(AUC:0.774,95%CI:0.713-0.835)had superior accuracy in predicting ER compared with the nomogram without postoperative STMs(AUC:0.688,95%CI:0.625-0.750)(P=0.016).Patients with a recurrence nomogram score(RNS)>1.56 were at high risk for ER,and had significantly poorer recurrence-free survival[median:3.08 months,interquartile range(IQR):1.80-8.15]than those with RNS≤1.56(14.00 months,IQR:6.67-24.80),P<0.001).CONCLUSION The postoperative STMs-based nomogram improves the predictive accuracy of ER in PDAC,stratifies the risk of ER,and identifies patients at high risk of ER for tailored adjuvant therapies.

Mixed pancreatic ductal adenocarcinoma and well-differentiated neuroendocrine tumor:A case report

BACKGROUND Pancreatic mixed neuroendocrine-non-neuroendocrine neoplasms(MiNENs)are rare malignancies affecting the pancreas.The World Health Organization defines MiNENs as neoplasms composed of morphologically recognizable neuroendocrine and non-neuroendocrine components,each constituting 30%or more of the tumor volume.Adenocarcinoma-neuroendocrine carcinoma is the most frequent MiNEN combination.A well-differentiated neuroendocrine tumor(NET)component is rarely reported in MiNENs.CASE SUMMARY Here we report a rare case with intermingled components of ductal adenocarcinoma and grade 1 well-differentiated NET in the pancreas.The two tumors show distinct histology and significant differentiation discrepancy(poorly differentiated high grade adenocarcinoma and well-differentiated low grade NET),and also present as metastases in separate lymph nodes.Next generation sequencing of the two components demonstrates KRAS and TP53 mutations in the ductal adenocarcinoma,but no genetic alterations in the NET,suggesting divergent origins for these two components.Although tumors like this meet the diagnostic criteria for MiNEN,clinicians often find the diagnosis and staging confusing and impractical for clinical management.CONCLUSION Mixed NET/non-NET tumors with distinct histology and molecular profiles might be better classified as collision tumors rather than MiNENs.

Prognostic significance of grade of malignancy based on histopathological differentiation and Ki-67 in pancreatic ductal adenocarcinoma

Objective:Tumor cell malignancy is indicated by histopathological differentiation and cell proliferation.Ki-67,an indicator of cellular proliferation,has been used for tumor grading and classification in breast cancer and neuroendocrine tumors.However,its prognostic significance in pancreatic ductal adenocarcinoma(PDAC)remains uncertain.Methods:Patients who underwent radical pancreatectomy for PDAC were retrospectively enrolled,and relevant prognostic factors were examined.Grade of malignancy(GOM),a novel index based on histopathological differentiation and Ki-67,is proposed,and its clinical significance was evaluated.Results:The optimal threshold for Ki-67 was determined to be 30%.Patients with a Ki-67 expression level>30%rather than≤30%had significantly shorter 5-year overall survival(OS)and recurrence-free survival(RFS).In multivariate analysis,both histopathological differentiation and Ki-67 were identified as independent prognostic factors for OS and RFS.The GOM was used to independently stratify OS and RFS into 3 tiers,regardless of TNM stage and other established prognostic factors.The tumor-nodemetastasis-GOM stage was used to stratify survival into 5 distinct tiers,and surpassed the predictive performance of TNM stage for OS and RFS.Conclusions:Ki-67 is a valuable prognostic indicator for PDAC.Inclusion of the GOM in the TNM staging system may potentially enhance prognostic accuracy for PDAC.

PRaG 3.0 therapy for human epidermal growth factor receptor 2-positive metastatic pancreatic ductal adenocarcinoma:A case report

BACKGROUND Pancreatic ductal adenocarcinoma(PDAC)is a highly fatal disease with limited effective treatment especially after first-line chemotherapy.The human epidermal growth factor receptor 2(HER-2)immunohistochemistry(IHC)positive is associated with more aggressive clinical behavior and shorter overall survival in PDAC.CASE SUMMARY We present a case of multiple metastatic PDAC with IHC mismatch repair proficient but HER-2 IHC weakly positive at diagnosis that didn’t have tumor regression after first-line nab-paclitaxel plus gemcitabine and PD-1 inhibitor treatment.A novel combination therapy PRaG 3.0 of RC48(HER2-antibody-drug conjugate),radio-therapy,PD-1 inhibitor,granulocyte-macrophage colony-stimulating factor and interleukin-2 was then applied as second-line therapy and the patient had confirmed good partial response with progress-free-survival of 6.5 months and overall survival of 14.2 month.She had not developed any grade 2 or above treatment-related adverse events at any point.Percentage of peripheral CD8^(+) Temra and CD4^(+) Temra were increased during first two activation cycles of PRaG 3.0 treatment containing radiotherapy but deceased to the baseline during the maintenance cycles containing no radiotherapy.CONCLUSION PRaG 3.0 might be a novel strategy for HER2-positive metastatic PDAC patients who failed from previous first-line approach and even PD-1 immunotherapy but needs more data in prospective trials.

Correlation of dynamic contrast-enhanced ultrasonography and the Ki-67 labelling index in pancreatic ductal adenocarcinoma

BACKGROUND Pancreatic ductal adenocarcinoma(PDAC)is a highly malignant and aggressive tumor,and high Ki-67 expression indicates poor histological differentiation and prognosis.Therefore,one of the challenges in diagnosing preoperatively patients with PDAC is predicting the degree of malignancy.Dynamic contrast-enhanced ultrasonography(DCE-US)plays a crucial role in abdominal tumor diagnosis,and can adequately show the microvascular composition within the tumors.However,the relationship between DCE-US and the Ki-67 labelling index remains unclear at the present time.AIM To predict the correlation between Ki-67 expression and the parameters of DCEUS.METHODS Patients with PDAC who underwent DCE-US were retrospectively analyzed.Patients who had received any treatment(radiotherapy or chemotherapy)prior to DCE-US;had incomplete clinical,imaging,or pathologic information;and had poor-quality image analysis were excluded.Correlations between Ki-67 expression and the parameters of DCE-US in patients with PDAC were assessed using Spearman’s rank correlation analysis.The diagnostic performances of these parameters in high Ki-67 expression group were evaluated according to receiver operating characteristic curve.RESULTS Based on the Ki-67 labelling index,30 patients were divided into two groups,i.e.,the high expression group and the low expression group.Among the relative quantitative parameters between the two groups,relative half-decrease time(rHDT),relative peak enhancement,relative wash-in perfusion index and relative wash-in rate were significantly different between two groups(P=0.018,P=0.025,P=0.028,P=0.035,respectively).The DCE-US parameter rHDT was moderately correlated with Ki-67 expression,and rHDT≥1.07 was more helpful in accurately diagnosing high Ki-67 expression,exhibiting a sensitivity and specificity of 53.8%and 94.1%,respectively.CONCLUSION One parameter of DCE-US,rHDT,correlates with high Ki-67 expression.It demonstrates that parameters obtained noninvasively by DCE-US could better predict Ki-67 expression in PDAC preoperatively.

FAM53B promotes pancreatic ductal adenocarcinoma metastasis by regulating macrophage M2 polarization

BACKGROUND Our study investigated the role of FAM53B in regulating macrophage M2 polarization and its potential mechanisms in promoting pancreatic ductal adenocarcinoma(PDAC)metastasis.AIM To further investigate the role of FAM53B in regulating macrophage M2 polarization and its potential mechanism in promoting PDAC metastasis.Our goal is to determine how FAM53B affects macrophage M2 polarization and to define its underlying mechanism in PDAC metastasis.METHODS Cell culture and various experiments,including protein analysis,immunohisto-chemistry,and animal model experiments,were conducted.We compared FAM53B expression between PDAC tissues and healthy tissues and assessed the correlation of FAM53B expression with clinical features.Our study analyzed the role of FAM53B in macrophage M2 polarization in vitro by examining the expression of relevant markers.Finally,we used a murine model to study the role of FAM53B in PDAC metastasis and analyzed the potential underlying mechanisms.RESULTS Our research showed that there was a significant increase in FAM53B levels in PDAC tissues,which was linked to adverse tumor features.Experimental findings indicated that FAM53B can enhance macrophage M2 polarization,leading to increased anti-inflammatory factor release.The results from the mouse model further supported the role of FAM53B in PDAC metastasis,as blocking FAM53B prevented tumor cell invasion and metastasis.CONCLUSION FAM53B promotes PDAC metastasis by regulating macrophage M2 polarization.This discovery could lead to the development of new strategies for treating PDAC.For example,interfering with the FAM53B signaling pathway may prevent cancer spread.Our research findings also provide important information for expanding our understanding of PDAC pathogenesis.

Computed tomography-based radiomics diagnostic approach for differential diagnosis between early-and late-stage pancreatic ductal adenocarcinoma

BACKGROUND One of the primary reasons for the dismal survival rates in pancreatic ductal adenocarcinoma(PDAC)is that most patients are usually diagnosed at late stages.There is an urgent unmet clinical need to identify and develop diagnostic methods that could precisely detect PDAC at its earliest stages.METHODS A total of 71 patients with pathologically proved PDAC based on surgical resection who underwent contrast-enhanced computed tomography(CT)within 30 d prior to surgery were included in the study.Tumor staging was performed in accordance with the 8th edition of the American Joint Committee on Cancer staging system.Radiomics features were extracted from the region of interest(ROI)for each patient using Analysis Kit software.The most important and predictive radiomics features were selected using Mann-Whitney U test,univar-iate logistic regression analysis,and minimum redundancy maximum relevance(MRMR)method.Random forest(RF)method was used to construct the radiomics model,and 10-times leave group out cross-validation(LGOCV)method was used to validate the robustness and reproducibility of the model.RESULTS A total of 792 radiomics features(396 from late arterial phase and 396 from portal venous phase)were extracted from the ROI for each patient using Analysis Kit software.Nine most important and predictive features were selected using Mann-Whitney U test,univariate logistic regression analysis,and MRMR method.RF method was used to construct the radiomics model with the nine most predictive radiomics features,which showed a high discriminative ability with 97.7%accuracy,97.6%sensitivity,97.8%specificity,98.4%positive predictive value,and 96.8%negative predictive value.The radiomics model was proved to be robust and reproducible using 10-times LGOCV method with an average area under the curve of 0.75 by the average performance of the 10 newly built models.CONCLUSION The radiomics model based on CT could serve as a promising non-invasive method in differential diagnosis between early and late stage PDAC.

Comparison of prognosis and postoperative morbidities between standard pancreaticoduodenectomy and the TRIANGLE technique for resectable pancreatic ductal adenocarcinoma

BACKGROUND Radical surgery combined with systemic chemotherapy offers the possibility of long-term survival or even cure for patients with pancreatic ductal adenocar-cinoma(PDAC),although tumor recurrence,especially locally,still inhibits the treatment efficacy.The TRIANGLE technique was introduced as an extended dissection procedure to improve the R0 resection rate of borderline resectable or locally advanced PDAC.However,there was a lack of studies concerning postoperative complications and long-term outcomes of this procedure on patients with resectable PDAC.PDAC.METHODS Patients with resectable PDAC eligible for PD from our hospital between June 2018 and December 2021 were enrolled in this retrospective cohort study.All the patients were divided into PDstandard and PDTRIANGLE groups according to the surgical procedure.Baseline characteristics,surgical data,and postoperative morbidities were recorded.All of the patients were followed up,and the date and location of tumor recurrence,and death were recorded.The Kaplan-Meier method and log-rank test were used for the survival analysis.RESULTS There were 93 patients included in the study and 37 underwent the TRIANGLE technique.Duration of operation was longer in the PDTRIANGLE group compared with the PDstandard group[440(410-480)min vs 320(265-427)min](P=0.001).Intraoperative blood loss[700(500-1200)mL vs 500(300-800)mL](P=0.009)and blood transfusion[975(0-1250)mL vs 400(0-800)mL](P=0.009)were higher in the PDTRIANGLE group.There was a higher incidence of surgical site infection(43.2%vs 12.5%)(P=0.001)and postoperative diarrhea(54.1%vs 12.5%)(P=0.001)in the PDTRIANGLE group.The rates of R0 resection and local recurrence,overall survival,and disease-free survival did not differ significantly between the two groups.CONCLUSION The TRIANGLE technique is safe,with acceptable postoperative morbidities compared with standardized PD,but it does not improve prognosis for patients with resectable PDAC.

Recurrence scoring system predicting early recurrence for patients with pancreatic ductal adenocarcinoma undergoing pancreatectomy and portomesenteric vein resection

BACKGROUND Pancreatectomy with concomitant portomesenteric vein resection(PVR)enables patients with portomesenteric vein(PV)involvement to achieve radical resection of pancreatic ductal adenocarcinoma,however,early recurrence(ER)is frequently observed.AIM To predict ER and identify patients at high risk of ER for individualized therapy.METHODS Totally 238 patients undergoing pancreatectomy and PVR were retrospectively enrolled and were allocated to the training or validating cohort.Univariate Cox and LASSO regression analyses were performed to construct serum recurrence score(SRS)based on 26 serum-derived parameters.Uni-and multivariate Cox regression analyses of SRS and 18 clinicopathological variables were performed to establish a Nomogram.Receiver operating characteristic curve analysis was used to evaluate the predictive accuracy.Survival analysis was performed using Kaplan-Meier method and log-rank test.RESULTS Independent serum-derived recurrence-relevant factors of LASSO regression model,including postoperative carbohydrate antigen 19-9,postoperative carcinoembryonic antigen,postoperative carbohydrate antigen 125,preoperative albumin(ALB),preoperative platelet to ALB ratio,and postoperative platelets to lymphocytes ratio,were used to construct SRS[area under the curve(AUC):0.855,95%CI:0.786–0.924].Independent risk factors of recurrence,including SRS[hazard ratio(HR):1.688,95%CI:1.075-2.652],pain(HR:1.653,95%CI:1.052-2.598),perineural invasion(HR:2.070,95%CI:0.827-5.182),and PV invasion(HR:1.603,95%CI:1.063-2.417),were used to establish the recurrence nomogram(AUC:0.869,95%CI:0.803-0.934).Patients with either SRS>0.53 or recurrence nomogram score>4.23 were considered at high risk for ER,and had poor long-term outcomes.CONCLUSION The recurrence scoring system unique for pancreatectomy and PVR,will help clinicians in predicting recurrence efficiently and identifying patients at high risk of ER for individualized therapy.

Comparison between solid pseudopapillary neoplasms of the pancreas and pancreatic ductal adenocarcinoma with cystic changes using computed tomography

BACKGROUND Solid pseudopapillary neoplasms of the pancreas(SPN)share similar imaging findings with pancreatic ductal adenocarcinoma with cystic changes(PDAC with cystic changes),which may result in unnecessary surgery.AIM To investigate the value of computed tomography(CT)in differentiation of SPN from PDAC with cystic changes.METHODS This study retrospectively analyzed the clinical and imaging findings of 32 patients diagnosed with SPN and 14 patients diagnosed with PDAC exhibiting cystic changes,confirmed through pathological diagnosis.Quantitative and qualitative analysis was performed,including assessment of age,sex,tumor size,shape,margin,density,enhancement pattern,CT values of tumors,CT contrast enhancement ratios,“floating cloud sign,”calcification,main pancreatic duct dilatation,pancreatic atrophy,and peripancreatic invasion or distal metastasis.Multivariate logistic regression analysis was used to identify relevant features to differentiate between SPN and PDAC with cystic changes,and receiver operating characteristic curves were obtained to evaluate the diagnostic performance of each variable and their combination.RESULTS When compared to PDAC with cystic changes,SPN had a lower age(32 years vs 64 years,P<0.05)and a slightly larger size(5.41 cm vs 3.90 cm,P<0.05).SPN had a higher frequency of“floating cloud sign”and peripancreatic invasion or distal metastasis than PDAC with cystic changes(both P<0.05).No significant difference was found with respect to sex,tumor location,shape,margin,density,main pancreatic duct dilatation,calcification,pancreatic atrophy,enhancement pattern,CT values of tumors,or CT contrast enhancement ratios between the two groups(all P>0.05).The area under the receiver operating characteristic curve of the combination was 0.833(95%confidence interval:0.708-0.957)with 78.6%sensitivity,81.3%specificity,and 80.4%accuracy in differentiation of SPN from PDAC with cystic changes.CONCLUSION A larger tumor size,“floating cloud sign,”and peripancreatic invasion or distal metastasis are useful CT imaging features that are more common in SPN and may help discriminate SPN from PDAC with cystic changes.

Parasympathetic neurogenesis is strongly associated with tumor budding and correlates with an adverse prognosis in pancreatic ductal adenocarcinoma

Objective： To investigate the frequency of parasympathetic neurogenesis and determine its association with tumor budding and prognosis in pancreatic ductal adenocarcinoma （PDAC）. Methods： Parasympathetic neurogenesis was defined as the distribution of abnormal parasympathetic nerves in the stroma tissue. Staining of vesicular acetylcholine transporter （VAChT）, as a marker for parasympathetic neurogenesis, was performed on a representative specimen of the tumor for 59 PDAC patients with available clinical, pathologic, and follow-up information. Three specimens containing normal pancreatic tissues were stained in parallel. The number of parasympathetic nerve fibers was counted in five high-power microscopic fields （5×0.785 mm2）. Cut-offvalues were calculated by receiver operating characteristic curve analysis. Results： VAChT-positive parasympathetic nerve fibers were not seen in the stroma of 3 cases of normal pancreatic tissues. In 59 PDAC cases, the range of parasympathetic neurogenesis was 4-38 fibers/（5×0.785） mm2, with a median of 18 fibers/（5×0.785） mm2. Patients with parasympathetic neurogenesis 〉 15 fibers/（5×0.785） mm2 were defined as the high-density group （39 patients, 66.1%）, and those with parasympathetic neurogenesis 〈15 fibers/（5×0.785） mm2 as the low-density group （20 patients, 33.9%）. The high-density group had a higher occurrence of tumor budding （P=0.001） and a higher rate of early recurrence （P=0.035）. Parasympathetic neurogenesis appeared to be an independent adverse prognostic factor [hazard ratio （HR）=2.45, 95% confidence interval （95% CI）： 1.25-4.81, P=0.009], in addition to American Joint Committee on Cancer （AJCC） stage （P=0.010） and tumor budding （P=0.009）. Conclusions： Parasympathetic neurogenesis is strongly associated with tumor budding and correlates with an adverse prognosis in PDAC.

Pancreatic ductal adenocarcinoma: Treatment hurdles, tumor microenvironment and immunotherapy

Pancreatic ductal adenocarcinoma(PDAC)is one of the most lethal diseases,with an average 5-year survival rate of less than 10%.Unfortunately,the majority of patients have unresectable,locally advanced,or metastatic disease at the time of diagnosis.Moreover,traditional treatments such as chemotherapy,surgery,and radiation have not been shown to significantly improve survival.Recently,there has been a swift increase in cancer treatments that incorporate immunotherapybased strategies to target all the stepwise events required for tumor initiation and progression.The results in melanoma,non-small-cell lung cancer and renal cell carcinoma are very encouraging.Unfortunately,the application of checkpoint inhibitors,including anti-CTLA4,anti-PD-1,and anti-PD-L1 antibodies,in pancreatic cancer has been disappointing.Many studies have revealed that the PDAC microenvironment supports tumor growth,promotes metastasis and consists of a physical barrier to drug delivery.Combination therapies hold great promise for enhancing immune responses to achieve a better therapeutic effect.In this review,we provide an outline of why pancreatic cancer is so lethal and of the treatment hurdles that exist.Particular emphasis is given to the role of the tumor microenvironment,and some of the latest and most promising studies on immunotherapy in PDAC are also presented.

Tumor microenvironment in pancreatic ductal adenocarcinoma:Implications in immunotherapy

Pancreatic ductal adenocarcinoma is one of the most aggressive and lethal cancers.Surgical resection is the only curable treatment option,but it is available for only a small fraction of patients at the time of diagnosis.With current therapeutic regimens,the average 5-year survival rate is less than 10%in pancreatic cancer patients.Immunotherapy has emerged as one of the most promising treatment options for multiple solid tumors of advanced stage.However,its clinical efficacy is suboptimal in most clinical trials on pancreatic cancer.Current studies have suggested that the tumor microenvironment is likely the underlying barrier affecting immunotherapy drug efficacy in pancreatic cancer.In this review,we discuss the role of the tumor microenvironment in pancreatic cancer and the latest advances in immunotherapy on pancreatic cancer.

Locoregional therapies and their effects on the tumoral microenvironment of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma(PDAC) is expected to become the second leading cause of death from cancer by 2030. Despite intensive research in the field of therapeutics, the 5-year overall survival is approximately 8%, with only 20% of patients eligible for surgery at the time of diagnosis. The tumoral microenvironment(TME) of the PDAC is one of the main causes for resistance to antitumoral treatments due to the presence of tumor vasculature, stroma, and a modified immune response. The TME of PDAC is characterized by high stiffness due to fibrosis, with hypo microvascular perfusion, along with an immunosuppressive environment that constitutes a barrier to effective antitumoral treatment. While systemic therapies often produce severe side effects that can alter patients’ quality of life, locoregional therapies have gained attention since their action is localized to the pancreas and can thus alleviate some of the barriers to effective antitumoral treatment due to their physical effects. Local hyperthermia using radiofrequency ablation and radiation therapy-most commonly using a local high single dose-are the two main modalities holding promise for clinical efficacy. Recently, irreversible electroporation and focused ultrasound-derived cavitation have gained increasing attention. To date, most of the data are limited to preclinical studies, but ongoing clinical trials may help better define the role of these locoregional therapies in the management of PDAC patients.

Antitumor effect of VEGFR2-targeted microbubble destruction with gemcitabine using an endoscopic ultrasound probe:In vivo mouse pancreatic ductal adenocarcinoma model

Background:Ultrasound-targeted microbubble destruction(UTMD)induces cellular inflow of drugs at low intensity,while high intensity eradicates tumor vessels.Since vascular endothelial growth factor receptor 2(VEGFR2)is highly expressed in pancreatic ductal adenocarcinoma(PDAC),VEGFR2-targeted microbubble(MB)might additionally increase the tissue specificity of drugs and thus improve antitumor effects.In addition,fixing the dual pulse intensity could maximize MB properties.This study evaluated the one-off(experiment 1)and cumulative(experiment 2)treatment effect of UTMD by regulating the dual pulse output applied to PDAC using VEGFR2-targeted MB.Methods:C57BL/6 mice inoculated with Pan-02 cells were allocated to five groups:VEGFR2-targeted MB+gemcitabine(GEM),VEGFR2-targeted MB,non-targeted MB+GEM,GEM,and control groups.After injection of GEM or GEM and either VEGFR2-targeted or non-targeted MB,UTMD was applied for several minutes at low intensity followed by high intensity application.In experiment 1,mice were treated by the protocol described above and then euthanized immediately or at the tumor diameter doubling time(TDT).In experiment 2,the same protocol was repeated weekly and mice were euthanized at TDT regardless of protocol completion.Histological analysis by CD31 and VEGFR2 staining provided microvascular density(MVD)and VEGFR2 expression along vessels(VEGFR2v)or intra/peripheral cells(VEGFR2c).Results:In experiment 1,TDT was significantly longer in the VEGFR2-targeted MB+GEM group compared to the non-targeted MB+GEM,GEM,and control groups,while the VEGFR2-targeted MB group showed no statistical significance.MVD and VEGFR2v in the immediate euthanasia was significantly lower in the VEGFR2-targeted MB+GEM and VEGFR2-targeted MB groups than other conditions.In experiment 2,the VEGFR2-targeted MB+GEM group produced significantly longer TDT than the GEM or control groups,whereas the VEGFR2-targeted MB group showed no significant difference.Histology revealed significantly reduced VEGFR2v and VEGFR2c in the VEGFR2-targeted and non-targeted MB+GEM groups,while only VEGFR2v was significantly less in the VEGFR2-targeted MB group.Conclusions:UTMD-mediated GEM therapy with the dual pulse application using VEGFR2-targeted MB substantially suppresses PDCA growth.

Targeted drug delivery systems for pancreatic ductal adenocarcinoma:overcoming tumor microenvironment challenges with CAF-specific nanoparticles

Pancreatic ductal adenocarcinoma(PDAC)stands as a profoundly heterogeneous and aggressive malignancy,manifesting a discouragingly limited response to conventional therapeutic interventions.Within the intricate tapestry of the tumor microenvironment(TME),cancer-associated fibroblasts(CAFs)emerge as pivotal constituents,wielding the capacity to propel the malignant attributes of neoplastic cells while bolstering their deftness in thwarting treatments.The rapid evolution of nanomedicinal technologies ushers in fresh avenues for thera-peutic paradigms meticulously honed to target CAFs.Notably,a recent proposition by Yuan et al.introduces a PDAC treatment strategy metaphorically akin to“shooting fish in a barrel.”By adeptly capitalizing on the spatial distribution of the CAF barricade encircling the tumor,this innovative approach orchestrates a metamorphosis of CAFs,transitioning them from impediments to drug delivery into reservoirs of therapeutic agents.The resultant outcome,an augmentation of chemotherapy and immunotherapy efficacy,attests to the transformative potential of this concept.The study not only bequeaths novel insights and methodologies to surmount barriers in drug delivery for tumor treatment but also holds promise in elevating the precision,efficacy,and safety of tailored therapeutic regimens.Within this discourse,we meticulously evaluate Yuan et al.’s research,scrutinizing its merits and limitations,and cast a forward-looking gaze upon the formulation,validation of efficacy,and clinical translation of nanomedicines targeting CAFs.

Expression and signifi cance of TLR4 and HIF-1α in pancreatic ductal adenocarcinoma

AIM:To investigate the expression of toll-like receptor(TLR) 4,nuclear factor-κB(NF-κB) p65 and hypoxiainducible transcription factor 1α(HIF-1α) in pancreatic ductal adenocarcinoma and their clinical significance.METHODS:The mRNA of TLR4 and HIF-1α were investigated by real-time polymerase chain reaction in 30 cases of pancreatic ductal adenocarcinoma and its adjacent tissues,and expression of TLR4,NF-κB p65 and HIF-1α protein were detected by immunohistochemistry in 65 cases of pancreatic ductal adenocarcinoma tissues and 38 cases of corresponding adjacent tissues.The relationship between TLR4 or HIF-1α and pathologic features,as well as the association between TLR4 and HIF-1α,were also analyzed.Kaplan-Meier method was used to assess the impact of expression of TLR4 and HIF-1α on survival of patients with pancreatic cancer.RESULTS:The relative quantif ication of TLR4 and HIF-1α mRNA in tumor tissues was 0.81±0.10 and 0.87±0.11,respectively,signif icantly higher than that in adjacent tissues(0.81±0.10 vs 0.70±0.16,P=0.002;0.87±0.11 vs 0.68±0.13,P=0.000).The protein expression of TLR4,NF-κB p65 and HIF-1α in tumor tissues was 69.20%,66.15% and 70.80%,respectively,being signif icantly higher than that in adjacent normal tissues(69.20% vs 39.50%,P=0.003;66.15% vs 31.58%,P=0.001;70.80% vs 36.80%,P=0.001).There was no signif icant correlation between TLR4 or HIF-1α expression and the age,gender,tumor location,the degree of tumor differentiation in the patients(P>0.05).However,there was signif icant correlation between the expression of TLR4 or HIF-1α and tumor size,lymph node metastasis,venous invasion and clinical staging(P<0.05).The expression of TLR4 and HIF-1α had a signif icant impact on survival of patients with pancreatic adenocarcinoma.CONCLUSION:TLR4,NF-κB p65 and HIF-1α are overexpressed in pancreatic adenocarcinoma,TLR4 may be partly involved in up-regulating HIF-1α,and both synergestically promote development of pancreatic adenocarcinoma.

Pathology of pancreatic ductal adenocarcinoma:Facts,challenges and future developments

Despite major improvements concerning its diagnosis and treatment,pancreatic ductal adenocarcinoma(PDAC) remains an aggressive disease with an extremely poor prognosis. Pathology,as interface discipline between basic and clinical medicine,has substantially contributed to the recent developments and has laid the basis for further progress. The definition and classification of precursor lesions of PDAC and their molecular characterization is a fundamental step for the potential identification of biomarkers and the development of imaging methods for early detection. In addition,by integrating findings in humans with the knowledge acquired through the investigation of transgenic mouse models for PDAC,a new model for pancreatic carcinogenesis has been proposed and partially validated in individuals with genetic predisposition for PDAC. The introduction and validation of a standardized system for pathology reporting based on the axial slicing technique has shown that most pancreatic cancer resections are R1 resections and that this is due to inherent anatomical and biological properties of PDAC.This standardized assessment of prognostic relevant parameters represents the basis for the successful conduction of multicentric studies and for the interpretation of their results.Finally,recent studies have shown that distinct molecular subtypes of PDAC exist and are associated with different prognosis and therapy response.The prospective validation of these results and the integration of molecular analyses in a comprehensive pathology report in the context of individualised cancer therapy represent a major challenge for the future.