Microbiota-derived 3-IAA influences chemotherapy efficacy in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is expected to be the second most deadly cancer by 2040, owing to the high incidence of metastatic disease and limited responses to treatment1,2. Less than half of all patients respond to the primary treatment for PDAC, chemotherapy3,4, and genetic alterations alone cannot explain this5. Diet is an environmental factor that can influence the response to therapies, but its role in PDAC is unclear. Here, using shotgun metagenomic sequencing and metabolomic screening, we show that the microbiota-derived tryptophan metabolite indole-3-acetic acid (3-IAA) is enriched in patients who respond to treatment. Faecal microbiota transplantation, short-term dietary manipulation of tryptophan and oral 3-IAA administration increase the efficacy of chemotherapy in humanized gnotobiotic mouse models of PDAC. Using a combination of loss- and gain-of-function experiments, we show that the efficacy of 3-IAA and chemotherapy is licensed by neutrophil-derived myeloperoxidase. Myeloperoxidase oxidizes 3-IAA, which in combination with chemotherapy induces a downregulation of the reactive oxygen species (ROS)-degrading enzymes glutathione peroxidase 3 and glutathione peroxidase 7. All of this results in the accumulation of ROS and the downregulation of autophagy in cancer cells, which compromises their metabolic fitness and, ultimately, their proliferation. In humans, we observed a significant correlation between the levels of 3-IAA and the efficacy of therapy in two independent PDAC cohorts. In summary, we identify a microbiota-derived metabolite that has clinical implications in the treatment of PDAC, and provide a motivation for considering nutritional interventions during the treatment of patients with cancer.

Effective sealing of biliary and pancreatic fistulas with a novel biodegradable polyurethane-based tissue sealant patch.

BACKGROUND: To date, no approved sealants for the prevention of postoperative pancreatic fistulas (POPFs) or bile leakage are available. The aim of the study is to assess the feasibility of a new synthetic and biodegradable polyurethane-based sealant patch (PBSP) for hepato-pancreato-biliary (HPB) surgery. METHODS: Benchmarking of the PBSP with commercially available products with a historical use in HPB surgery (Tachosil®, Hemopatch®, Surgicel® and Veriset®) was followed by performance testing in randomized controlled porcine animal studies. These studies focused on haemostasis as well as the prevention of POPFs and bile leakage. RESULTS: The newly designed PBSP demonstrated the strongest adherence to liver tissue compared to Tachosil®, Hemopatch® and Veriset®. The new patch was the only patch with complete intra- and postoperative hemostasis (72 h after application) compared to Tachosil and Veriset in a porcine liver abrasion study on 12 animals. In addition, the new patch demonstrably prevents the development of POPFs. The rate of postoperative pancreatitis and clinically relevant POPFs was significantly lower compared to the control groups in a porcine pancreatic fistula model based on 14 animals (14-day follow-up). Furthermore, the incidence of biloma after 7 days, considered as significant bile leakage, was significantly lower in the new PBSP compared to the Veriset® group. The PBSP was as effective as suturing in a porcine bile leakage model (7-day follow-up). CONCLUSION: The PBSP induces constant hemostasis in the context of liver resection and prevents pancreatic fistulas and bile leakage. The promising preclinical data implicate clinical trials for further evaluation of this newly developed patch.

Truncated O-GalNAc glycans impact on fundamental signaling pathways in pancreatic cancer.

Truncated O-GalNAc glycosylation is an important feature of pancreatic ductal adenocarcinomas (PDAC) and expression of truncated O-GalNAc glycans is strongly associated with decreased survival and poor prognosis. It has been proven, that aberrant O-GalNAc glycosylation influence PDAC signaling to promote oncogenic properties, but elucidation of the influence of truncated O-GalNAc glycosylation on different signaling molecules has just been started. We herein elucidated the impact of aberrant O-GalNAc glycosylation on two important PDAC signaling pathways, namely AKT/mTOR and RAS/MAPK. In PDAC cells expressing truncated O-GalNAc glycans, we identified differentially expressed proteins associated with AKT/mTOR and RAS/MAPK pathways using quantitative proteomics. Since AKT, a key-signaling molecule in PDAC, was among the identified proteins, we analyzed AKT and found a strikingly enhanced S473 phosphorylation and identified a previously unknown O-GalNAc-modification. Consecutive analysis of COSMC knockdowns in PDAC revealed strong effects on AKT upstream and downstream effector molecules. Interestingly, truncated O-GalNAc glycans could facilitate an mTORC1 inhibitor resistance using AZD8055. In addition, as AKT/mTOR pathway has extensive cross talks with RAS/MAPK pathway we analyzed the pathways and found it negatively regulated. Finally, we found that the expression of epithelial-mesenchymal-transition markers, key features of aggressive PDACs cells, are enhanced and truncated O-GalNAc glycans enhance pancreatic cancer cell growth in a xenograft mouse model. Our study demonstrates that truncated O-GalNAc glycans have a strong impact on AKT/mTOR and RAS/MAPK signaling pathways, are modulated by EGF or IGF-1 signaling and should be considered for targeted therapy of these pathways in PDAC.

Biperiden and mepazine effectively inhibit MALT1 activity and tumor growth in pancreatic cancer.

MALT1 is a key mediator of NF-κB signaling and a main driver of B-cell lymphomas. Remarkably, MALT1 is expressed in the majority of pancreatic ductal adenocarcinomas (PDACs) as well, but absent from normal exocrine pancreatic tissue. Following, MALT1 shows off to be a specific target in cancer cells of PDAC without affecting regular pancreatic cells. Therefore, we studied the impact of pharmacological MALT1 inhibition in pancreatic cancer and showed promising effects on tumor progression. Mepazine (Mep), a phenothiazine derivative, is a known potent MALT1 inhibitor. Newly, we described that biperiden (Bip) is a potent MALT1 inhibitor with even less pharmacological side effects. Thus, Bip is a promising drug leading to reduced proliferation and increased apoptosis in PDAC cells in vitro and in vivo. By compromising MALT1 activity, nuclear translocation of c-Rel is prevented. c-Rel is critical for NF-κB-dependent inhibition of apoptosis. Hence, off-label use of Bip or Mep represents a promising new therapeutic approach to PDAC treatment. Regularly, the Anticholinergicum Bip is used to treat neurological side effects of Phenothiazines, like extrapyramidal symptoms.

The Main Bottleneck for Non-Metastatic Pancreatic Adenocarcinoma in Past Decades: A Population-Based Analysis.

BACKGROUND Despite recent advancements in surgical techniques, chemotherapy, and radiotherapy, the 5-year survival rate of patients with pancreatic ductal adenocarcinoma (PDAC) remains an unsatisfactory ~8%. MATERIAL AND METHODS Data were extracted to identify patients with non-metastatic pancreatic adenocarcinoma diagnosed in the periods 1988-1996 and 2010-2014 in the Surveillance, Epidemiology, and End Results (SEER) database. The statistical analyses were performed with the log-rank test, Pearson's chi-square test, propensity score matching, and Cox regression model. RESULTS The hazard ratio (HR) of surgery was reduced from 0.454 to 0.302 in Cox regression modeling, and there was no overlapping about the 95% confidence intervals (CI) of surgery between the 2 periods. The HR values of radiotherapy, which were new prognostic factor for resectable PDAC in 2010-2014, were reduced in both the resectable and unresectable groups. The upgraded chemotherapy regimen reduced the HR values from 0.738 to 0.689 in all PADC patients, and from 0.656 to 0.588 in unresectable PDAC. The log-rank test results showed that advances in surgery significantly improved the median survival from 13 months to 32 months. Radiotherapeutic and chemotherapeutic advancements extended median survival by 12 months and 11 months, respectively, in resectable PDAC. The median survivals were extended by 3 months for both of radiotherapy and chemotherapy in unresectable PDAC. CONCLUSIONS The development of chemotherapy and radiotherapy has been slow, especially for unresectable PDAC. Although advances in surgery contributed significantly to improved survival for resectable PDAC, lack of early diagnostic tools, which lead to low resection rates, remain a barrier for all PDAC patients.

HSP90 is a promising target in gemcitabine and 5-fluorouracil resistant pancreatic cancer.

Chemotherapy (CT) options in pancreatic cancer (PC) are limited to gemcitabine and 5-fluorouracil (5-FU). Several identified molecular targets in PC represent client proteins of HSP90. HSP90 is a promising target since it interferes with many oncogenic signaling pathways simultaneously. The aim of this study was to evaluate the efficacy of different HSP90 inhibitors in gemcitabine and 5-FU resistant PC. PC cell lines 5061, 5072 and 5156 were isolated and brought in to culture from patients being operated at our institution. L3.6pl cell line served as a control. Anti-proliferative efficacy of three different HSP90 inhibitors (17-AAG, 17-DMAG and 17-AEPGA) was evaluated by the MTT assay. Alterations in signaling pathway effectors and apoptosis upon HSP90 inhibition were determined by western blot analysis and annexin V/PI staining. The cell lines 5061, 5072 and 5156 were resistant to gemcitabine and 5-FU. In contrast 17-AAG and the water-soluble derivates 17-DMAG and 17-AEPGA displayed high anti-proliferative activity in all tested cell lines. The calculated IC50 was below 1 µM. Highly significant down regulation of epidermal-growth-factor-receptor, insulin-like-growth-factor-receptor-1, AKT and MAPK reflected the intracellular molecular signaling-network disruption. Furthermore, besides HSP70 also HSP27 was upregulated in all cell lines. Apoptosis occurred early under HSP90 inhibition and was determined by annexin V/PI staining and CASPASE-3 and PARP assay. In contrast, gemcitabine treated cells did not show any apoptosis. HSP90 inhibition disrupts multiple signaling cascades in gemcitabine and 5-FU resistant PC simultaneously and promotes cancer cell apoptosis. Watersoluble 17-DMAG is equally effective as 17-AAG. HSP27, besides HSP70, may represent an effective response marker of successful HSP90 inhibition.

COSMC knockdown mediated aberrant O-glycosylation promotes oncogenic properties in pancreatic cancer.

BACKGROUND: Human pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and lethal malignancies in the world and despite great efforts in research types of treatment remain limited. A frequently detected alteration in PDACs is a truncated O-linked N-acetylgalactosamine (GalNAc) glycosylation with expression of the Tn antigen. Changes in O-glycosylation affect posttranslationally modified O-GalNAc proteins resulting in profound cellular alterations. Tn antigen is a tumor associated glycan detected in 75-90 % of PDACs and up to 67 % in its precursor lesions. Since the role of Tn antigen expression in PDAC is insufficiently understood we analyzed the impact of COSMC mediated Tn antigen expression in two human PDAC cell lines on cellular oncogenic properties. METHODS: Forced expression of Tn antigen on O-glycosylated proteins in pancreatic cancer cells was induced by lentiviral-mediated knockdown of the COSMC chaperone, which prevented O-glycan elongation beyond the initial GalNAcα1- residue on O-linked glycoproteins. Altered O-GalNAc glycosylation was analyzed in human pancreatic cancer cell lines Panc-1 and L3.6pl using Western and Far-Western blot as well as immunocytochemical techniques. To assess the biological implications of COSMC function on oncogenic properties, cell viability assays, scratch assays combined with live cell imaging, migration and apoptosis assays were performed. Lectin based glycoprotein enrichment with subsequent mass spectrometric analysis identified new cancer O-GalNAc modified proteins. Expression of Tn antigen bearing Nucleolin in patient derived PDAC tumor specimens was evaluated and correlated with clinicopathological data. RESULTS: Tn antigen expression was induced on various O-GalNAc glycoproteins in COSMC deficient cell lines compared to the control. Proliferation was reduced (p < 0.001) in COSMC knockdown cells, whereas migration was increased (p < 0.001) and apoptosis was decreased (p = 0.03), highlighting the importance of Tn antigen expression on metastatic and anti-apoptotic behavior of PDAC derived cells. Nucleolin was identified as O-GalNAc modified protein in COSMC deficient PDAC cell lines. Interestingly, immunohistochemical staining and co-localization studies of patient derived PDACs revealed poor survival for patients with strong co-localization of Tn antigen and Nucleolin (p = 0.037). CONCLUSION: This study substantiates the influence of altered O-glycan (Tn/STn) expression on oncogenic properties in pancreatic cancer and identifies O-GalNAc modified Nucleolin as novel prognostic marker.

A Comprehensive Analysis of Tn and STn Antigen Expression in Esophageal Adenocarcinoma.

Differential glycosylation, marked by the presence of truncated O-glycans, is a distinctive feature of epithelial-derived cancers. However, there is a notable gap in research regarding the expression of Tn and STn antigens in esophageal adenocarcinoma (EAC). To address this, we employed commercially available antibodies, previously validated for Tn and STn antigens, to analyze two cohorts of EAC tissues. Initially, large-area tissue sections from formalin-fixed paraffin-embedded (FFPE) EAC and corresponding healthy tissues were subjected to immunohistochemistry (IHC) staining and scoring. Subsequently, we evaluated the RNA expression levels of crucial O-glycosylation related genes-C1GALT1 and C1GALT1C1-using a quantitative real-time polymerase chain reaction (qRT-PCR). In a comprehensive analysis, a substantial cohort of EAC tissues (n = 311 for Tn antigen, n = 351 for STn antigen) was investigated and correlated with clinicopathological data. Our findings revealed that Tn and STn antigens are highly expressed (approximately 71% for both) in EAC, with this expression being tumor-specific. Notably, Tn antigen expression correlates significantly with the depth of tumor cell infiltration (p = 0.026). These antigens emerge as valuable markers and potential therapeutic targets for esophageal adenocarcinoma.

KDM5 family of demethylases promotes CD44-mediated chemoresistance in pancreatic adenocarcinomas.

A growing body of evidence suggests that the histone demethylase-lysine demethylase 5 (KDM5) family is associated with drug resistance in cancer cells. However, it is still not clear whether KDM5 family members promote chemotherapy resistance in pancreatic ductal adenocarcinomas (PDAC). Comprehensive bioinformatics analysis was performed to investigate the prognostic value, and functional mechanisms of KDM5 family members in PDAC. The effects of KDM5 family members on drug resistance in PDAC cells and the relationship with CD44, as a stem cell marker, were explored by gene knockout and overexpression strategies. Finally, our findings were validated by functional experiments such as cell viability, colony formation and invasion assays. We found that the expression of KDM5A/C was significantly higher in gemcitabine-resistant cells than in sensitive cells, consistent with the analysis of the GSCALite database. The knockdown of KDM5A/C in PDAC cells resulted in diminished drug resistance, less cell colonies and reduced invasiveness, while KDM5A/C overexpression showed the opposite effect. Of note, the expression of KDM5A/C changed accordingly with the knockdown of CD44. In addition, members of the KDM5 family function in a variety of oncogenic pathways, including PI3K/AKT and Epithelial-Mesenchymal Transition. In conclusion, KDM5 family members play an important role in drug resistance and may serve as new biomarkers or potential therapeutic targets in PDAC patients.

Potential role of the bitter taste receptor T2R14 in the prolonged survival and enhanced chemoresponsiveness induced by apigenin.

Bitter taste receptors (T2Rs) are G protein­coupled receptors originally detected in the gustatory system. More recently, T2Rs have been shown to be expressed in extra­oral cells eliciting non­gustatory functions. Emerging evidence has suggested a potential role for T2R signaling in diverse pathophysiological conditions, including cancer. -The aim of the present study was to evaluate the expression of T2R14 in pancreatic ductal adenocarcinoma (PDAC) and to assess its involvement in the anticancer effects induced by apigenin, a natural ligand of T2R14. For this purpose, T2R14 expression was explored in PDAC tumor tissue and tumor­derived cell lines. Using the cell lines expressing the highest levels of T2R14, its effects on chemoresponsiveness and migration upon activation with apigenin were investigated in vitro. To the best of our knowledge, the present study was the first to confirm the expression of the T2R family member T2R14 in PDAC. Patients with relatively high levels of T2R14 expression exhibited significantly prolonged overall survival compared with that of patients with low T2R14 expression. Furthermore, novel functions for apigenin were revealed; notably, apigenin was shown to elicit cytotoxic, anti­migratory and chemosensitizing effects to 5­fluoruracil (5­FU) and to 5­FU, leucovorin, irinotecan and oxaliplatin in pancreatic cancer cells. In conclusion, the present study extended the evidence for the anticancer effects of apigenin and strongly indicated the functional relevance of T2R14 in PDAC, even though their respective underlying pathways appear to be independent of each other.

Vascular endothelial growth factor receptor 2 gene polymorphisms as predictors for tumor recurrence and overall survival in non-small-cell lung cancer.

PURPOSE: VEGFR-2 gene displays several functional germline polymorphisms with impact on VEGFR-2 mediated angiogenesis. Our purpose was to evaluate VEGFR-2 polymorphisms as prognostic markers for tumor recurrence and overall survival (OS) in non-small-cell lung cancer (NSCLC). METHODS: In total, 209 Caucasian patients who had been surgically treated for NSCLC between 1996 and 2010 were included in this study. Genotyping of peripheral blood cells was performed by TaqMan® genotyping assays or polymerase chain reaction for five VEGFR-2 polymorphisms. Chi- square test, Kaplan-Meier estimator, and Cox regression hazard model were used to assess the prognostic value of VEGFR-2 polymorphisms. RESULTS: VEGFR-2+4422 (AC)10-14 polymorphism was identified as a positive prognostic marker for time to metastasis (11/12 vs. 11/11 (AC) repeats: hazard ratio (HR), 0.28; 95% confidence interval (CI), 0.11-0.75; p=0.012) and OS (11/12 vs. 11/11 (AC) repeats: HR, 0.41; 95% CI, 0.21-0.82; p=0.012) in squamous cell carcinoma. For adenocarcinoma, VEGFR-2-906 C>T (C/T vs. CC: HR, 0.19; 95% CI, 0.43-0.82; p=0.027) and VEGFR-2-271 G>A (G/A vs. G/G: HR, 0.25; 95% CI, 0.07-0.86; p=0.027) predicted longer time to local recurrence and VEGFR-2-906 C>T was a predictor for better OS (T/T vs. C/C: HR, 0.28; 95% CI, 0.09-0.84; p=0.024). CONCLUSIONS: VEGFR2 germline polymorphisms predict tumor recurrence and OS in NSCLC.

Survival effects of primary and metastatic surgical treatment in metastatic small intestinal tumors: A propensity score-matching study.

OBJECTIVE: To analyze the effects of primary tumor resection and metastatic lesion resection on the survival of metastatic small intestinal tumors. METHODS: The research subjects were patients with metastatic small bowel tumors identified from 2004 to 2016 in the Surveillance, Epidemiology, and End Results (SEER) database. Propensity score matching and Kaplan-Meier analyses were performed to analyze the effect of surgery on the prognosis. RESULTS: A total of 4,034 patients from the SEER database were analyzed. Both before and after the propensity score-matching analysis, the prognosis of patients who underwent primary tumor surgery and metastatic surgery was better than that of patients who did not undergo surgery; all were patients with metastatic small bowel adenocarcinoma (mSIA) or metastatic small intestinal neuroendocrine tumors (mSI-NETs) (all p < .005). Patients with mSIA and adequate lymph node dissection had a longer prognosis than mSIA patients with inadequate lymph node dissection, but this survival benefit was not present in mSI-NET patients. It made no difference in the prognosis of mSIA and mSI-NETs whether localized surgery or intestine-ectomy was performed. Patients with mSIA who underwent primary and metastatic excision plus chemotherapy had the best overall survival and cancer-specific survival rates, whereas mSI-NET patients who underwent primary and metastatic excision had the best overall survival and cancer-specific survival rates (all p < .001). CONCLUSION: In these carefully selected patients, primary tumor resection and/or metastatic lesion resection significantly improved the survival rates for patients with mSIA and mSI-NETs. The mSIA patients with resectable primary tumors seemed to require a sufficient number of lymph node dissections more than the patients with well-differentiated mSI-NETs.

Prognostic factors and individualized nomograms predicting overall survival in stage IV rectal cancer patients with different metastatic status: a SEER-based study.

Background: The prognosis of rectal cancer patients with different metastatic status was significantly different. Our aim was to identify prognostic factors for metastatic rectal cancer (mRC) patients with different metastatic status and to construct specific nomograms to predict overall survival (OS). Methods: This study retrospectively analyzed mRC patients from 2010 to 2016 in the Surveillance, Epidemiology, and End Results Program database. All patients were ultimately divided into four groups: synchronous liver metastasis, synchronous lung metastasis, synchronous other organs metastasis and synchronous multiple metastases. Univariate and multivariate cox analyses were performed to screen out independent factors for each group. Individualized nomograms were constructed in different metastatic modes. The concordance index (C-index), decision curve analysis (DCA), time-dependent receiver operating characteristic (ROC) curve and calibration curve were performed to verify these nomograms. Results: Finally, 10,407 mRC patients were included in this study. Age, tumor grade, surgery of primary tumor, and chemotherapy were identified as common independent prognostic factors for each subgroup (all P<0.05). Other independent prognostic factors specific to each group included radiotherapy and marital status in the liver metastasis group, race, N stage, and the presence or absence of site-specific metastases in the multiple metastases group (all P<0.05). Higher T staging suggested worse OS in the group with liver, lung, and multiple site metastases. Individualized nomograms predicting 1-, 2-, and 3-year OS for each group were constructed by combining all independently significant risk factors in each group. The area under the curve (AUC) values and C-indexes of these nomograms created by each subgroup were greater than 0.7. All calibration curves and DCA curves showed that these nomograms had good clinical application significance. Conclusions: Individualized prognostic nomograms were constructed for mRC patients with different metastatic status based on different prognostic factors. These nomograms presented satisfactory predictive effects, which helps to provide survival assessment and individualized treatment decision-making for mRC patients with different metastatic status.

Cytoskeletal and Cytoskeleton-Associated Proteins: Key Regulators of Cancer Stem Cell Properties.

Cancer stem cells (CSCs) are a subpopulation of cancer cells possessing stemness characteristics that are closely associated with tumor proliferation, recurrence and resistance to therapy. Recent studies have shown that different cytoskeletal components and remodeling processes have a profound impact on the behavior of CSCs. In this review, we outline the different cytoskeletal components regulating the properties of CSCs and discuss current and ongoing therapeutic strategies targeting the cytoskeleton. Given the many challenges currently faced in targeted cancer therapy, a deeper comprehension of the molecular events involved in the interaction of the cytoskeleton and CSCs will help us identify more effective therapeutic strategies to eliminate CSCs and ultimately improve patient survival.

The Extracellular Matrix: A Key Accomplice of Cancer Stem Cell Migration, Metastasis Formation, and Drug Resistance in PDAC.

Pancreatic ductal adenocarcinoma (PDAC) is rich in dense fibrotic stroma that are composed of extracellular matrix (ECM) proteins. A disruption of the balance between ECM synthesis and secretion and the altered expression of matrix remodeling enzymes lead to abnormal ECM dynamics in PDAC. This pathological ECM promotes cancer growth, survival, invasion, and alters the behavior of fibroblasts and immune cells leading to metastasis formation and chemotherapy resistance, which contribute to the high lethality of PDAC. Additionally, recent evidence highlights that ECM, as a major structural component of the tumor microenvironment, is a highly dynamic structure in which ECM proteins establish a physical and biochemical niche for cancer stem cells (CSCs). CSCs are characterized by self-renewal, tumor initiation, and resistance to chemotherapeutics. In this review, we will discuss the effects of the ECM on tumor biological behavior and its molecular impact on the fundamental signaling pathways in PDAC. We will also provide an overview of how the different ECM components are able to modulate CSCs properties and finally discuss the current and ongoing therapeutic strategies targeting the ECM. Given the many challenges facing current targeted therapies for PDAC, a better understanding of molecular events involving the interplay of ECM and CSC will be key in identifying more effective therapeutic strategies to eliminate CSCs and ultimately to improve survival in patients that are suffering from this deadly disease.

The survival impact of radiotherapy on synchronous metastatic rectal cancer: metastatic site can serve for radiotherapy-decision.

Purpose: The metastatic site seems to represent a malignancy with a different biological characteristic. Radiotherapy, as a successful, well-tolerated, cost-effective and time-efficient intervention, is able to provide clear benefits for the treatment of locally advanced rectal cancer and has become an essential component of palliative oncology care. The real-world effect of radiotherapy on the survival outcomes of metastatic rectal cancer (mRC) patients might do exist and was worth exploring. Patients and methods: Data were extracted from the Surveillance, Epidemiology, and End Results (SEER) database in this retrospective analysis. The statistical methods included Pearson's chi-square test, Log-rank test, Cox regression model and propensity score matching (PSM). Results: The multivariable Cox regression displayed that radiotherapy may not be used as a prognostic factor for mRC (p=0.057). However, radiotherapy may be associated with the prognosis if the metastatic site was excluded from the multivariate analysis (p<0.001). Radiotherapy seemed to fail to improve OS before PSM (p<0.001) and after PSM without the metastatic site as a matching factor (p<0.001). Nevertheless, there was no significant survival difference between radiotherapy and non-radiotherapy cohort after PSM with the metastatic site as a matching factor (p=0.057). All of M1a rectal cancer patients appear to obtain survival benefit from radiotherapy without the impact of PSM (p<0.001). Notwithstanding, radiotherapy was associated with improved OS of patients with rectal liver-limited metastasis (p=0.023) and did not appear to provide survival benefit for rectal lung-limited (p=0.386) and other-limited metastasis (p=0.385). Both of M1b mRC with and without liver metastasis did not seem to obtain survival benefit from radiotherapy. Conclusions: Carefully selected data from the SEER database suggested that radiotherapy appears to improve overall survival only in patients with rectal liver-limited metastasis.

The Survival Effect of Radiotherapy on Stage IIB/III Pancreatic Cancer Undergone Surgery in Different Age and Tumor Site Groups: A Propensity Scores Matching Analysis Based on SEER Database.

BACKGROUND: It remains controversial whether radiotherapy (RT) improves survival in patients with stage IIB/III PDAC. A growing number of studies have found that patients' age at diagnosis and tumor site not only affect prognosis, but also may lead to different treatment responses. Therefore, the purpose of this study was to verify whether the survival effect of radiotherapy in patients with stage IIB/III PDAC varies across age and tumor site groups. METHODS: The target population was selected from PDAC patients undergone surgery in the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2016. This study performed the Pearson's chi-square test, Cox regression analysis, Kaplan-Meier (K-M) method, and focused on propensity frequency matching analysis. RESULTS: Neither neoadjuvant radiotherapy (nRT) nor adjuvant radiotherapy (aRT) patient group had probably improved survival among early-onset patients. For middle-aged patients, nRT seemed to fail to extend overall survival (OS), while aRT might improve the OS. Plus, both nRT and aRT were associated with improved survival in elderly patients. The aRT might be related with survival benefits in patients with pancreatic head cancer, while nRT was not. And RT in patients with PDAC at other sites did not appear to provide a survival benefit. CONCLUSION: Carefully selected data from the SEER database suggested that age and tumor location may be the reference factors to guide the selection of RT for patients with stage IIB/III PDAC. These findings are likely to contribute to the development of personalized treatment for patients with stage IIB/III PDAC.

The survival impact of palliative radiotherapy on synchronous metastatic pancreatic ductal adenocarcinoma: metastatic site can serve for radiotherapy-decision.

Background: The metastatic site seems to represent a malignancy with a different biological characteristic and is an important prognostic factor in metastatic pancreatic ductal adenocarcinoma (mPDAC). Palliative radiotherapy is a therapeutic option, and usually used for pain management in the treatment of mPDAC. The real-world effect of radiotherapy on the survival outcomes of mPDAC patients might do exist and is worth exploring. Methods: Data from the Surveillance, Epidemiology, and End Results (SEER) was extracted to identify mPDAC diagnosed in the periods of 2010-2016. The statistical methods included Pearson's chi-square test, Log-rank test, Cox regression model and propensity score matching (PSM). Results: Radiotherapy was able to improve the overall survival of PDAC with liver metastasis (p<0.001), but not for PDAC patients with lung (p=0.130), bone (p=0.451) and brain metastasis (p=0.226) before PSM. Radiotherapy can only a prognostic factor for PDAC liver metastasis (p=0.001) in the cox regression analysis. The survival curves provided consistent results with cox regression analysis (PDAC with liver metastasis: p=0.023, PDAC with lung metastasis: p=0.528, PDAC with bone metastasis: p=0.210, PDAC with brain metastasis: p=0.106) after PSM. We continue to divided PDAC liver patients into PDAC-liver-metastasis with and without lung, bone, and/or brain (LBB) metastasis. Finally, radiotherapy can be used as a feasible treatment to prolong the overall survival of patients with PDAC liver metastasis without LBB metastasis. Conclusions: Radiotherapy can be used as a feasible treatment to prolong the overall survival of patients with PDAC liver metastasis without LBB metastasis.

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

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.

Neoadjuvant radiotherapy for locoregional Siewert type II gastroesophageal junction adenocarcinoma: A propensity scores matching analysis.

OBJECTIVE: To analyze the effect of neoadjuvant radiotherapy (nRT) on prognosis in patients with locoregional Siewert type II gastroesophageal junction adenocarcinoma (GEA). METHOD: All patients pathologically diagnosed as Siewert type II GEA between 2004 and 2015 were retrieved from the Surveillance, Epidemiology and Final Results (SEER) database. We analyzed the impact of different treatment regimens on the prognosis in each stage. Survival analysis was performed by Kaplan-Meier (K-M) method. Multivariate Cox model and propensity score matching was further used to verify the results. RESULTS: 4,160 patients were included in this study. The efficacy of nRT was superior to that of adjuvant radiotherapy (aRT) (p = 0.048), which was the same as that of surgery combined with chemotherapy (p = 0.836), but inferior to the overall survival (OS) of surgical treatment alone (p<0.001) in T1-2N0M0 patients. Patients receiving nRT had distinctly better survival than those receiving surgical treatment alone (p = 0.008), but had similar survival compared with patients treated with aRT (p = 0.989) or surgery combined with chemotherapy (p = 0.205) in the T3N0/T1-3N+M0 subgroup. The efficacy of nRT is clearly stronger than that of surgical therapy alone (p<0.001), surgery combined with chemotherapy (p<0.001), and aRT (p = 0.008) in patients with T4 stage. The survival analysis results were consistent before and after propensity score matching. CONCLUSION: In these carefully selected patients, the present study made the following recommendations: nRT can improve the prognosis of patients with T3N0M0/T1-3N+M0 and T4 Siewert type II GEA, and it seems to be a better treatment for T4 patients. Surgery alone seems to be sufficient, and nRT is not conducive to prolonging the survival of Siewert II GEA patients with T1-2N0M0 stage. Of course, further prospective trials are needed to verify this conclusion.