Best imaging signs identified by radiomics could outperform the model: application to differentiating lung carcinoid tumors from atypical hamartomas.

OBJECTIVES: Lung carcinoids and atypical hamartomas may be difficult to differentiate but require different treatment. The aim was to differentiate these tumors using contrast-enhanced CT semantic and radiomics criteria. METHODS: Between November 2009 and June 2020, consecutives patient operated for hamartomas or carcinoids with contrast-enhanced chest-CT were retrospectively reviewed. Semantic criteria were recorded and radiomics features were extracted from 3D segmentations using Pyradiomics. Reproducible and non-redundant radiomics features were used to training a random forest algorithm with cross-validation. A validation-set from another institution was used to evaluate of the radiomics signature, the 3D 'median' attenuation feature (3D-median) alone and the mean value from 2D-ROIs. RESULTS: Seventy-three patients (median 58 years [43‒70]) were analyzed (16 hamartomas; 57 carcinoids). The radiomics signature predicted hamartomas vs carcinoids on the external dataset (22 hamartomas; 32 carcinoids) with an AUC = 0.76. The 3D-median was the most important in the model. Density thresholds < 10 HU to predict hamartoma and > 60 HU to predict carcinoids were chosen for their high specificity > 0.90. On the external dataset, sensitivity and specificity of the 3D-median and 2D-ROIs were, respectively, 0.23, 1.00 and 0.13, 1.00 < 10 HU; 0.63, 0.95 and 0.69, 0.91 > 60 HU. The 3D-median was more reproducible than 2D-ROIs (ICC = 0.97 95% CI [0.95‒0.99]; bias: 3 ± 7 HU limits of agreement (LoA) [- 10‒16] vs. ICC = 0.90 95% CI [0.85‒0.94]; bias: - 0.7 ± 21 HU LoA [- 4‒40], respectively). CONCLUSIONS: A radiomics signature can distinguish hamartomas from carcinoids with an AUC = 0.76. Median density < 10 HU and > 60 HU on 3D or 2D-ROIs may be useful in clinical practice to diagnose these tumors with confidence, but 3D is more reproducible. CRITICAL RELEVANCE STATEMENT: Radiomic features help to identify the most discriminating imaging signs using random forest. 'Median' attenuation value (Hounsfield units), extracted from 3D-segmentations on contrast-enhanced chest-CTs, could distinguish carcinoids from atypical hamartomas (AUC = 0.85), was reproducible (ICC = 0.97), and generalized to an external dataset. KEY POINTS: • 3D-'Median' was the best feature to differentiate carcinoids from atypical hamartomas (AUC = 0.85). • 3D-'Median' feature is reproducible (ICC = 0.97) and was generalized to an external dataset. • Radiomics signature from 3D-segmentations differentiated carcinoids from atypical hamartomas with an AUC = 0.76. • 2D-ROI value reached similar performance to 3D-'median' but was less reproducible (ICC = 0.90).

Immunoscore immune checkpoint using spatial quantitative analysis of CD8 and PD-L1 markers is predictive of the efficacy of anti- PD1/PD-L1 immunotherapy in non-small cell lung cancer.

BACKGROUND: Anti-PD-1 and PD-L1 antibodies (mAbs) are approved immunotherapy agents to treat metastatic non-small cell lung cancer (NSCLC) patients. Only a minority of patients responds to these treatments and biomarkers predicting response are currently lacking. METHODS: Immunoscore-Immune-Checkpoint (Immunoscore-IC), an in vitro diagnostic test, was used on 471 routine single FFPE-slides, and the duplex-immunohistochemistry CD8 and PD-L1 staining was quantified using digital-pathology. Analytical validation was performed on two independent cohorts of 206 NSCLC patients. Quantitative parameters related to cell location, number, proximity and clustering were analysed. The Immunoscore-IC was applied on a first cohort of metastatic NSCLC patients (n = 133), treated with anti-PD1 or anti-PD-L1 mAbs. Another independent cohort (n = 132) served as validation. FINDINGS: Anti-PDL1 clone (HDX3) has similar characteristics as anti-PD-L1 clones (22C3, SP263). Densities of PD-L1+ cells, CD8+ cells and distances between CD8+ and PD-L1+ cells were quantified and the Immunoscore-IC classification was computed. Using univariate Cox model, 5 histological dichotomised variables (CD8 free of PD-L1+ cells, CD8 clusters, CD8 cells in proximity of PD-L1 cells, CD8 density and PD-L1 cells in proximity of CD8 cells) were significantly associated with Progression-Free Survival (PFS) (all P < 0.0001). Immunoscore-IC classification improved the discriminating power of prognostic model, which included clinical variables and pathologist PD-L1 assessment. In two categories, the Immunoscore-IC risk-score was significantly associated with patients' PFS (HR = 0.39, 95% CI (0.26-0.59), P < 0.0001) and Overall Survival (OS) (HR = 0.42, 95% CI (0.27-0.65), P < 0.0001) in the training-set. Further increased hazard ratios (HR) were found when stratifying patients into three-category Immunoscore-IC (IS-IC). All patients with Low-IS-IC progressed in less than 18 months, whereas PFS at 36 months were 34% and 33% of High-IS-IC patients in the training and validation sets, respectively. INTERPRETATION: Immunoscore-IC is a powerful tool to predict the efficacy of immune-checkpoint inhibitors (ICIs) in patients with NSCLC. FUNDING: Veracyte, INSERM, Labex Immuno-Oncology, Transcan ERAnet European project, ARC, SIRIC, CARPEM, Ligue Contre le Cancer, ANR, QNRF, INCa France, Louis Jeantet Prize Foundation.

[Impact of digital pathology implementation in Reunion Island]. / Intérêt de la pathologie numérique à La Réunion.

In recent decades, the major scientific advances in oncology have complexified anatomic pathology practice. Collaboration with local and national pathologists is essential for ensuring a high-quality diagnosis. Anatomic pathology is undergoing a digital revolution that implements whole slide imaging in routine pathologic diagnosis. Digital pathology improves diagnostic efficiency, allows remote peer review and consultations (telepathology), and enables the use of artificial intelligence. The implementation of digital pathology is of particular interest in isolated territories, facilitating access to expertise and therefore to specialized diagnosis. This review discusses the impact of digital pathology implementation in French overseas territories, particularly in Reunion Island.

Establishment of a pancreatic adenocarcinoma molecular gradient (PAMG) that predicts the clinical outcome of pancreatic cancer.

BACKGROUND: A significant gap in pancreatic ductal adenocarcinoma (PDAC) patient's care is the lack of molecular parameters characterizing tumours and allowing a personalized treatment. METHODS: Patient-derived xenografts (PDX) were obtained from 76 consecutive PDAC and classified according to their histology into five groups. A PDAC molecular gradient (PAMG) was constructed from PDX transcriptomes recapitulating the five histological groups along a continuous gradient. The prognostic and predictive value for PMAG was evaluated in: i/ two independent series (n = 598) of resected tumours; ii/ 60 advanced tumours obtained by diagnostic EUS-guided biopsy needle flushing and iii/ on 28 biopsies from mFOLFIRINOX treated metastatic tumours. FINDINGS: A unique transcriptomic signature (PAGM) was generated with significant and independent prognostic value. PAMG significantly improves the characterization of PDAC heterogeneity compared to non-overlapping classifications as validated in 4 independent series of tumours (e.g. 308 consecutive resected PDAC, uHR=0.321 95% CI [0.207-0.5] and 60 locally-advanced or metastatic PDAC, uHR=0.308 95% CI [0.113-0.836]). The PAMG signature is also associated with progression under mFOLFIRINOX treatment (Pearson correlation to tumour response: -0.67, p-value < 0.001). INTERPRETATION: PAMG unify all PDAC pre-existing classifications inducing a shift in the actual paradigm of binary classifications towards a better characterization in a gradient. FUNDING: Project funding was provided by INCa (Grants number 2018-078 and 2018-079, BACAP BCB INCa_6294), Canceropole PACA, DGOS (labellisation SIRIC), Amidex Foundation, Fondation de France, INSERM and Ligue Contre le Cancer.

Immediate or Delayed Transplantation of a Vein Conduit Filled with Nasal Olfactory Stem Cells Improves Locomotion and Axogenesis in Rats after a Peroneal Nerve Loss of Substance.

Over the recent years, several methods have been experienced to repair injured peripheral nerves. Among investigated strategies, the use of natural or synthetic conduits was validated for clinical application. In this study, we assessed the therapeutic potential of vein guides, transplanted immediately or two weeks after a peroneal nerve injury and filled with olfactory ecto-mesenchymal stem cells (OEMSC). Rats were randomly allocated to five groups. A3 mm peroneal nerve loss was bridged, acutely or chronically, with a 1 cm long femoral vein and with/without OEMSCs. These four groups were compared to unoperated rats (Control group). OEMSCs were purified from male olfactory mucosae and grafted into female hosts. Three months after surgery, nerve repair was analyzed by measuring locomotor function, mechanical muscle properties, muscle mass, axon number, and myelination. We observed that stem cells significantly (i) increased locomotor recovery, (ii) partially maintained the contractile phenotype of the target muscle, and (iii) augmented the number of growing axons. OEMSCs remained in the nerve and did not migrate in other organs. These results open the way for a phase I/IIa clinical trial based on the autologous engraftment of OEMSCs in patients with a nerve injury, especially those with neglected wounds.

Validation of the QR1 Antibody for the Evaluation of PD-L1 Expression in Non-Small Cell Lung Adenocarcinomas.

The evaluation of Programmed cell Death Ligand 1 (PD-L1) expression in the tumor cells with immunohistochemistry is a mandatory diagnostic step in the treatment of lung cancer. It is important to utilize validated antibodies that can reliably detect PD-L1 positive cells. Different antibodies have already been studied. In this present study, we compared a new clone (QR1, Quartett) with reference clones to determine if it can be used in place of previously identified reference clones. We built a tissue micro array (TMA) from 110 lung adenocarcinomas and compared it using immunohistodetection of four different clones: QR1, 22c3, Sp263, and E1L3N. We analyzed the correlation between the sample duplicates for each clone and then a correlation and the concordance between the clones were calculated. A total of 101 patients were exploitable; the duplicates for each clone had a strong correlation. The correlation was the strongest (r=0.82) between QR1 and 22c3 and less strong with the other clones. Totals of 78%, 79%, and 97% of the QR1 cases were concordant with 22c3 for the thresholds of <1%, 1% to 49%, and ≥50%, respectively. The sensitivities and specificities of QR1, compared with 22c3, were >75% and 81%, respectively. PD-L1 expression, analyzed in lung adenocarcinomas with QR1, is highly correlated and concordant with the main reference clone used in most laboratories (22c3). It can be used to replace the latter in clinical routine.

Neutrophil extracellular traps are associated with the pathogenesis of diffuse alveolar hemorrhage in murine lupus.

Diffuse alveolar hemorrhage (DAH) is a life-threatening complication of systemic lupus erythematosus (SLE) and systemic vasculitis. Although initially described to have antibacterial properties, increasing evidence suggests that neutrophil extracellular traps (NETs) have a detrimental role in both autoimmune diseases and acute lung injury. We investigated whether NETs could be detected in a murine model of pristane-induced lupus DAH and contribute to lung injury. Such NETs might constitute a therapeutic target. NETs were characterized by immunofluorescence staining of DNA, neutrophil elastase and citrullinated histones. Evaluation of lung injury was performed by haematoxylin-eosin staining and a quantification program. Clinical status of the mice was assessed by measurement of arterial oxygen saturation and survival curves after recombinant human deoxyribonuclease-1 (Rh-DNase-1) inhalations or polymorphonuclear neutrophil (PMN) depletion. Pristane was found to promote NETs formation in vitro and in vivo. Treatment of mice with Rh-DNase-1 inhalations cleared NETs and reduced lung injury. Clinical status improved significantly, with increased arterial oxygenation and survival. Following PMN depletion, NETs were absent with a subsequent reduction of lung injury and improved arterial oxygenation. These results support a pathogenic role of PMNs and NETs in lung injury during pristane-induced DAH. Targeting NETs with Rh-DNase-1 inhalations could constitute an interesting adjuvant therapy in human DAH.

Efficacy of Immune Checkpoint Inhibitors in KRAS-Mutant Non-Small Cell Lung Cancer (NSCLC).

INTRODUCTION: KRAS mutation is the most frequent molecular alteration found in advanced NSCLC; it is associated with a poor prognosis without available targeted therapy. Treatment options for NSCLC have been recently enriched by the development of immune checkpoint inhibitors (ICIs), and data about its efficacy in patients with KRAS-mutant NSCLC are discordant. This study assessed the routine efficacy of ICIs in advanced KRAS-mutant NSCLC. METHODS: In this retrospective study, clinical data were extracted from the medical records of patients with advanced NSCLC treated with ICIs and with available molecular analysis between April 2013 and June 2017. Analysis of programmed death ligand 1 (PD-L1) expression was performed if exploitable tumor material was available. RESULTS: A total of 282 patients with ICI-treated (in the first line or more) advanced NSCLC (all histological subgroups) who were treated with ICIs (anti-programmed death 1, anti-PD-L1, or anti-cytotoxic T-lymphocyte associated protein 4 antibodies), including 162 (57.4%) with KRAS mutation, 27 (9.6%) with other mutations, and 93 (33%) with a wild-type phenotype, were identified. PD-L1 analysis was available for 128 patients (45.4%), of whom 45.3% and 19.5% had PD-L1 expression of 1% or more and 50%, respectively (49.5% and 21.2%, respectively, in the case of the 85 patients with KRAS-mutant NSCLC). No significant difference was seen in terms of objective response rates, progression-free survival, or overall survival between KRAS-mutant NSCLC and other NSCLC. No significant differences in overall survival or progression-free survival were observed between the major KRAS mutation subtypes (G12A, G12C, G12D, G12V, and G13C). In KRAS-mutant NSCLC, unlike in non-KRAS-mutant NSCLC, the efficacy of ICIs is consistently higher, even though not statistically significant, for patients with PD-L1 expression in 1% or more of tumor cells than for those with PD-L1 expression in less than 1% of tumor cells, and this finding is especially true when PD-L1 expression is high (PD-L1 expression ≥50%). CONCLUSION: For patients with KRAS-mutant NSCLC (all mutational subtypes), the efficacy of ICI is similar to that for patients with other types of NSCLC. PD-L1 expression seems to be more relevant for predicting the efficacy of ICIs in KRAS-mutant NSCLC than it is in other types of NSCLC.

[Detection of ALK and ROS1 rearrangements by immunocytochemistry on cytological samples]. / Mise en évidence du réarrangement d'ALK et ROS1 en immunocytochimie sur liquides de ponction.

The identification of ALK and ROS1 rearrangements has become essential for the theranostic management of patients with non-small cell lung cancer, especially in stage IV or inoperable patients. These testings are now performed by immunohistochemistry on histological samples and confirmed by fluorescent in situ hybridization in case of positive or doubtful results. The diagnosis of lung cancer is often performed at an advanced or metastatic stage and cytological sample could be the only material containing malignant cells available at these stages. Therefore, the detection of ALK and ROS1 rearrangement by immunocytochemical analysis on cytological specimens is needed. We performed this test on 27 cytological samples of lung adenocarcinomas, and we compared our results with several other techniques: on the same sample or on biopsy in another laboratory, on the same sample by fluorescent in situ hybridization and/or immunochemistry. We found a very good concordance between all these techniques, thus validating our immunocytochemical method on cytological samples according to the ISO 15189 norm.

[Diffuse esophageal leiomyomatosis and Alport's syndrome: A case report and review of the literature]. / Léiomyomatose œsophagienne diffuse et syndrome d'Alport : rapport d'un cas.

Diffuse esophageal leiomyomatosis is a rare esophageal tumor characterized by circumferential thickening of smooth muscle layers. Diffuse esophageal leiomyomatosis can be associated with Alport's syndrome and therefore diagnosed by skin biopsy. Alport syndrome is a hereditary disease usually defined by the association of glomerular nephropathy and perceptual deafness. Here we describe the management of a young women with a diffuse esophageal leiomyomatosis and a past history of uterine leiomyoma. The surgical treatment depends on the esophageal extent of the disease. Association between diffuse esophageal leiomyomatosis and early uterine leiomyomas could be also observed and leading to Alport's syndrome diagnosis despite the absence of renal abnormalities.

SMARCA4-deficient Thoracic Sarcomas: Clinicopathologic Study of 30 Cases With an Emphasis on Their Nosology and Differential Diagnoses.

SMARCA4-deficient thoracic sarcoma (SMARCA4-DTS) is a recently described entity with an aggressive clinical course and specific genetic alterations of the BAF chromatin remodeling complex. In the present study, we reviewed the clinical and pathologic features of 30 cases of SMARCA4-DTS, discussed its main differential diagnoses and the challenging diagnostic scenarios that the average pathologist may face. In addition, we tested the specificity of the "SMARCA4-DTS immunohistochemical signature" (co-loss of SMARCA4 and SMARCA2 with overexpression of SOX2) in a large cohort of intrathoracic malignancies. Patients ranged from 28 to 90 years of age (median: 48 y), with a marked male predominance (male:female=9:1) and they were usually smokers. Tumors were generally large compressive masses located in the mediastinum (n=13), pleura (n=5), lung (n=2) or in 2 or more of these topographies (n=10). Treatment strategies were varied, including 1 case treated with EZH2 inhibitors. Median overall survival was 6 months. Histologically, tumors were poorly differentiated frequently showing rhabdoid features. A subset of cases showed a focal myxoid stroma (7%, n=2/30) and rare cases displayed a previously unreported pattern simulating desmoplastic small round cell tumors (7%, n=2/30). Making a diagnosis was challenging when dealing with biopsy material from massively necrotic tumors and in this setting the expression of SOX2, CD34, and SALL4 proved useful. All tested cases displayed concomitant loss of SMARCA4 and SMARCA2 and most tumors expressed epithelial markers (Pan-keratin or EMA) (n=29/30), SOX2 (n=26/27), and CD34 (n=17/27). SMARCB1 expression was retained in all cases (23/23). SALL4 and Claudin-4 were expressed in a subset of cases (n=7/21 and 2/19, respectively). TTF-1 and P63 were focally expressed in 1 case each. P40 and NUT were not expressed (0/23 and 0/20, respectively) The SMARCA4-DTS immunohistochemical signature was both sensitive and specific, with only a subset of small cell carcinoma of the ovary hypercalcemic type showing overlapping phenotypes. Our study confirms and expands the specific features of SMARCA4-DTS, emphasizing the fact that they can be straightforwardly identified by pathologists.

A prospective clinical and biological database for pancreatic adenocarcinoma: the BACAP cohort.

BACKGROUND: The prognosis for pancreatic cancer remains poor despite diagnostic advances and treatments with new chemotherapeutic regimens. The five year survival rate remains below 3%. Consequently, there is an urgent need for new treatments to significantly improve the prognosis. In addition, there is a big gap in terms of the screening, early diagnosis and prevention of pancreatic cancer the incidence of which is increasing dramatically. METHODS: Design: the BACAP cohort is a prospective multicenter pancreatic cancer cohort (pancreatic ductal carcinoma) with clinical and multiple biological samples; Participating centers: 15 French academic and private hospitals; Study Population: any cytologically and/or histologically proven pancreatic carcinoma regardless of the stage (resectable, borderline, locally advanced or metastatic) or treatment (surgery, palliative chemotherapy, best supportive care). At least 1500 patients will be included. Clinical data collected include: disease presentation, epidemiological and social factors, baseline biology, radiology, endoscopic ultrasound, staging, pathology, treatments, follow-up (including biological and radiological), and survival. All these data are collected and stored through an e-observation system at a centralized data center. Biological samples and derived products (i.e. before any treatment): blood, saliva, endoscopic ultrasound-guided fine needle aspiration materials from the primary tumor, fine needle biopsy of metastases and surgically resected tissue. DNA and RNA are extracted from fine needle aspiration materials and are quantified and characterized for quality. Whole blood, plasma and serum are isolated from blood samples. Frozen tissues were specifically allocated to the cohort. All derived products and saliva are stored at - 80 °C. Main end-points: i) to centralize clinical data together with multiple biological samples that are harmonized in terms of sampling, the post sampling process and storage; ii) to identify new molecular markers for the diagnosis, prognosis and possibly the predictive response to pancreatic cancer surgery and or chemotherapy. DISCUSSION: The BACAP cohort is a unique prospective biological clinical database that provides the opportunity to identify correlations between the presence/expression of a broad panel of biomarkers (DNA, RNA, miRNA, proteins, etc.), epidemiological and social data, various clinical situations, various stages and the differentiation of the tumor, treatments and survival. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02818829 . Registration date: June 30, 2016.

Distinct epigenetic landscapes underlie the pathobiology of pancreatic cancer subtypes.

Recent studies have offered ample insight into genome-wide expression patterns to define pancreatic ductal adenocarcinoma (PDAC) subtypes, although there remains a lack of knowledge regarding the underlying epigenomics of PDAC. Here we perform multi-parametric integrative analyses of chromatin immunoprecipitation-sequencing (ChIP-seq) on multiple histone modifications, RNA-sequencing (RNA-seq), and DNA methylation to define epigenomic landscapes for PDAC subtypes, which can predict their relative aggressiveness and survival. Moreover, we describe the state of promoters, enhancers, super-enhancers, euchromatic, and heterochromatic regions for each subtype. Further analyses indicate that the distinct epigenomic landscapes are regulated by different membrane-to-nucleus pathways. Inactivation of a basal-specific super-enhancer associated pathway reveals the existence of plasticity between subtypes. Thus, our study provides new insight into the epigenetic landscapes associated with the heterogeneity of PDAC, thereby increasing our mechanistic understanding of this disease, as well as offering potential new markers and therapeutic targets.

[PD-L1 testing in non-small cell lung carcinoma: Guidelines from the PATTERN group of thoracic pathologists]. / Tests immunohistochimiques PD-L1 dans les cancers du poumon non à petites cellules : recommandations par le groupe PATTERN de pathologistes thoraciques.

Lung cancer is the leading cause of cancer death in France with low response rates to conventional chemotherapy. Nevertheless, new therapies have emerged recently, among which PD1 immune checkpoint inhibitors (ICI), such as nivolumab (OPDIVO®, Bristol-Myers Squibb) and pembrolizumab (KEYTRUDA®, Merck & Co), or PD-L1 ICI, such as atezolizumab (TECENTRIQ®, Genentech), durvalumab (IMFINZI®, Astra-Zeneca), and avelumab (BAVENCIO®, EMD Serono). The prescription of pembrolizumab for advanced stage non-small cell lung carcinoma (NSCLC) patients requires the demonstration of PD-L1 expression by tumor cells by immunohistochemistry (IHC) (minimum of 50% of positive tumor cells is required for first-line setting, and of 1% for second-line and beyond) and PD-L1 assay is now considered as a companion diagnostic tool for this drug. Numerous standardized PD-L1 assays performed on dedicated platforms have been validated in clinical trials, each antibody being associated to one specific PD1 or PD-L1 inhibitor. However, not all pathologists have access to the dedicated platforms and the high cost of these assays is still a limitation to their implementation; in addition, the small size of the NSCLC tumor samples does not allow to perform at the same time multiple assays for multiple drugs. The use of laboratory-developed tests seems feasible but their validation must guarantee the same sensitivities and specificities as standardized tests. In this context, the French group of thoracic pathologists PATTERN has teamed up with thoracic oncologists to provide recommendations on the indication, the critical technical steps and the interpretation of the PD-L1 IHC test to help pathologists to implement quickly and in the best conditions this new theranostic test.

Cadherin-1 and cadherin-3 cooperation determines the aggressiveness of pancreatic ductal adenocarcinoma.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is characterised by an extensive tissue invasion and an early formation of metastasis. Alterations in the expression of cadherins have been reported in PDAC. Yet, how these changes contribute to tumour progression is poorly understood. Here, we investigated the relationship between cadherins expression and PDAC development. METHODS: Cadherins expression was assessed by immunostaining in both human and murine tissue specimens. We have generated pancreatic cancer cell lines expressing both cadherin-1 and cadherin-3 or only one of these cadherins. Functional implications of such genetic alterations were analysed both in vitro and in vivo. RESULTS: Cadherin-3 is detected early at the plasma membrane during progression of pancreatic intraepithelial neoplasia 1 (PanIN-1) to PDAC. Despite tumoural cells turn on cadherin-3, a significant amount of cadherin-1 remains expressed at the cell surface during tumourigenesis. We found that cadherin-3 regulates tumour growth, while cadherin-1 drives type I collagen organisation in the tumour. In vitro assays showed that cadherins differentially participate to PDAC aggressiveness. Cadherin-3 regulates cell migration, whereas cadherin-1 takes part in the invadopodia activity. CONCLUSIONS: Our results show differential, but complementary, roles for cadherins during PDAC carcinogenesis and illustrate how their expression conditions the PDAC aggressiveness.

Pancreatic Adenocarcinoma Therapeutic Targets Revealed by Tumor-Stroma Cross-Talk Analyses in Patient-Derived Xenografts.

Preclinical models based on patient-derived xenografts have remarkable specificity in distinguishing transformed human tumor cells from non-transformed murine stromal cells computationally. We obtained 29 pancreatic ductal adenocarcinoma (PDAC) xenografts from either resectable or non-resectable patients (surgery and endoscopic ultrasound-guided fine-needle aspirate, respectively). Extensive multiomic profiling revealed two subtypes with distinct clinical outcomes. These subtypes uncovered specific alterations in DNA methylation and transcription as well as in signaling pathways involved in tumor-stromal cross-talk. The analysis of these pathways indicates therapeutic opportunities for targeting both compartments and their interactions. In particular, we show that inhibiting NPC1L1 with Ezetimibe, a clinically available drug, might be an efficient approach for treating pancreatic cancers. These findings uncover the complex and diverse interplay between PDAC tumors and the stroma and demonstrate the pivotal role of xenografts for drug discovery and relevance to PDAC.

Collagen-derived proline promotes pancreatic ductal adenocarcinoma cell survival under nutrient limited conditions.

Tissue architecture contributes to pancreatic ductal adenocarcinoma (PDAC) phenotypes. Cancer cells within PDAC form gland-like structures embedded in a collagen-rich meshwork where nutrients and oxygen are scarce. Altered metabolism is needed for tumour cells to survive in this environment, but the metabolic modifications that allow PDAC cells to endure these conditions are incompletely understood. Here we demonstrate that collagen serves as a proline reservoir for PDAC cells to use as a nutrient source when other fuels are limited. We show PDAC cells are able to take up collagen fragments, which can promote PDAC cell survival under nutrient limited conditions, and that collagen-derived proline contributes to PDAC cell metabolism. Finally, we show that proline oxidase (PRODH1) is required for PDAC cell proliferation in vitro and in vivo. Collectively, our results indicate that PDAC extracellular matrix represents a nutrient reservoir for tumour cells highlighting the metabolic flexibility of this cancer.

Anti-proliferative and anti-secretory effects of everolimus on human pancreatic neuroendocrine tumors primary cultures: is there any benefit from combination with somatostatin analogs?

Therapeutic management of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) is challenging. The mammalian target of rapamycin (mTOR) inhibitor everolimus recently obtained approval from the Food and Drug Administration for the treatment of patients with advanced pancreatic neuroendocrine tumors (pNETs). Despite its promising antitumor efficacy observed in cell lines, clinical benefit for patients is unsatisfactory. The limited therapeutic potential of everolimus in cancer cells has been attributed to Akt activation due to feedback loops relief following mTOR inhibition. Combined inhibition of Akt might then improve everolimus antitumoral effect. In this regard, the somatostatin analog (SSA) octreotide has been shown to repress the PI3K/Akt pathway in some tumor cell lines. Moreover, SSAs are well tolerated and routinely used to reduce symptoms caused by peptide release in patients carrying functional GEP-NETs. We have recently established and characterized primary cultures of human pNETs and demonstrated the anti-proliferative effects of both octreotide and pasireotide. In this study, we aim at determining the antitumor efficacy of everolimus alone or in combination with the SSAs octreotide and pasireotide in primary cultures of pNETs. Everolimus reduced both Chromogranin A secretion and cell viability and upregulated Akt activity in single treatment. Its anti-proliferative and anti-secretory efficacy was not improved combined with the SSAs. Both SSAs did not overcome everolimus-induced Akt upregulation. Furthermore, caspase-dependent apoptosis induced by SSAs was lost in combined treatments. These molecular events provide the first evidence supporting the lack of marked benefit in patients co-treated with everolimus and SSA.