A new pancreatic adenocarcinoma-derived organoid model of acquired chemoresistance to FOLFIRINOX: First insight of the underlying mechanisms.

BACKGROUND INFORMATION: Although improvements have been made in the management of pancreatic adenocarcinoma (PDAC) during the past 20 years, the prognosis of this deadly disease remains poor with an overall 5-year survival under 10%. Treatment with FOLFIRINOX, a combined regimen of 5-fluorouracil, irinotecan (SN-38) and oxaliplatin, is nonetheless associated with an excellent initial tumour response and its use has allowed numerous patients to go through surgery while their tumour was initially considered unresectable. These discrepancies between initial tumour response and very low long-term survival are the consequences of rapidly acquired chemoresistance and represent a major therapeutic frontier. To our knowledge, a model of resistance to the combined three drugs has never been described due to the difficulty of modelling the FOLFIRINOX protocol both in vitro and in vivo. Patient-derived tumour organoids (PDO) are the missing link that has long been lacking in the wide range of epithelial cancer models between 2D adherent cultures and in vivo xenografts. In this work we sought to set up a model of PDO with resistance to FOLFIRINOX regimen that we could compare to the paired naive PDO. RESULTS: We first extrapolated physiological concentrations of the three drugs using previous pharmacodynamics studies and bi-compartmental elimination models of oxaliplatin and SN-38. We then treated PaTa-1818x naive PDAC organoids with six cycles of 72 h-FOLFIRINOX treatment followed by 96 h interruption. Thereafter, we systematically compared treated organoids to PaTa-1818x naive organoids in terms of growth, proliferation, viability and expression of genes involved in cancer stemness and aggressiveness. CONCLUSIONS: We reproductively obtained resistant organoids FoxR that significantly showed less sensitivity to FOLFORINOX treatment than the PaTa-1818x naive organoids from which they were derived. Our resistant model is representative of the sequential steps of chemoresistance observed in patients in terms of growth arrest (proliferation blockade), residual disease (cell quiescence/dormancy) and relapse. SIGNIFICANCE: To our knowledge, this is the first genuine in vitro model of resistance to the three drugs in combined therapy. This new PDO model will be a great asset for the discovery of acquired chemoresistance mechanisms, knowledge that is mandatory before offering new therapeutic strategies for pancreatic cancer.

Bariatric Surgery Provides Long-term Resolution of Nonalcoholic Steatohepatitis and Regression of Fibrosis.

BACKGROUND AND AIMS: Studies are needed to determine the long-term effects of bariatric surgery for patients with nonalcoholic steatohepatitis (NASH). We evaluated sequential liver samples, collected the time of bariatric surgery and 1 and 5 years later, to assess the long-term effects of bariatric surgery in patients with NASH. METHODS: We performed a prospective study of 180 severely obese patients with biopsy-proven NASH, defined by the NASH clinical research network histologic scores. The patients underwent bariatric surgery at a single center in France and were followed for 5 years. We obtained liver samples from 125 of 169 patients (76%) having reached 1 year and 64 of 94 patients (68%) having reached 5 years after surgery. The primary endpoint was the resolution of NASH without worsening of fibrosis at 5 years. Secondary end points were improvement in fibrosis (reduction of ≥1 stage) at 5 years and regression of fibrosis and NASH at 1 and 5 years. RESULTS: At 5 years after bariatric surgery, NASH was resolved, without worsening fibrosis, in samples from 84% of patients (n = 64; 95% confidence interval, 73.1%-92.2%). Fibrosis decreased, compared with baseline, in samples from 70.2% of patients (95% CI, 56.6%-81.6%). Fibrosis disappeared from samples from 56% of all patients (95% CI, 42.4%-69.3%) and from samples from 45.5% of patients with baseline bridging fibrosis. Persistence of NASH was associated with no decrease in fibrosis and less weight loss (reduction in body mass index of 6.3 ± 4.1 kg/m2 in patients with persistent NASH vs reduction of 13.4 ± 7.4 kg/m2; P = .017 with resolution of NASH). Resolution of NASH was observed at 1 year after bariatric surgery in biopsies from 84% of patients, with no significant recurrence between 1 and 5 years (P = .17). Fibrosis began to decrease by 1 year after surgery and continued to decrease until 5 years (P < .001). CONCLUSIONS: In a long-term follow-up of patients with NASH who underwent bariatric surgery, we observed resolution of NASH in liver samples from 84% of patients 5 years later. The reduction of fibrosis is progressive, beginning during the first year and continuing through 5 years.

The Impact of Modern Chemotherapy and Chemotherapy-Associated Liver Injuries (CALI) on Liver Function: Value of 99mTc-Labelled-Mebrofenin SPECT-Hepatobiliary Scintigraphy.

BACKGROUND: Chemotherapy is increasingly used before hepatic resection, with controversial impact regarding liver function. This study aimed to assess the capacity of 99mTc-labelled-mebrofenin SPECT-hepatobiliary scintigraphy (HBS) to predict liver dysfunction due to chemotherapy and/or chemotherapeutic-associated liver injuries (CALI), such as sinusoidal obstruction syndrome (SOS) and nonalcoholic steatohepatitis (NASH) activity score (NAS). METHODS: From 2011 to 2015, all consecutive noncirrhotic patients scheduled for a major hepatectomy (≥ 3 segments) gave informed consent for preoperative SPECT-HBS allowing measurements of segmental liver function. As primary endpoint, HBS results were compared between patients with versus without (1) preoperative chemotherapy (≤ 3 months); and (2) CALI, mainly steatosis, NAS (Kleiner), or SOS (Rubbia-Brandt). Secondary endpoints were (1) other factors impairing function; and (2) impact of chemotherapy, and/or CALI on hepatocyte isolation outcome via liver tissues. RESULTS: Among 115 patients, 55 (47.8%) received chemotherapy. Sixteen developed SOS and 35 NAS, with worse postoperative outcome. Overall, chemotherapy had no impact on liver function, except above 12 cycles. In patients with CALI, a steatosis ≥ 30% significantly compromised function, as well as NAS, especially grades 2-5. Conversely, SOS had no impact, although subjected to very low patients number with severe SOS. Other factors impairing function were diabetes, overweight/obesity, or fibrosis. Similarly, chemotherapy in 73 of 164 patients had no effect on hepatocytes isolation outcome; regarding CALI, steatosis ≥ 30% and NAS impaired the yield and/or viability of hepatocytes, but not SOS. CONCLUSIONS: In this first large, prospective study, HBS appeared to be a valuable tool to select heavily treated patients at risk of liver dysfunction through steatosis or NAS.

A tool to predict progression of non-alcoholic fatty liver disease in severely obese patients.

BACKGROUND & AIMS: Severely obese patients are a growing population at risk of non-alcoholic fatty liver disease (NAFLD). Considering the increasing burden, a predictive tool of NAFLD progression would be of interest. Our objective was to provide a tool allowing general practitioners to identify and refer the patients most at risk, and specialists to estimate disease progression and adapt the therapeutic strategy. METHODS: This predictive tool is based on a Markov model simulating steatosis, fibrosis and non-alcoholic steatohepatitis (NASH) evolution. This model was developped from data of 1801 severely obese, bariatric surgery candidates, with histological assessment, integrating duration of exposure to risk factors. It is then able to predict current disease severity in the absence of assessment, and future cirrhosis risk based on current stage. RESULTS: The model quantifies the impact of sex, body-mass index at 20, diabetes, age of overweight onset, on progression. For example, for 40-year-old severely obese patients seen by the general practitioners: (a) non-diabetic woman overweight at 20, and (b) diabetic man overweight at 10, without disease assessment, the model predicts their current risk to have NASH or F3-F4: for (a) 5.7% and 0.6%, for (b) 16.1% and 10.0% respectively. If those patients have been diagnosed F2 by the specialist, the model predicts the 5-year cirrhosis risk: 1.8% in the absence of NASH and 6.0% in its presence for (a), 10.3% and 26.7% respectively, for (b). CONCLUSIONS: This model provides a decision-making tool to predict the risk of liver disease that could help manage severely obese patients.

Donor-to-recipient transmission and reactivation in a kidney transplant recipient of an inherited chromosomally integrated HHV-6A: Evidence and outcomes.

Human herpesvirus (HHV)-6A can be inherited and chromosomally integrated (iciHHV-6A), and donor-to-recipient transmission has been reported in solid organ transplant. However, when HHV-6A reactivation happens after transplant, the source of HHV-6A is often not evident and its pathogenicity remains unclear. Here, we present an exhaustive case of donor-to-recipient transmission and reactivation of iciHHV-6A through kidney transplant. The absence of HHV-6A genome from the nails of the recipient excluded a recipient-related iciHHV-6A. Viral loads > 7 log10 copies/106 cells in donor blood samples and similarities of U38, U39, U69, and U100 viral genes between donor, recipient, and previously published iciHHV-6A strains are proof of donor-related transmission. Detection of noncoding HHV-6 snc-RNA14 using fluorescence in situ hybridization analysis and immunofluorescence staining of HHV-6A gp82/gp105 late proteins on kidney biopsies showed evidence of reactivation in the transplanted kidney. Because HHV-6A reactivation can be life threatening in immunocompromised patients, we provide several tools to help during the complete screening and diagnosis.

[Incidental finding of leukocyte cell-derived chemotaxin 2 - Associated amyloidosis in a liver]. / Découverte fortuite d'une atteinte hépatique d'amylose à leukocyte chemotactic factor 2.

Leukocyte cell-derived chemotaxin 2-associated amyloidosis (ALECT2) is a recently described of amyloidosis described in the United States in 2007. It is a systemic disease that is predominantly associated with some ethnics groups. ALECT2 is usually diagnosed on a kidney biopsy performed in the context of slowly progressive chronic renal disease but can also be found incidentally on a liver sample. We report the case of a Syrian patient who benefited from a partial hepatectomy for the treatment of multiple metastasis of a colorectal adenocarcinoma. Microscopic analysis of the surgical specimen revealed numerous amyloid deposits that did not match any of the usual forms of liver amyloidosis after immunohistochemistry typing. Some morphologic features of the deposits were highly suggestive of ALECT2. Complementary immunohistochemical study and mass spectrometry confirmed the diagnosis.

Diagnostic accuracy of a panel of immunohistochemical and molecular markers to distinguish Merkel cell carcinoma from other neuroendocrine carcinomas.

Merkel cell carcinoma is a rare neuroendocrine carcinoma of the skin mostly induced by Merkel cell polyomavirus integration. Cytokeratin 20 (CK20) positivity is currently used to distinguish Merkel cell carcinomas from other neuroendocrine carcinomas. However, this distinction may be challenging in CK20-negative cases and in cases without a primary skin tumor. The objectives of this study were first to evaluate the diagnostic accuracy of previously described markers for the diagnosis of Merkel cell carcinoma and second to validate these markers in the setting of difficult-to-diagnose Merkel cell carcinoma variants. In a preliminary set (n = 30), we assessed optimal immunohistochemical patterns (CK20, thyroid transcription factor 1 [TTF-1], atonal homolog 1 [ATOH1], neurofilament [NF], special AT-rich sequence-binding protein 2 [SATB2], paired box protein 5, terminal desoxynucleotidyl transferase, CD99, mucin 1, and Merkel cell polyomavirus-large T antigen) and Merkel cell polyomavirus load thresholds (real-time PCR). The diagnostic accuracy of each marker was then assessed in a validation set of 103 Merkel cell carcinomas (9 CK20-negative cases and 15 cases without a primary skin tumor) and 70 extracutaneous neuroendocrine carcinoma cases. The most discriminant markers for a diagnosis of Merkel cell carcinoma were SATB2, NF expression, and Merkel cell polyomavirus DNA detection (positive likelihood ratios: 36.6, 44.4, and 28.2, respectively). Regarding Merkel cell carcinoma variants, cases without a primary skin tumor retained a similar immunohistochemical  profile and CK20-negative tumors displayed a different profile (decrease frequency of NF and SATB2 expression), but Merkel cell polyomavirus DNA remained detected (78% of cases by qPCR). Moreover, 8/9 (89%) CK20-negative Merkel cell carcinoma cases but only 3/61 (5%) CK20-negative extracutaneous neuroendocrine cases were positive for at least one of these markers. In conclusion, detection of SATB2 and NF expression and Merkel cell polyomavirus DNA helps distinguish between Merkel cell carcinoma classical and variant cases and extracutaneous neuroendocrine carcinomas.

Morphologic and immunophenotypical features distinguishing Merkel cell polyomavirus-positive and negative Merkel cell carcinoma.

In 2008, Feng et al. identified Merkel cell polyomavirus integration as the primary oncogenic event in ~80% of Merkel cell carcinoma cases. The remaining virus-negative Merkel cell carcinoma cases associated with a high mutational load are most likely caused by UV radiation. The current study aimed to compare the morphological and immunohistochemical features of 80 virus-positive and 21 virus-negative Merkel cell carcinoma cases. Microscopic evaluation revealed that elongated nuclei-similar to the spindle-shape variant of small cell lung cancer-were less frequent in Merkel cell polyomavirus-positive Merkel cell carcinoma compared to the virus-negative subset (p = 0.005). Moreover, virus-negative cases more frequently displayed a "large-cell neuroendocrine carcinoma" phenotype with larger cell size (p = 0.0026), abundant cytoplasm (p = 4×10-7) and prominent nucleoli (p = 0.002). Analysis of immunohistochemical data revealed frequent positivity for thyroid transcription factor 1 and cytokeratin 7, either absence or overexpression of p53, as well as frequent lack of neurofilament expression in virus-negative cases. By contrast, cytokeratin 8, 18 and 20 and a CD99 with a dot pattern as well as high EMA expression were identified as characteristic features of virus-positive Merkel cell carcinoma. In particular, the CD99 dot-like expression pattern was strongly associated with presence of the Merkel cell polyomavirus in Merkel cell carcinoma (sensitivity = 81%, specificity = 90%, positive likelihood ratio = 8.08). To conclude, virus-positive and -negative Merkel cell carcinoma are characterized by distinct morphological and immunohistochemical features, which implies a significant difference in tumor biology and behavior. Importantly, we identified the CD99 staining pattern as a marker indicating the virus status of this skin cancer.

Prevalence of Eosinophilic Esophagitis in Adolescents With Esophageal Atresia.

BACKGROUND AND OBJECTIVE: Eosinophilic esophagitis (EoE) is an increasingly recognized childhood disease. Esophageal atresia (EA) is the most frequent congenital malformation of the esophagus. Recently, cases of EoE occurring in patients with EA have been reported, although the exact prevalence of EoE in EA remains unknown. The aim is to investigate the prevalence of EoE among EA in adolescents and to describe these patients' characteristics. METHODS: Systematic upper gastrointestinal endoscopies with multistage esophageal biopsies were prospectively performed in 63 adolescents with EA. A standardized form was used to collect clinical and endoscopic data. Diagnosis of EoE was made as ≥15 intraepithelial eosinophils/high power field, whatever the response on proton pump inhibitors therapy. RESULTS: Six patients (9.5%) presented an EoE (17-100 eosinophils/high power field). An atopic condition was reported more frequently in the eosinophil ≥15 group than in patients with no EoE (66% vs 16%; P = 0.014). Except for chest pain, symptoms and endoscopic features were similar in patients with EoE and patients with no EoE. CONCLUSION: In our series of 63 patients born with EA, mainly distal tracheoesophageal fistula, the prevalence of EoE is increased, and therefore should be considered in adolescents with EA.

[Large scale teaching in pathology]. / Pédagogie à grande échelle en ACP.

Medical education is currently facing great changes that affect all medical specialties, including anatomical pathology. Due to rapidly increasing medical knowledge and diagnostic complexity, we are living an era of teaching resources mutualization. We present different tools that allow large numbers of students to access courses, self-evaluations, and competencies assessments. MOOC platforms and e-learning platforms are central to these new online tools, which include the French National Platform of Medical Specialties, dedicated to the teaching of 50,000 medical residents in France. We also discuss "serious games" and the use of images and virtual slides in anatomical pathology teaching. These new modalities can deliver essential knowledge to large student populations, but they must be used in conjunction with adapted teacher-led courses focusing on competencies and professional skills in order to be fully effective.

Clinicopathological description of 43 oncocytic adrenocortical tumors: importance of Ki-67 in histoprognostic evaluation.

Oncocytic adrenocortical tumors are a rare subtype of adrenal tumors with challenging diagnosis and histoprognostic assessment. It is usually believed that oncocytic adrenocortical tumors have a more indolent clinical behavior than conventional adrenocortical tumors. As the Weiss score overestimates the malignancy of oncocytic adrenocortical tumors owing to intrinsic parameters, alternative scores have been proposed. The Lin-Weiss-Bisceglia score is currently recommended. We performed a large nationwide multicenter retrospective clinicopathologic study of oncocytic adrenocortical tumors. Among the 43 patients in our cohort, 40 patients were alive without disease, 2 patients died of their disease and 1 patient was alive with relapse after a median follow-up of 38 months (20-59). Our data revealed that over 50% of the oncocytic adrenocortical tumor cases were diagnosed as carcinoma whatever the classification systems used, including the Lin-Weiss-Bisceglia score. The exception is the Helsinki score, which incorporates the Ki-67 proliferation index and was the most specific prognostic score for oncocytic adrenocortical tumor malignancy without showing a loss in sensitivity. A comparison of malignant oncocytic adrenocortical tumors with conventional adrenocortical carcinomas matched for age, sex, ENS@T stage and surgical resection status showed significant better overall survival of malignant oncocytic adrenocortical tumors.

The FREGAT biobank: a clinico-biological database dedicated to esophageal and gastric cancers.

BACKGROUND: While the incidence of esophageal and gastric cancers is increasing, the prognosis of these cancers remains bleak. Endoscopy and surgery are the standard treatments for localized tumors, but multimodal treatments, associated chemotherapy, targeted therapies, immunotherapy, radiotherapy, and surgery are needed for the vast majority of patients who present with locally advanced or metastatic disease at diagnosis. Although survival has improved, most patients still present with advanced disease at diagnosis. In addition, most patients exhibit a poor or incomplete response to treatment, experience early recurrence and have an impaired quality of life. Compared with several other cancers, the therapeutic approach is not personalized, and research is much less developed. It is, therefore, urgent to hasten the development of research protocols, and consequently, develop a large, ambitious and innovative tool through which future scientific questions may be answered. This research must be patient-related so that rapid feedback to the bedside is achieved and should aim to identify clinical-, biological- and tumor-related factors that are associated with treatment resistance. Finally, this research should also seek to explain epidemiological and social facets of disease behavior. METHODS: The prospective FREGAT database, established by the French National Cancer Institute, is focused on adult patients with carcinomas of the esophagus and stomach and on whatever might be the tumor stage or therapeutic strategy. The database includes epidemiological, clinical, and tumor characteristics data as well as follow-up, human and social sciences quality of life data, along with a tumor and serum bank. DISCUSSION: This innovative method of research will allow for the banking of millions of data for the development of excellent basic, translational and clinical research programs for esophageal and gastric cancer. This will ultimately improve general knowledge of these diseases, therapeutic strategies and patient survival. This database was initially developed in France on a nationwide basis, but currently, the database is available for worldwide contributions with respect to the input of patient data or the request for data for scientific projects. TRIAL REGISTRATION: The FREGAT database has a dedicated website ( www.fregat-database.org ) and is registered on the Clinicaltrials.gov site, number NCT 02526095 , since August 8, 2015.

Foxa2, a novel protein partner of the tumour suppressor menin, is deregulated in mouse and human MEN1 glucagonomas.

Foxa2, known as one of the pioneer factors, plays a crucial role in islet development and endocrine functions. Its expression and biological functions are regulated by various factors, including, in particular, insulin and glucagon. However, its expression and biological role in adult pancreatic α-cells remain elusive. In the current study, we showed that Foxa2 was overexpressed in islets from α-cell-specific Men1 mutant mice, at both the transcriptional level and the protein level. More importantly, immunostaining analyses showed its prominent nuclear accumulation, specifically in α-cells, at a very early stage after Men1 disruption. Similar nuclear FOXA2 expression was also detected in a substantial proportion (12/19) of human multiple endocrine neoplasia type 1 (MEN1) glucagonomas. Interestingly, our data revealed an interaction between Foxa2 and menin encoded by the Men1 gene. Furthermore, using several approaches, we demonstrated the relevance of this interaction in the regulation of two tested Foxa2 target genes, including the autoregulation of the Foxa2 promoter by Foxa2 itself. The current study establishes menin, a novel protein partner of Foxa2, as a regulator of Foxa2, the biological functions of which extend beyond the pancreatic endocrine cells. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Repeated Resections of Hepatic and Pulmonary Metastases from Colorectal Cancer Provide Long-Term Survival.

BACKGROUND: Liver and lungs are the two most frequent sites of metastatic spread of colorectal cancer (CRC). Complete resection of liver and/or lung metastases is the only chance of cure, and several studies have reported an improved survival after an aggressive treatment. Nevertheless, CRC liver metastases (CLM) have been recognized as a pejorative factor for patients undergoing pulmonary metastasectomy. We report our experience with patients successively operated on for CRC hepatic and pulmonary metastasis (CPM) and seek to identify prognostic factors. METHODS: All consecutive patients who had resection of CPM and CLM between 2001 and 2014 were enrolled in the study. Clinicopathological and survival data were retrospectively analysed. RESULTS: Forty-six patients underwent resections of both CLM and CPM. Hepatic resection preceded pulmonary resection in most cases (91.3%). The median intervals between the resection of the primary tumour and the hepatic recurrence and between hepatic and pulmonary recurrences were 12 months [0-72] and 21.5 months [1-84], respectively. The mortality rate following CPM resection was 4.3%. After a median follow-up of 41.5 months [0-126], 35 patients recurred of whom 14 (40%) and 11(31.4%) could benefit from repeated resection of recurrent CLM and CPM, respectively. The median and 5-year overall survivals (OS) were 53 months and 49%, respectively. No prognostic factor was identified. CONCLUSION: An aggressive management of CLM and CPM, including repeated resections, may provide a long-term survival comparable to survival of patients with unique metastasectomy. The absence of prognostic factor may reflect the highly selected pattern of the eligible patients.

Depletion of MUC5B mucin in gastrointestinal cancer cells alters their tumorigenic properties: implication of the Wnt/ß-catenin pathway.

Secreted mucins are large O-glycosylated proteins that participate in the protection/defence of underlying mucosae in normal adults. Alteration of their expression is a hallmark of numerous epithelial cancers and has often been correlated to bad prognosis of the tumour. The secreted mucin MUC5B is overexpressed in certain subtypes of gastric and intestinal cancers, but the consequences of this altered expression on the cancer cell behaviour are not known. To investigate the role of MUC5B in carcinogenesis, its expression was knocked-down in the human gastric cancer cell line KATO-III and in the colonic cancer cell line LS174T by using transient and stable approaches. Consequences of MUC5B knocking-down on cancer cells were studied with respect to in vitro proliferation, migration and invasion, and in vivo on tumour growth using a mouse subcutaneous xenograft model. Western blotting, luciferase assay and qRT-PCR were used to identify proteins and signalling pathways involved. In vitro MUC5B down-regulation leads to a decrease in proliferation, migration and invasion properties in both cell lines. Molecular mechanisms involved the alteration of ß-catenin expression, localization and activity and decreased expression of several of its target genes. In vivo xenografts of MUC5B-deficient cells induced a decrease in tumour growth when compared with MUC5B-expressing Mock cells. Altogether, the present study shows that down-regulation of MUC5B profoundly alters proliferation, migration and invasion of human gastrointestinal cancer cells and that these alterations may be, in part, mediated by the Wnt/ß-catenin pathway emphasizing the potential of MUC5B as an actor of gastrointestinal carcinogenesis.

[FREGAT: French clinico-biological database dedicated to esogastric cancers]. / FREGAT : base clinicobiologique nationale française dédiée à la recherche sur les cancers œsogastriques.

Even though esogastric cancers are estimated at 1.5 million new cases worldwide with an expected 2.11 million new cases by 2025, prognosis remains poor and research is unsatisfactory compared to other cancers. There is an urgent need to intensify research via innovative and ambitious programs to improve patient's survival and quality of life. Incidence of esogastric cancers is particularly high in France, and the creation of a national clinicobiological database prospectively collecting epidemiological, human and social, clinical, pathological, biological data, sustained by biobanks of blood and tissues, is a critical point to improve research and care for these cancers considering all determinants of the disease with a more integrated approach. FREGAT clinicobiological database, funded and labeled by the French NCI in 2012, gathers the vast majority of university hospitals and cancer centers in France. This research relies on preexisting networks ensuring its efficacy and quality. Beyond significant increase of inclusions opened since January 2015, the establishment of public multiprivate industrial partnerships and creation of numerous French and European scientific projects, make FREGAT a decisive tool for research on esogastric cancers.

Micro-RNAs miR-29a and miR-330-5p function as tumor suppressors by targeting the MUC1 mucin in pancreatic cancer cells.

MUC1 is an oncogenic mucin overexpressed in several epithelial cancers, including pancreatic ductal adenocarcinoma, and is considered as a potent target for cancer therapy. To control cancer progression, miRNAs became very recently, major targets and tools to inhibit oncogene expression. Inhibiting MUC1 using miRNAs appears thus as an attractive strategy to reduce cancer progression. However, potent miRNAs and associated mechanisms regulating MUC1 expression remain to be identified. To this aim, we undertook to study MUC1 regulation by miRNAs in pancreatic cancer cells and identify those with tumor suppressive activity. MiRNAs potentially targeting the 3'-UTR, the coding region, or the 5'-UTR of MUC1 were selected using an in silico approach. Our in vitro and in vivo experiments indicate that miR-29a and miR-330-5p are strong inhibitors of MUC1 expression in pancreatic cancer cells through direct binding to MUC1 3'-UTR. MUC1 regulation by the other selected miRNAs (miR-183, miR-200a, miR-876-3p and miR-939) was found to be indirect. MiR-29a and miR-330-5p are also deregulated in human pancreatic cancer cell lines and tissues and in pancreatic tissues of Kras(G12D) mice. In vitro, miR-29a and miR-330-5p inhibit cell proliferation, cell migration, cell invasion and sensitize pancreatic cancer cells to gemcitabine. In vivo intra-tumoral injection of these two miRNAs in xenografted pancreatic tumors led to reduced tumor growth. Altogether, we have identified miR-29a and miR-330-5p as two new tumor suppressive miRNAs that inhibit the expression of MUC1 oncogenic mucin in pancreatic cancer cells.

The serrated neoplasia pathway of colorectal tumors: Identification of MUC5AC hypomethylation as an early marker of polyps with malignant potential.

The serrated neoplasia pathway accounts for 20-30% of colorectal cancers (CRC), which are characterized by extensive methylation (CpG island methylation phenotype, CIMP), frequent BRAF mutation and high microsatellite instability (MSI). We recently identified MUC5AC mucin gene hypomethylation as a specific marker of MSI CRC. The early identification of preneoplastic lesions among serrated polyps is currently challenging. Here, we performed a detailed pathological and molecular analysis of a large series of colorectal serrated polyps and evaluated the usefulness of mucin genes MUC2 and MUC5AC to differentiate serrated polyps and to identify lesions with malignant potential. A series of 330 colorectal polyps including 218 serrated polyps [42 goblet cell-rich hyperplastic polyps (GCHP), 68 microvesicular hyperplastic polyps (MVHP), 100 sessile serrated adenoma (SSA) and eight traditional serrated adenoma (TSA)] and 112 conventional adenomas was analyzed for BRAF/KRAS mutations, MSI, CIMP, MLH1 and MGMT methylation, and MUC2 and MUC5AC expression and methylation. We show that MUC5AC hypomethylation is an early event in the serrated neoplasia pathway, and specifically detects MVHP and SSA, arguing for a filiation between MVHP, SSA and CIMP-H/MSI CRC, whereas GCHP and TSA arise from a distinct pathway. Moreover, MUC5AC hypomethylation specifically identified serrated lesions with BRAF mutation, CIMP-H or MSI, suggesting that it may be useful to identify serrated neoplasia pathway-related precursor lesions. Our data suggest that MVHP should be recognized among HP and require particular attention.

Prevalence of Barrett Esophagus in Adolescents and Young Adults With Esophageal Atresia.

OBJECTIVE: To study the prevalence of Barrett esophagus (BE) (gastric and/or intestinal metaplasia) in adolescents treated for esophageal atresia (EA). SUMMARY OF BACKGROUND DATA: EA patients are at high risk of BE. METHODS: This multicenter prospective study included EA patients aged 15 to 19 years. All eligible patients were proposed an upper endoscopy with multistaged esophageal biopsies under general anesthesia. Histological suspicion of metaplasia was confirmed centrally. RESULTS: One hundred twenty patients [mean age, 16.5 years (±1.4)] were included; 70% had been treated for gastroesophageal reflux disease (GERD) during infancy. At evaluation, 8% were undernourished, 41% had received antireflux surgery, and 41% presented with GERD symptoms, although only 28% were receiving medical treatment. Esophagitis was found at endoscopy in 34% and confirmed at histology in 67%. BE was suspected after endoscopy in 37% and was confirmed by histology for 43% of patients (50 gastric and 1 intestinal metaplasia). No endoscopic or histological anomalies were found at the anastomosis site. BE was not significantly related to clinical symptoms. In multivariate analysis, BE was associated with EA without fistula (P = 0.03), previous multiple antireflux surgery (P = 0.04), esophageal dilation (P = 0.04), suspicion of BE at endoscopy (P < 0.001), and histological esophagitis (P = 0.02). CONCLUSIONS: Patients with EA are at high risk of persistent GERD and BE. The development of BE is related to GERD history. Long-term systematic follow-up of the esophageal mucosa including multistaged biopsies is required, even in asymptomatic patients. (NCT02495051).