Exosomal glypican-1 is elevated in pancreatic cancer precursors and can signal genetic predisposition in the absence of endoscopic ultrasound abnormalities

BACKGROUND Individuals within specific risk groups for pancreatic ductal adenocarcinoma(PDAC)[mucinous cystic lesions(MCLs),hereditary risk(HR),and new-late onset diabetes mellitus(NLOD)]represent an opportunity for early cancer detection.Endoscopic ultrasound(EUS)is a premium image modality for PDAC screening and precursor lesion characterization.While no specific biomarker is currently clinically available for this purpose,glypican-1(GPC1)is overexpressed in the circulating exosomes(crExos)of patients with PDAC compared with healthy subjects or those harboring benign pancreatic diseases.AIM To evaluate the capacity of GPC1+crExos to identify individuals at higher risk within these specific groups,all characterized by EUS.METHODS This cross-sectional study with a prospective unicentric cohort included 88 subjects:40 patients with MCL,20 individuals with HR,and 20 patients with NLOD.A control group(CG)was submitted to EUS for other reasons than pancreatic pathology,with normal pancreas and absence of hereditary risk factors(n=8).The inclusion period was between October 2016 and January 2019,and the study was approved by the Ethics Committee of Centro Hospitalar Universitário de São João,Porto,Portugal.All patients provided written informed consent.EUS and blood tests for quantification of GPC1+crExos by flow cytometry and carbohydrate antigen 19-9(CA 19-9)levels by ELISA were performed in all subjects.EUS-guided tissue acquisition was done whenever necessary.For statistical analysis,SPSS®27.0(IBM Corp.,Armonk,NY,United States)version was used.All graphs were created using GraphPad Prism 7.00(GraphPad Software,San Diego,CA,United States).RESULTS Half of MCLs harbored worrisome features(WF)or high-risk stigmata(HRS).Pancreatic abnormalities were detected by EUS in 10.0%and 35.0%in HR and NLOD individuals,respectively,all considered non-malignant and“harmless.”Median levels of GPC1+crExos were statistically different:MCL[99.4%,interquartile range(IQR):94.9%-99.8%],HR(82.0%,IQR:28.9%-98.2%),NLOD(12.6%,IQR:5.2%-63.4%),and CG(16.2%,IQR:6.6%-20.1%)(P<0.0001).Median levels of CA 19-9 were within the normal range in all groups(standard clinical cut-off of 37 U/mL).Within HR,individuals with a positive history of cancer had higher median levels of GPC1+crExos(97.9%;IQR:61.7%-99.5%),compared to those without(59.7%;IQR:26.3%-96.4%),despite no statistical significance(P=0.21).Pancreatic cysts with WF/HRS were statistically associated with higher median levels of GPC1+crExos(99.6%;IQR:97.6%-99.8%)compared to those without(96.5%;IQR:81.3%-99.5%)(P=0.011),presenting an area under the receiver operating characteristic curve value of 0.723(sensitivity 75.0%and specificity 67.7%,using a cutoff of 98.5%;P=0.012).CONCLUSION GPC1+crExos may act as biomarker to support the diagnosis and stratification of PDAC precursor lesions,and in signaling individuals with genetic predisposition in the absence of EUS abnormalities.

Early detection of pancreatic cancer

The diagnosis of pancreatic cancer associates an appalling significance.Detection of preinvasive stage of pancreatic cancer will ameliorate the survival of this deadly disease.Premalignant lesions such as Intraductal Papillary Mucinous Neoplasms or Mucinous Cystic Neoplasms of the pancreas are detectable on imaging exams and this permits their management prior their invasive development.Pancreatic intraepithelial neoplasms(PanIN)are the most frequent precursors of pancreatic adenocarcinoma(PDAC),and its particular type PanIN high-grade represents the malignant non-invasive form of PDAC.Unfortunately,PanINs are not detectable on radiologic exams.Nevertheless,they can associate indirect imaging signs which would rise the diagnostic suspicion.When this suspicion is established,the patient will be enrolled in a follow-up strategy that includes performing of blood test and serial imaging test such as computed tomography or magnetic resonance imaging,which will cost in the best-case scenario a burden of healthcare systems,and potential mortality in the worst-case scenario when the patient underwent resection surgery,worthless when there is no moderate or high grade dysplasia in the final histopathology.This issue will be avoid having at its disposal a diagnostic technique capable of detecting high-grade PanIN lesions,such is the cytology of pancreatic juice obtained by nasopancreatic intubation.Herein,we review the possibility of detection of early malignant lesions before they become invasive PADC.

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

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

C4.4A as a biomarker in pulmonary adenocarcinoma and squamous cell carcinoma

The high prevalence and mortality of lung cancer, together with a poor 5-year survival of only approximately 15%, emphasize the need for prognostic and predictive factors to improve patient treatment. C4.4A, a member of the Ly6/uP AR family of membrane proteins, qualifies as such a potential informative biomarker in non-small cell lung cancer. Under normal physiological conditions, it is primarily expressed in suprabasal layers of stratified squamous epithelia. Consequently, it is absent from healthy bronchial and alveolar tissue, but nevertheless appears at early stages in the progression to invasivecarcinomas of the lung, i.e., in bronchial hyperplasia/metaplasia and atypical adenomatous hyperplasia. In the stages leading to pulmonary squamous cell carcinoma, expression is sustained in dysplasia, carcinoma in situ and invasive carcinomas, and this pertains to the normal presence of C4.4A in squamous epithelium. In pulmonary adenocarcinomas, a fraction of cases is positive for C4.4A, which is surprising, given the origin of these carcinomas from mucin-producing and not squamous epithelium. Interestingly, this correlates with a highly compromised patient survival and a predominant solid tumor growth pattern. Circumstantial evidence suggests an inverse relationship between C4.4A and the tumor suppressor LKB1. This might provide a link to the prognostic impact of C4.4A in patients with adenocarcinomas of the lung and could potentially be exploited for predicting the efficacy of treatment targeting components of the LKB1 pathway.

Sporadic versus hereditary gastrinomas of the duodenum and pancreas: Distinct clinico-pathological and epidemiological features

Gastrinomas are defined as gastrin secreting tumors that are associated with Zollinger-Ellison syndrome （ZES）. ZES is characterized by elevated fasting gastrin serum levels, positive secretin stimulation test and clinical symptoms such as recurrent peptic ulcer disease, gastroesophageal reflux disease and occasional diarrhea. Genetically, nonhereditary （sporadic） gastrinomas are distinguished from hereditary gastrinomas, which are associated with multiple endocrine neoplasia type 1 （MEN1） syndrome. In general, duodenal gastrinomas are small and solitary if they are sporadic and multiple as well as hereditary. The sporadic gastrinomas occur in the duodenum or in the pancreas while the hereditary gastrinomas almost all occur in the duodenum. Our series of 77 sporadic duodenal neuroendocrine tumors （NETs） includes 18 patients （23.4%） with gastrinomas and ZES. Of 535 sporadic NETs in the pancreas collected from the NET archives of the departments of pathology in Zürich, Switzerland, and Kiel, Germany, 24 patients （4.5%） suffered from sporadic pancreatic gastrinomas and ZES. These NETs have to be distinguished from tumors with immunohistochemical positivity for gastrin but without evidence of ZES. An additional 19 patients suffered from MEN1 and ZES. These patients showed exclusively duodenal gastrinomas, but not pancreatic gastrinomas. The prognosis of sporadic and MEN1- associated duodenal gastrinomas is better than that of pancreatic gastrinomas, since they progress slowly to liver metastasis. In summary, sporadic and MEN1- associated gastrinomas in the duodenum and pancreas show different clinico-pathological and genetic features. The incidence of sporadic duodenal gastrin-producing tumors is increasing, possibly due to optimized diagnostic procedures. In contrast, pancreatic MEN1- associated gastrinomas seem to be extremely rare. A considerable subset of tumors with immunohistochemical expression of gastrin but without evidence of ZES should be designated as functionally inactive NETs expressing gastrin, but not as gastrinomas.

Pathological,molecular,and clinical characteristics of cholangiocarcinoma:A comprehensive review

Cholangiocarcinomas are a heterogeneous group of highly aggressive cancers that may arise anywhere within the biliary tree.There is a wide geographical variation with regards to its incidence,and risk-factor associations which may include liver fluke infection,primary sclerosing cholangitis,and hepatolithiasis amongst others.These tumours are classified into intrahepatic,perihilar and distal based on their anatomical location.Morphologically,intrahepatic cholangiocarcinomas are further sub-classified into small and large duct variants.Perihilar and distal cholangiocarcinomas are usually mucin-producing tubular adenocarcinomas.Cholangiocarcinomas develop through a multistep carcinogenesis and are preceded by dysplastic and in situ lesions.While clinical characteristics and management of these tumours have been extensively elucidated in literature,their ultra-structure and tumour biology remain relatively unknown.This review focuses on the current knowledge of pathological characteristics,molecular alterations of cholangiocarcinoma,and its precursor lesions(including biliary intraepithelial neoplasia,intraductal papillary neoplasms of the bile duct,intraductal tubulopapillary neoplasms and mucinous cystic neoplasm).