CD71 in Gestational Pathology: A Versatile Immunohistochemical Marker With New Possible Applications

Glucagon-Producing Pancreatic Neuroendocrine Tumors (Glucagonomas) are Enriched in Aggressive Neoplasms with ARX and PDX1 Co-expression, DAXX/ATRX Mutations, and ALT (Alternative Lengthening of Telomeres)

Glucagonomas are functioning pancreatic neuroendocrine tumors (PanNETs) responsible for glucagonoma syndrome. This study aims to shed light on the clinicopathological and molecular features of these neoplasms. Six patients with glucagonomas were identified. All neoplasms were investigated with immunohistochemistry for neuroendocrine markers (Synaptophysin, Chromogranin-A), ATRX, DAXX, ARX, and PDX1 transcription factors. Fluorescent in situ hybridization (FISH) for assessing alternative lengthening of telomeres (ALT), and next-generation sequencing (NGS) for molecular profiling were performed. All cases were large single masses (mean size of 8.2 cm), with necrolytic migratory erythema as the most common symptom (6/6 cases, 100%). All neoplasms were well-differentiated G1 tumors, except one case that was G2. The tumors consistently showed classic/conventional histomorphology, with solid-trabecular and nested architecture. Lymphatic and vascular invasion (6/6, 100%), perineural infiltration (4/6, 66.6%), and nodal metastasis (4/6, 66.6%) were frequently observed. Transcription factors expression showed strong ARX expression in all tumors, and PDX1 expression in 5/6 cases (83.3%), indicating co-occurring alpha- and beta-cell differentiation. NGS showed recurrent somatic MEN1 and ATRX/DAXX biallelic inactivation. Cases with ATRX or DAXX mutations also showed matched loss of ATRX or DAXX protein expression and ALT. One case harbored somatic MUTYH inactivation and showed a high tumor mutational burden (TMB, 41.0 mut/Mb). During follow-up, one patient died of the disease, and four patients developed distant metastasis. Pancreatic glucagonomas are distinct PanNETs with specific clinicopathological and molecular features, including histological aspects of biological aggressiveness, co-occurring alpha- and beta-cell differentiation, MEN1 and DAXX/ATRX mutations enrichment, and the possible presence of high-TMB as an actionable marker.

Long-Term Survivor of Intrahepatic Cholangiocarcinoma for over 18 Years: Case Study with Longitudinal Histo-molecular and Tumor Immune Microenvironment Characterization and Systematic Review of the Literature

BACKGROUND

Intrahepatic cholangiocarcinoma is a biliary neoplasm usually showing a dismal prognosis. In early stages, surgical resection is the best treatment option, significantly increasing the overall survival. This approach is also recommended in the case of relapsing disease. In this study, we report the case of a patient affected by intrahepatic cholangiocarcinoma with multiple relapses and still alive for over 18 years. We also provide a systematic review regarding long-survivor (> 60 months) of intrahepatic cholangiocarcinoma.

CASE PRESENTATION

A 41-year-old woman with no pathological history was diagnosed with localized intrahepatic cholangiocarcinoma and surgically treated with left hepatectomy. After the first intervention, the patients underwent three further surgical resections because of locoregional recurrences. Histologically, there were some significant similarities among all neoplasms, including the tubule-glandular architecture, but also morphological heterogeneity. The tumor immune microenvironment remained stable across the different lesions. The molecular analysis with next-generation sequencing demonstrated that all neoplasms shared the same genomic profile, including NBN and NOTCH3 mutations and chromosomes 1 and 3 alterations.

CONCLUSIONS

This case study highlights the essential role of a stringent follow-up after resection of intrahepatic cholangiocarcinoma for detecting early relapsing tumors. Moreover, it shows the importance of the molecular characterization of multiple tumors for understanding their real nature. The accurate study of long-surviving patients highlights the features that are critical for outcome improvement.

Clinical and Genomic Characterization of Pancreatic Ductal Adenocarcinoma with Signet-Ring/Poorly Cohesive Cells

Signet-ring cell (SRC)/poorly cohesive cell carcinoma is an aggressive variant of pancreatic ductal adenocarcinoma (PDAC). This study aimed to clarify its clinicopathologic and molecular profiles based on a multi-institutional cohort of 20 cases. The molecular profiles were investigated using DNA and RNA sequencing. The clinicopathologic parameters and molecular alterations were analyzed based on survival indices and using a validation/comparative cohort of 480 conventional PDAC patients. The primary findings were as follows: (1) clinicopathologic features: SRC carcinomas are highly aggressive neoplasms with poor prognosis, and the lungs are elective metastatic sites; (2) survival analysis: a higher SRC component was indicative of poorer prognosis. In particular, the most clinically significant threshold of SRC was 80%, showing statistically significant differences in both disease-specific and disease-free survival; (3) genomic profiles: SRC carcinomas are similar to conventional PDAC with the most common alterations affecting the classic PDAC drivers KRAS (70% of cases), TP53 (55%), SMAD4 (25%), and CDKN2A (20%). EGFR alterations, RET::CCDC6 fusion gene, and microsatellite instability (3 different cases, 1 alteration per case) represent novel targets for precision oncology. The occurrence of SMAD4 mutations was associated with poorer prognosis; (4) pancreatic SRC carcinomas are genetically different from gastric SRC carcinomas: CDH1, the classic driver gene of gastric SRC carcinoma, is not altered in pancreatic SRC carcinoma; (5) transcriptome analysis: the cases clustered into 2 groups, one classical/exocrine-like, and the other squamous-like; and (6) SRC carcinoma-derived organoids can be successfully generated, and their cultures preserve the histologic and molecular features of parental SRC carcinoma. Although pancreatic SRC carcinoma shares similarities with conventional PDAC regarding the most important genetic drivers, it also exhibits important differences. A personalized approach for patients with this tumor type should consider the clinical relevance of histologic determination of the SRC component and the presence of potentially actionable molecular targets.

Recurrent gastric amphicrine tumor with neuroendocrine and pancreatic acinar cell differentiation and somatic MEN1 inactivation arisen during immunotherapy

Amphicrine neoplasms (ANs) are poorly understood epithelial malignancies composed of cells with co-existing exocrine-neuroendocrine features. Here, we report a recurrent mucin-producing gastric amphicrine tumor co-expressing neuroendocrine (chromogranin-A, synaptophysin, and CD56) and pancreatic acinar cell (BCL10 and trypsin) markers, arisen in a 64-year-old woman during adjuvant immunotherapy for melanoma. Ki-67 was < 2%. The gastric background context was atrophic gastritis. Next-generation sequencing showed MEN1 mutation (p.P71fs*42) coupled with loss of heterozygosity. The key lessons were as follows: (1) gastric ANs can show the co-existence of exocrine mucin-producing elements with neuroendocrine and pancreatic acinar differentiation; (2) they may represent a new entity arising in the context of atrophic gastritis and during immunotherapy; (3) they should be considered in the diagnostic workup of gastric neuroendocrine tumors; and (4) their molecular profile can show striking similarities with well-differentiated neuroendocrine tumors. These findings may be of help to improve the knowledge and the biological taxonomy of ANs.

Characterization and digital spatial deconvolution of the immune microenvironment of intraductal oncocytic papillary neoplasms (IOPN) of the pancreas

Intraductal oncocytic papillary neoplasm (IOPN) of the pancreas is a distinct entity from intraductal papillary mucinous neoplasms (IPMNs) and is considered one of the precursor lesions of pancreatic cancer. Through immunohistochemistry (IHC) and an artificial intelligence (AI)-based approach, this study aims at characterizing its immune microenvironment. Whole-slide IHC was performed on a cohort of 15 IOPNs, 2 of which harboring an associated adenocarcinoma. The following markers were tested: CD3, CD4, CD8, CD20, CD68, CD163, PD-1, PD-L1, MLH1, PMS2, MSH2, and MSH6. The main findings can be summarized as follows: (i) CD8+ T lymphocytes were the predominant immune cells (p < 0.01); (ii) the vast majority of macrophages were concurrently CD68+ and CD163+; (iii) all tumors showed an activated PD-1/PD-L1 axis, but none had mismatch repair deficiency; (iv) AI-based analysis revealed the presence of 2 distinct regions in each case, namely, Re1, localized at the center of the tumor, and Re2, located at tumor periphery; (v) the infiltrating component of the 2 invasive IOPNs showed a smaller extent of Re1 and a reduced rate of CD4+ cells, as well as a larger extent of Re2 and increased rate of CD8+ cells. IOPNs are lesions enriched in immune cells, with a predominance of CD8+ T lymphocytes and class 2 macrophages. Differently from IPMN-oncogenesis, the progression towards invasive carcinoma is accompanied by an increased rate of CD8+ lymphocytes. This finding may suggest the presence of an active self-immune surveillance in invasive IOPNs, potentially explaining, at least in part, the excellent survival rate of IOPN patients.

Endoscopic ultrasound fine-needle biopsy to assess DAXX/ATRX expression and alternative lengthening of telomeres status in non-functional pancreatic neuroendocrine tumors

BACKGROUND/OBJECTIVES

Death domain-associated protein (DAXX) and/or α-thalassemia/mental retardation X-linked (ATRX) chromatin remodeling genes mutations and alternative lengthening of telomeres (ALT) activation are associated with more aggressive behavior of non-functional pancreatic neuroendocrine tumors (NF-PanNETs). We aimed to evaluate the reliability of such markers on endoscopic-ultrasound fine-needle biopsy (EUS-FNB) specimens.

METHODS

Patients who underwent EUS-FNB and subsequent surgical resection for PanNETs between January 2017 and December 2019 were retrospectively identified. Immunohistochemistry (IHC) to evaluate DAXX/ATRX expression and fluorescence in situ hybridization (FISH) for ALT status were performed. Primary outcome was the concordance rate of markers expression between EUS-FNB and surgical specimens. Secondary aims were association between markers and lesion aggressiveness, their diagnostic performance in predicting aggressiveness, and agreement of preoperative and post-surgical Ki67-based grading.

RESULTS

Forty-one NF-PanNETs (mean diameter 36.1 ± 26.5 mm) were included. Twenty-four showed features of lesion aggressiveness. Concordance of expressions of DAXX, ATRX, and ALT status between EUS-FNB and surgical specimens were 95.1% (κ = 0.828; p < 0.001), 92.7% (κ = 0.626; p < 0.001), and 100% (κ = 1; p < 0.001), respectively. DAXX/ATRX loss and ALT-positivity were significantly (p < 0.05) associated with metastatic lymphnodes and lymphovascular invasion. The combination of all tumor markers (DAXX/ATRX loss + ALT-positivity + grade 2) reached an accuracy of 73.2% (95%CI 57.1-85.8) in identifying aggressive lesions. Pre- and post-operative ki-67-based grading was concordant in 80.5% of cases (k = 0.573; p < 0.001).

CONCLUSION

DAXX/ATRX expression and ALT status can be accurately evaluated in a preoperative setting on EUS-FNB samples, potentially improving the identification of patients with increased risk and poorer prognosis.

Juvenile polyposis diagnosed with an integrated histological, immunohistochemical and molecular approach identifying new SMAD4 pathogenic variants

Juvenile polyposis (JP) is a rare familial syndrome characterized by the development of numerous hamartomatous polyps of the gastrointestinal tract and by an increased risk of developing gastrointestinal cancers. It follows a pattern of autosomal dominant inheritance and is associated with germline variants of SMAD4 or BMPR1A genes. Differential diagnosis may be difficult based on histology alone, due to morphological similarities to other familial syndromes. Here we report a case of familial JP diagnosed in a 50-years woman with a familial history positive for gastrointestinal cancers and other tumor types. The patient presented with severe iron deficiency anemia and showed numerous polyps in the stomach and jejunum according to endoscopy and imaging. She underwent an intra-gastric laparoscopic removal of the major gastric polyp, followed by jejunal exploration and resection of a segment with multiple neoformations. Histological examination revealed the presence of hamartomatous polyposis. Gastric and intestinal samples were analyzed with next-generation sequencing. Molecular analysis showed that the patient harbored a germline splicing site variant of SMAD4, c.1139 + 3A > G, which was complemented by different somatic variants of the same gene in the different polyps. Immunohistochemistry for SMAD4 confirmed loss of protein expression in the polyps, with regular expression in normal cells. cDNA sequencing further confirmed the findings. We thus definitively diagnosed the woman as having JP thanks to an integrated approach based on histology, immunohistochemistry and molecular analysis. The identified variants, all previously reported as variants of unknown significance, were classified as pathogenic as they complemented each other leading to SMAD4 loss.

Challenges in diagnosing hydatidiform moles: a review of promising molecular biomarkers

INTRODUCTION

Hydatidiform moles (HMs) are pathologic conceptions with unique genetic bases and abnormal placental villous tissue. Overlapping ultrasonographical and histological manifestations of molar and non-molar (NM) gestations and HMs subtypes makes accurate diagnosis challenging. Currently, immunohistochemical analysis of p57 and molecular genotyping have greatly improved the diagnostic accuracy.

AREAS COVERED

The differential expression of molecular biomarkers may be valuable for distinguishing among the subtypes of HMs and their mimics. Thus, biomarkers may be the key to refining HMs diagnosis. In this review, we summarize the current challenges in diagnosing HMs, and provide a critical overview of the recent literature about potential diagnostic biomarkers and their subclassifications. An online search on PubMed, Web of Science, and Google Scholar databases was conducted from the inception to 1 April 2022.

EXPERT OPINION

the emerging biomarkers offer new possibilities to refine the diagnosis for HMs and pregnancy loss. Although the additional studies are required to be quantified and investigated in clinical trials to verify their diagnostic utility. It is important to explore, validate, and facilitate the wide adoption of newly developed biomarkers in the coming years.

"Pure" hepatoid tumors of the pancreas harboring CTNNB1 somatic mutations: a new entity among solid pseudopapillary neoplasms

Hepatoid tumors (HTs) represent a rare group of neoplasms that are histologically similar to hepatocellular carcinoma but arise outside the liver. The current World Health Organization classification recognizes the hepatoid morphology of pancreatic tumors only as a possible variant of pancreatic ductal adenocarcinoma (PDAC). Here, we describe two cases of "pure" HT of the pancreas showing common features and characterized by indolent biological behavior. These tumors were roundish nodules with pushing borders, hyaline globules, and pure hepatoid histology; they were diffusely positive for β-catenin and LEF1 on immunohistochemistry. At next-generation sequencing, both neoplasms harbored only one pathogenic somatic mutation that affected the CTNNB1 gene at exon 3 and showed a loss of heterozygosity on chromosomes 18 and 21. By integrating macroscopic and microscopic features, along with their molecular profiles, we advocate that such tumors represent a distinct entity from PDAC and should be considered a new variant of solid pseudopapillary neoplasms. The recognition of this new neoplastic category may have immediate implications not only for tumor taxonomy but also for clinical practice.

Molecular Analysis of an Intestinal Neuroendocrine/Non-neuroendocrine Neoplasm (MiNEN) Reveals MLH1 Methylation-driven Microsatellite Instability and a Monoclonal Origin: Diagnostic and Clinical Implications

Mixed neuroendocrine/non-neuroendocrine neoplasms (MiNEN) are rare mixed epithelial neoplasms in which a neuroendocrine component is combined with a non-neuroendocrine component. Here, we provide the clinical, pathologic, and molecular report of a 73-year-old-man presenting with an intestinal MiNEN. The lesion was composed of a well-differentiated G3 neuroendocrine tumor and a colloid adenocarcinoma. The molecular characterization was performed using a multigene next-generation sequencing panel. The neoplasm displayed microsatellite instability due to MLH1 promoter methylation. The extended molecular profile documented the same mutations affecting ARID1A, ASXL1, BLM, and RNF43 genes in both components, indicating a monoclonal origin of the tumor. Regarding component-specific gene mutations, BRCA2 was specifically altered in the neuroendocrine area. It may represent a new actionable target for precision oncology in MiNEN, but the lack of its alteration in the colloid component calls for further considerations on intratumor heterogeneity. The most important finding with potential immediate implications regards the presence of microsatellite instability: it indicates that this molecular alteration should become part of the diagnostic algorithm for these rare neoplasms.

PD-L1 and Notch as novel biomarkers in pancreatic sarcomatoid carcinoma: a pilot study

BACKGROUND

The improved immunological understanding revealed the tumor microenvironment as an appealing driver to restore the immune response against cancer cells resulting in a paradigm shift in the oncology field. However, the complexity of the tumor milieu suggests the role of several pathways linking in immunomodulation mechanisms. Pancreatic cancer represents a model of the intricate relationship between malignant cells and their surrounding neighborhood.

RESEARCH DESIGN AND METHODS

In this study, we analyzed, retrospectively, six cases of rare pancreatic sarcomatoid carcinoma (PSC) and evaluated the expression of PD-L1 and Notch, aiming to explore new attributes in immunophenotype.

RESULTS

PD-L1 CPS ≥ 1was common in PSCs (83%) with half samples expressing PD-L1 CPS ≥ 50. Notch1 and Notch3 demonstrated a high range of expression. A direct significant correlation between PD-L1 and Notch3 overexpression (r = 0.7; p = 0.036) has been observed. Immunofluorescence studies revealed a co-localization of Notch3 and PD-L1 when both proteins were over-expressed within cytoplasmic or membranous compartments of the same cells.

CONCLUSIONS

Our data identify a unique biological characterization of this rare pancreatic histotype. These findings provide a rationale for future studies evaluating the potential crosstalk between PD-L1/PD-1 axis and Notch pathways and prompting the development of novel therapeutics strategy.

Diagnostic value of glycophorin-A in comparison with P57 immunohistochemical staining method in differentiating complete and partial molar pregnancies

INTRODUCTION

Current histomorphological criteria in distinguishing two subtypes of hydatidiform moles has considerable inter-observer variability and limitations. In this regard, ancillary studies can aid pathologist to obtain an accurate diagnosis. Herein, we evaluated the utility of Glycophorin-A (GLA) in differentiating complete and partial moles.

MATERIALS AND METHODS

In this case-control study, formalin-fixed paraffin-embedded blocks of 47 patients with pathologic diagnosis of complete and 42 partial hydatidiform moles were included and the diagnoses were confirmed by immunohistochemistry (IHC) for P57. Sections from all samples were stained for GLA using IHC method. Using 2 × 2 tables, the sensitivity, specifity, Positive and Negative Predictive Values (PPV and NPV) as well as accuracy of GLA were determined.

RESULTS

Primary pathologic diagnosis was changed in 7.1% and types of hydatidiform mole were specified in 11.9% of the cases after review of the slides and IHC study for P57. NRBCs were found in 52.7% of the PM cases and none of CMs by pathologist in H&E sections. IHC study for GLA revealed positive result in one case of complete moles (2%) and 31 case of partial mole samples (73.8%). It was negative in 98% of the complete mole and 11 (26.2%) of partial mole cases.

DISCUSSION

The results of this study showed a significant association between GLA immunoreactivity and type of molar pregnancy. Diagnostic sensitivity, specificity and accuracy of this marker for discrimination of molar pregnancy were 73.8%, 98% and 86.5%, respectively. Therefore, this marker can be utilized in differentiating partial and complete hydatidiform mole.

Solid Pseudopapillary Neoplasm of the Pancreas and Abdominal Desmoid Tumor in a Patient Carrying Two Different BRCA2 Germline Mutations: New Horizons from Tumor Molecular Profiling

This case report describes the history of a 41 year-old woman with a solid pseudopapillary neoplasm (SPN) of the pancreas and a metachronous abdominal desmoid tumor (DT) that occurred two years after the SPN surgical resection. At next-generation sequencing of 174 cancer-related genes, both neoplasms harbored a CTNNB1 somatic mutation which was different in each tumor. Moreover, two BRCA2 pathogenic mutations were found in both tumors, confirmed as germline by the sequencing of normal tissue. The BRCA2 mutations were c.631G>A, resulting in the amino-acid change p.V211I, and c.7008-2A>T, causing a splice acceptor site loss. However, as the two neoplasms showed neither loss of heterozygosity nor somatic mutation in the second BRCA2 allele, they cannot be considered as BRCA-dependent tumors. Nevertheless, this study highlights the important opportunities opened by extensive tumor molecular profiling. In this particular case, it permitted the detection of BRCA2-germline mutations, essential for addressing the necessary BRCA-related genetic counseling, surveillance, and screening for the patient and her family.

CD117 Is a Specific Marker of Intraductal Papillary Mucinous Neoplasms (IPMN) of the Pancreas, Oncocytic Subtype

The intraductal oncocytic papillary neoplasm (IOPN) of the pancreas has been recognized by WHO classification as a unique intraductal papillary mucinous neoplasm (IPMN) category. IOPN is composed of oxyphil cells, usually expressing MUC5AC, MUC6, and Hep Par-1, and harboring PRKACA/B fusion genes as their genetic hallmark. Although IOPNs are associated with an infiltrative adenocarcinoma in up to 30% of cases, the survival rate after surgical resection approaches 100%. This highlights the importance of the correct IOPN diagnosis, above all in cases with an associated invasive component. In this study, the immunohistochemical expression of CD117 was investigated in 111 IPMNs, including 17 oncocytic, 45 gastric, 20 pancreatico-biliary, and 29 intestinal IPMNs. We also tested the expression of MUC5AC, MUC6, and Hep Par-1 in the IOPN cohort. CD117 positivity was significantly more frequent in IOPNs compared to the other IPMN subtypes (p < 0.0001). Furthermore, within IOPN, a lower or absent CD117, MUC5AC, MUC6, and Hep Par-1 expression tended to be associated with the presence of an infiltrative component. Our findings shed light into the biology of these complex lesions, which are confirmed to be a distinctive IPMN subtype; notably, CD117 emerged as a potential, additional tool in the differential diagnosis of IPMNs.

A case report of three synchronous tumors in the same pancreatic specimen

It is known that Duodenal adenocarcinoma (DA) is a rare malignant solid tumor that cause occlusion symptoms with orthodox dysphagia when locally advanced. Pancreatic neuroendocrine tumors (PanNETs) account for about 2% of all pancreatic neoplasms. The combination of these two lesions, with the synchronous presence of ectopic pancreatic tissue (EPT) of the duodenum, has never been described in literature, to our knowledge. Here we report a case of combined DA, EPT and PanNET affecting a 71-year-old woman.

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Simultaneous presence of Duodenal adenocarcinoma pancreatic neuroendocrine tumor ectopic pancreatic tissue of duodenum.

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Biochemical tests did not reveal abnormalities: CA 19-9 was normal, CEA was 153 U/L.

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Ultrasonography confirmed a nodule dislocating pancreas investigated with contrast-enhanced CT and esophagogastroduodenoscopy.

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The association between duodenal adenocarcinomas, PanNET and ectopic pancreatic tissue (EPT) of the duodenum is really rare.

Improvement of maternal and fetal outcomes in women with sickle cell disease treated with early prophylactic erythrocytapheresis

BACKGROUND

The desire for pregnancy in sickle cell disease (SCD) women has become a true challenge for hematologists, requiring a multidisciplinary approach. Erythrocytapheresis (ECP) is an important therapeutic tool in SCD, but only limited data on starting time and the effects of ECP during pregnancy are available.

STUDY DESIGN AND METHODS

This is a double-center retrospective cross-sectional study on a total of 46 single pregnancies in SCD women from January 2008 to June 2017. ECP was started at 10.7 ± 5.2 weeks of gestation, and prophylactic enoxaparin (4,000 U daily) was introduced due to the reported high prevalence of thromboembolic events in pregnant SCD women.

RESULTS

The alloimmunization ratio was 2.1 per 1,000 and the alloimmunization rate was 5.6%. In early ECP-treated SCD women, no severe vaso-occlusive crisis, sepsis or severe infection, or preeclampsia or eclampsia were observed. We found normal umbilical arterial impedance during pregnancy, suggesting an optimal uteroplacental function in early ECP-treated SCD women. This was also supported by the improvement in newborn birthweights compared to previous studies. In our cohort, three SCD women were started later on ECP (20-25 weeks), and gestation ended with late fetal loss. Placenta pathology documented SCD-related damage and erythroblasts in placental vessels, indicating fetal hypoxia.

CONCLUSIONS

Collectively, our data generate a rationale to support a larger clinical trial of early ECP program in SCD pregnancy.

Pulmonary Adenocarcinoma With Enteric Differentiation: Immunohistochemistry and Molecular Morphology

Pulmonary adenocarcinoma with enteric differentiation (PAED) is a rare subtype of lung adenocarcinoma recently recognized in the WHO classification. It is defined as an adenocarcinoma in which the enteric component exceeds 50% and have to show the expression of at least 1 immunohistochemical marker of enteric differentiation. Although the definition of this tumor type is very important, above all in the differential diagnosis between a primary lung tumor and a metastasis of colorectal adenocarcinoma, this cancer still lacks a distinctive immunohistochemical and molecular signature. We recruited the largest series in the literature of PAEDs according to the morphology and the positivity for intestinal markers. Then, we evaluated the immunohistochemical and molecular profile of these adenocarcinomas. In our series, CDX-2 and CK7 were the immunohistochemical markers mostly expressed by PAEDs. There was an inverse relationship between the expression of pnuemocytes markers, such as TTF-1, and intestinal markers. Molecular analysis revealed KRAS as the most frequently mutated gene (>60% of cases), with very few cases harboring abnormalities affecting EGFR, BRAF, and ALK genes. PAEDs are morphologically very heterogenous. The immunohistochemical profile based on CDX-2 and CK7 positivity of PAEDs appears very robust to support this diagnosis, and it is applicable also on small biopsies. KRAS appears as the most important mutated gene in such tumors.

CD71+ Erythroid Suppressor Cells Promote Fetomaternal Tolerance through Arginase-2 and PDL-1

Survival of the allogeneic pregnancy depends on the maintenance of immune tolerance to paternal alloantigens at the fetomaternal interface. Multiple localized mechanisms contribute to the fetal evasion from the mother's immune rejection as the fetus is exposed to a wide range of stimulatory substances such as maternal alloantigens, microbes and amniotic fluids. In this article, we demonstrate that CD71⁺ erythroid cells are expanded at the fetomaternal interface and in the periphery during pregnancy in both humans and mice. These cells exhibit immunosuppressive properties, and their abundance is associated with a Th2 skewed immune response, as their depletion results in a proinflammatory immune response at the fetomaternal interface. In addition to their function in suppressing proinflammatory responses in vitro, maternal CD71⁺ erythroid cells inhibit an aggressive allogeneic response directed against the fetus such as reduction in TNF-α and IFN-γ production through arginase-2 activity and PD-1/programmed death ligand-1 (PDL-1) interactions. Their depletion leads to the failure of gestation due to the immunological rejection of the fetus. Similarly, fetal liver CD71⁺ erythroid cells exhibit immunosuppressive activity. Therefore, immunosuppression mediated by CD71⁺ erythroid cells on both sides (mother/fetus) is crucial for fetomaternal tolerance. Thus, our results reveal a previously unappreciated role for CD71⁺ erythroid cells in pregnancy and indicate that these cells mediate homeostatic immunosuppressive/immunoregulatory responses during pregnancy.

Cell of origin markers identify different prognostic subgroups of lung adenocarcinoma

Strong prognostic markers able to stratify lung adenocarcinoma (ADC) patients are lacking. We evaluated whether a six-immunohistochemical markers panel (TTF1, SP-A, Napsin A, MUC5AC, CDX2 and CK5), defining the putative neoplastic "cell of origin," allows to identify prognostic subgroups among lung ADC. We screened a large cohort of ADC specimens (2003-2013) from Torino Institutional Repository identifying: (i) marker positivity by immunohistochemistry, (ii) main morphological appearance by light microscopy, (iii) presence of "hotspot" mutations of candidate genes by Sequenom technology. To evaluate possible predictors of survival and time to recurrence, uni- and multivariable-adjusted comparisons were performed. We identified 4 different subgroups: "alveolar," "bronchiolar," "mixed" and "null type." Alveolar-differentiated ADC were more common in young (P=.065), female (P=.083) patients, frequently harboring EGFR-mutated (P=.003) tumors with acinar pattern (P<.001). Bronchiolar-differentiated ADC were more associated with mucinous and solid pattern (P<.001), higher degree of vascular invasion (P=.01) and KRAS gene mutations (P=.07). Bronchiolar, mixed, and null types were independent negative predictors for overall survival, and the latter two had a shorter time to recurrence. This "Cell of Origin" classifier is more predictable than morphology and genetics and is an independent predictor of survival on a multivariate analysis.

Fhit down-regulation is an early event in pancreatic carcinogenesis

Aberrant Fhit expression characterizes a large proportion of primary pancreatic ductal adenocarcinomas (PDACs), but fragmentary information is available on Fhit expression during the phenotypic changes of pancreatic ductal epithelium during multistep transformation. We assessed Fhit expression by immunohistochemistry in two different multistep pancreatic carcinogenic processes: pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasia (IPMN). We considered 105 surgically treated PDACs/IPMNs and selected 30 samples of non-neoplastic pancreatic parenchyma, 50 PanIN lesions, 30 IPMNs, 15 IPMNs with associated invasive carcinoma, and 60 adenocarcinomas. Normal pancreatic ducts and surrounding acinar cells consistently showed moderate to strong Fhit immunoreactivity. Significant down-regulation of Fhit expression was observed in association with increasing severity of dysplastia/neoplastia in both carcinogenic processes. This was further confirmed by studying multiple lesions obtained from the same surgical specimen. Of 60 PDACs, only 14 showed Fhit expression comparable to normal pancreatic ductal epithelium, while the remainder (77%) showed clearly negative or reduced Fhit expression. This study demonstrates that Fhit down-regulation is an early event in both multistep carcinogenic processes leading to PDAC.

Pulmonary adenocarcinoma with enteric differentiation: Dissecting oncogenic genes alterations with DNA sequencing and FISH analysis

BACKGROUND

Pulmonary Adenocarcinoma with Enteric Differentiation (PAED) is a rare subtype of adenocarcinoma of emerging interest, recently introduced in the 2015 WHO classification. However, little is known about major molecular signatures of this class of adenocarcinomas and information about new biomarkers totally lack.

METHODS

We examined the NRAS, PIK3CA, EGFR, KRAS and BRAF status through mass spectrometry sequencing and ALK rearrangement by FISH in a series of 8 PAEDs.

RESULTS

1/8 (12.5%) case had a simultaneous PIK3CA mutation (E545K) and an EML4-ALK translocation. KRAS gene showed a mutation in the codon 12 in 4/8 of PAED (50%), NRAS, BRAF and EGFR genes were wild type in all tumor samples.

CONCLUSIONS

We concluded that PIK3CA mutations and ALK rearrangement occur also in PAEDs, while NRAS mutations might be a very rare event similarly to pulmonary adenocarcinomas of conventional type. KRAS is the prevailing gene mutated in this class of adenocarcinoma.

A rare case of three different tumors in the same pancreatic specimen: a case report and brief review of the literature

Solid pseudopapillary tumors (SPT) of the pancreas are rare neoplasms mainly affecting young women. Pancreatic serous cystadenomas (SCAs) and pancreatic neuroendocrine tumors (PanNETs) account for about 2% of all pancreatic neoplasms. The combination of these three lesions, to our knowledge, has never been described in literature. Here we report a case of combined SPT, SCA and PanNET affecting a 33-year-old woman.

RASSF1 tumor suppressor gene in pancreatic ductal adenocarcinoma: correlation of expression, chromosomal status and epigenetic changes

BACKGROUND

The Ras Association Domain Family Member 1 (RASSF1) is one of the most frequently reported methylation-inactivated tumor suppressor genes in primary pancreatic ductal adenocarcinomas (PDAC). Limited information is still available about the impact of RASSF1 gene silencing on the expression of its different isoforms in neoplastic cells.

METHODS

A series of 96 primary PDAC, with known clinico-pathological parameters, was tested for RASSF1 methylation status by methylation-specific PCR, RASSF1 locus copy number alterations by fluorescence in situ hybridization, and Rassf1a protein expression by immunohistochemistry. A further series of 14 xenografted primary PDAC and 8 PDAC-derived cell lines were tested to obtain a detailed methylation mapping of CpG islands A and C of the RASSF1 locus by pyrosequencing and to evaluate the expression of Rassf1 variants by qRT-PCR.

RESULTS

Methylation of CpG island A of the RASSF1 gene was observed in 35% of the tumors and allelic loss of RASSF1 locus was seen in 30 disomic and in 20 polysomic cases (52%). Rassf1a immunohistochemical expression was downregulated in half of primary PDAC, and this downregulation was neither correlated with methylation of RASSF1 promoter nor with RASSF1 copy number alterations. RASSF1 status did not influence patients' prognosis. The expression of the seven RASSF1 isoforms in xenografts and cell lines showed that RASSF1A, RASSF1B, and RASSF1C isoforms were present in all xenografts and cell lines, whereas RASSF1D, RASSF1E, and RASSF1F isoforms were variably expressed among samples. RASSF1G was never expressed in either xenografts or cell lines. The variable expression of RASSF1 isoforms in PDAC xenografts and cell lines was not dependent on RASSF1 methylation status of CpG islands A and C.

CONCLUSIONS

RASSF1 alterations occurring in PDAC mainly consist in variations of expression of the different isoforms. Different genetic mechanisms seem to contribute to RASSF1 deregulation in this setting, but RASSF1 methylation does not seem to substantially affect RASSF1 isoforms expression.