D3 Extended Mesenterectomy in Right Colectomy for Cancer: A Cadaver Simulation Model.

BACKGROUND: D3 extended mesenterectomy (D3EM) for right colon cancer has received increased attention owing to suggested improvement of oncological outcomes. The aim of this study was to evaluate the proficiency-based progression of content-valid metrics in a cadaveric model for right colectomy with D3EM. MATERIALS AND METHODS: Three expert surgeons were enrolled. Surgeon one performed the procedure robotically and surgeons two and three performed open D3EM. Proficiency-based progression was recorded for eight content-valid outcomes. The superior mesenteric vein (SMV) and artery were cannulated by independent observers to evaluate vascular tears. The specimens were analyzed for lymph node harvest by a pathologist blinded to surgical access and to the surgeon. RESULTS: Operating times did not differ among surgeons (50.2, 32.4 and 43.7 min). SMV tears occurred in procedures A and B only. There was no significant progression in lymph node harvest for D2 (p=0.913) and D3EM (p=0.264). CONCLUSIONS: Cadaveric training in D3EM was associated with progression in avoidance of vascular tears with no significant changes in operating time and lymph node harvest.

TLR-9 and IL-15 Synergy Promotes the In Vitro Clonal Expansion of Chronic Lymphocytic Leukemia B Cells.

Clinical progression of B cell chronic lymphocytic leukemia (B-CLL) reflects the clone's Ag receptor (BCR) and involves stroma-dependent B-CLL growth within lymphoid tissue. Uniformly elevated expression of TLR-9, occasional MYD88 mutations, and BCR specificity for DNA or Ags physically linked to DNA together suggest that TLR-9 signaling is important in driving B-CLL growth in patients. Nevertheless, reports of apoptosis after B-CLL exposure to CpG oligodeoxynucleotide (ODN) raised questions about a central role for TLR-9. Because normal memory B cells proliferate vigorously to ODN+IL-15, a cytokine found in stromal cells of bone marrow, lymph nodes, and spleen, we examined whether this was true for B-CLL cells. Through a CFSE-based assay for quantitatively monitoring in vitro clonal proliferation/survival, we show that IL-15 precludes TLR-9-induced apoptosis and permits significant B-CLL clonal expansion regardless of the clone's BCR mutation status. A robust response to ODN+IL-15 was positively linked to presence of chromosomal anomalies (trisomy-12 or ataxia telangiectasia mutated anomaly + del13q14) and negatively linked to a very high proportion of CD38(+) cells within the blood-derived B-CLL population. Furthermore, a clone's intrinsic potential for in vitro growth correlated directly with doubling time in blood, in the case of B-CLL with Ig H chain V region-unmutated BCR and <30% CD38(+) cells in blood. Finally, in vitro high-proliferator status was statistically linked to diminished patient survival. These findings, together with immunohistochemical evidence of apoptotic cells and IL-15-producing cells proximal to B-CLL pseudofollicles in patient spleens, suggest that collaborative ODN and IL-15 signaling may promote in vivo B-CLL growth.

A graded neonatal mouse model of necrotizing enterocolitis demonstrates that mild enterocolitis is sufficient to activate microglia and increase cerebral cytokine expression.

Background: Necrotizing enterocolitis (NEC) is an inflammatory gastrointestinal process that afflicts approximately 10% of preterm infants born in the United States each year, with a mortality rate of 30%. NEC severity is graded using Bell's classification system, from stage I mild NEC to stage III severe NEC. Over half of NEC survivors present with neurodevelopmental impairment during adolescence, a long-term complication that is poorly understood but can occur even after mild NEC. Although multiple animal models exist, none allow the experimenter to control nor represent the gradient of symptom severities seen in NEC patients. We bridge this knowledge gap by developing a graded murine model of NEC and studying its relationship with neuroinflammation across a range of NEC severities. Methods: Postnatal day 3 (P3) C57BL/6 mice were fed a formula containing different concentrations (0% control, 0.25%, 1%, 2%, and 3%) of dextran sodium sulfate (DSS). P3 mice were fed every 3 hours for 72-hours. We collected data on weight gain and behavior (activity, response, body color) during feeding. At the end of the experiment, we collected tissues (intestine, liver, plasma, brain) for immunohistochemistry, immunofluorescence, and cytokine and chemokine analysis. Results: Throughout NEC induction, mice fed higher concentrations of DSS died sooner, lost weight faster, and became sick or lethargic earlier. Intestinal characteristics (dilation, color, friability) were worse in mice fed with higher DSS concentrations. Histology revealed small intestinal disarray among mice fed all DSS concentrations, while higher DSS concentrations resulted in reduced small intestinal cellular proliferation and increased hepatic and systemic inflammation. In the brain, IL-2, G-CSF, and CXCL1 concentrations increased with higher DSS concentrations. Although the number of neurons and microglia in the CA1 hippocampal region did not differ, microglial branching was significantly reduced in DSS-fed mice. Conclusion: We characterize a novel graded model of NEC that recapitulates the full range of NEC severities. We show that mild NEC is sufficient to initiate neuroinflammation and microglia activation. This model will facilitate studies on the neurodevelopmental effects of NEC.

Krüppel-like Factor 5 Plays an Important Role in the Pathogenesis of Chronic Pancreatitis.

Chronic pancreatitis results in the formation of pancreatic intraepithelial neoplasia (PanIN) and poses a risk of developing pancreatic cancer. Our previous study demonstrated that Krüppel-like factor 5 (KLF5) is necessary for forming acinar-to-ductal metaplasia (ADM) in acute pancreatitis. Here, we investigated the role of KLF5 in response to chronic injury in the pancreas. Human tissues originating from chronic pancreatitis patients showed increased levels of epithelial KLF5. An inducible genetic model combining the deletion of Klf5 and the activation of KrasG12D mutant expression in pancreatic acinar cells together with chemically induced chronic pancreatitis was used. The chronic injury resulted in increased levels of KLF5 in both control and KrasG12D mutant mice. Furthermore, it led to numerous ADM and PanIN lesions and extensive fibrosis in the KRAS mutant mice. In contrast, pancreata with Klf5 loss (with or without KrasG12D) failed to develop ADM, PanIN, or significant fibrosis. Furthermore, the deletion of Klf5 reduced the expression level of cytokines and fibrotic components such as Il1b, Il6, Tnf, Tgfb1, Timp1, and Mmp9. Notably, using ChIP-PCR, we showed that KLF5 binds directly to the promoters of Il1b, Il6, and Tgfb1 genes. In summary, the inactivation of Klf5 inhibits ADM and PanIN formation and the development of pancreatic fibrosis.

Intratumoral Budding and Tumor Microenvironment in Pretreatment Rectal Cancer Biopsies Predict the Response to Neoadjuvant Chemoradiotherapy.

Tumor budding at the invasive tumor front (peritumoral budding) is an established prognostic factor in colorectal cancer. However, the significance of intratumoral budding (ITB) in pretreatment biopsies is still uncertain. Our study aims to investigate the association of ITB and tumor microenvironment in pretreatment rectal cancer biopsies with pathologic response to neoadjuvant chemoradiotherapy. Pretreatment biopsies of low-grade rectal cancer from 37 patients who underwent resection after neoadjuvant chemoradiotherapy were retrospectively reviewed to evaluate ITB, type of tumor stroma, and intraepithelial lymphocytes. ITB was counted on a single hotspot in 1 HPF upon pan-keratin immunohistochemical staining. Intraepithelial lymphocytes was graded semiquantitatively as "absent" (≤2/HPF) or "present" (>2/HPF). The tumor stroma was classified as either immature type or maturing type. In pretreatment biopsies, ITB was observed in 34/37 patients (92%). High-grade ITB was significantly associated with a poor pathologic response to neoadjuvant chemoradiotherapy (tumor regression score 2 to 3, P<0.001; and higher posttreatment T stage, P=0.002). Immature type of stroma was significantly associated with both high-grade ITB in biopsies (P=0.02) and a poor pathologic response to neoadjuvant chemoradiotherapy (tumor regression score 2 to 3, P=0.005). In multivariate analysis, ITB and the type of stroma remained the significant parameters for prediction of response to neoadjuvant treatment. Our study indicates that ITB and tumor microenvironment in pretreatment biopsies are strong predictors of response to neoadjuvant chemoradiotherapy, which may assist risk stratification and clinical management in rectal cancer patients.

Findings of Hepatic Severe Acute Respiratory Syndrome Coronavirus-2 Infection.

BACKGROUND & AIMS: Liver injury due to coronavirus disease 2019 (COVID-19) is being increasingly recognized. Abnormal liver chemistry tests of varying severities occur in a majority of patients. However, there is a dearth of accompanying liver histologic studies in these patients. METHODS: The current report details the clinical courses of 2 patients having severe COVID-19 hepatitis. Liver biopsies were analyzed under light microscopy, portions of liver tissue were hybridized with a target probe to the severe acute respiratory syndrome coronavirus-2 S gene, and small sections from formalin-fixed paraffin-embedded liver tissue were processed for electron microscopy. RESULTS: The liver histology of both cases showed a mixed inflammatory infiltrate with prominent bile duct damage, endotheliitis, and many apoptotic bodies. In situ hybridization and electron microscopy suggest the intrahepatic presence of severe acute respiratory syndrome coronavirus-2, the findings of which may indicate the possibility of direct cell injury. CONCLUSIONS: On the basis of the abundant apoptosis and severe cholangiocyte injury, these histopathologic changes suggest a direct cytopathic injury. Furthermore, some of the histopathologic changes may resemble acute cellular rejection occurring after liver transplantation. These 2 cases demonstrate that severe COVID-19 hepatitis can occur even in the absence of significant involvement of other organs.

Primary CNS anaplastic diffuse large B-cell lymphoma mimicking undifferentiated metastatic tumors: a case report.

Primary central nervous system lymphoma (PCNSL) is a rare intracranial tumor, with an annual incidence of six per million population. Anaplastic variant of primary CNS diffuse large B-cell lymphoma is less common; to our knowledge, there is only one other case report in the world literature. We describe a 71 year old immunocompetent female without significant past medical history who presented with confusion and a homogeneously enhancing midline mass. The patient underwent craniotomy for tumor biopsy, followed by high-dose methotrexate-based chemotherapy despite a remarkably low performance status. Histologically, this tumor was composed of undifferentiated polymorphic tumor cells, multi-nucleated giant cells, extensive necrosis, and conspicuous mitotic activity, mimicking undifferentiated metastatic tumors. Immunohistochemical stains demonstrated immunopositivity of tumor cells for CD20, MUM-1, and BCL-6, and negative staining for CD3, CD10, and CD30. The clinical course, diagnostic workup, pathologic correlates, and treatment outcomes are described.

Fifteen-Year Follow-Up of a Patient with Acinar Cystic Transformation of the Pancreas and Literature Review.

Acinar cystic transformation (ACT), also known as "acinar cell cystadenoma," is a rare and newly recognized benign pancreatic cystic neoplasm. However, its true malignant potential remains unknown. Here, we report a case of ACT with 15-year follow-up. A 10-year-old female initially presented with abdominal pain and was found to have a cystic lesion in the region of pancreatic head on computed tomography scan. She underwent an exploratory laparotomy, and the intraoperative biopsy of the cyst wall showed a true pancreatic cyst without malignancy. Her symptoms subsequently resolved, and she was placed under close ultrasound surveillance. For the next fifteen years, the patient was asymptomatic without any complications and had a successful pregnancy. Surveillance showed the tumor grew in size from 4.2 cm to 6.2 cm in diameter. In the latest five months, she noted occasional abdominal pain. A pylorus-preserving pancreaticoduodenectomy was performed. The resected cystic lesion was multilocular and lined by a single layer of bland epithelium ranging from nondescript flat/cuboidal epithelium to apparent acinar cells which were strongly positive for trypsin, so the final diagnosis was confirmed to be ACT. The prior biopsy was retrospectively reviewed to reveal similar epithelial lining. To the best of our knowledge, this is the longest period of follow-up for ACT to date. Our findings suggest that ACT is a slow-growing neoplasm without malignant transformation after fifteen years. Therefore, we recommend biopsy for histologic diagnosis followed by close ultrasound surveillance without surgical intervention in asymptomatic or young ACT patients.

Keratin 17 identifies the most lethal molecular subtype of pancreatic cancer.

Although the overall five-year survival of patients with pancreatic ductal adenocarcinoma (PDAC) is dismal, there are survival differences between cases with clinically and pathologically indistinguishable characteristics, suggesting that there are uncharacterized properties that drive tumor progression. Recent mRNA sequencing studies reported gene-expression signatures that define PDAC molecular subtypes that correlate with differences in survival. We previously identified Keratin 17 (K17) as a negative prognostic biomarker in other cancer types. Here, we set out to determine if K17 is as accurate as molecular subtyping of PDAC to identify patients with the shortest survival. K17 mRNA was analyzed in two independent PDAC cohorts for discovery (n = 124) and validation (n = 145). Immunohistochemical localization and scoring of K17 immunohistochemistry (IHC) was performed in a third independent cohort (n = 74). Kaplan-Meier and Cox proportional-hazard regression models were analyzed to determine cancer specific survival differences in low vs. high mRNA K17 expressing cases. We established that K17 expression in PDACs defines the most aggressive form of the disease. By using Cox proportional hazard ratio, we found that increased expression of K17 at the IHC level is also associated with decreased survival of PDAC patients. Additionally, within PDACs of advanced stage and negative surgical margins, K17 at both mRNA and IHC level is sufficient to identify the subgroup with the shortest survival. These results identify K17 as a novel negative prognostic biomarker that could inform patient management decisions.

Aggressive natural killer cell leukemia mimicking interstitial lung diseases with the activation of the mitogen-activated protein kinase pathway.

Aggressive natural killer (NK) cell leukemia (ANKL) is a rare form of leukemia with an aggressive clinical course. It commonly involves the peripheral blood, bone marrow, liver, and spleen but rarely involves the lungs. We report a 36 year-old woman who presented with pulmonary lesions we suspected to be interstitial lung disease on an imaging study. A lung biopsy showed extensive lymphoid infiltrate growing along pre-existing alveolar septa without destroying the alveolar spaces. Further workup revealed hepatomegaly, borderline splenomegaly, and multiple lymphadenopathies. Her laboratory tests showed leukocytosis, anemia, thrombocytopenia, abnormal liver enzymes, and elevated lactate dehydrogenase. A bone marrow (BM) aspirate smear revealed many intermediate to large lymphocytes with dispersed chromatin, basophilic cytoplasm, and some azurophilic granules. A BM biopsy showed hypercellularity with interstitial lymphoid infiltrate in a background of trilineage hematopoiesis and histiocytosis with hemophagocytosis. Immunohistochemical studies performed on both the lung and BM biopsies showed the neoplastic cells to be positive for CD2, CD3, CD7, CD56, granzyme B, phosphor-MAPK (pMAPK), EBER (Epstein-Barr Virus-encoded small RNA) by in situ hybridization; they were negative for CD4, CD5, CD8, CD30, LMP1, and phospho-STAT3 (pSTAT3). A flow cytometry analysis of the BM aspirate identified a population of atypical lymphocytes with the NK cell phenotype. Molecular studies were negative for T-cell receptor gene rearrangements, and the neoplastic cells displayed a complex karyotype. The patient responded initially to chemotherapy but died of multiorgan failure two months after the diagnosis. We present a case of ANKL mimicking interstitial lung disease with the activation of MAPK pathway.

Multiregion Comprehensive Genomic Profiling of a Gastric Mixed Neuroendocrine-Nonneuroendocrine Neoplasm with Trilineage Differentiation.

Mixed neuroendocrine-nonneuroendocrine neoplasms (MiNENs) are a group of rare tumors previously known as mixed adenoneuroendocrine carcinomas (MANECs). The neuroendocrine component is high-grade and may consist of small-cell carcinoma or large-cell neuroendocrine carcinoma. The nonneuroendocrine component may consist of adenocarcinoma or squamous cell carcinoma. We report a unique case of a MiNEN with trilineage differentiation: large-cell neuroendocrine carcinoma, squamous cell carcinoma, and adenocarcinoma. The reported patient presented with symptoms of an upper gastrointestinal bleed and was ultimately diagnosed with a MiNEN with trilineage differentiation. This is the first report of this exceedingly rare tumor type to include next-generation sequencing of the 3 separate tumor entities. In addition, we review the current literature and discuss the role of next-generation sequencing in classifying and treating MiNEN tumors.

Phospho-Aspirin (MDC-22) Prevents Pancreatic Carcinogenesis in Mice.

Pancreatic cancer is a deadly disease with a dismal 5-year survival rate of <6%. The currently limited treatment options for pancreatic cancer underscore the need for novel chemopreventive and therapeutic agents. Accumulating evidence indicates that aspirin use is associated with a decreased risk of pancreatic cancer. However, the anticancer properties of aspirin are restricted by its gastrointestinal toxicity and its limited efficacy. Therefore, we developed phospho-aspirin (MDC-22), a novel derivative of aspirin, and evaluated its chemopreventive efficacy in preclinical models of pancreatic cancer. Phospho-aspirin inhibited the growth of human pancreatic cancer cell lines 8- to 12-fold more potently than aspirin; based on the 24-hour IC50 values. In a Panc-1 xenograft model, phospho-aspirin, at a dose of 100 mg/kg/d 5 times per week for 30 days, reduced tumor growth by 78% (P < 0.01 vs. vehicle control). Furthermore, phospho-aspirin prevented pancreatitis-accelerated acinar-to-ductal metaplasia in mice with activated Kras. In p48-Cre;Kras(G12D) mice, cerulein treatment (6 hourly injections two times per week for 3 weeks) led to a significant increase in ductal metaplasia, replacing the majority of the exocrine compartment. Administration of phospho-aspirin 100 mg/kg/day five times per week for 21 days (starting on the first day of cerulein injection) inhibited the acinar-to-ductal metaplasia, reducing it by 87% (P < 0.01, vs. cerulein-treated control). Phospho-aspirin appeared to be safe, with the animals showing no signs of toxicity during treatment. Mechanistically, phospho-aspirin inhibited EGFR activation in pancreatic cancer, an effect consistently observed in pancreatic cancer cells, primary acinar explants and in vivo In conclusion, our findings indicate that phospho-aspirin has strong anticancer efficacy in preclinical models of pancreatic cancer, warranting its further evaluation. Cancer Prev Res; 9(7); 624-34. ©2016 AACR.

Mantle cell lymphoma with in situ or mantle zone growth pattern: a study of five cases and review of literature.

We present two rare cases of in situ mantle cell lymphoma ("in situ MCL") and three cases of MCL with mantle zone growth pattern (MCL-MZGP). The patients include four males and one female, with a median age of 66 years (range, 52 to 86 years). Two present with isolated lymphadenopathy and three with multiple lymphadenopathy. At presentation, the complete blood count (CBC) and serum lactate dehydrogenase (LDH) are normal in all cases. Histologic examination reveals an in situ pattern in two cases and a mantle zone growth pattern in three cases. The staging bone marrow biopsies show minimal involvement by lymphoma in one case and no morphologic evidence of lymphoma in four cases. All cases are positive for cyclin D1, including two with typical MCL phenotype and three with CD5-negativity. Four out of five cases express kappa light chain. FISH study for t(11;14) is performed in three cases, of which one is positive and two are inconclusive. For four patients with a median follow-up of 38 months, three are in clinical remission and one has persistent disease. In conclusion, the "in situ MCL" is associated with incidental finding, indolent clinical course and lower tumor burden. The predominant usage of kappa light chain and frequent CD5-negativity observed in our cases are unusual. We review the clinical and laboratory features of "in situ MCL" cases in the literature.

Primary mediastinal giant cell tumor.

Giant cell tumor of soft tissue is a rare tumor first described by Salm and Sissons in 1972 as being a distinct entity.(1) Histologically, it is composed of multinucleated giant cells dispersed among mononuclear cells, and is indistinguishable from its bone equivalent.(2) The majority of these tumors have been reported to occur in the lower extremity.(2,3) We describe a case of giant cell tumor of soft tissue within the posterior mediastinum. The only other report of a primary mediastinal giant cell tumor of soft tissue in the English literature was published by Fu et al. in 2002, in which they described two patients with posterior mediastinal masses.(4).