Machine learning analyses of highly-multiplexed immunofluorescence identifies distinct tumor and stromal cell populations in primary pancreatic tumors.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a formidable challenge for patients and clinicians. OBJECTIVE: To analyze the distribution of 31 different markers in tumor and stromal portions of the tumor microenvironment (TME) and identify immune cell populations to better understand how neoplastic, non-malignant structural, and immune cells, diversify the TME and influence PDAC progression. METHODS: Whole slide imaging (WSI) and cyclic multiplexed-immunofluorescence (MxIF) was used to collect 31 different markers over the course of nine distinctive imaging series of human PDAC samples. Image registration and machine learning algorithms were developed to largely automate an imaging analysis pipeline identifying distinct cell types in the TME. RESULTS: A random forest algorithm accurately predicted tumor and stromal-rich areas with 87% accuracy using 31 markers and 77% accuracy using only five markers. Top tumor-predictive markers guided downstream analyses to identify immune populations effectively invading into the tumor, including dendritic cells, CD4+ T cells, and multiple immunoregulatory subtypes. CONCLUSIONS: Immunoprofiling of PDAC to identify differential distribution of immune cells in the TME is critical for understanding disease progression, response and/or resistance to treatment, and the development of new treatment strategies.

Pulmonary Hypertensive Changes Secondary to COVID-19 Pneumonia in a Chronically SARS-CoV-2-Infected Bilateral Lung Explant.

COVID-19, the syndrome caused by the novel coronavirus SARS-CoV-2, has spread throughout the world, causing the death of at least three million people. For the over 81 million who have recovered, however, the long-term effects are only beginning to manifest. We performed a bilateral lung transplant on a 31-year-old male patient for chronic hypoxic respiratory failure, severe pulmonary hypertension and radiographically identified pulmonary fibrosis five months after an acute COVID-19 infection. The explant demonstrated moderate pulmonary vascular remodeling with intimal thickening and medial hypertrophy throughout, consistent with pulmonary hypertension. The parenchyma demonstrated an organizing lung injury in the proliferative phase, with severe fibrosis, histiocytic proliferation, type II pneumocyte hyperplasia, and alveolar loss consistent with known COVID-19 pneumonia complications.This report highlights a novel histologic finding in severe, chronic COVID-19. Although the findings in acute COVID-19 pneumonia have been well-examined at autopsy, the chronic course of this complex disease is not yet understood. The case presented herein suggests that COVID-induced pulmonary hypertension may become more common as more patients survive severe SARS-CoV-2-related pneumonia. Pulmonologists and pulmonary pathologists should be aware of this possible association and look for the clinical, radiographic, and histologic criteria in the appropriate clinical setting.

NCCN Guidelines® Insights: Genetic/Familial High-Risk Assessment: Colorectal, Version 1.2021.

Identifying individuals with hereditary syndromes allows for timely cancer surveillance, opportunities for risk reduction, and syndrome-specific management. Establishing criteria for hereditary cancer risk assessment allows for the identification of individuals who are carriers of pathogenic genetic variants. The NCCN Guidelines for Genetic/Familial High-Risk Assessment: Colorectal provides recommendations for the assessment and management of patients at risk for or diagnosed with high-risk colorectal cancer syndromes. The NCCN Genetic/Familial High-Risk Assessment: Colorectal panel meets annually to evaluate and update their recommendations based on their clinical expertise and new scientific data. These NCCN Guidelines Insights focus on familial adenomatous polyposis (FAP)/attenuated familial adenomatous polyposis (AFAP) syndrome and considerations for management of duodenal neoplasia.

Prospective Statewide Study of Universal Screening for Hereditary Colorectal Cancer: The Ohio Colorectal Cancer Prevention Initiative.

Hereditary cancer syndromes infer high cancer risks and require intensive surveillance. Identification of high-risk individuals among patients with colorectal cancer (CRC) needs improvement. METHODS: Three thousand three hundred ten unselected adults who underwent surgical resection for primary invasive CRC were prospectively accrued from 51 hospitals across Ohio between January 1, 2013, and December 31, 2016. Universal Tumor screening (UTS) for mismatch repair (MMR) deficiency was performed for all, and pathogenic germline variants (PGVs) were identified using multigene panel testing (MGPT) in those who met at least one inclusion criterion: MMR deficiency, diagnosed < 50 years, multiple primary tumors (CRC or endometrial cancer), or with a first-degree relative with CRC or endometrial cancer. RESULTS: Five hundred twenty-five patients (15.9%) had MMR deficiency. Two hundred thirty-four of 3,310 (7.1%; 16% of the 1,462 who received MGPT) had 248 PGVs in cancer susceptibility genes. One hundred forty-two (4.3%) had a PGV in an MMR gene, and 101 (3.1%) had a PGV in a non-MMR gene. Ten with Lynch syndrome (LS) also had a non-MMR PGV and were included in both groups. Two (0.06%) had constitutional MLH1 hypermethylation. Of unexplained MMR-deficient patients, 88.4% (76 of 86) had double somatic MMR mutations. Testing for only MMR genes in MMR-deficient patients would have missed 18 non-MMR gene PGVs (7.3% of total PGVs identified). Had UTS been the only method used to screen for hereditary cancer syndromes, 38.6% (91 of 236) would have been missed, including 6.3% (9 of 144) of those with LS. These results have treatment implications as 5.3% (175 of 3,310) had PGVs in genes with therapeutic targets. CONCLUSION: UTS alone is insufficient for identifying a large proportion of CRC patients with hereditary syndromes, including some with LS. At a minimum, 7.1% of individuals with CRC have a PGV and pan-cancer MGPT should be considered for all patients with CRC.

MUC4 enhances gemcitabine resistance and malignant behaviour in pancreatic cancer cells expressing cancer-associated short O-glycans.

Pancreatic ductal adenocarcinoma (PDAC) is highly lethal. MUC4 (mucin4) is a heavily glycosylated protein aberrantly expressed in PDAC and promotes tumorigenesis via an unknown mechanism. To assess this, we genetically knocked out (KO) MUC4 in PDAC cells that did not express and did express truncated O-glycans (Tn/STn) using CRISPR/Cas9 technology. We found that MUC4 knockout cells possess less tumorigenicity in vitro and in vivo, which was further reduced in PDAC cells that express aberrant overexpression of truncated O-glycans. Also, MUC4KO cells showed a further reduction of epidermal growth factor receptors (ErbB) and their downstream signaling pathways in truncated O-glycan expressing PDAC cells. Tn-MUC4 specific 3B11 antibody inhibited MUC4-induced ErbB receptor and its downstream signaling cascades. MUC4 knockout differentially regulates apoptosis and cell cycle arrest in branched and truncated O-glycan expressing PDAC cells. Additionally, MUC4KO cells were found to be more sensitive to gemcitabine treatment. They possessed the upregulated expression of hENT1 and hCNT3 compared to parental cells, which were further affected in cells with aberrant O-glycosylation. Taken together, our results indicate that MUC4 enhances the malignant properties and gemcitabine resistance in PDAC tumors that aberrantly overexpress truncated O-glycans via altering ErbB/AKT signaling cascades and expression of nucleoside transporters, respectively.

The importance of transects for characterizing aged organic contaminant plumes in groundwater.

A complex mixture of dissolved organic contaminants, emanating from a many decades-old, residual, dense non-aqueous phase liquid (DNAPL) source, migrates through unconfined, moderately heterogeneous, glacial-derived sediments and sedimentary rock in a residential area of Dane County, Wisconsin, USA. A portion of this contaminant plume intersects a large man-made pond, roughly 400 m downgradient of the source zone. Depth-discrete, multilevel groundwater sampling, detailed sedimentological logs, and hydraulic head profiles were used to delineate the spatial distribution of hydraulic, geologic, organic contaminant, and redox hydrochemical conditions within the established plume along two transects immediately upgradient of the pond. Twenty-one contaminants were detected and classified into four major contaminant groups: chlorinated ethenes, chlorinated ethanes, aromatics (BTEX: benzene, toluene, ethylbenzene, xylene), and aliphatic ketones. Within the glacial sediments and shallow bedrock, zones of reductive dechlorination of chlorinated ethenes and ethanes were juxtaposed with zones of BTEX and ketone degradation. Spatial heterogeneity in the concentration and distribution of contaminant groups and redox conditions was observed over lateral distances of tens of meters and vertical distances of tens of centimeters along the two transects. Although the site was situated in a complex glacial depositional environment, lithologic and hydraulic heterogeneity surprisingly only had a modest influence on the spatial distribution of plume contaminants. Depth-discrete sampling along paired, closely spaced transects (~20 m apart) was essential to assess internal plume composition/concentration evolution along flow paths with strong attenuation over short migration distances. This study shows how paired, highly resolved transects can enhance understanding of transverse and longitudinal variability in areas where contaminant-induced redox conditions control reaction zones and strong plume attenuation.

Including colon in intestinal transplantation: a focus on post-transplant renal function - a retrospective study.

Intestinal transplant recipients experience a high rate of renal complications secondary to dehydration due to increased ostomy output. It is hypothesized that inclusion of donor colon in the intestinal allograft may improve renal function in patients without functional native colon by improving fluid absorption. A single-center retrospective study of intestinal transplant recipients compared outcomes of patients receiving en bloc colon as part an intestinal allograft (ICTx), and those not receiving colon (CCNTx), as well as a control group of intestinal transplant recipients with functional native colon (ITx). Forty-seven patients (ICTx n = 17, CCNTx n = 15, ITx n = 15) were studied. One-year post-transplant renal function, as measured by change in glomerular filtration rate (GFR) and blood urea nitrogen (BUN) from baseline, was superior in ICTx (mean delta-GFR of -1.31 and delta-BUN of -1.46) compared to CCNTx (-6.54 and 17.54, P = 0.05 and P = 0.17, respectively) and similar to the ITx controls (0.55 and 2.09). Recipients of donor colon experienced a higher rate of ileostomy reversal when compared to CCNTx (62.5% vs. 20%, P = 0.0008), which was similar to the ITx controls (60%). These findings support the inclusion of en bloc donor colon in the intestinal allograft for recipients without functional native colon.

Elevating pancreatic cystic lesion stratification: Current and future pancreatic cancer biomarker(s).

Pancreatic ductal adenocarcinoma (PDAC) is an incredibly deadly disease with a 5-year survival rate of 9%. The presence of pancreatic cystic lesions (PCLs) confers an increased likelihood of future pancreatic cancer in patients placing them in a high-risk category. Discerning concurrent malignancy and risk of future PCL progression to cancer must be carefully and accurately determined to improve survival outcomes and avoid unnecessary morbidity of pancreatic resection. Unfortunately, current image-based guidelines are inadequate to distinguish benign from malignant lesions. There continues to be a need for accurate molecular and imaging biomarker(s) capable of identifying malignant PCLs and predicting the malignant potential of PCLs to enable risk stratification and effective intervention management. This review provides an update on the current status of biomarkers from pancreatic cystic fluid, pancreatic juice, and seromic molecular analyses and discusses the potential of radiomics for differentiating PCLs harboring cancer from those that do not.

Metabolic Alterations in Pancreatic Cancer Progression.

Pancreatic cancer is the third leading cause of cancer-related deaths in the USA. Pancreatic tumors are characterized by enhanced glycolytic metabolism promoted by a hypoxic tumor microenvironment and a resultant acidic milieu. The metabolic reprogramming allows cancer cells to survive hostile microenvironments. Through the analysis of the principal metabolic pathways, we identified the specific metabolites that are altered during pancreatic cancer progression in the spontaneous progression (KPC) mouse model. Genetically engineered mice exhibited metabolic alterations during PanINs formation, even before the tumor development. To account for other cells in the tumor microenvironment and to focus on metabolic adaptations concerning tumorigenic cells only, we compared the metabolic profile of KPC and orthotopic tumors with those obtained from KPC-tumor derived cell lines. We observed significant upregulation of glycolysis and the pentose phosphate pathway metabolites even at the early stages of pathogenesis. Other biosynthetic pathways also demonstrated a few common perturbations. While some of the metabolic changes in tumor cells are not detectable in orthotopic and spontaneous tumors, a significant number of tumor cell-intrinsic metabolic alterations are readily detectable in the animal models. Overall, we identified that metabolic alterations in precancerous lesions are maintained during cancer development and are largely mirrored by cancer cells in culture conditions.

Combined Collagen-Induced Arthritis and Organic Dust-Induced Airway Inflammation to Model Inflammatory Lung Disease in Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is characterized by extra-articular involvement including lung disease, yet the mechanisms linking the two conditions are poorly understood. The collagen-induced arthritis (CIA) model was combined with the organic dust extract (ODE) airway inflammatory model to assess bone/joint-lung inflammatory outcomes. DBA/1J mice were intranasally treated with saline or ODE daily for 5 weeks. CIA was induced on days 1 and 21. Treatment groups included sham (saline injection/saline inhalation), CIA (CIA/saline), ODE (saline/ODE), and CIA + ODE (CIA/ODE). Arthritis inflammatory scores, bones, bronchoalveolar lavage fluid, lung tissues, and serum were assessed. In DBA/1J male mice, arthritis was increased in CIA + ODE > CIA > ODE versus sham. Micro-computed tomography (µCT) demonstrated that loss of BMD and volume and deterioration of bone microarchitecture was greatest in CIA + ODE. However, ODE-induced airway neutrophil influx and inflammatory cytokine/chemokine levels in lavage fluids were increased in ODE > CIA + ODE versus sham. Activated lung CD11c+ CD11b+ macrophages were increased in ODE > CIA + ODE > CIA pattern, whereas lung hyaluronan, fibronectin, and amphiregulin levels were greatest in CIA + ODE. Serum autoantibody and inflammatory marker concentrations varied among experimental groups. Compared with male mice, female mice showed less articular and pulmonary disease. The interaction of inhalation-induced airway inflammation and arthritis induction resulted in compartmentalized responses with the greatest degree of arthritis and bone loss in male mice with combined exposures. Data also support suppression of the lung inflammatory response, but increases in extracellular matrix protein deposition/interstitial disease in the setting of arthritis. This coexposure model could be exploited to better understand and treat RA-lung disease. © 2019 American Society for Bone and Mineral Research.

Bovine milk-derived extracellular vesicles enhance inflammation and promote M1 polarization following agricultural dust exposure in mice.

Occupational agricultural dust exposure can cause severe lung injury, including COPD and asthma exacerbations. Cell-derived extracellular vesicles can mediate inflammatory responses and immune activation, but the contribution of diet-derived extracellular vesicles to these processes is poorly understood. We investigated whether bovine milk-derived extracellular vesicles modulate inflammatory responses to agricultural dust exposures in a murine model. C57BL/6 mice were fed either an extracellular vesicle-enriched modification of the AIN-93G diet with lyophilized bovine milk (EV) or a control diet wherein the milk was presonicated, disrupting the milk extracellular vesicles and thereby leading to RNA degradation (DEV). Mice were maintained on the diets for 5-7 weeks and challenged with a single (acute) intranasal instillation of a 12.5% organic dust extract (DE) or with 15 instillations over 3 weeks (repetitive exposure model). Through these investigations, we identified significant interactions between diet and DE when considering numerous inflammatory outcomes, including lavage inflammatory cytokine levels and cellular infiltration into the lung airways. DE-treated peritoneal macrophages also demonstrated altered polarization, with EV-fed mouse macrophages exhibiting an M1 shift compared to an M2 phenotype in DEV-fed mice (IL-6, TNF, IL-12/23 all significantly elevated, and IL-10 and arginase decreased in EV macrophages, ex vivo). In complementary in vitro studies, mouse macrophages treated with purified milk-derived EV were found to express similar polarization phenotypes upon DE stimulation. These results suggest a role for dietary extracellular vesicles in the modulation of lung inflammation in response to organic dust which may involve macrophage phenotype polarization.

Human papillomavirus and the landscape of secondary genetic alterations in oral cancers.

Human papillomavirus (HPV) is a necessary but insufficient cause of a subset of oral squamous cell carcinomas (OSCCs) that is increasing markedly in frequency. To identify contributory, secondary genetic alterations in these cancers, we used comprehensive genomics methods to compare 149 HPV-positive and 335 HPV-negative OSCC tumor/normal pairs. Different behavioral risk factors underlying the two OSCC types were reflected in distinctive genomic mutational signatures. In HPV-positive OSCCs, the signatures of APOBEC cytosine deaminase editing, associated with anti-viral immunity, were strongly linked to overall mutational burden. In contrast, in HPV-negative OSCCs, T>C substitutions in the sequence context 5'-ATN-3' correlated with tobacco exposure. Universal expression of HPV E6*1 and E7 oncogenes was a sine qua non of HPV-positive OSCCs. Significant enrichment of somatic mutations was confirmed or newly identified in PIK3CA, KMT2D, FGFR3, FBXW7, DDX3X, PTEN, TRAF3, RB1, CYLD, RIPK4, ZNF750, EP300, CASZ1, TAF5, RBL1, IFNGR1, and NFKBIA Of these, many affect host pathways already targeted by HPV oncoproteins, including the p53 and pRB pathways, or disrupt host defenses against viral infections, including interferon (IFN) and nuclear factor kappa B signaling. Frequent copy number changes were associated with concordant changes in gene expression. Chr 11q (including CCND1) and 14q (including DICER1 and AKT1) were recurrently lost in HPV-positive OSCCs, in contrast to their gains in HPV-negative OSCCs. High-ranking variant allele fractions implicated ZNF750, PIK3CA, and EP300 mutations as candidate driver events in HPV-positive cancers. We conclude that virus-host interactions cooperatively shape the unique genetic features of these cancers, distinguishing them from their HPV-negative counterparts.

Diagnostic Accuracy of Preoperative Imaging for Differentiation of Branch Duct Versus Mixed Duct Intraductal Papillary Mucinous Neoplasms.

OBJECTIVE: The aim of this study is to determine the diagnostic accuracy of preoperative evaluation to detect main pancreatic duct involvement in pancreatic cystic lesions thus differentiating mixed intraductal papillary mucinous neoplasm (IPMN) from branch duct (BD)-IPMN. METHODS: The pathology database of pancreatic resections from 2000 to 2014 was reviewed. Main pancreatic duct-IPMNs and IPMNs with intracystic mass/nodules were excluded. The preoperative test characteristics were analyzed using surgical histopathology as the "gold standard." RESULTS: Sixty BD-IPMNs and 23 mixed-IPMNs were identified. Mixed-IPMNs were larger (mean [standard deviation], 4.14 [2.9] vs 2.74 [1.9] mm; P = 0.03) and demonstrated frequent high-grade dysplasia/adenocarcinoma (43% vs 12%, P = 0.004) than BD-IPMNs. Endoscopic ultrasound (EUS) (sensitivity, 80%; specificity, 78%; accuracy, 79%) had the best diagnostic accuracy, whereas magnetic resonance imaging (MRI) (sensitivity, 83%; specificity, 63%; accuracy, 68%) had the highest sensitivity for the diagnosis of mixed-IPMN. A combination of EUS and MRI reached maximum sensitivity but with decreased accuracy (sensitivity, 100%; specificity, 64%; accuracy, 67%). The area under the curve for receiver operation curve was 0.71 whereas the optimal cyst size to detect main duct involvement was 3 cm. CONCLUSIONS: For preoperative evaluation of pancreatic cystic lesions without evidence of intracystic nodules, a combination of MRI and EUS should be considered for improved detection of main duct involvement.

NF-κB regulates GDF-15 to suppress macrophage surveillance during early tumor development.

Macrophages are attracted to developing tumors and can participate in immune surveillance to eliminate neoplastic cells. In response, neoplastic cells utilize NF-κB to suppress this killing activity, but the mechanisms underlying their self-protection remain unclear. Here, we report that this dynamic interaction between tumor cells and macrophages is integrally linked by a soluble factor identified as growth and differentiation factor 15 (GDF-15). In vitro, tumor-derived GDF-15 signals in macrophages to suppress their proapoptotic activity by inhibiting TNF and nitric oxide (NO) production. In vivo, depletion of GDF-15 in Ras-driven tumor xenografts and in an orthotopic model of pancreatic cancer delayed tumor development. This delay correlated with increased infiltrating antitumor macrophages. Further, production of GDF-15 is directly regulated by NF-κB, and the colocalization of activated NF-κB and GDF-15 in epithelial ducts of human pancreatic adenocarcinoma supports the importance of this observation. Mechanistically, we found that GDF-15 suppresses macrophage activity by inhibiting TGF-ß-activated kinase (TAK1) signaling to NF-κB, thereby blocking synthesis of TNF and NO. Based on these results, we propose that the NF-κB/GDF-15 regulatory axis is important for tumor cells in evading macrophage immune surveillance during the early stages of tumorigenesis.

In vivo and ex vivo confocal endomicroscopy of pancreatic cystic lesions: A prospective study.

AIM: To investigate the reproducibility of the in vivo endoscopic ultrasound (EUS) - guided needle based confocal endomicroscopy (nCLE) image patterns in an ex vivo setting and compare these to surgical histopathology for characterizing pancreatic cystic lesions (PCLs). METHODS: In a prospective study evaluating EUS-nCLE for evaluation of PCLs, 10 subjects underwent an in vivo nCLE (AQ-Flex nCLE miniprobe; Cellvizio, MaunaKea, Paris, France) during EUS and ex vivo probe based CLE (pCLE) of the PCL (Gastroflex ultrahigh definition probe, Cellvizio) after surgical resection. Biopsies were obtained from ex vivo CLE-imaged areas for comparative histopathology. All subjects received intravenous fluorescein prior to EUS and pancreatic surgery for in vivo and ex vivo CLE imaging respectively. RESULTS: A total of 10 subjects (mean age 53 ± 12 years; 5 female) with a mean PCL size of 34.8 ± 14.3 mm were enrolled. Surgical histopathology confirmed 2 intraductal papillary mucinous neoplasms (IPMNs), 3 mucinous cystic neoplasms (MCNs), 2 cystic neuroendocrine tumors (cystic-NETs), 1 serous cystadenoma (SCA), and 2 squamous lined PCLs. Characteristic in vivo nCLE image patterns included papillary projections for IPMNs, horizon-type epithelial bands for MCNs, nests and trabeculae of cells for cystic-NETs, and a "fern pattern" of vascularity for SCA. Identical image patterns were observed during ex vivo pCLE imaging of the surgically resected PCLs. Both in vivo and ex vivo CLE imaging findings correlated with surgical histopathology. CONCLUSION: In vivo nCLE patterns are reproducible in ex vivo pCLE for all major neoplastic PCLs. These findings add further support the application of EUS-nCLE as an imaging biomarker in the diagnosis of PCLs.

Sinonasal adenoid cystic carcinoma: Treatment outcomes and association with human papillomavirus.

BACKGROUND: The purpose of this study was to review long-term outcomes of sinonasal adenoid cystic carcinoma (ACC) and to clarify its association with human papillomavirus (HPV). METHODS: The medical records of 23 patients with sinonasal ACC treated with primary surgical resection between 1998 and 2013 were reviewed. Tissue specimens were available for 17 patients. The p16 testing was performed using immunohistochemistry (IHC), and HPV infection was determined using quantitative polymerase chain reaction (PCR) with primers targeting the E6/E7 region. RESULTS: Two of the 17 samples showed strong and diffuse p16 staining, whereas the remaining 15 cases showed p16-positivity isolated to the luminal cells. Only one of the p16-positive cases was positive for HPV. The 5-year local failure, disease-free survival (DFS), and overall survival (OS) were 51%, 52%, and 62%, respectively. CONCLUSION: Local failures are common with advanced sinonasal ACC, and the association of HPV with true sinonasal ACC is low.

Myeloid-derived cullin 3 promotes STAT3 phosphorylation by inhibiting OGT expression and protects against intestinal inflammation.

Signal transducer and activator of transcription 3 (STAT3) is a key mediator of intestinal inflammation and tumorigenesis. However, the molecular mechanism that modulates STAT3 phosphorylation and activation is not fully understood. Here, we demonstrate that modification of STAT3 with O-linked ß-N-acetylglucosamine (O-GlcNAc) on threonine 717 (T717) negatively regulates its phosphorylation and targets gene expression in macrophages. We further found that cullin 3 (CUL3), a cullin family E3 ubiquitin ligase, down-regulates the expression of the O-GlcNAc transferase (OGT) and inhibits STAT3 O-GlcNAcylation. The inhibitory effect of CUL3 on OGT expression is dependent on nuclear factor E2-related factor-2 (Nrf2), which binds to the Ogt promoter region and increases gene transcription. Myeloid deletion of Cul3 led to defective STAT3 phosphorylation in colon macrophages, which was accompanied by exacerbated colonic inflammation and inflammation-driven tumorigenesis. Thus, this study identifies a new form of posttranslational modification of STAT3, modulating its phosphorylation, and suggests the importance of immunometabolism on colonic inflammation and tumorigenesis.

Molecular genetics of microsatellite-unstable colorectal cancer for pathologists.

BACKGROUND: Microsatellite-unstable colorectal cancers (CRC) that are due to deficient DNA mismatch repair (dMMR) represent approximately 15% of all CRCs in the United States. These microsatellite-unstable CRCs represent a heterogenous group of diseases with distinct oncogenesis pathways. There are overlapping clinicopathologic features between some of these groups, but many important differences are present. Therefore, determination of the etiology for the dMMR is vital for proper patient management and follow-up. MAIN BODY: Epigenetic inactivation of MLH1 MMR gene (sporadic microsatellite-unstable CRC) and germline mutation in an MMR gene (Lynch syndrome, LS) are the two most common mechanisms in the pathogenesis of microsatellite instability in CRC. However, in a subset of dMMR CRC cases that are identified by screening tests, no known LS-associated genetic alterations are appreciated by current genetic analysis. When the etiology for dMMR is unclear, it leads to patient anxiety and creates challenges for clinical management. CONCLUSION: It is critical to distinguish LS patients from other patients with tumors due to dMMR, so that the proper screening protocol can be employed for the patients and their families, with the goal to save lives while avoiding unnecessary anxiety and costs. This review summarizes the major pathogenesis pathways of dMMR CRCs, their clinicopathologic features, and practical screening suggestions. In addition, we include frequently asked questions for MMR immunohistochemistry interpretation.

Hypoxic repression of pyruvate dehydrogenase activity is necessary for metabolic reprogramming and growth of model tumours.

Tumour cells fulfil the bioenergetic and biosynthetic needs of proliferation using the available environmental metabolites. Metabolic adaptation to hypoxia causes decreased mitochondrial function and increased lactate production. This work examines the biological importance of the hypoxia-inducible inhibitory phosphorylations on the pyruvate dehydrogenase E1α subunit. Pancreatic cancer cell lines were genetically manipulated to alter the net phosphorylation of PDH E1α through reduced kinase expression or enhanced phosphatase expression. The modified cells were tested for hypoxic changes in phosphorylated E1α, mitochondrial metabolism and growth as xenografted tumours. Even though there are four PDHK genes, PDHK1 is essential for inhibitory PDH phosphorylation of E1α at serine 232, is partially responsible for modification of serines 293 and 300, and these phosphorylations are necessary for model tumour growth. In order to determine the clinical relevance, a cohort of head and neck cancer patient biopsies was examined for phosphorylated E1α and expression of PDHK1. Patients with detectable 232 phosphorylation or expression of PDHK1 tend to have worse clinical outcome. These data show that PDHK1 activity is unique and non-redundant in the family of PHDK enzymes and a PDHK1 specific inhibitor would therefore have anti-cancer activity with reduced chance of side effects from inhibition of other PDHKs.