Assessing the learning curve associated with a novel flexible robot in the pre-clinical and clinical setting.

BACKGROUND: Transoral robotic surgery has been successfully used by head and neck surgeons for a variety of procedures but is limited by rigid instrumentation and line-of-sight visualization. Non-linear systems specifically designed for the aerodigestive tract are needed. Ease of use of these new systems in both training and clinical environments is critical in its widespread adoption. METHODS: Residents, fellows, and junior faculty performed four tasks on an anatomical airway mannequin using the Medrobotics FLEX™ Robotic System: expose and incise the tonsil, grasp the epiglottis, palpate the vocal processes, and grasp the interarytenoid space. These tasks were performed once a day for four days; after a 4-month time gap, subjects were asked to perform these same tasks for three more days. Time to task completion and total distance driven were tracked. In addition, a retrospective analysis was performed analyzing one attending physician's experience with clinical usage of the robot. RESULTS: 13 subjects completed the initial round of the mannequin simulation and 8 subjects completed the additional testing 4 months later. Subjects rapidly improved their speed and efficiency at task completion. Junior residents were slower in most tasks initially compared to senior trainees but quickly reached similar levels of efficiency. Following the break there was minimal degradation in skills and continued improvement in efficiency was observed with additional trials. There was significant heterogeneity in the analyzed clinical cases, but when analyzing cases of similar complexity and pathology, clear decreases in overall operative times were demonstrable. CONCLUSION: Novice users quickly gained proficiency with the FLEX™ Robotic System in a training environment, and these skills are retained after several months. This learning could translate to the clinical setting if a proper training regimen is developed. The Medrobotics FLEX™ Robotic System shows promise as a surgical tool in head and neck surgery in this study.

Robust Cell Detection and Segmentation for Image Cytometry Reveal Th17 Cell Heterogeneity.

Image cytometry enables quantitative cell characterization with preserved tissue architecture; thus, it has been highlighted in the advancement of multiplex immunohistochemistry (IHC) and digital image analysis in the context of immune-based biomarker monitoring associated with cancer immunotherapy. However, one of the challenges in the current image cytometry methodology is a technical limitation in the segmentation of nuclei and cellular components particularly in heterogeneously stained cancer tissue images. To improve the detection and specificity of single-cell segmentation in hematoxylin-stained images (which can be utilized for recently reported 12-biomarker chromogenic sequential multiplex IHC), we adapted a segmentation algorithm previously developed for hematoxlin and eosin-stained images, where morphological features are extracted based on Gabor-filtering, followed by stacking of image pixels into n-dimensional feature space and unsupervised clustering of individual pixels. Our proposed method showed improved sensitivity and specificity in comparison with standard segmentation methods. Replacing previously proposed methods with our method in multiplex IHC/image cytometry analysis, we observed higher detection of cell lineages including relatively rare TH 17 cells, further enabling sub-population analysis into TH 1-like and TH 2-like phenotypes based on T-bet and GATA3 expression. Interestingly, predominance of TH 2-like TH 17 cells was associated with human papilloma virus (HPV)-negative status of oropharyngeal squamous cell carcinoma of head and neck, known as a poor-prognostic subtype in comparison with HPV-positive status. Furthermore, TH 2-like TH 17 cells in HPV-negative head and neck cancer tissues were spatiotemporally correlated with CD66b+ granulocytes, presumably associated with an immunosuppressive microenvironment. Our cell segmentation method for multiplex IHC/image cytometry potentially contributes to in-depth immune profiling and spatial association, leading to further tissue-based biomarker exploration. © 2019 International Society for Advancement of Cytometry.

Intraoperative Ultrasonography During Transoral Robotic Surgery.

OBJECTIVE: This study describes the potential application of intraoperative ultrasound imaging during transoral robotic surgery (TORS). METHODS: Ultrasound imaging was performed during transoral robotic resection of oropharyngeal tumors in 10 patients at a tertiary academic center. Ultrasound imaging was utilized to identify large-caliber vessels adjacent to the surgical site. Measurements were also taken on the ultrasound of tumor thickness to determine the deep margin. Following resection, the tumor was sectioned, and a gross measurement of the tumor thickness was obtained. RESULTS: Intraoperative ultrasound use led to the identification of larger-caliber blood vessels within the operative field prior to encountering them visually. Ultrasound could also aid in defining deep tumor margins; the tumor thickness measured via ultrasound was found to be accurate within 1 to 2 mm of the grossly measured tumor thickness. This allowed for focused, careful dissection to protect and avoid blood vessels during dissection as well as improved tumor resection. CONCLUSIONS: The use of intraoperative ultrasound provides additional information to the head and neck surgeon during TORS. This may be used to identify blood vessels and assess tumor margins, thereby improving the safety and efficacy of TORS.

Superior laryngeal nerve monitoring using laryngeal surface electrodes and intraoperative neurophysiological monitoring during thyroidectomy.

The objective of this study is to establish normative waveform data for the external branch of the superior laryngeal nerve (SLN) utilizing laryngeal surface electrodes and intraoperative neurophysiological monitoring (IONM) in conjunction with a clinical neurophysiologist. A retrospective chart review of 91 consecutive at-risk SLN were identified in 51 patients in whom IONM using laryngeal surface electrodes was performed by a clinical neurophysiologist using Dragonfly (Neurovision Medical Products, Ventura, CA) recording electrodes and a Protektor (Natus Medical Inc., San Carlos, CA)16 channel- intraoperative nerve monitoring system. Inclusion criteria were met for 30 SLN. Data collected included preoperative diagnosis, surgical procedure, rates of nerve identification and stimulation, and waveform characteristics. Waveform analysis for 30 SLN yielded a peak latency of 4.0 ± 0.2 ms, onset latency 2.3 ± 0.1 ms, peak-to-peak amplitude of 220.4 ± 31.1 µV, onset-to-peak amplitude of 186.0 ± 25.0 µV, and stimulation current threshold of 0.55 ± 0.03 mA (data = mean ± SEM). Two patients had abnormal SLN function documented clinically on postoperative laryngoscopic examination. Laryngeal surface electrodes were successfully utilized to identify and monitor SLN function intraoperatively. IONM using laryngeal surface electrodes enables analysis of waveform morphology and latency in addition to threshold and amplitude data obtained with the traditional NIM system, potentially improving the performance of nerve monitoring during thyroid surgery.

Acute and definitive management of oropharyngeal hemorrhage in patients with squamous cell carcinoma of the oropharynx.

BACKGROUND: Massive oropharyngeal bleeding post-chemoradiotherapy is a life-threatening condition that requires emergent management. METHODS: This retrospective case series included 11 patients with oropharyngeal squamous cell carcinoma who suffered from massive bleeding during or following treatment with definitive chemoradiotherapy. Details of acute and definitive management of oropharyngeal bleeding are reported. RESULTS: Nine of 11 hemorrhagic events occurred a mean (SD) of 88.6 days (53.6) after radiotherapy. Airway intubation and embolization were performed in 10 of 11 patients, followed by surgery in 7 of 11 patients. The most commonly embolized vessels were the external carotid and lingual arteries. At the time of discharge, 3 of 11 patients had a tracheostomy, and 7 of 11 continued to use a gastrostomy tube. Four patients died. CONCLUSIONS: Hemorrhagic complications in oropharyngeal cancer treatment require emergent responses. Developing a workflow for coordination between multidisciplinary teams can maximize probability of survival and decrease morbidity.

Comparison of da Vinci Single Port vs Si Systems for Transoral Robotic-Assisted Surgery: A Review With Technical Insights.

Importance: Transoral robot-assisted surgery (TORS) continues to have a major role in the treatment of oropharyngeal cancer. As new iterations of robotic technology are increasingly utilized, it is important to share learning experiences and clinical outcomes data, to optimize technical efficiency and clinical care. Observations: This was a retrospective review of a large academic institution's initial clinical use of the da Vinci Single Port (SP) compared with the da Vinci Si (Si) system. A total of 205 TORS cases were reviewed: 109 in the SP group (November 22, 2018, through September 30, 2020), and 96 in the Si group (January 1, 2016, through November 12, 2018). Both groups had comparable operative times, rates of postoperative pharyngeal hemorrhage, length of hospital stay, and duration of nasogastric feeding tube use. There was no difference in pathological characteristics, rates of positive margins, or indications for or time to initiation of adjuvant therapy between the groups. The collective experience of 6 faculty members-who have trained 139 TORS surgeons for the SP system rollout-was compiled to provide a summary of learning experiences and technical notes on safe and efficient operation of the SP system. Conclusions and Relevance: This Review found that the functional and oncologic outcomes were comparable between TORS cases performed with the Si and SP systems, and they had similar complication rates. Recognized advantages of the SP over the Si system include the availability of bipolar-energized instruments, a usable third surgical arm, and improved camera image quality.

Response to Neoadjuvant Targeted Therapy in Operable Head and Neck Cancer Confers Survival Benefit.

PURPOSE: Neoadjuvant targeted therapy provides a brief, preoperative window of opportunity that can be exploited to individualize cancer care based on treatment response. We investigated whether response to neoadjuvant therapy during the preoperative window confers survival benefit in patients with operable head and neck squamous cell carcinoma (HNSCC). PATIENTS AND METHODS: A pooled analysis of treatment-naïve patients with operable HNSCC enrolled in one of three clinical trials from 2009 to 2020 (NCT00779389, NCT01218048, NCT02473731). Neoadjuvant regimens consisted of EGFR inhibitors (n = 83) or anti-ErbB3 antibody therapy (n = 9) within 28 days of surgery. Clinical to pathologic stage migration was compared with disease-free survival (DFS) and overall survival (OS) while adjusting for confounding factors using multivariable Cox regression. Circulating tumor markers validated in other solid tumor models were analyzed. RESULTS: 92 of 118 patients were analyzed; all patients underwent surgery following neoadjuvant therapy. Clinical to pathologic downstaging was more frequent in patients undergoing neoadjuvant targeted therapy compared with control cohort (P = 0.048). Patients with pathologic downstage migration had the highest OS [89.5%; 95% confidence interval (CI), 75.7-100] compared with those with no stage change (58%; 95% CI, 46.2-69.8) or upstage (40%; 95% CI, 9.6-70.4; P = 0.003). Downstage migration remained a positive prognostic factor for OS (HR, 0.22; 95% CI, 0.05-0.90) while adjusting for measured confounders. Downstage migration correlated with decreased circulating tumor markers, SOX17 and TAC1 (P = 0.0078). CONCLUSIONS: Brief neoadjuvant therapy achieved pathologic downstaging in a subset of patients and was associated with significantly better DFS and OS as well as decreased circulating methylated SOX17 and TAC1.

Follow-Up Phone Interviews and Attendance Motivation From A Free Head and Neck Cancer Screening.

INTRODUCTION: Head and Neck Cancer Awareness and Screening Programs (HNCASP) are popular community outreach events hosted by academic and community otolaryngology departments. However, long-term follow-up of participants is lacking. PATIENTS AND METHODS: Participants of a HNCASP held at an academic cancer center prospectively filled out demographic and risk factor surveys followed by HNC screening examination. A phone interview was conducted for participants between 2012 and 2016 with suspicious findings to assess outcomes. RESULTS: Participants were largely Caucasian, female, and had health insurance, reflecting the setting at an academic medical center. Despite this, there were 156 (16.8%) positive screenings; 47 of these completed follow up interviews. Twelve (1.1% of all participants) cancer cases were confirmed. DISCUSSION: A significant proportion of HNCASP participants benefited from this screening opportunity. Education regarding HNC is the primary benefit and motivational factor for attendance of HNCASPs, although a significant subset of patients was identified that needed follow-up, and several cancers were detected.

Epithelial NF-kappaB enhances transmucosal fluid movement by altering tight junction protein composition after T cell activation.

In inflammatory bowel disease (IBD), aberrant activation of innate and adaptive immune responses enhances mucosal permeability through mechanisms not completely understood. To examine the role of epithelial nuclear factor (NF-kappaB) in IBD-induced enhanced permeability, epithelial-specific IkappaBalpha mutant (NF-kappaB super repressor) transgenic (TG) mice were generated. NF-kB activation was inhibited in TG mice, relative to wild-type mice, following T cell-mediated immune cell activation using an anti-CD3 monoclonal antibody. Furthermore, epithelial NF-kappaB super repressor protein inhibited diarrhea and blocked changes in transepithelial resistance and transmucosal flux of alexa350 (0.35 kDa) and dextran3000 (3 kDa). In vivo perfusion loop studies in TG mice revealed reversed net water secretion and reduced lumenal flux of different molecular probes (bovine serum albumin, alexa350, and dextran3000). Cell-imaging and immunoblotting of low-density, detergent-insoluble membrane fractions confirmed that tight junction proteins (occludin, claudin-1 and zona occludens-1) are internalized through an NF-kappaB-dependent pathway. Taken together, these data suggest that IBD-associated diarrhea results from NF-kappaB-mediated tight junction protein internalization and increased paracellular permeability. Thus, reduction of epithelial NF-kappaB activation in IBD may repair defects in epithelial barrier function, reduce diarrhea, and limit protein (eg, serum albumin) losses. Epithelial NF-kappaB activation induced by mucosal T cells, therefore, actively plays a role in opening paracellular spaces to promote transmucosal fluid effux into the intestinal lumen.

Predictors of survival outcomes in sinonasal squamous cell carcinoma: an analysis of the National Cancer Database.

BACKGROUND: Sinonasal squamous cell carcinoma (SNSCC) is a rare malignancy that poses management challenges. Although surgery and chemoradiation therapy (CRT) remain therapeutic mainstays, induction chemotherapy (IC) has emerged as a useful adjunct with locally advanced disease. This study used the National Cancer Data Base (NCDB) to examine treatment outcomes for patients diagnosed with SNSCC. METHODS: The NCDB (2004-2015) was queried for cases with SNSCC. Multivariate hazard regression modeling was used to identify significant predictors of 24-month and 60-month overall survival (OS) including treatment modality. RESULTS: A total of 3516 patients with SNSCC met inclusion criteria, including 1750 patients (49.8%) treated with surgery ± adjuvant therapy, 1352 (38.5%) treated with definitive radiotherapy (RT) or CRT, 300 (8.5%) who underwent IC followed by definitive CRT, and 114 (3.2%) who received IC followed by surgery and adjuvant therapy. Hazard modeling for confirmed treatment modality significantly associated (p < 0.001) with OS after adjustment. Patients who received surgical intervention ± adjuvant therapy had lower 24-month and 60-month mortality risk compared to definitive RT or CRT (hazard ratio [HR] ≥ 1.97; p < 0.001) or IC followed by definitive CRT (HR ≥ 1.73; p < 0.001). Compared to primary surgery ± adjuvant therapy, patients undergoing IC then surgery had similar 24-month and 60-month OS (p ≥ 0.672) after adjustment. CONCLUSION: Multimodality therapy, including surgical intervention, associates with improved OS after multifactorial adjustments. IC followed by surgery associated with improved OS compared to IC, followed by CRT and CRT alone. Study results highlight the utility of surgery toward optimizing OS in patients with SNSCC and demonstrates the potential utility of IC when primary surgical management is not preferred.

Circulating hybrid cells predict presence of occult nodal metastases in oral cavity carcinoma.

BACKGROUND: Levels of circulating hybrid cells (CHCs), a newly identified circulating tumor cell (CTC), correlate with disease stage and progression in cancer. We investigated their utility to risk-stratify patients with clinically N0 (cN0) oral cavity squamous cell carcinoma (OCSCC), and to identify patients with occult cervical lymph node metastases (pN+). METHODS: We analyzed peripheral blood samples for CHCs with co-expression of cytokeratin (tumor) and CD45 (leukocyte) from 22 patients with cN0 OCSCC using immunofluorescence microscopy, then correlated levels with pathologic lymph node status. RESULTS: CHC levels exceeded CTCs and correlated with the presence of both clinically overt (p = 0.002) and occult nodal metastases (p = 0.006). CONCLUSIONS: For evaluated cN0 OCSCC patients, those with cN0 → pN+ status harbored elevated CHC levels compared to patients without occult disease. Our findings highlight a promising blood-based biologic assay with potential utility to determine the necessity of surgical neck dissection for staging and treatment.

Spatial Profiles of Intratumoral PD-1+ Helper T Cells Predict Prognosis in Head and Neck Squamous Cell Carcinoma.

Background: Functional interactions between immune cells and neoplastic cells in the tumor immune microenvironment have been actively pursued for both biomarker discovery for patient stratification, as well as therapeutic anti-cancer targets to improve clinical outcomes. Although accumulating evidence indicates that intratumoral infiltration of immune cells has prognostic significance, limited information is available on the spatial infiltration patterns of immune cells within intratumoral regions. This study aimed to understand the intratumoral heterogeneity and spatial distribution of immune cell infiltrates associated with cell phenotypes and prognosis in head and neck squamous cell carcinoma (HNSCC). Methods: A total of 88 specimens of oropharyngeal squamous cell carcinoma, categorized into discovery (n = 38) and validation cohorts (n = 51), were analyzed for immune contexture by multiplexed immunohistochemistry (IHC) and image cytometry-based quantification. Tissue segmentation was performed according to a mathematical morphological approach using neoplastic cell IHC images to dissect intratumoral regions into tumor cell nests versus intratumoral stroma. Results: Tissue segmentation revealed heterogeneity in intratumoral T cells, varying from tumor cell nest-polarized to intratumoral stroma-polarized distributions. Leukocyte composition analysis revealed higher ratios of TH1/TH2 in tumor cell nests with higher percentages of helper T cells, B cells, and CD66b+ granulocytes within intratumoral stroma. A discovery and validation approach revealed a high density of programmed death receptor-1 (PD-1)+ helper T cells in tumor cell nests as a negative prognostic factor for short overall survival. CD163+ tumor-associated macrophages (TAM) provided the strongest correlation with PD-1+ helper T cells, and cases with a high density of PD-1+ helper T cells and CD163+ TAM had a significantly shorter overall survival than other cases. Conclusion: This study reveals the significance of analyzing intratumoral cell nests and reports that an immune microenvironment with a high density of PD-1+ helper T cells in tumoral cell nests is a poor prognostic factor for HNSCC.

Relevance of circulating hybrid cells as a non-invasive biomarker for myriad solid tumors.

Metastatic progression defines the final stages of tumor evolution and underlies the majority of cancer-related deaths. The heterogeneity in disseminated tumor cell populations capable of seeding and growing in distant organ sites contributes to the development of treatment resistant disease. We recently reported the identification of a novel tumor-derived cell population, circulating hybrid cells (CHCs), harboring attributes from both macrophages and neoplastic cells, including functional characteristics important to metastatic spread. These disseminated hybrids outnumber conventionally defined circulating tumor cells (CTCs) in cancer patients. It is unknown if CHCs represent a generalized cancer mechanism for cell dissemination, or if this population is relevant to the metastatic cascade. Herein, we detect CHCs in the peripheral blood of patients with cancer in myriad disease sites encompassing epithelial and non-epithelial malignancies. Further, we demonstrate that in vivo-derived hybrid cells harbor tumor-initiating capacity in murine cancer models and that CHCs from human breast cancer patients express stem cell antigens, features consistent with the potential to seed and grow at metastatic sites. Finally, we reveal heterogeneity of CHC phenotypes reflect key tumor features, including oncogenic mutations and functional protein expression. Importantly, this novel population of disseminated neoplastic cells opens a new area in cancer biology and renewed opportunity for battling metastatic disease.

Mechanism underlying inhibition of intestinal apical Cl/OH exchange following infection with enteropathogenic E. coli.

Enteropathogenic E. coli (EPEC) is a major cause of infantile diarrhea, but the pathophysiology underlying associated diarrhea is poorly understood. We examined the role of the luminal membrane Cl(-)/OH(-) exchange process in EPEC pathogenesis using in vitro and in vivo models. Cl(-)/OH(-) exchange activity was measured as OH(-) gradient-driven (36)Cl(-) uptake. EPEC infection (60 minutes-3 hours) inhibited apical Cl(-)/OH(-) exchange activity in human intestinal Caco-2 and T84 cells. This effect was dependent upon the bacterial type III secretory system (TTSS) and involved secreted effector molecules EspG and EspG2, known to disrupt the host microtubular network. The microtubule-disrupting agent colchicine (100 muM, 3 hours) also inhibited (36)Cl(-) uptake. The plasma membrane expression of major apical anion exchanger DRA (SLC26A3) was considerably reduced in EPEC-infected cells, corresponding with decreased Cl(-)/OH(-) exchange activity. Confocal microscopic studies showed that EPEC infection caused a marked redistribution of DRA from the apical membrane to intracellular compartments. Interestingly, infection of cells with an EPEC mutant deficient in espG significantly attenuated the decrease in surface expression of DRA protein as compared with treatment with wild-type EPEC. EPEC infection in vivo (1 day) also caused marked redistribution of surface DRA protein in the mouse colon. Our data demonstrate that EspG and EspG2 play an important role in contributing to EPEC infection-associated inhibition of luminal membrane chloride transport via modulation of surface DRA expression.

Targeted epithelial tight junction dysfunction causes immune activation and contributes to development of experimental colitis.

BACKGROUND & AIMS: Inflammatory bowel disease (IBD) is a multifactorial disease thought to be caused by alterations in epithelial function, innate and adaptive immunity, and luminal microbiota. The specific role of epithelial barrier function remains undefined, although increased activity of intestinal epithelial myosin light chain kinase (MLCK), which is the primary mechanism of tumor necrosis factor-induced barrier dysfunction, occurs in human IBD. Our aim was to determine whether, in an intact epithelium, primary dysregulation of the intestinal epithelial barrier by pathophysiologically relevant mechanisms can contribute to development of colitis. METHODS: We developed transgenic (Tg) mice that express constitutively active MLCK (CA-MLCK) specifically within intestinal epithelia. Their physiology, immune status, and susceptibility to disease were assessed and compared with non-Tg littermate controls. RESULTS: CA-MLCK Tg mice demonstrated significant barrier loss but grew and gained weight normally and did not develop spontaneous disease. CA-MLCK Tg mice did, however, develop mucosal immune activation demonstrated by increased numbers of lamina propria CD4(+)lymphocytes, redistribution of CD11c+cells, increased production of interferon-gamma and tumor necrosis factor, as well as increased expression of epithelial major histocompatibility complex class I. When challenged with CD4+CD45+Rb(hi) lymphocytes, Tg mice developed an accelerated and more severe form of colitis and had shorter survival times than non-Tg littermates. CONCLUSIONS: Primary pathophysiologically relevant intestinal epithelial barrier dysfunction is insufficient to cause experimental intestinal disease but can broadly activate mucosal immune responses and accelerate the onset and severity of immune-mediated colitis.

High-dimensional multiplexed immunohistochemical characterization of immune contexture in human cancers.

Biomarker assessments of tumor specimens is widely used in cancer research to audit tumor cell intrinsic as well as tumor cell extrinsic features including the diversity of immune, stromal, and mesenchymal cells. To comprehensively and quantitatively audit the tumor-immune microenvironment (TiME), we developed a novel multiplex immunohistochemistry (mIHC) platform and computational image processing workflow using a single formalin-fixed paraffin-embedded (FFPE) tissue section. Herein, we validated this platform using nine matched primary newly diagnosed and recurrent head and neck squamous cell carcinoma (HNSCC) sections sequentially subjected to immunodetection with a panel of 29 antibodies identifying malignant tumor cells, and 17 distinct leukocyte lineages and their functional states. Image cytometric analysis was applied to interpret chromogenic signals from digitally scanned and coregistered light microscopy-based images enabling identification and quantification of individual tumor cells, structural features, immune cell phenotypes and their functional state. In agreement with our previous study via a 12-plex imaging mIHC platform, myeloid-inflamed status in newly diagnosed primary tumors associated with significantly short progression free survival, independent of lymphoid-inflamed status. Spatial distribution of tumor and immune cell lineages in TiME was also examined and revealed statistically significant CD8+ T cell exclusion from tumor nests, whereas regulatory T cells and myeloid cells, when present in close proximity to tumor cells, highly associated with rapid cancer recurrence. These findings indicate presence of differential immune-spatial profiles in newly diagnosed and recurrent HNSCC, and establish the robustness of the 29-plex mIHC platform and associated analytics for quantitative analysis of single tissue sections revealing longitudinal TiME changes.

Coordinated epithelial NHE3 inhibition and barrier dysfunction are required for TNF-mediated diarrhea in vivo.

Acute T cell-mediated diarrhea is associated with increased mucosal expression of proinflammatory cytokines, including the TNF superfamily members TNF and LIGHT. While we have previously shown that epithelial barrier dysfunction induced by myosin light chain kinase (MLCK) is required for the development of diarrhea, MLCK inhibition does not completely restore water absorption. In contrast, although TNF-neutralizing antibodies completely restore water absorption after systemic T cell activation, barrier function is only partially corrected. This suggests that, while barrier dysfunction is critical, other processes must be involved in T cell-mediated diarrhea. To define these processes in vivo, we asked whether individual cytokines might regulate different events in T cell-mediated diarrhea. Both TNF and LIGHT caused MLCK-dependent barrier dysfunction. However, while TNF caused diarrhea, LIGHT enhanced intestinal water absorption. Moreover, TNF, but not LIGHT, inhibited Na+ absorption due to TNF-induced internalization of the brush border Na+/H+ exchanger NHE3. LIGHT did not cause NHE3 internalization. PKCalpha activation by TNF was responsible for NHE3 internalization, and pharmacological or genetic PKCalpha inhibition prevented NHE3 internalization, Na+ malabsorption, and diarrhea despite continued barrier dysfunction. These data demonstrate the necessity of coordinated Na+ malabsorption and barrier dysfunction in TNF-induced diarrhea and provide insight into mechanisms of intestinal water transport.

Elevated incidence of head and neck cancer in solid organ transplant recipients.

BACKGROUND: Solid organ transplant recipients are known to be at an increased risk of cancer development, but research on head and neck cancer in transplant recipients has been limited and prior risk assessments may not be accurate. METHODS: A retrospective review using a national Veterans Administration database to query outpatient problem lists for ICD codes indicating solid organ transplant and subsequent diagnosis of head and neck cancer. RESULTS: In a study of 30 939 656 patients (37 969 solid organ transplants and 113 995 head and neck cancers), history of transplant significantly predicted head and neck cancer, with relative risks ranging from 1.85 (thyroid) to 2.91 (salivary gland). Worse overall survival (OS) was seen for head and neck cancer patients with prior transplants. CONCLUSIONS: In a large case-control study, prior transplant was a risk factor for head and neck cancer development and worse OS for head and neck cancer patients.

Tumor immune microenvironment characteristics of papillary thyroid carcinoma are associated with histopathological aggressiveness and BRAF mutation status.

BACKGROUND: Papillary thyroid carcinoma (PTC) follows an indolent course; however, up to 30% of patients develop recurrent disease requiring further treatment. Profiling PTC immune complexity may provide new biomarkers for improved risk prediction. METHODS: Immune complexity profiles were quantitatively evaluated by multiplex immunohistochemistry (mIHC) in archived tissue sections from 39 patients with PTC, and were assessed for correlations with aggressive histopathological features based on the presence of lymphovascular invasion and/or extrathyroidal extension, and BRAF V600E mutational status. RESULTS: mIHC revealed two distinct immune clusters stratifying patients: a lymphoid-inflamed group (higher CD8+ T cells, reduced dendritic and mast cells) and a myeloid/hypo-inflamed group that correlated with aggressive pathological features. BRAF mutation was not associated with aggressive pathological features but did correlate with increased mast cell density. CONCLUSIONS: Distinct immune microenvironments exist in PTC correlating with pathological aggressiveness. Immune-based biomarkers associated with possible tumor-immune interactions may be used for risk stratification.

Epithelial myosin light chain kinase-dependent barrier dysfunction mediates T cell activation-induced diarrhea in vivo.

Disruption of the intestinal epithelial barrier occurs in many intestinal diseases, but neither the mechanisms nor the contribution of barrier dysfunction to disease pathogenesis have been defined. We utilized a murine model of T cell-mediated acute diarrhea to investigate the role of the epithelial barrier in diarrheal disease. We show that epithelial barrier dysfunction is required for the development of diarrhea. This diarrhea is characterized by reversal of net water flux, from absorption to secretion; increased leak of serum protein into the intestinal lumen; and altered tight junction structure. Phosphorylation of epithelial myosin II regulatory light chain (MLC), which has been correlated with tight junction regulation in vitro, increased abruptly after T cell activation and coincided with the development of diarrhea. Genetic knockout of long myosin light chain kinase (MLCK) or treatment of wild-type mice with a highly specific peptide MLCK inhibitor prevented epithelial MLC phosphorylation, tight junction disruption, protein leak, and diarrhea following T cell activation. These data show that epithelial MLCK is essential for intestinal barrier dysfunction and that this barrier dysfunction is critical to pathogenesis of diarrheal disease. The data also indicate that inhibition of epithelial MLCK may be an effective non-immunosuppressive therapy for treatment of immune-mediated intestinal disease.