Mouse Esophagus Research Articles

Isolation of Myofibroblasts from Mouse and Human Esophagus

Isolation of Myofibroblasts from Mouse and Human Esophagus

Isolation of esophageal stem cells with potential for therapy.

PurposeLong-gap esophageal atresia represents a significant challenge for pediatric surgeons and current surgical approaches are associated with significant morbidity. A tissue-engineered esophagus, comprising cells seeded onto a scaffold, represents a therapeutic alternative. In this study, we aimed to determine the optimal techniques for isolation and culture of mouse esophageal epithelial cells and to isolate CD34-positive esophageal epithelial stem cells from cadaveric mouse specimens.MethodsPrimary epithelial cells were isolated from mouse esophagi by enzymatic dissociation from the mucosal layer (Dispase, Trypsin/EDTA) using three different protocols. In protocol A, isolated mucosa was minced and incubated with trypsin once. In protocol B, intact mucosal sheets underwent two trypsin incubations yielding a single-cell suspension. In protocol C, intact mucosa explants were plated epithelial side down. Epithelial cells were cultured on collagen-coated wells.ResultsInitial findings showed that Protocol B gave the best results in terms of yield, viability, and least contamination with different cell types and microbes. Esophageal epithelial cells isolated using Protocol B were stained for CD34 and sorted using fluorescence-activated cell sorting (FACS). Of the total cells sorted, 8.3 % (2–11.3) [%median (range)] were CD34 positive.ConclusionsOur results demonstrate that mouse esophageal epithelial cells can be successfully isolated from fresh mouse esophagi using two consecutive trypsin incubations of intact mucosal sheets. Furthermore, the cells obtained using this method were successfully stained for CD34, a putative esophageal epithelial stem cell marker. Further research into the factors necessary for the successful proliferation of CD34 positive stem cell lines is needed to progress toward clinical application.

Cellular Heterogeneity in the Mouse Esophagus Implicates the Presence of a Nonquiescent Epithelial Stem Cell Population

Because the esophageal epithelium lacks a defined stem cell niche, it is unclear whether all basal epithelial cells in the adult esophagus are functionally equivalent. In this study, we showed that basal cells in the mouse esophagus contained a heterogeneous population of epithelial cells, similar to other rapidly cycling tissues such as the intestine or skin. Using a combination of cell-surface markers, we separated primary esophageal tissue into distinct cell populations that harbored differences in stem cell potential. We also used an invitro 3D organoid assay to demonstrate that Sox2, Wnt, and bone morphogenetic protein signaling regulate esophageal self-renewal. Finally, we labeled proliferating basal epithelial cells invivo to show differing cell-cycle profiles and proliferation kinetics. Based on our results, we propose that a nonquiescent stem cell population resides in the basal epithelium of the mouse esophagus.

High accumulation of arsenic in the esophagus of mice after exposure to arsenite.

Arsenic-induced toxicity appears to be dependent on the tissue- or cell-specific accumulation of this metalloid. An early study showed that arsenic was retained in the esophagus as well as the liver, kidney cortex and skin of marmosets after intraperitoneal administration of (74)As-arsenite. However, there is little available information regarding the distribution of arsenic in the esophagus. Here, we compared the retention of arsenic in the esophagus, liver, lung, kidney and heart in mice intraperitoneally administered 1 or 5mg/kg sodium arsenite (As(III)) daily for 3 or 7days. The results showed that the arsenic concentration was highest in the esophagus. We compared the mRNA levels of aquaglyceroporin (AQP) 3, AQP7 and AQP9, which are responsible for arsenic influx, and those of multidrug-resistance protein (MRP) 1 and MRP2, which are responsible for arsenic efflux. The levels of AQP3 mRNA in the esophagus were much higher than those in liver, lung and heart, while the mRNA levels of MRP2 were very low in the esophagus. In addition, we found extremely low expression of Nrf2 in the esophagus at the basal and under the activated conditions, which might have resulted in low levels of glutamyl-cysteine ligase catalytic and modulatory subunits, and subsequently in the low levels of glutathione. Thus, the highest retention of arsenic was detected in the esophagus after intraperitoneal administration of As(III) to mice, and this appeared to result from multiple factors, including high expression of AQP3, low expression of MRP2, low capacity of glutathione synthesis and low activation of Nrf2.

Distribution of transient receptor potential cation channel subfamily V member 1-expressing nerve fibers in mouse esophagus.

Transient receptor potential cation channel subfamily V member 1 (TRPV1) plays a role in esophageal function. However, the distribution of TRPV1 nerve fibers in the esophagus is currently not well understood. In the present study, we investigated the distribution of TRPV1 and neurotransmitters released from TRPV1 nerve fibers in the mouse lower esophagus. Furthermore, we investigated changes in the presence of TRPV1 in the mouse model of esophagitis. Numerous TRPV1-immunoreactive nerve fibers were seen in both the submucosal layer and myenteric plexus of the lower esophagus and colocalized with calcitonin gene-related peptide (CGRP). TRPV1 colocalized with substance P in axons in the submucosal layer and myenteric plexus. TRPV1 colocalized with neuronal nitric oxide synthase in the myenteric plexus. We observed some colocalization of CGRP with the vesicular acetylcholine (ACh) transporter, packaging of ACh into synaptic vesicles after its synthesis in terminal cytoplasm, in the submucosal layer and myenteric plexus. In the esophagitis model, the number of the TRPV1 nerve fibers did not change, but their immunoreactive intensity increased compared with sham-operated mice. Inhibitory effect of exogenous capsaicin on electrically stimulated twitch contraction significantly increased in esophagitis model compared with the effect in sham-operated mice. Overall, these results suggest that TRPV1 nerve fibers projecting to both the submucosal and muscle layer of the esophagus are extrinsic spinal and vagal afferent neurons. Furthermore, TRPV1 nerve fibers contain CGRP, substance P, nitric oxide, and ACh. Therefore, acid influx-mediated TRPV1 activation may play a role in regulating esophageal relaxation.

Characterization of the nerve-stellate cell interactions in pancreatic cancer

Glial cell line-derived neurotrophic factor (GDNF) is expressed in the gastrointestinal tract of the developing mouse and appears to play an important role in the migration of enteric neuron precursors into and along the small and large intestines. Two other GDNF family members, neurturin and artemin, are also expressed in the developing gut although artemin is only expressed in the esophagus. We examined the effects of GDNF, neurturin, and artemin on neural crest cell migration and neurite outgrowth in explants of mouse esophagus, midgut, and hindgut. Both GDNF and neurturin induced neural crest cell migration and neurite outgrowth in all regions examined. In the esophagus, the effect of GDNF on migration and neurite outgrowth declined with age between E11.5 and E14.5, but neurturin still had a strong neurite outgrowth effect at E14.5. Artemin did not promote neural migration or neurite outgrowth in any region investigated. The effects of GDNF family ligands are mediated by the Ret tyrosine kinase. We examined the density of neurons in the esophagus of Ret−/− mice, which lack neurons in the small and large intestines. The density of esophageal neurons in Ret−/− mice was only about 4% of the density of esophageal neurons in Ret+/− and Ret+/+ mice. These results show that GDNF and neurturin promote migration and neurite outgrowth of crest-derived cells in the esophagus as well as the intestine. Moreover, like intestinal neurons, the development of esophageal neurons is largely Ret-dependent.

Juvenile megaesophagus in PKCα-deficient mice is associated with an increase in the segment of the distal esophagus lined by smooth muscle cells

Megaesophagus in mice has been associated with several genetic defects. In the present study we expand the range of genes associated with esophageal function and morphology by protein kinase C alpha (PKCα). PKCα-deficient mice showed a six times increased prevalence of megaesophagus at the age of 9–10 weeks compared to wild-type animals. In contrast, in a restricted number of 14-month-old animals of both genotypes a similar prevalence of megaesophagus was found. Megaesophagus was associated with an increased portion of the distal esophagus lined by smooth muscle cells. Achalasia-like degeneration or loss of neuronal cells, inflammation or fibrosis was not present in any of the animals. The results of the study therefore suggest that PKCα expression is associated with a delayed replacement of embryonic smooth muscle by skeletal muscle at the distal esophagus and consecutive megaesophagus in young mice, which, however, is not present at the same prevalence at an advanced age.

ER stress induces epithelial differentiation in the mouse oesophagus

ObjectiveStress in the endoplasmic reticulum (ER) leads to activation of the unfolded protein response (UPR). Xbp1, a key component of the UPR has recently been linked to the risk of...

Characterization of eosinophilic esophagitis murine models using optical coherence tomography

Pre-clinical studies using murine models are critical for understanding the pathophysiological mechanisms underlying immune-mediated disorders such as Eosinophilic esophagitis (EoE). In this study, an optical coherence tomography (OCT) system capable of providing three-dimensional images with axial and transverse resolutions of 5 µm and 10 µm, respectively, was utilized to obtain esophageal images from a murine model of EoE-like disease ex vivo. Structural changes in the esophagus of wild-type (Tslpr(+/+) ) and mutant (Tslpr(-/-) ) mice with EoE-like disease were quantitatively evaluated and food impaction sites in the esophagus of diseased mice were monitored using OCT. Here, the capability of OCT as a label-free imaging tool devoid of tissue-processing artifacts to effectively characterize murine EoE-like disease models has been demonstrated.

Effects of Stress on Mouse β-Defensin-3 Expression in the Upper Digestive Mucosa

PurposeGastrointestinal integrity and immune surveillance are affected by stress. Stress also adversely affects mucosal barrier function. β-defensins constitute an integral component of the innate immune system as antimicrobial peptides, serving as the first line of defense against microbial pathogens at the epithelial surfaces of the upper digestive mucosa. The primary objective of this study was to determine the effects of stress on the expression profile of mouse β-defensin-3 in the upper digestive mucosa of mice with diabetes.Materials and MethodsWe established a mouse model of restraint stress by using NSY/Hos mice with type 2 diabetes mellitus. We used real-time polymerase chain reaction, in situ hybridization, and immunohistochemistry to investigate the effects of stress and glucocorticoid administration on mouse β-defensin-3 expression in the upper digestive mucosa of the gingiva, esophagus, and stomach.ResultsMouse β-defensin-3 mRNA expression was higher in the esophagus than in the gingiva or stomach (p<0.05). In the esophagus, mouse β-defensin-3 mRNA expression was lower in stressed mice than in non-stressed mice (p<0.05). Furthermore, immunoreactivity to mouse β-defensin-3 protein was lower in the esophagus of stressed mice than non-stressed mice, consistent with the results of mRNA expression analysis. Systemic glucocorticoid administration also downregulated esophageal mouse β-defensin-3 mRNA expression.ConclusionOur novel findings show that stress decreases mouse β-defensin-3 expression in the esophagus of mice with diabetes, possibly due to increased endogenous glucocorticoid production. It appears to be highly likely that stress management may normalize mucosal antimicrobial defenses in patients with diabetes.

Localization of receptors for calcitonin-gene-related peptide to intraganglionic laminar endings of the mouse esophagus: peripheral interaction between vagal and spinal afferents?

The calcitonin-gene-related peptide (CGRP) receptor is a heterodimer of calcitonin-receptor-like receptor (CLR) and receptor-activity-modifying protein 1 (RAMP1). Despite the importance of CGRP in regulating gastrointestinal functions, nothing is known about the distribution and function of CLR/RAMP1 in the esophagus, where up to 90% of spinal afferent neurons contain CGRP. We detected CLR/RAMP1 in the mouse esophagus using immunofluorescence and confocal laser scanning microscopy and examined their relationship with neuronal elements of the myenteric plexus. Immunoreactivity for CLR and RAMP1 colocalized with VGLUT2-positive intraganglionic laminar endings (IGLEs), which were contacted by CGRP-positive varicose axons presumably of spinal afferent origin, typically at sites of CRL/RAMP1 immunoreactivity. This provides an anatomical basis for interaction between spinal afferent fibers and IGLEs. Immunoreactive CLR and RAMP1 also colocalized in myenteric neurons. Thus, CGRP-containing spinal afferents may interact with both vagal IGLEs and myenteric neurons in the mouse esophagus, possibly modulating motility reflexes and inflammatory hypersensitivity.

Muscarinic acetylcholine receptors in the mouse esophagus: focus on vagal intraganglionic laminar endings (IGLEs)

IGLEs represent the only low-threshold vagal mechanosensory terminals in the tunica muscularis of the esophagus. Previously, close relationships of vesicular glutamate transporter 2 (VGLUT2) immunopositive IGLEs and cholinergic varicosities suggestive for direct contacts were described in almost all mouse esophageal myenteric ganglia. Possible cholinergic influence on IGLEs requires specific acetylcholine receptors. In particular, the occurrence and location of neuronal muscarinic acetylcholine receptors (mAChR) in the esophagus were not yet characterized.

Characterization of esophageal defects in the crouzon mouse model

Mutations in Fibroblastic Growth Factor Receptors (FGFR) have been associated with human craniosynostotic birth defects like Crouzon syndrome. Several anecdotes and case reports have indicated higher incidence of gastrointestinal tract disorders in FGFR-associated craniosynostotic birth defects. Our objective was to characterize esophageal defects in a mouse model of human Crouzon syndrome, with a mutation in codon 290 of FGFR2. Dissected esophagi of Fgfr2(W290R) postnatal heterozygous (HET) and wild-type mice were analyzed by histological staining, immunohistochemically with cell proliferation marker, and functionally by strain gauge measures of electrically evoked contractile force. The esophagi of HETs were noticeably smaller but with wider lumen than those of wild-type littermates. The HET esophagi showed a decrease in proliferation and an increase in expression of Sonic Hedgehog as compared to wild-type esophagi. Histological investigations revealed reduced amounts and disorganization of collagen in muscle layers. Functional analysis revealed altered contractile properties in HET with reduced peak amplitude and prolonged duration of evoked contractile force response and lower stimulation threshold. The defects observed in the esophagus of the mutant may explain some of the clinical symptoms observed in humans, for example, recurrent vomiting, gastroesophageal reflux, and esophageal strictures. Taken together, our results provide evidence for the importance of Fibroblastic Growth Factor signaling in the growth and patterning of the esophagus, providing a possible scientific basis for the gastrointestinal tract clinical findings in craniosynostotic patients. Furthermore, the findings also provide a sound scientific rationale for any changes in the clinical management of gastrointestinal tract problems in patients with craniosynostotic defects.

Neurotransmitters in parasympathetic ganglionic neurons and nerves in mouse lower airway smooth muscle

In most species, including humans, lower airway smooth muscle (ASM) contains nerve terminals from two distinct populations of parasympathetic ganglionic neurons based on neurotransmitter phenotype: cholinergic and non-adrenergic non-cholinergic (NANC), causing contraction and relaxation, respectively, of ASM. Using immunohistological staining, the density and distribution of NANC-associated neurotransmitters, vasoactive intestinal peptide (VIP) and nitric oxide synthase were 6% of total nerve profiles compared to 19% cholinergic nerves in ASM in mouse (C57BL/6) central airways. The location of the NANC parasympathetic neurons innervating the tracheal ASM, as determined by retrograde neuronal tracer from the trachealis muscle, was the myenteric plexus of the esophagus, closely associated with the outer striated longitudinal muscle layers; the majority of the retrograde-labeled neurons were VIP- and NOS-IR. The results of these experiments provide the first direct evidence that VIP-IR and NOS-IR neurons intrinsic to the mouse esophagus project axons to the adjacent trachealis muscle.

Muscarinic acetylcholine receptors in the mouse esophagus: focus on intraganglionic laminar endings (IGLEs)

IGLEs represent the only low-threshold vagal mechanosensory terminals in the tunica muscularis of the esophagus. Previously, close relationships of vesicular glutamate transporter 2 (VGLUT2) immunopositive IGLEs and cholinergic varicosities suggestive for direct contacts were described in almost all mouse esophageal myenteric ganglia. Possible cholinergic influence on IGLEs requires specific acetylcholine receptors. In particular, the occurrence and location of neuronal muscarinic acetylcholine receptors (mAChR) in the esophagus were not yet characterized. This study aimed at specifying relationships of VGLUT2 immunopositive IGLEs and vesicular acetylcholine transporter (VAChT)-immunopositive varicosities using pre-embedding electron microscopy and the location of mAChR1-3 (M1-3) within esophagus and nodose ganglia using multilabel immunofluorescence and retrograde tracing. Electron microscopy confirmed synaptic contacts between cholinergic varicosities and IGLEs. M1- and M2-immunoreactivities (-iry; -iries) were colocalized with VGLUT2-iry in subpopulations of IGLEs. Retrograde Fast Blue tracing from the esophagus showed nodose ganglion neurons colocalizing tracer and M2-iry. M1-3-iries were detected in about 80% of myenteric ganglia and in about 67% of myenteric neurons. M1- and M2-iry were present in many fibers and varicosities within myenteric ganglia. Presynaptic M2-iry was detected in all, presynaptic M3-iry in one-fifth of motor endplates of striated esophageal muscles. M1-iry could not be detected in motor endplates of the esophagus, but in sternomastoid muscle. Acetylcholine probably released from varicosities of both extrinsic and intrinsic origin may influence a subpopulation of esophageal IGLEs via M2 and M1-receptors.

Su1736 Live Imaging of Single Cell Reveals Single Stem Cell Dynamics in an Organoid Derived From Murine Small Intestine

G A A b st ra ct s differentiation, thus showing that in analogy to the intestine, esophageal stemness is lost. Using RNA micro-arrays, we identified a gene signature of 47 genes that were lost in both individual cell lines upon induction of ER stress. Of these genes, we found 29 genes to be restricted to the basal layer of the mouse esophagus. Out of these 29, nine genes show expression in only a small proportion of the basal cells, potentially marking stem cells. Conclusion: ER stress depletes esophageal precursor cells. Our in vitro screen combined with in situ hybridization identified nine genes that are specifically expressed in a subset of proliferating genes, thereby potentially marking esophageal stem cells.

Abstract 2733: K14-GFP-miR-31 transgenic mice confer high susceptibility to squamous cell tumorigenesis on oral tongue and esophagus.

Abstract Squamous cell carcinoma (SCC) occurring on head and neck region and esophagus causes tremendous cancer mortality around the world. Effects from tobacco and/or alcoholic carcinogens and other factors are highly associated with the prevalence of these malignancies. MiRNAs are small non-coding RNAs mediating the RNA interference on targeted mRNAs. They play important roles in the pathogenesis of malignancies. miR-31 is among the most eminently up-regulated miRNAs in SCC occurring in head and neck region and esophagus. To elucidate the molecular pathogenesis of SCC, we established miR-31 transgenic mouse lines, in which miR-31 is under the control of K14 promoter and co-expressed with GFP. GFP and miR-31 were detected in basal and suprabasal squamous cells of skin, oral cavity and esophagus in these transgenic mice. The transgenic mice exhibited higher potential for tumor induction than wild type mice on oral tongue and esophagus by 4-nitroquinoline 1-oxide (4NQO) treatment. The precancerous lesions on oral tongues and esophagus in transgenic mice were also in more advanced stages in contrast to counterparts of wild type mice. Homozygous transgenic mice had the worst prognosis than the others. 4NQO induction also up-regulated miR-31 expression in tumors of wild type mice. The tumors induced in transgenic mice expressed more abundant miR-31 and VEGF, and less abundance of factor inhibiting HIF (FIH) than tumors in wild type mice. Base excision repair genes were validated as targets of miR-31 in human SCC cell lines, and the expression of these target genes were also decreased in the squamous epithelium of transgenic mice. This study identifies the high sensitivity of K14-GFP-miR-31 transgenic mice for chemical carcinogen-induced squamous cell tumorigenesis, and this could be associated with the down-regulation of tumor suppressor genes and the impairment of repair activity to counteract carcinogenic stimuli in squamous cells. Citation Format: Ssu-Hsueh Tseng, Yong-Syu Lee, Kuo-Wei Chang, Shu-Chun Lin. K14-GFP-miR-31 transgenic mice confer high susceptibility to squamous cell tumorigenesis on oral tongue and esophagus. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2733. doi:10.1158/1538-7445.AM2013-2733

Cycling progenitors maintain epithelia while diverse cell types contribute to repair

It has recently been shown that stem and progenitor cells undergo population self-renewal to maintain epithelial homeostasis. The fate of individual cells is stochastic but the production of proliferating and differentiating cells is balanced across the population. This new paradigm, originating in mouse epidermis and since extended to mouse oesophagus and mouse and Drosophila intestine, is in contrast to the long held model of epithelial maintenance by exclusively asymmetric division of stem cells. Recent lineage tracing studies have now shown that wound responses vary between tissues, and that a stem cell reserve is not essential as cycling progenitors and even differentiating cells contribute to regeneration.

Insignificant effect of cleistanthin A and cleistanthin B on motor function in animal models

Aim: To study the in vitro and in vivo effects of cleistanthin A and cleistanthin B on the cholinergic receptors and the motor function using mouse as an animal model. Materials and Methods: The cleistanthin A and cleistanthin B were isolated from the leaves of Cleistanthus collinus using column chromatography and purified. The effect of cleistanthins A and B on locomotor activity, motor co-ordination and grip strength in mice were evaluated using actophotometer, rota-rod apparatus and grip strength test respectively ( in vivo ). The effect of cleistanthins A and B on nicotinic acetylcholine receptor was studied using a mouse esophagus preparation ( in vitro ) and the concentration-response curves of carbachol and cleistanthins A and B were recorded using a data acquisition system (Biopac Inc. USA) through a variable transducer (500 g). Results: Cleistanthins A and B did not have any significant effect on locomotor activity, motor co-ordination and grip strength when they were used upto 400 mg/kg BW. Cleistanthins A and B did not show any significant inhibitory effect on nicotinic acetylcholine receptors in isolated mouse esophagus tissue preparation at 1, 3, and 10 μg doses. Conclusion: Cleistanthins A and B do not have significant activity on the motor system when used upto 400 mg/kg in mice and also they did not have any effect on nicotinic acetylcholine receptors when used upto 10 μ g in the isolated mouse esophagus preparation.

Abstract A38: Aberrant expression of cell growth-critical genes in 4-nitroquinoline 1-oxide-induced mouse tumors and in human esophageal cancer tissues

Abstract Background: An animal model of 4-nitroquinoline 1-oxide(4-NQO)-induced oral and esophageal cancer is useful in study of human diseases, but the underlying molecular events remain to be determined. Tobacco smoke, the major risk factor for human oral and esophageal squamous cell carcinoma, alters expression of certain cell growth-critical genes (e.g., p-ERK1/2, COX-2, and RAR-β2). This study aimed to detect expression of these genes in 4-NQO-induced mouse tumors and then in esophageal cancer cell lines and tissues for association with clinicopathological and survival data from patients. Methods: C57LB6/129Sv mice were given in the drinking water to produce oral and esophageal cancers. qRT-PCR, Western blot, and immunohistochemistry were used to detect gene expressions in mouse tissues or human esophageal cancer tissues. Methylation-specific PCR and DNA sequence were performed to assess promoter methylation of RAR-β2 promoter. the Kaplan-Meier analysis was performed to associate gene expression with survival of patients. Results: 4-NQO induced premalignant and malignant lesions in mouse oral cavity and esophagus in a dose-dependent manner, which pathologically and morphologically mimicked human oral and esophageal cancers. Molecularly, 4-NQO inhibited RAR-β2 but induced p-Erk1/2 and COX-2 expression and RAR-β2 gene promoter methylation in mouse tumors. In vitro treatment with 4-NQO altered expression of RAR-β2, p-Erk1/2, and COX-2 in esophageal cell lines. Ex vivo expression of p-Erk1/2 and COX-2 in 90 cases of esophageal cancer patients was upregulated and p-ERK1/2 expression was associated with advanced clinical tumor stage and consumption of hot beverage, while COX-2 expression was associated with tumor de-differentiation in esophageal cancers. Furthermore, expression of p-Erk1/2 was associated with worse overall survival of esophageal cancer patients (p = 0.014), while COX-2 expression didn't reach statistically significant (p = 0.19). Knockdown of COX-2 expression using transient transfection of a COX-2 antisense expression vector inhibited Ki67 expression, an indicator of cell proliferation, in esophageal cancer cells. Conclusion: 4-NQO-induced lesions in mouse oral cavity and esophagus not only pathologically and morphologically mimicked human oral and esophageal cancers, but also shared some molecular alterations (e.g., aberrant expression of RAR-β2, p-Erk1/2, and COX-2). This study further demonstrated that targeting of the altered RAR-β2-led gene pathway could effectively suppress development of these now deadly cancers. Citation Format: Zhengduo Yang, Baoxiang Guan, Taoyan Men, Junya Fujimoto, Xiaochun Xu. Aberrant expression of cell growth-critical genes in 4-nitroquinoline 1-oxide-induced mouse tumors and in human esophageal cancer tissues. [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr A38.