Diagnostic and Prognostic Markers for Pancreatitis and Pancreatic Ductal Adenocarcinoma.

Diagnostic markers are desperately needed for the early detection of pancreatic ductal adenocarcinoma (PDA). We describe sets of markers expressed in temporal order in mouse models during pancreatitis, PDA initiation and progression. Cell type specificity and the differential expression of PDA markers were identified by screening single cell (sc) RNAseq from tumor samples of a mouse model for PDA (KIC) at early and late stages of PDA progression compared to that of a normal pancreas. Candidate genes were identified from three sources: (1) an unsupervised screening of the genes preferentially expressed in mouse PDA tumors; (2) signaling pathways that drive PDA, including the Ras pathway, calcium signaling, and known cancer genes, or genes encoding proteins that were identified by differential mass spectrometry (MS) of mouse tumors and conditioned media from human cancer cell lines; and (3) genes whose expression is associated with poor or better prognoses (PAAD, oncolnc.org). The developmental progression of PDA was detected in the temporal order of gene expression in the cancer cells of the KIC mice. The earliest diagnostic markers were expressed in epithelial cancer cells in early-stage, but not late-stage, PDA tumors. Other early markers were expressed in the epithelium of both early- and late-state PDA tumors. Markers that were expressed somewhat later were first elevated in the epithelial cancer cells of the late-stage tumors, then in both epithelial and mesenchymal cells, or only in mesenchymal cells. Stromal markers were differentially expressed in early- and/or late-stage PDA neoplasia in fibroblast and hematopoietic cells (lymphocytes and/or macrophages) or broadly expressed in cancer and many stromal cell types. Pancreatitis is a risk factor for PDA in humans. Mouse models of pancreatitis, including caerulein treatment and the acinar-specific homozygous deletion of differentiation transcription factors (dTFs), were screened for the early expression of all PDA markers identified in the KIC neoplasia. Prognostic markers associated with a more rapid decline were identified and showed differential and cell-type-specific expression in PDA, predominately in late-stage epithelial and/or mesenchymal cancer cells. Select markers were validated by immunohistochemistry in mouse and human samples of a normal pancreas and those with early- and late-stage PDA. In total, we present 2165 individual diagnostic and prognostic markers for disease progression to be tested in humans from pancreatitis to late-stage PDA.

Key transcriptional effectors of the pancreatic acinar phenotype and oncogenic transformation.

Proper maintenance of mature cellular phenotypes is essential for stable physiology, suppression of disease states, and resistance to oncogenic transformation. We describe the transcriptional regulatory roles of four key DNA-binding transcription factors (Ptf1a, Nr5a2, Foxa2 and Gata4) that sit at the top of a regulatory hierarchy controlling all aspects of a highly differentiated cell-type-the mature pancreatic acinar cell (PAC). Selective inactivation of Ptf1a, Nr5a2, Foxa2 and Gata4 individually in mouse adult PACs rapidly altered the transcriptome and differentiation status of PACs. The changes most emphatically included transcription of the genes for the secretory digestive enzymes (which conscript more than 90% of acinar cell protein synthesis), a potent anabolic metabolism that provides the energy and materials for protein synthesis, suppressed and properly balanced cellular replication, and susceptibility to transformation by oncogenic KrasG12D. The simultaneous inactivation of Foxa2 and Gata4 caused a greater-than-additive disruption of gene expression and uncovered their collaboration to maintain Ptf1a expression and control PAC replication. A measure of PAC dedifferentiation ranked the effects of the conditional knockouts as Foxa2+Gata4 > Ptf1a > Nr5a2 > Foxa2 > Gata4. Whereas the loss of Ptf1a or Nr5a2 greatly accelerated Kras-mediated transformation of mature acinar cells in vivo, the absence of Foxa2, Gata4, or Foxa2+Gata4 together blocked transformation completely, despite extensive dedifferentiation. A lack of correlation between PAC dedifferentiation and sensitivity to oncogenic KrasG12D negates the simple proposition that the level of differentiation determines acinar cell resistance to transformation.

Understanding the Wellbeing Effects of a Community Music Program for People With Disabilities: A Mixed Methods, Person-Centered Study.

People with disabilities face inequalities in mental wellbeing, for which social exclusion is a contributing factor. Musical activities offer a promising but complex intervention, making impacts on a population with highly varied characteristics and needs challenging to capture. This paper reports on a mixed methods, person-centered study investigating a community music intervention for such a population. Three groups of adult service users with varied disabilities (either physical, learning, or both), took part in weekly music workshops in different locations. Music staff, housing and resource center staff, as well as participants and members of their families, took part in semi-structured interviews. A quantitative measure administered by service staff was used to rate service users' social development. Two lay researchers, both individuals with a disability contributed to all aspects of the study. Interviews were analyzed through thematic analysis. Improvements in individuals' self-expression, confidence, mood, and social skills were consistent with previous findings. Differences in effect between centers included: Group 1, some of whom had previous experience of workshops, showed an improvement in musical skills; Group 2 showed a mixed response, some participated with enthusiasm but others chose art activities over music workshops; Group 3 had lasting positive impact, this group had very limited opportunities for music due to their rural location. Quantitative analysis showed significant increase over all groups in communication, interaction with others, and joint attention. The intervention was beneficial for participants in separate locations in similar ways, but also highlighted that context and prior experience mediated effects in distinct ways. The lay researchers enhanced the qualitative analysis by emphasizing (1) the importance of recognizing participants' self-expression in non-verbal modes of communication and (2) the importance of having music staff with a disability to provide a positive role model. This paper proposes that mixed methods person-centered research is the most suitable approach to capture and understand the multiple and varied effects of this complex intervention for a diverse group of participants.

Concerted cell and in vivo screen for pancreatic ductal adenocarcinoma (PDA) chemotherapeutics.

PDA is a major cause of US cancer-related deaths. Oncogenic Kras presents in 90% of human PDAs. Kras mutations occur early in pre-neoplastic lesions but are insufficient to cause PDA. Other contributing factors early in disease progression include chronic pancreatitis, alterations in epigenetic regulators, and tumor suppressor gene mutation. GPCRs activate heterotrimeric G-proteins that stimulate intracellular calcium and oncogenic Kras signaling, thereby promoting pancreatitis and progression to PDA. By contrast, Rgs proteins inhibit Gi/q-coupled GPCRs to negatively regulate PDA progression. Rgs16::GFP is expressed in response to caerulein-induced acinar cell dedifferentiation, early neoplasia, and throughout PDA progression. In genetically engineered mouse models of PDA, Rgs16::GFP is useful for pre-clinical rapid in vivo validation of novel chemotherapeutics targeting early lesions in patients following successful resection or at high risk for progressing to PDA. Cultured primary PDA cells express Rgs16::GFP in response to cytotoxic drugs. A histone deacetylase inhibitor, TSA, stimulated Rgs16::GFP expression in PDA primary cells, potentiated gemcitabine and JQ1 cytotoxicity in cell culture, and Gem + TSA + JQ1 inhibited tumor initiation and progression in vivo. Here we establish the use of Rgs16::GFP expression for testing drug combinations in cell culture and validation of best candidates in our rapid in vivo screen.

Our Virtual Tribe: Sustaining and Enhancing Community via Online Music Improvisation.

This article documents experiences of Glasgow Improvisers Orchestra's virtual, synchronous improvisation sessions during COVID-19 pandemic via interviews with 29 participants. Sessions included an international, gender balanced, and cross generational group of over 70 musicians all of whom were living under conditions of social distancing. All sessions were recorded using Zoom software. After 3 months of twice weekly improvisation sessions, 29 interviews with participants were undertaken, recorded, transcribed, and analyzed. Key themes include how the sessions provided opportunities for artistic development, enhanced mood, reduced feelings of isolation, and sustained and developed community. Particular attention is placed upon how improvisation as a universal, real time, social, and collaborative process facilitates interaction, allowing the technological affordances of software (latencies, sound quality, and gallery/speaker view) and hardware (laptop, tablet, instruments, microphones, headphones, and objects in room) to become emergent properties of artistic collaborations. The extent to which this process affects new perceptual and conceptual breakthroughs for practitioners is discussed as is the crucial and innovative relationship between audio and visual elements. Analysis of edited films of the sessions highlight artistic and theoretical and conceptual issues discussed. Emphasis is given to how the domestic environment merges with technologies to create The Theatre of Home.

Prevention and Reversion of Pancreatic Tumorigenesis through a Differentiation-Based Mechanism.

Activating mutations in Kras are nearly ubiquitous in human pancreatic cancer and initiate precancerous pancreatic intraepithelial neoplasia (PanINs) when induced in mouse acinar cells. PanINs normally take months to form but are accelerated by deletion of acinar cell differentiation factors such as Ptf1a, suggesting that loss of cell identity is rate limiting for pancreatic tumor initiation. Using a genetic mouse model that allows for independent control of oncogenic Kras and Ptf1a expression, we demonstrate that sustained Ptf1a is sufficient to prevent Kras-driven tumorigenesis, even in the presence of tumor-promoting inflammation. Furthermore, reintroducing Ptf1a into established PanINs reverts them to quiescent acinar cells in vivo. Similarly, Ptf1a re-expression in human pancreatic cancer cells inhibits their growth and colony-forming ability. Our results suggest that reactivation of an endogenous differentiation program can prevent and reverse oncogene-driven transformation in cells harboring tumor-driving mutations, introducing a potential paradigm for solid tumor prevention and treatment.

The Social Impact of Musical Engagement for Young Adults With Learning Difficulties: A Qualitative Study.

There is evidence that music interventions can offer opportunities for creative, psychological, and social developments for individuals with mild to profound learning disabilities, addressing the disadvantages they face in respect of social outcomes. This paper reports on a qualitative study investigating a community music intervention for such a population. Thirty-seven adult service users (12 female, 25 male) took part in weekly music workshops for 10 weeks. Their learning difficulties ranged from mild to profound, and their levels of independence ranged from requiring constant one-to-one care to living alone in sheltered accommodation. Interviews were conducted at multiple time points with music and resource center staff as well as participants and members of their families and other center users; researchers also observed all workshops, taking field notes. Thematic analysis of the data informed understanding of the disadvantages facing participants, their experience of the workshop program and its immediate and wider social outcomes, as well as suggesting key mechanisms for effects. Disadvantages and barriers facing participants included: limited access to enjoying or learning music; boredom, isolation, and limited networks; lack of experience of new social contexts; and an associated lack of confidence, low mood or self-esteem. Participants were found to enjoy and sustain engagement with a program of dedicated group music workshops delivered by staff trained in an empathic and inclusive approach. Impacts included an ongoing enthusiasm to engage in music; wider recognition of musicality; increased self-confidence; being happier, more relaxed, and/or enthusiastic after the workshops; better ability to interact with unfamiliar situations and people; and participation in social activities for an unprecedented length of time. Key factors in achieving those impacts are that participants: had fun and interacted socially; felt secure, welcomed, and involved at all times; exercised choice; worked with others in nonverbal tasks; and encountered challenge while engaging and progressing at their own rate.

Exploring the Self through Songwriting: An Analysis of Songs Composed by People with Acquired Neurodisability in an Inpatient Rehabilitation Program.

BACKGROUND: Neurological trauma is associated with significant damage to people's pre-injury self-concept. Therapeutic songwriting has been linked with changes in self-concept and improved psychological well-being. OBJECTIVE: This study analyzed the lyrics of songs composed by inpatients with neurological injuries who participated in a targeted songwriting program. The aim of this study was to understand which of the subdomains of the self-concept were the most frequently expressed in songs. METHODS: An independent, deductive content analysis of 36 songs composed by 12 adults with spinal cord injury or brain injury (11 males, mean age 41 years +/- 13) were undertaken by authors 1 and 2. RESULTS: Deductive analysis indicated that when writing about the past self, people created songs that reflected a strong focus on family and descriptions of their personality. In contrast, there is a clear preoccupation with the physical self, on the personal self, and a tendency for spiritual and moral reflections to emerge during the active phase of rehabilitation (song about the present self). Statistical analyses confirmed a significant self-concept subdomain by song interaction, F(10, 110) = 5.98, p < .001, ηp2 = .35), which was primarily due to an increased focus on physical self-concept and a reduced focus on family self-concept in the present song, more than in either past or future songs. CONCLUSIONS: The analysis process confirmed that songwriting is a vehicle that allows for exploration of self-concept in individuals with neurological impairments. Songwriting may serve as a therapeutic tool to target the most prevalent areas of self-concept challenges for clients undergoing inpatient neurological rehabilitation programs.

Transcriptional Maintenance of Pancreatic Acinar Identity, Differentiation, and Homeostasis by PTF1A.

Maintenance of cell type identity is crucial for health, yet little is known of the regulation that sustains the long-term stability of differentiated phenotypes. To investigate the roles that key transcriptional regulators play in adult differentiated cells, we examined the effects of depletion of the developmental master regulator PTF1A on the specialized phenotype of the adult pancreatic acinar cell in vivo Transcriptome sequencing and chromatin immunoprecipitation sequencing results showed that PTF1A maintains the expression of genes for all cellular processes dedicated to the production of the secretory digestive enzymes, a highly attuned surveillance of unfolded proteins, and a heightened unfolded protein response (UPR). Control by PTF1A is direct on target genes and indirect through a ten-member transcription factor network. Depletion of PTF1A causes an imbalance that overwhelms the UPR, induces cellular injury, and provokes acinar metaplasia. Compromised cellular identity occurs by derepression of characteristic stomach genes, some of which are also associated with pancreatic ductal cells. The loss of acinar cell homeostasis, differentiation, and identity is directly relevant to the pathologies of pancreatitis and pancreatic adenocarcinoma.

MIST1 Links Secretion and Stress as both Target and Regulator of the Unfolded Protein Response.

Transcriptional networks that govern secretory cell specialization, including instructing cells to develop a unique cytoarchitecture, amass extensive protein synthesis machinery, and be embodied to respond to endoplasmic reticulum (ER) stress, remain largely uncharacterized. In this study, we discovered that the secretory cell transcription factor MIST1 (Bhlha15), previously shown to be essential for cytoskeletal organization and secretory activity, also functions as a potent ER stress-inducible transcriptional regulator. Genome-wide DNA binding studies, coupled with genetic mouse models, revealed MIST1 gene targets that function along the entire breadth of the protein synthesis, processing, transport, and exocytosis networks. Additionally, key MIST1 targets are essential for alleviating ER stress in these highly specialized cells. Indeed, MIST1 functions as a coregulator of the unfolded protein response (UPR) master transcription factor XBP1 for a portion of target genes that contain adjacent MIST1 and XBP1 binding sites. Interestingly, Mist1 gene expression is induced during ER stress by XBP1, but as ER stress subsides, MIST1 serves as a feedback inhibitor, directly binding the Xbp1 promoter and repressing Xbp1 transcript production. Together, our findings provide a new paradigm for XBP1-dependent UPR regulation and position MIST1 as a potential biotherapeutic for numerous human diseases.

MIST1 and PTF1 Collaborate in Feed-Forward Regulatory Loops That Maintain the Pancreatic Acinar Phenotype in Adult Mice.

Much remains unknown regarding the regulatory networks formed by transcription factors in mature, differentiated mammalian cells in vivo, despite many studies of individual DNA-binding transcription factors. We report a constellation of feed-forward loops formed by the pancreatic transcription factors MIST1 and PTF1 that govern the differentiated phenotype of the adult pancreatic acinar cell. PTF1 is an atypical basic helix-loop-helix transcription factor complex of pancreatic acinar cells and is critical to acinar cell fate specification and differentiation. MIST1, also a basic helix-loop-helix transcription factor, enhances the formation and maintenance of the specialized phenotype of professional secretory cells. The MIST1 and PTF1 collaboration controls a wide range of specialized cellular processes, including secretory protein synthesis and processing, exocytosis, and homeostasis of the endoplasmic reticulum. PTF1 drives Mist1 transcription, and MIST1 and PTF1 bind and drive the transcription of over 100 downstream acinar genes. PTF1 binds two canonical bipartite sites within a 0.7-kb transcriptional enhancer upstream of Mist1 that are essential for the activity of the enhancer in vivo MIST1 and PTF1 coregulate target genes synergistically or additively, depending on the target transcriptional enhancer. The frequent close binding proximity of PTF1 and MIST1 in pancreatic acinar cell chromatin implies extensive collaboration although the collaboration is not dependent on a stable physical interaction.

Isolated Pancreatic Aplasia Due to a Hypomorphic PTF1A Mutation.

Homozygous truncating mutations in the helix-loop-helix transcription factor PTF1A are a rare cause of pancreatic and cerebellar agenesis. The correlation of Ptf1a dosage with pancreatic phenotype in a mouse model suggested the possibility of finding hypomorphic PTF1A mutations in patients with pancreatic agenesis or neonatal diabetes but no cerebellar phenotype. Genome-wide single nucleotide polymorphism typing in two siblings with neonatal diabetes from a consanguineous pedigree revealed a large shared homozygous region (31 Mb) spanning PTF1A Sanger sequencing of PTF1A identified a novel missense mutation, p.P191T. Testing of 259 additional patients using a targeted next-generation sequencing assay for 23 neonatal diabetes genes detected one additional proband and an affected sibling with the same homozygous mutation. All four patients were diagnosed with diabetes at birth and were treated with insulin. Two of the four patients had exocrine pancreatic insufficiency requiring replacement therapy but none of the affected individuals had neurodevelopmental delay. Transient transfection assays of the mutant protein demonstrated a 75% reduction in transactivation activity. This study shows that the functional severity of a homozygous mutation impacts the severity of clinical features found in patients.

Reliability and Validity of the Meaningfulness of Songwriting Scale (MSS) with Adults on Acute Psychiatric and Detoxification Units.

BACKGROUND: Songwriting is an intervention with demonstrated clinical benefit for a range of clinical populations. Researchers argue that positive outcomes are in part the result of the meaningfulness of the creative process. However, no measure currently exists to quantify the extent of meaning derived from songwriting processes. OBJECTIVE: To psychometrically evaluate the Meaningfulness of Songwriting Scale (MSS) as a measure of meaning of a therapeutic songwriting process. METHOD: 147 participants receiving short-term mental health care (39 acute psychiatric care; 108 detoxification unit) were asked to complete the MSS and the Short State Flow Scale immediately following a songwriting music therapy session. Six hours later, participants completed the MSS a second time. Analyses were performed by participant cohort to determine the content validity, internal consistency, test-retest reliability, measurement error, and construct validity. RESULTS: Findings indicated that the MSS has good content validity, strong internal consistency (α = 0.98, acute psychiatric group, and α = 0.96, detoxification group), acceptable test-retest reliability (ICC2,1 = 0.93, acute psychiatric group, and ICC2,1 = 0.89, detoxification group), and construct validity (acute group was r = 0.68, p < 0.001, and detoxification group was r = 0.56, p < 0.001). Measurement error was greater in the detoxification group, suggesting that the measure may be unstable for this group. CONCLUSIONS: Preliminary evidence supports MSS use for research with inpatients on acute psychiatric units; however, cautious use is recommended for use with inpatients in detoxification units due to measurement error.

The acinar differentiation determinant PTF1A inhibits initiation of pancreatic ductal adenocarcinoma.

Understanding the initiation and progression of pancreatic ductal adenocarcinoma (PDAC) may provide therapeutic strategies for this deadly disease. Recently, we and others made the surprising finding that PDAC and its preinvasive precursors, pancreatic intraepithelial neoplasia (PanIN), arise via reprogramming of mature acinar cells. We therefore hypothesized that the master regulator of acinar differentiation, PTF1A, could play a central role in suppressing PDAC initiation. In this study, we demonstrate that PTF1A expression is lost in both mouse and human PanINs, and that this downregulation is functionally imperative in mice for acinar reprogramming by oncogenic KRAS. Loss of Ptf1a alone is sufficient to induce acinar-to-ductal metaplasia, potentiate inflammation, and induce a KRAS-permissive, PDAC-like gene expression profile. As a result, Ptf1a-deficient acinar cells are dramatically sensitized to KRAS transformation, and reduced Ptf1a greatly accelerates development of invasive PDAC. Together, these data indicate that cell differentiation regulators constitute a new tumor suppressive mechanism in the pancreas.

Dominant and context-specific control of endodermal organ allocation by Ptf1a.

The timing and gene regulatory logic of organ-fate commitment from within the posterior foregut of the mammalian endoderm is largely unexplored. Transient misexpression of a presumed pancreatic-commitment transcription factor, Ptf1a, in embryonic mouse endoderm (Ptf1a(EDD)) dramatically expanded the pancreatic gene regulatory network within the foregut. Ptf1a(EDD) temporarily suppressed Sox2 broadly over the anterior endoderm. Pancreas-proximal organ territories underwent full tissue conversion. Early-stage Ptf1a(EDD) rapidly expanded the endogenous endodermal Pdx1-positive domain and recruited other pancreas-fate-instructive genes, thereby spatially enlarging the potential for pancreatic multipotency. Early Ptf1a(EDD) converted essentially the entire glandular stomach, rostral duodenum and extrahepatic biliary system to pancreas, with formation of many endocrine cell clusters of the type found in normal islets of Langerhans. Sliding the Ptf1a(EDD) expression window through embryogenesis revealed differential temporal competencies for stomach-pancreas respecification. The response to later-stage Ptf1a(EDD) changed radically towards unipotent, acinar-restricted conversion. We provide strong evidence, beyond previous Ptf1a inactivation or misexpression experiments in frog embryos, for spatiotemporally context-dependent activity of Ptf1a as a potent gain-of-function trigger of pro-pancreatic commitment.

The nuclear hormone receptor family member NR5A2 controls aspects of multipotent progenitor cell formation and acinar differentiation during pancreatic organogenesis.

The orphan nuclear receptor NR5A2 is necessary for the stem-like properties of the epiblast of the pre-gastrulation embryo and for cellular and physiological homeostasis of endoderm-derived organs postnatally. Using conditional gene inactivation, we show that Nr5a2 also plays crucial regulatory roles during organogenesis. During the formation of the pancreas, Nr5a2 is necessary for the expansion of the nascent pancreatic epithelium, for the subsequent formation of the multipotent progenitor cell (MPC) population that gives rise to pre-acinar cells and bipotent cells with ductal and islet endocrine potential, and for the formation and differentiation of acinar cells. At birth, the NR5A2-deficient pancreas has defects in all three epithelial tissues: a partial loss of endocrine cells, a disrupted ductal tree and a >90% deficit of acini. The acinar defects are due to a combination of fewer MPCs, deficient allocation of those MPCs to pre-acinar fate, disruption of acinar morphogenesis and incomplete acinar cell differentiation. NR5A2 controls these developmental processes directly as well as through regulatory interactions with other pancreatic transcriptional regulators, including PTF1A, MYC, GATA4, FOXA2, RBPJL and MIST1 (BHLHA15). In particular, Nr5a2 and Ptf1a establish mutually reinforcing regulatory interactions and collaborate to control developmentally regulated pancreatic genes by binding to shared transcriptional regulatory regions. At the final stage of acinar cell development, the absence of NR5A2 affects the expression of Ptf1a and its acinar specific partner Rbpjl, so that the few acinar cells that form do not complete differentiation. Nr5a2 controls several temporally distinct stages of pancreatic development that involve regulatory mechanisms relevant to pancreatic oncogenesis and the maintenance of the exocrine phenotype.

Music, health, and well-being: a review.

The relationship between arts participation and health is currently very topical. Motivated by a desire to investigate innovative, non-invasive, and economically viable interventions that embrace contemporary definitions of health, practitioners and researchers across the world have been developing and researching arts inventions. One of the key drivers in this vigorous research milieu is the growth of qualitative research within health care contexts and researchers interested in exploring the potential benefits of musical participation have fully embraced the advances that have taken place in health-related qualitative research. The following article presents a number of different types of qualitative research projects focused on exploring the process and outcomes of music interventions. It also presents a new conceptual model for music, health and well-being. This new model develops on a previous version of MacDonald, Kreutz, and Mitchell (2012b) by incorporating new elements and contextualization and providing detailed experimental examples to support the various components.

The Parahox gene Pdx1 is required to maintain positional identity in the adult foregut.

The homeobox gene Pdx1 is a key regulator of pancreas and foregut development. Loss of Pdx1 expression results in pancreas agenesis and impaired development of the gastro-duodenal domain including Brunner’s glands. We previously demonstrated a key role for Pdx1 in maintaining the integrity and function of insulin-secreting beta cells in the adult pancreas. In the present study, we aimed to determine if expression of Pdx1 is required to maintain the cellular identity of the gastro-duodenal domain in adult mice. Immunohistological studies were performed in a mouse model in which expression of Pdx1 was conditionally repressed with the doxycycline-responsive tetracycline transactivator system. Mice in which Pdx1 was chronically repressed developed hamartomas in the gastro-duodenal domain. These lesions appeared to arise from ectopic foci of anteriorized cells, consistent with a localised anterior homeotic shift. They emerge with the intercalation of tissue between the anteriorized and normal domains and appear strikingly similar to lesions in the colon of mice heterozygous for another Parahox gene, Cdx2. Continuing expression of Pdx1 into adult life is required to maintain regional cellular identity in the adult foregut, specifically at the gastro-duodenal boundary. Loss of Pdx1 expression leads to anterior transformation and intercalary regeneration of ectopic tissue. We propose a model in which the posterior dominance of classical Hox genes is mirrored by the Parahox genes, providing further evidence of the functional conservation of the Parahox genes. These findings may have implications for further understanding the molecular basis of gastro-duodenal metaplasia and gastro-intestinal transformations such as Barrett’s esophagus.