CDX-1 and CDX-2 are expressed in human colonic mucosa and are down-regulated in patients with Hirschsprung's disease associated enterocolitis

Hirschsprung's disease associated enterocolitis: A comprehensive review

Hirschsprung's disease (HSCR) is a congenital disorder characterized by failure of the neural crest cells to migrate and populate the distal bowel during gestation affecting different lengths of intestine leading to a distal functional obstruction. Surgical treatment is needed to correct HSCR once the diagnosis is confirmed by demonstrating the absence of ganglion cells or aganglionosis of the affected bowel segment. Hirschsprung's disease associated enterocolitis (HAEC) is an inflammatory complication associated with HSCR that can present either in the pre- or postoperative period and associated with increased morbidity and mortality. The pathogenesis of HAEC remains poorly understood, but intestinal dysmotility, dysbiosis and impaired mucosal defense and intestinal barrier function appear to play a significant role. There is no clear definition for HAEC, but the diagnosis is primarily clinical, and treatment is guided based on severity. Here, we aim to provide a comprehensive review of the clinical presentation, etiology, pathophysiology, and current therapeutic options for HAEC.

Cancer of Unknown Primary: Challenges and Progress in Clinical Management

Distant metastases are the main cause of cancer-related deaths in patients with advanced tumors. A standard diagnostic workup usually contains the identification of the tissue-of-origin of metastatic tumors, although under certain circumstances, it remains elusive. This disease setting is defined as cancer of unknown primary (CUP). Accounting for approximately 3-5% of all cancer diagnoses, CUPs are characterized by an aggressive clinical behavior and represent a real therapeutic challenge. The lack of determination of a tissue of origin precludes CUP patients from specific evidence-based therapeutic options or access to clinical trial, which significantly impacts their life expectancy. In the era of precision medicine, it is essential to characterize CUP molecular features, including the expression profile of non-coding RNAs, to improve our understanding of CUP biology and identify novel therapeutic strategies. This review article sheds light on this enigmatic disease by summarizing the current knowledge on CUPs focusing on recent discoveries and emerging diagnostic strategies.

Associations of SLC6A20 genetic polymorphisms with Hirschsprung's disease in a Southern Chinese population

Hirschsprung's disease (HSCR) is a neurodevelopmental disorder characterized by the absence of nerves in intestine with strong genetic components. SLC6A20 was found to be associated with HSCR in Korean population waiting for replication in an independent cohort. In the present study, ten single nucleotide polymorphisms (SNPs) in the SLC6A20 were selected from Southern Chinese with 1470 HSCR cases and 1473 ethnically matched healthy controls. Our results indicated that SNP rs7640009 was associated with HSCR and SLC6A20 has a gene-dose effect in the extent of the aganglionic segment during enteric nervous system (ENS) development. It is the first time to reveal the relationship between SNP rs2191026 and HSCR-associated enterocolitis (HAEC) susceptibility.

Novel Insights into the Pathogenesis of Hirschsprung's-associated Enterocolitis

Objective:

To systematically summary the updated results about the pathogenesis of Hirschsprung's-associated enterocolitis (HAEC). Besides, we discussed the research key and direction based on these results.

Data Sources:

Our data cited in this review were obtained mainly from PubMed from 1975 to 2015, with keywords “Hirschsprung enterocolitis”, “Hirschsprung's enterocolitis”, “Hirschsprung's-associated enterocolitis”, “Hirschsprung-associated enterocolitis”, “HAEC”, and “EC”.

Study Selection:

Articles regarding the pathogenesis of HAEC were selected, and the articles mainly regarding the diagnosis, surgical approach, treatment, and follow-up were excluded.

Results:

Several factors, mainly including mucus barrier, intestinal microbiota, and immune function, as well as some other factors such as genetic variations and surgical reasons, have been found to be related to the pathogenesis of HAEC. Changed quantity and barrier property of mucus, different composition of microbiota, and an abnormal immune state work together or separately trigger HAEC.

Conclusions:

The maintenance of intestinal homeostasis is due to a well cooperation of microbiota, mucus barrier, and immune system. If any part presents abnormal, intestinal homeostasis will be broken. Meanwhile, for patients with Hirschsprung's disease or HAEC, dysfunction of these parts has been found. Thus, the happening of HAEC may be mainly attributed to the disorders of intestinal microbiota, mucus barrier, and immune system.

Practical Applications in Immunohistochemistry: Carcinomas of Unknown Primary Site

CONTEXT

-Identification of the site of origin of carcinoma of unknown primary using immunohistochemistry is a frequent requirement of anatomic pathologists. Diagnostic accuracy is crucial, particularly in the current era of targeted therapies and smaller sample sizes.

OBJECTIVES

-To provide practical guidance and suggestions for classifying carcinoma of unknown primary using both proven and new antibodies, as well as targeting panels based on integration of morphologic and clinical features.

DATA SOURCES

-Literature review, the authors' practice experience, and authors' research.

CONCLUSIONS

-With well-performed and interpreted immunohistochemistry panels, anatomic pathologists can successfully identify the site of origin of carcinoma of unknown primary. It is crucial to understand not only the diagnostic uses of the many available antibodies but also the potential limits and pitfalls.

Transanal rectal mucosectomy and partial internal anal sphincterectomy for Hirschsprung's disease

PURPOSE

Hirschsprung-associated enterocolitis (HAEC) is a serious complication of Hirschsprung's disease (HD), with generalized sepsis and high mortality rate. Although the surgical correction of HD is mostly successful, challenges remain in the management of children with repeated episodes of enterocolitis. The authors describe a novel modification of transanal rectal mucosectomy and partial internal anal sphincterectomy (TRM-PIAS) for HD.

METHODS

One hundred twenty-seven HD children aged from 8 days to 16 years who successfully underwent TRM-PIAS were reviewed. TRM-PIAS was carried out circumferentially along the anorectal line. Anterior dissection was conducted between the rectal submuscosal layer and the rectal muscular sleeve. The posterior dissection was performed along the plane between internal and external anal sphincters. Normal colon was pulled through and anastomosed to anal mucosa. Aganglionic segment, rectal mucosa, part of internal anal sphincter and posterior rectal muscular cuff were removed. Twenty-five age-matched children without defecation dysfunction were used as the control group in the study of anal resting pressure.

RESULTS

Patients were followed up for 6-12 years (median: 8.2 years). The median age at last follow-up was 12.2 years (7.2-20.1 years). The incidence of enterocolitis decreased from 33.9% (43/127) preoperatively to 1.6% (2/127) postoperatively (P<0.01). The incidence of constipation decreased from 100% (127/127) preoperatively to 2.4% (3/127) postoperatively (P<0.01). Soiling rate on postoperative 1 month was 32.3%. It gradually decreased to 1.6% 6 months later. Anorectal manometries showed that mean anal resting pressure was significantly reduced from 37.9±12.5 mm Hg preoperatively to 20.2±6.4 mm Hg on postoperative 1 month and 24.8±9.9 mm Hg on postoperative 6 months, which were similar to age-matched normal controls (27.9±9.6 mm Hg, P>0.05).

CONCLUSIONS

TRM-PIAS is effective in treatment of HD. It is associated with low postoperative HD-associated enterocolitis.

Hirschsprung-associated enterocolitis: pathogenesis, treatment and prevention

Hirschsprung-associated enterocolitis (HAEC) is a common and sometimes life-threatening complication of Hirschsprung disease (HD). Presenting either before or after definitive surgery for HD, HAEC may manifest clinically as abdominal distension and explosive diarrhea, along with emesis, fever, lethargy, and even shock. The pathogenesis of HAEC, the subject of ongoing research, likely involves a complex interplay between a dysfunctional enteric nervous system, abnormal mucin production, insufficient immunoglobulin secretion, and unbalanced intestinal microflora. Early recognition of HAEC and preventative practices, such as rectal washouts following a pull-through, can lead to improved outcomes. Treatment strategies for acute HAEC include timely resuscitation, colonic decompression, and antibiotics. Recurrent or persistent HAEC requires evaluation for mechanical obstruction or residual aganglionosis, and may require surgical treatment with posterior myotomy/myectomy or redo pull-through. This chapter describes the incidence, pathogenesis, treatment, and preventative strategies in management of HAEC.

The pathogenesis of Hirschsprung's disease-associated enterocolitis

Hirschsprung's disease-associated enterocolitis (HAEC) remains the most life-threatening complication in Hirschsprung disease (HD) patients. The pathogenesis of HAEC has not been determined and many hypotheses regarding the etiology of HAEC have been proposed. These include a possible causal relationship between the abnormal enteric nervous system development in HD and the development of enterocolitis. Based on the complex genetic causes of HD that have been discovered and the resultant heterogeneous group of patients that exists, the causes of HAEC are likely multiple. New insights regarding the relationship of the role of the enteric nervous system and its interaction between intestinal barrier function, innate host immunity, and commensal microflora have been discovered, which may shed light on this perplexing problem. This review presents current known risk factors of HAEC and the proposed theories and supporting evidence for the potential etiologies of HAEC.

Ephrin-A1 inhibits NSCLC tumor growth via induction of Cdx-2 a tumor suppressor gene

Background

Tumor formation is a complex process which involves constitutive activation of oncogenes and suppression of tumor suppressor genes. Receptor EphA2 and its ligand ephrin-A1 form an important cell communication system with its functional role in cell-cell interaction and tumor growth. Loss of cell-cell adhesion is central to the cellular transformation and acquisition of metastatic potential. Claudins, the integrated tight junction (TJ) cell-cell adhesion proteins located on the apico-lateral portion of epithelial cells, functions in maintaining cell polarity. There is extensive evidence implicating Eph receptors and ephrins in malignancy, but the mechanisms how these molecular players affect TJ proteins and regulate tumor growth are not clear. In the present study we hypothesized that EphA2 signaling modulates claudin-2 gene expression via induction of cdx-2, a tumor suppressor gene in NSCLC cells.

Methods

The expression of EphA2, claudin-2 was determined in various NSCLC cell lines by using real-time quantitative polymerase chain reaction and Western blot analysis. The claudin-2 expression was also analyzed by immunofluorescence analysis. EphA2 and erk1/erk2 phosphorylation in ephrin-A1 activated cells was evaluated by Western blot analysis. The cell proliferation and tumor colony formation were determined by WST-1 and 3-D matrigel assays respectively.

Results

NSCLC cells over expressed receptor EphA2 and claudin-2. Ephrin-A1 treatment significantly down regulated the claudin-2 and EphA2 expression in NSCLC cells. The transient transfection of cells with vector containing ephrin-A1 construct (pcDNA-EFNA1) decreased the expression of claudin-2, EphA2 when compared to empty vector. In addition ephrin-A1 activation increased cdx-2 expression in A549 cells. In contrast over-expression of EphA2 with plasmid pcDNA-EphA2 up regulated claudin-2 mRNA expression and decreased cdx-2 expression. The transient transfection of cells with vector containing cdx-2 construct (pcMV-cdx-2) decreased the expression of claudin-2 in A549 cells. Moreover, silencing the expression of receptor EphA2 by siRNA significantly reduced claudin-2 expression and decreased cell proliferation and tumor formation. Furthermore, silencing cdx-2 gene expression before ephrin-A1 treatment increased claudin-2 expression along with increased cell proliferation and tumor growth in A549 cells.

Conclusions

Our study suggests that EphA2 signaling up-regulates the expression of the TJ-protein claudin-2 that plays an important role in promoting cell proliferation and tumor growth in NSCLC cells. We conclude that receptor EphA2 activation by ephrin-A1 induces tumor suppressor gene cdx-2 expression which attenuates cell proliferation, tumor growth and thus may be a promising therapeutic target against NSCLC.

What is the most common complication after one-stage transanal pull-through in infants with Hirschsprung's disease?

BACKGROUND

Hirschsprung's disease (HD) is a relatively common congenital disease that could be suspected by clinical symptoms, abdominal plain X-ray, and finally diagnosed by rectal biopsy. In 80% cases, rectosigmoid junction is involved. Recently, one-stage transanal pull-through (TAPT) procedure has been popular and may have several complications.

METHODS AND PATIENTS

During a 4-year period, 86 infants (28 girls, 58 boys) with mean age 8 days (3-33) and clinically suspected to HD were admitted in our center. HD was proved by rectal biopsy. All patients after full bowel preparation and rectal washout were candidates for TAPT operation. A Swenson-like procedure was performed and the anastomosis was done between the well blood supply ganglionic colon and the rectum at 1 cm above dentate line. Interrupted suture with 5-0 Vicryl was used. Nelaton tube (12 F) inserted in the pelvis via transprineal for drainage of blood or collection. From February 2008 in 30 cases, prophylactic Hegar dilatation was performed 2 weeks after operation.

RESULTS

Anal stricture in 12 cases (14%) was treated by anal dilation in 10 cases and 2 cases corrected by surgical management. Entrocolitis in 4 cases (5%) was treated by medical management. In two cases, retrocolic abscess had spontaneous drainage via tube drain. There was no anastomotic stricture after starting prophylactic anal bouginage.

CONCLUSION

TAPT has many advantages, low complications and the results are excellent. It seems the most common complication is anastomotic stricture that responds well to prophylactic bouginage. We recommend prophylactic anal bouginage with Hegar probe at 2 weeks after operation. Long-term follow-up is needed to evaluate the outcomes of our operations.

Patterns of postoperative enterocolitis in children with Hirschsprung's disease combined with hypoganglionosis

OBJECTIVE

The relationship between postoperative enterocolitis (EC) and Hirschsprung's disease (HD) combined with hypoganglionosis (HYP) has not been thoroughly reported elsewhere. The aim of this study was to investigate the incidence of EC after operation in children with HD combined with HYP and to identify new strategies to prevent postoperative EC.

METHODS

From 1998 to 2005, 97 children with HD underwent the modified Swenson's procedure in this institute. They were classified into 2 groups based on pathologic investigation as follows: group A contained 70 patients with HD and group B contained 27 patients with HD complicated with HYP. The mean follow-up time from the time of the operation was 3.4 years (range, 1.5-8 years). The incidence of postoperative EC and anorectal functions were evaluated and compared between these 2 groups.

RESULTS

Eight cases (11.4%) in group A developed postoperative EC, whereas 11 (40.7%) in group B did so. The incidence of postoperative EC in group A was significantly lower than that in group B (P < .005). According to the Rintala scoring system, the percentage of patients with an excellent score in group A (85.7%) was significantly higher than that in group B (P < .05). The recurrence rate of constipation in group B was 14.8% (4/27), whereas it was 2.8% (2/70) in group A.

CONCLUSIONS

Postoperative EC is associated with retained proximal HYP, which suggests that HYP could be, at minimum, a predictive marker for this complication. Complete resection of HYP segment could potentially minimize the incidence of postoperative EC and alleviate the severity of EC.

An approach to minimize postoperative enterocolitis in Hirschsprung's disease

BACKGROUND/PURPOSE

Enterocolitis (EC) is a common and severe complication after pull-through for Hirschsprung's disease; its pathogenesis remains unclear, but the role of coexistent intestinal neuronal dysplasia (IND) in the proximal colon may be relevant. This study evaluated the relationship between postoperative EC and IND and assessed whether a surgical protocol including resection of coexistent IND could prevent postoperative EC.

METHODS

Between June 1993 and June 2002, 36 patients with aganglionosis were submitted to definitive surgical treatment. There were 2 sequential sets of patients: group I (n = 17), in whom the resection was confined to the aganglionic colon, and group II (n = 19), who were additionally submitted to resection of the coexistent IND segment; excision was restricted to the hepatic flexure in long segmental IND. The prevalence of postoperative EC and anorectal function were evaluated and compared between the 2 groups.

RESULTS

There was no mortality. Fifteen patients had isolated aganglionosis, and 21 presented with aganglionosis plus proximal IND. All 6 children who developed postoperative EC had coexistent IND. In group I, 9 patients had coexistent IND and 5 developed postoperative EC (5/17, 29%). In group II, 12 patients had coexistent IND but only 1 patient, with long segmental IND, developed postoperative EC (1/19, 5%). Among the patients with proximal IND, the prevalence of postoperative EC was 29%; but it was significantly lower in group II than in group I (1/12 or 8% vs 5/9 or 56%; P = .02). Anorectal function was excellent or good in more than 80% of the patients in both groups.

CONCLUSIONS

Postoperative EC was associated with retained proximal IND, suggesting that coexisting IND may be, at least, a predictive marker for this complication. Histochemical characterization of the proximal colon with no radical resection of the IND segment seems to be an effective and safe approach to minimize the prevalence of postoperative EC.

TTF-1 and RET promoter SNPs: regulation of RET transcription in Hirschsprung's disease

Single nucleotide polymorphisms (SNPs) of the coding regions of receptor tyrosine kinase gene (RET) are associated with Hirschsprung's disease (HSCR, aganglionic megacolon). These SNPs, individually or combined, may act as a low penetrance susceptibility locus and/or be in linkage disequilibrium (LD) with another susceptibility locus located in RET regulatory regions. Because two RET promoter SNPs have been found associated with HSCR, in LD with HSCR-associated RET coding region haplotypes, their implication in the transcriptional regulation of RET is of major interest. Analysis of 172 sporadic HSCR patients also revealed the presence of HSCR-associated RET promoter SNPs in LD with the main coding region RET haplotype observed in Chinese patients. By using a weighted logistic regression approach, we determined that of all SNPs tested in our study, the promoter SNPs are the most correlated to the disease. Functional analysis of the RET promoter SNPs in the context of additional 5' regulatory regions demonstrated that the HSCR-associated alleles decrease RET transcription. These SNPs overlap a TTF-1 binding site and TTF-1-activated RET transcription is also decreased by the HSCR-associated SNPs. Moreover, we identified an HSCR patient with a Gly322Ser TTF-1 mutation that compromises activation of transcription from HSCR-associated RET promoter haplotypes. Interestingly, we show that the pattern of RET and TTF-1 expression is coincident in developing human gut. We also present a detailed profile of the RET gene in our population, which provides an insight into the higher incidence of the disease in China.

Enterocolitis complicating Hirschsprung's disease

Enterocolitis remains a relatively common complication of Hirschsprung's disease with significant morbidity and mortality. The etiology of Hirschsprung's enterocolitis (HEC) is multifactorial and remains poorly understood. Preventative measures and better treatment modalities will evolve out of a better understanding of the underlying pathophysiology. Prompt recognition of HEC allows early intervention and a potential reduction in disease severity and mortality. This review of HEC describes the epidemiology, clinical and pathological features and current best practice in management. Some of the areas of research into etiology and treatment are discussed.

CDX-2 Homeobox Gene Product Expression in Neuroendocrine Tumors

CDX-2 is a homeobox gene product essential for intestinal development and differentiation. It can be used as a specific marker of colorectal adenocarcinomas and other tumors with intestinal differentiation, but little is known about its expression in endocrine and neuroendocrine (NE) cells and NE primary and metastatic tumors. Using the Cdx-2-88 monoclonal antibody, we evaluated CDX-2 expression in routine samples of 20 normal endocrine/NE tissues and of 299 samples of well-differentiated NE tumors (WDNET) and high-grade NE carcinomas (NEC) from different sites. For 17 cases, we examined primary and corresponding metastatic lesions. We also examined 8 cytologic samples of liver metastases derived from 4 ileal WDNETs, 1 lung WDNET, and 3 pancreatic endocrine tumors. CDX-2 mRNA expression with RT-PCR technique on frozen material was evaluated in 5 WDNETs. CDX-2 was expressed in normal NE cells of the intestine and gastric fundus. High CDX-2 expression was seen in all ileal and appendiceal WDNET, while low levels were seen in WDNETs from stomach, duodenum, and rectum; no reactivity was seen in other WDNETs. Low levels of CDX-2 expression were seen in one third of nonfunctioning pancreatic WDNET where it was more frequently observed in cases with metastatic disease (P = 0.002). CDX-2 was identified in all cytologic specimens of metastatic ileal WDNETs. CDX-2 mRNA analysis confirmed immunohistochemical results. CDX-2 was expressed at high levels in 81% of intestinal NEC. Unexpectedly, variable levels of expression of CDX-2 were seen also in 39% of NEC of other sites, without any relation with the site of origin. This reactivity frequently overlapped TTF-1 expression, suggesting deregulated expression of homeobox genes in NEC. The restricted pattern of CDX-2 expression may have diagnostic value in the identification of the primary site of a metastatic WDNET. Conversely, a limited diagnostic role is suggested for CDX-2 in NEC because of its frequent expression in nongastrointestinal tumors.

HOXB5 expression is spatially and temporarily regulated in human embryonic gut during neural crest cell colonization and differentiation of enteric neuroblasts

HOX genes from paralogous groups 4 and 5 are particularly relevant to the gut neuromusculature development because these genes are expressed at the splanchnic mesoderm surrounding the gut diverticulum, and at the level of the neural tube from where the vagal neural crest cells (NCCs) originate. In this study, we examined the migration and differentiation of NCCs, and investigated the expression patterns of HOXB5 in human embryonic guts. Human embryos of gestational week-4 to -8.5 were studied. Vagal NCCs enter the esophagus, migrate, and colonize the entire gut in a rostrocaudal manner between week-4 and week-7. The migrating NCCs in gut express HOXB5. Two separate and discontinuous mesenchymal expression domains of HOXB5 were detected in the gut: the distal domain preceding the migratory NCCs; and the proximal domain overlapping with the NCCs. The two expression domains shift caudally in parallel with the rostrocaudal migration of NCCs between week-4 and week-5. Neuron and glia differentiation of NCCs are concomitant with HOXB5 down-regulation in NCCs and the mesenchyme. By week-7, myenteric plexuses have formed; HOXB5 expression is switched on in the plexuses. We found that (1) the migratory route of NCCs in human embryonic gut was similar to that in mice and chicks; and (2) the expression pattern of HOXB5 correlated with the migration and differentiation of NCCs, suggesting a regulatory role of HOXB5 in the development of NCCs.

Hirschsprung's Disease

Hirschsprung's disease (HSCR) is the most common congenital malformation of the enteric nervous system and requires early diagnosis and surgical repair for the best comprehensive outcome. The early diagnosis of this disorder permits the use of primary endorectal pull-through (PERPT), which is now the definitive surgical therapy for HSCR. PERPT has become the preferred method of treatment for HSCR, and large numbers of successfully treated patients have been described in the recent medical literature. The rate of postoperative complications is generally similar to that following a two-stage surgical repair, but PERPT patients may be at a slightly higher risk for Hirschsprung's-associated enterocolitis. Despite recent surgical advances in the treatment of HSCR, a two-stage surgical repair involving a temporary diverting colostomy may still be necessary in up to one third of patients. Candidates for a staged repair include those HSCR patients with long-segment or total colonic disease or when there has been a delay in diagnosis that results in a markedly dilated proximal colon or patient clinical instability. Internal anal sphincter hypertonicity, occurring either as isolated primary anal achalasia or as a postoperative complication, can be successfully managed by either botulinum toxin injections or anal myectomy. The measurement of colonic motility in surgically repaired patients with a long-standing postoperative abnormality of bowel function can identify several distinct motility disorders that are amenable to separate and individualized therapies. The single most important element in the management of HSCR remains the clinical judgement of the surgeon of record, who utilizes all discernible clinical data to elect the manner of surgical repair in a given patient.

CDX-2 homeobox gene expression is a reliable marker of colorectal adenocarcinoma metastases to the lungs

Lung metastases from colorectal carcinomas (CRC) can be resected with improved survival. The distinction between primary lung adenocarcinomas and metastases from CRC may sometimes be difficult, especially on cytologic specimens or small bronchoscopic biopsies. Immunohistochemistry may be of help in this setting: available markers include TTF-1 and SP-A, which are markers of lung origin, whereas there are no good markers of intestinal origin, besides cytokeratin 7 and 20 coexpression pattern, which is not very specific. The nuclear CDX-2 transcription factor, which is the product of a homeobox gene necessary for intestinal organogenesis, is expressed in normal colonic epithelia and most colorectal adenocarcinomas, and could potentially be of diagnostic usefulness. Our aim was to investigate CDX-2 immunohistochemical expression using a new monoclonal antibody and to verify if CDX-2 can be a reliable marker to identify the colorectal origin of lung metastases. CDX-2 expression was evaluated in formalin-fixed, paraffin-embedded samples of normal adult human tissues (50 samples) and in 299 surgically resected carcinomas of different origins, including 125 non-lung adenocarcinomas, 117 primary lung tumors, 5 mesotheliomas, and 52 adenocarcinomas metastatic to the lung. CDX-2 was also evaluated on a series of 20 bioptic and 10 cytologic specimens (5 cases of colorectal metastases to the lung, 5 cases of metastases from other organs, and 10 primary lung adenocarcinomas). In normal tissues CDX-2 immunoreactivity was observed only in ileal and colorectal epithelia. CDX-2 was expressed in almost all primary and metastatic CRC (88 of 90) and was never observed in primary lung tumors. CDX-2 was also expressed in a limited group of adenocarcinomas of other sites (gastric, biliopancreatic, and mucinous ovarian adenocarcinomas). CDX-2 could be easily detected in all bioptic and cytologic samples of CRC metastases. CDX-2 is a reliable, specific, and sensitive immunohistochemical marker of normal and neoplastic intestinal epithelium. CDX-2 can be easily applied to routine histologic and cytologic material and is therefore a useful marker in the differential diagnosis of primary versus metastatic adenocarcinomas in the lung, and among metastases from an unknown primary, supports intestinal origin.

Glial cell line-derived neurotrophic factor family receptors are abnormally expressed in aganglionic bowel of a subpopulation of patients with Hirschsprung's disease

Hirschsprung's disease (HSCR), a congenital disease, is characterized by the absence of ganglion cells in the ganglion plexuses of the caudal most gut. In the aganglionic colon, the plexus remnants are replaced by aggregates of glial cells and hypertrophied nerve fibers. Signaling of glial cell line-derived neurotrophic factor (GDNF)-GFRAs-receptor tyrosine kinase (RET) is crucial for the development and maintenance of ganglion cells. Mutations of genes such as GDNF and RET lead to the perturbation of this signaling pathway, which causes HSCR. To understand the role of GFRAs in ganglion cells and the pathogenesis of HSCR, we intended to determine the specific cell lineages in the enteric nervous system that normally express GFRAs but are affected in HSCR. We studied colon biopsy specimens from 13 patients with HSCR (aged 1 day to 38 months) and 6 age-matched patients without HSCR as normal controls. RT-PCR, in situ hybridization, and immunohistochemistry were performed to examine the expression and cellular distributions of GFRAs in resected bowel segments of normal infants and those with HSCR. In normal infants and normoganglionic colon of patients with HSCR, the expression of GFRA1 was restricted to the glial cells and neurones of the ganglion plexuses. GFRAs expression was found to be markedly reduced in the aganglionic colons of 3 infants with HSCR but was unaffected in the aganglionic colons of 10 other infants with HSCR. Residual GFRA expression was restricted to enteric glial cells in the plexus remnants of the aganglionic colons. Hypertrophied nerve fibers were not found to express GFRA1. We provide the first evidence that abnormal expression of GFRAs in the enteric nervous system may be involved in the pathogenesis of HSCR in a subpopulation of patients.