p63 Coordinates anogenital modeling and epithelial cell differentiation in the developing female urogenital tract

High incidence of imperforate vagina in ADGRA3-deficient mice

BACKGROUND

Ten percent of the female population suffers from congenital abnormalities of the vagina, uterus, or oviducts, with severe consequences for reproductive and psychological health. Yet, the underlying causes of most of these malformations remain largely unknown. ADGRA3 (GPR125) is involved in WNT signaling and planar cell polarity, mechanisms vital to female reproductive tract development. Although ADGRA3 is a well-established spermatogonial stem cell marker, its role within the female urogenital system remains unclear.

RESULTS

In this study, we found Adgra3 to be expressed throughout the murine female urogenital system, with higher expression pre-puberty than after sexual maturation. We generated a global Adgra3-/- mouse line and observed imperforate vagina in 44% of Adgra3-/- females, resulting in distension of the reproductive tract and infertility. Ovarian morphology, plasma estradiol, ovarian Cyp19a1, and vaginal estrogen receptor α (Esr1) expression were unaffected. However, compared to controls, a significantly lower bone mineral density was found in Adgra3-/- mice. Whereas vaginal opening in mice is an estrogen-dependent process, 17β-estradiol treatment failed to induce vaginal canalization in Adgra3-/- mice. Furthermore, a marked reduction in vaginal and ovarian progesterone receptor expression was observed concomitant with an upregulation of apoptotic regulators Bcl2, Bid, and Bmf in adult Adgra3-/- females with a closed vagina.

CONCLUSIONS

Our collective results shed new insights into the complex mechanisms by which the adhesion receptor ADGRA3 regulates distal vaginal tissue remodeling during vaginal canalization via altered sex hormone responsiveness and balance in apoptotic regulators. This highlights the potential of ADGRA3 as a target in diagnostic screening and/or therapy for obstructive vaginal malformations in humans.

Human Pluripotent Stem Cell Derived Organoids Reveal a Role for WNT Signaling in Dorsal-Ventral Patterning of the Hindgut

The cloaca is a transient structure that forms in the terminal hindgut giving rise to the rectum dorsally and the urogenital sinus ventrally. Similarly, human hindgut cultures derived from human pluripotent stem cells generate human colonic organoids (HCOs) which also contain co-developing urothelial tissue. In this study, our goal was to identify pathways involved in cloacal patterning and apply this to human hindgut cultures. RNA-seq data comparing dorsal versus ventral cloaca in e10.5 mice revealed that WNT signaling was elevated in the ventral versus dorsal cloaca. Inhibition of WNT signaling in hindgut cultures biased their differentiation towards a colorectal fate. WNT activation biased differentiation towards a urothelial fate, giving rise to human urothelial organoids (HUOs). HUOs contained cell types present in human urothelial tissue. Based on our results, we propose a mechanism whereby WNT signaling patterns the ventral cloaca, prior to cloacal septation, to give rise to the urogenital sinus.

The role of p63 in embryonic external genitalia outgrowth in mice

Embryonic external genitalia (genital tubercle [GT]) protrude from the cloaca and outgrow as cloacal development progresses. Individual gene functions and knockout phenotypes in GT development have been extensively analyzed; however, the interactions between these genes are not fully understood. In this study, we investigated the role of p63, focusing on its interaction with the Shh-Wnt/Ctnnb1-Fgf8 pathway, a signaling network that is known to play a role in GT outgrowth. p63 was expressed in the epithelial tissues of the GT at E11.5, and the distal tip of the GT predominantly expressed the ΔNp63α isoform. The GTs in p63 knockout embryos had normal Shh expression, but CTNNB1 protein and Fgf8 gene expression in the distal urethral epithelium was decreased or lost. Constitutive expression of CTNNB1 in p63-null embryos restored Fgf8 expression, accompanied by small bud structure development; however, such bud structures could not be maintained by E13.5, at which point mutant GTs exhibited severe abnormalities showing a split shape with a hemorrhagic cloaca. Therefore, p63 is a key component of the signaling pathway that triggers Fgf8 expression in the distal urethral epithelium and contributes to GT outgrowth by ensuring the structural integrity of the cloacal epithelia. Altogether, we propose that p63 plays an essential role in the signaling network for the development of external genitalia.

Embryology and anatomy of anorectal malformations

The etiology of anorectal malformations (ARM) is complicated because of the spectrum of anomalies seen clinically, many of which are isolated and seemingly unique. Recent studies suggest that ARMs result from abnormal cloacal membrane (CM) development that contributes to disrupt normal local muscle and nerve development. If CM maldevelopment is severe, the rectal pouch lies above the pelvic floor, resulting in asymmetric and/or deviated musculature, so a midline incision is likely to cause trauma or be detrimental. Autonomic nerve plexuses can be associated with a fistula tract in ARMs and are also at risk for damage during surgery and contribute to genitourinary complications. Understanding the anatomy and development of the perineum is crucial for treating the broad spectrum of anomalies associated with ARMs and may assist in predicting/managing other related morbidity.

miR-203a-3p, ABL1 and TP63 gene expression is altered in the endometrium of women with endometriosis

OBJECTIVE

Many genes and miRNAs have been shown to be associated with the pathogenesis of endometriosis. TP63 (p63) is implicated in lineage specification, proliferative potential, differentiation, cell death and survival. The ABL1 proto-oncogene encodes a cytoplasmic and nuclear protein tyrosine kinase implicated in cell differentiation, cell division, and cell adhesion. Moreover, hsa-miR-203a-3p was reported to play pivotal roles in tumor progression by targeting multiple genes, including ABL1 and TP63. The aim of this study was to investigate the expression of ABL1, TP63, and miR-203a-3p in endometriosis.

METHODS

This study included 30 women with endometriosis (stage III: n = 12 and stage IV: n = 18) and 30 age-matched controls. Total RNA extraction and cDNA synthesis were performed, and a quantitative polymerase chain reaction technique was used to determine the expression of miR-203a-3p, TP63, and ABL1.

RESULTS

TP63 and ABL1 were significantly overexpressed in stages III and IV endometriosis as compared to controls (p < .0001). Moreover, overexpression of ABL1 and TP63 was observed in stage IV compared to stage III (p = .0006 and p = .0002, respectively). Furthermore, significant increase miR-203a-3p expression has been seen in stage IV endometriosis compared to controls (p = .006). The expression of miR-203a-3p in stage III was not significant compared to stage IV and control (p = .33 and p = .43, respectively).

CONCLUSION

It is concluded that miR-203a-3p, ABL1 and TP63 gene expression is altered in the endometrium of patients with endometriosis. It is also suggested that miR-203a-3p, ABL1, and TP63 might be candidate factors for the pathogenesis of endometriosis and suggesting its therapeutic potential in endometriosis.

Construction of Copy Number Variation Map Identifies Small Regions of Overlap and Candidate Genes for Atypical Female Genitalia Development

Copy number variations (CNVs) have been implicated in various conditions of differences of sexual development (DSD). Generally, larger genomic aberrations are more often considered disease-causing or clinically relevant, but over time, smaller CNVs have been associated with various forms of DSD. The main objective of this study is to identify small CNVs and the smallest regions of overlap (SROs) in patients with atypical female genitalia (AFG) and build a CNV map of AFG. We queried the DECIPHER database for recurrent duplications and/or deletions detected across the genome of AFG individuals. From these data, we constructed a chromosome map consisting of SROs and investigated such regions for genes that may be associated with the development of atypical female genitalia. Our study identified 180 unique SROs (7.95 kb to 45.34 Mb) distributed among 22 chromosomes. The most SROs were found in chromosomes X, 17, 11, and 22. None were found in chromosome 3. From these SROs, we identified 22 genes as potential candidates. Although none of these genes are currently associated with AFG, a literature review indicated that almost half were potentially involved in the development and/or function of the reproductive system, and only one gene was associated with a disorder that reported an individual patient with ambiguous genitalia. Our data regarding novel SROs requires further functional investigation to determine the role of the identified candidate genes in the development of atypical female genitalia, and this paper should serve as a catalyst for downstream molecular studies that may eventually affect the genetic counseling, diagnosis, and management of these DSD patients.

ΔNp63α promotes Epstein-Barr virus latency in undifferentiated epithelial cells

Epstein-Barr virus (EBV) is a human herpesvirus that causes infectious mononucleosis and contributes to both B-cell and epithelial-cell malignancies. EBV-infected epithelial cell tumors, including nasopharyngeal carcinoma (NPC), are largely composed of latently infected cells, but the mechanism(s) maintaining viral latency are poorly understood. Expression of the EBV BZLF1 (Z) and BRLF1 (R) encoded immediate-early (IE) proteins induces lytic infection, and these IE proteins activate each other's promoters. ΔNp63α (a p53 family member) is required for proliferation and survival of basal epithelial cells and is over-expressed in NPC tumors. Here we show that ΔNp63α promotes EBV latency by inhibiting activation of the BZLF1 IE promoter (Zp). Furthermore, we find that another p63 gene splice variant, TAp63α, which is expressed in some Burkitt and diffuse large B cell lymphomas, also represses EBV lytic reactivation. We demonstrate that ΔNp63α inhibits the Z promoter indirectly by preventing the ability of other transcription factors, including the viral IE R protein and the cellular KLF4 protein, to activate Zp. Mechanistically, we show that ΔNp63α promotes viral latency in undifferentiated epithelial cells both by enhancing expression of a known Zp repressor protein, c-myc, and by decreasing cellular p38 kinase activity. Furthermore, we find that the ability of cis-platinum chemotherapy to degrade ΔNp63α contributes to the lytic-inducing effect of this agent in EBV-infected epithelial cells. Together these findings demonstrate that the loss of ΔNp63α expression, in conjunction with enhanced expression of differentiation-dependent transcription factors such as BLIMP1 and KLF4, induces lytic EBV reactivation during normal epithelial cell differentiation. Conversely, expression of ΔNp63α in undifferentiated nasopharyngeal carcinoma cells and TAp63α in Burkitt lymphoma promotes EBV latency in these malignancies.

Transitional cell metaplasia of the uterine cervix: A histopathological and immunohistochemical analysis suggesting a possible role of androgenic conversion during urothelial-like differentiation in peri/postmenopausal women

Transitional cell metaplasia (TCM) of the uterine cervix and vagina is typically seen in patients with adrenogenital syndrome with high serum androgen levels and in those under androgen treatment as well as in some peri/postmenopausal women. Considering that TCM occurs in patients with increased serum androgen levels, a microenvironment with altered sex hormones might be involved in the urothelial-like differentiation observed in TCM. To investigate a histogenetic role of androgen in TCM development, we compared the distribution patterns and intensity of androgen receptor (AR), estrogen receptor (ER), GATA3 (a transcription factor involved in androgen regulation), Ki-67, and AKR1C3 (an enzyme involved in androgen biosynthesis) expression in normal exocervical mucosa in young women (n = 25), senile atrophy (n = 23), and TCM (n = 29). In TCM, AR, ER, AKR1C3, and GATA3, expression was stronger and significantly increased upward into the intermediate and superficial layers compared with the senile atrophic mucosa and normal mucosa in young women. The epithelial layer in TCM is thicker than that in senile atrophic mucosa, although both conditions may occur in the same age group. Proliferation in TCM was significantly lower than that in young women but slightly higher than that in senile atrophy. Considering the conversion activity of AKR1C3, thicker epithelial layers in TCM compared with those in senile atrophy might be due to increased conversion of androstenedione to testosterone via increased AKR1C3 activity, increased conversion of testosterone to 17β-estradiol by aromatization, and AR activation.

CircAMD1 regulates proliferation and collagen synthesis via sponging miR-27a-3p in P63-mutant human dermal fibroblasts

Transcription factor p63 has critical functions in epidermal, hindgut/anorectal, and limb development. Human mutations in P63 correlate with congenital syndromes affecting the skin, anorectal, and limbs. Nevertheless, less are detected regarding networks and functions controlled by P63 mutations in dermal fibroblasts, which are closely related to skin physiology. To screen for new targets, we employed microarray technology to investigate the R226Q P63 mutation with regards to the resulting circular RNA (circRNA) profiles from P63 point mutations in human dermal fibroblasts (HDFs). In this study, we show that P63-mutant HDFs display reduced proliferation, collagen synthesis, and myofibroblast differentiation; circAMD1 was also downregulated in P63-mutant HDFs compared with wild-type HDFs. Furthermore, overexpressing circAMD1 rescued the functional and phenotypic alterations of p63-mutant HDFs. We as well determined that miR-27a-3p was circAMD1 target involved in effects of circAMD1 in P63-mutant HDFs. Collectively, our data show that circAMD1 functions as a miR-27a-3p sponge that inhibits the functional and phenotypical alteration of P63-mutant HDFs and may be a critical marker in pathogenesis regarding P63-associated traits.

The development of the human vaginal fornix and the portio cervicis

Introduction

One of the transitional zones of the human body is situated in the cervix uteri. The developmental differentiation of epithelial and stromal characteristics in such a region is of high clinical interest. However, few studies have focused on the development of this region, and information in anatomical and clinical textbooks is limited. We therefore examined the development of the human vaginal fornix and the cervix uteri during prenatal development.

Materials and Methods

We examined 29 female embryos and fetuses between 20 and 34 weeks and two newborns using histology and immunohistochemistry.

Results

The characteristic shape of the portiocervicis and the vaginal fornix first became visible in mid‐term fetuses because of the different muscular coats and of an uncategorized Müllerian‐derived epithelium, which was rapidly replaced by a multilayered squamous epithelium. Only thereafter, in older fetuses, were there organogenetic differentiation of the epithelia and the underlying stroma of the cervical canal. UGS‐derived p63/CK17‐positive cells could be identified as precursor cells for the squamous epithelium, and Müllerian‐derived CK7‐positive cells for the columnar‐type epithelium. Both cell types and different stromal zones were already present in a prenatal transformation zone. Initial functional differentiation could be observed in perinatal stages.

Conclusions

Our results on prenatal human development strongly support the view that two different cell lineages meet at the transitional zone of the cervix uteri and that these lineages depend on alternative signals from the underlying stromal compartment.

Functional Gene Expression Differentiation of the Notch Signaling Pathway in Female Reproductive Tract Tissues-A Comprehensive Review With Analysis

The Notch pathway involves evolutionarily conserved signaling regulating the development of the female tract organs such as breast, ovary, cervix, and uterine endometrium. A great number of studies revealed Notch aberrancies in association with their carcinogenesis and disease progression, the management of which is still challenging. The present study is a comprehensive review of the available literature on Notch signaling during the normal development and carcinogenesis of the female tract organs. The review has been enriched with our analyses of the TCGA data including breast, cervical, ovarian, and endometrial carcinomas concerning the effects of Notch signaling at two levels: the core components and downstream effectors, hence filling the lack of global overview of Notch-driven carcinogenesis and disease progression. Phenotype heterogeneity regarding Notch signaling was projected in two uniform manifold approximation and projection algorithm dimensions, preceded by the principal component analysis step reducing the data burden. Additionally, overall and disease-free survival analyses were performed with the optimal cutpoint determination by Evaluate Cutpoints software to establish the character of particular Notch components in tumorigenesis. In addition to the review, we demonstrated separate models of the examined cancers of the Notch pathway and its targets, although expression profiles of all normal tissues were much more similar to each other than to its cancerous compartments. Such Notch-driven cancerous differentiation resulted in a case of opposite association with DFS and OS. As a consequence, target genes also show very distinct profiles including genes associated with cell proliferation and differentiation, energy metabolism, or the EMT. In conclusion, the observed Notch associations with the female tract malignancies resulted from differential expression of target genes. This may influence a future analysis to search for new therapeutic targets based on specific Notch pathway profiles.

Aberrant DNA methylation in the PAX2 promoter is associated with Müllerian duct anomalies

PURPOSE

Abnormalities during Müllerian duct and female reproductive tract formation during embryonic development result in Müllerian duct anomalies (MDA). Previous studies have identified a role for mutations in related genes and DNA copy number variation (CNV). However, the correlation between gene methylation and MDA remains to be understood.

METHODS

Endometrial tissues were collected from patients with septate (n = 23) or normal uterus (n = 28). We detected the methylation status of CpG sites and mRNA levels of nine candidate genes, including HOXA10, EMX2, TP63, ITGB3, PAX2, LHX1, GSC, WNT4, and H19, using MethyTarget and quantitative real-time polynucleotide chain reaction (qRT-PCR), respectively RESULTS: Compared with healthy controls, we detected three hypomethylated CpG sites (P < 0.05) and increased mRNA levels of PAX2 (P < 0.05) in individuals with MDA. HOXA10, EMX2, TP63, ITGB3, LHX1, and GSC had 1, 1, 2, 1, 5, and 2 differentially methylated CpG sites (P < 0.05), respectively, but there were no significant differences in their mRNA levels (P > 0.05). WNT4 and H19 did not show differences in methylation (P > 0.05) and mRNA levels (P > 0.05).

CONCLUSIONS

Aberrant DNA methylation within the promoter of PAX2 may contribute to the development of MDA by regulating its gene expression. However, the methylation status of HOXA10, EMX2, TP63, ITGB3, LHX1, GSC, WNT4, and H19, may not contribute to the development of MDA.

Novel phenotype of syndromic premature ovarian insufficiency associated with TP63 molecular defect

There is growing evidence that TP63 is associated with isolated as well as syndromic premature ovarian insufficiency (POI). We report two adolescent sisters diagnosed with undetectable ovaries, uterine hypoplasia, and mammary gland hypoplasia. A novel paternally inherited nonsense variant in TP63 [NM_003722.4 c.1927C > T,p.(Arg643*)] in exon 14 was identified by exome sequencing. One of the syndromes linked to TP63 is limb mammary syndrome (LMS), an autosomal dominant inherited disorder characterized by ectrodactyly, hypoplasia of mammary-gland and nipple, lacrimal duct stenosis, nail dysplasia, dental anomalies, cleft palate and/or cleft lip and absence of skin and hair defects. The TP63 variant segregated with symptoms of LMS in the family, however, no affected individual had limb defects. The phenotype reported here represents a novel syndromic phenotype associated with TP63. Reported cases with TP63 associated POI are reviewed.

Bmp4 is an essential growth factor for the initiation of genital tubercle (GT) outgrowth

The external genitalia are appendage organs outgrowing from the posterior body trunk. Murine genital tubercle (GT), anlage of external genitalia, initiates its outgrowth from embryonic day (E) 10.5 as a bud structure. Several growth factors such as fibroblast growth factor (FGF), Wnt and Sonic hedgehog (Shh) are essential for the GT outgrowth. However, the mechanisms of initiation of GT outgrowth are poorly understood. We previously identified bone morphogenetic protein (Bmp) signaling as a negative regulator for GT outgrowth. We show here novel aspects of Bmp4 functions for GT outgrowth. We identified the Bmp4 was already expressed in cloaca region at E9.5, before GT outgrowth. To analyze the function of Bmp4 at early stage for the initiation of GT outgrowth, we utilized the Hoxa3-Cre driver and Bmp4 ^flox/flox mouse lines. Hoxa3 ^Cre/+ ; Bmp4 ^flox/flox mutant mice showed the hypoplasia of GT with reduced expression of outgrowth promoting genes such as Wnt5a, Hoxd13 and p63, whereas Shh expression was not affected. Formation of distal urethral epithelium (DUE) marked by the Fgf8 expression is essential for controlling mesenchymal genes expression in GT and subsequent its outgrowth. Furthermore, Fgf8 expression was dramatically reduced in such mutant mice indicating the defective DUE formation. Hence, current results indicate that Bmp4 is an essential growth factor for the initiation of GT outgrowth independent of Shh signaling. Thus, Bmp4 positively regulates for the formation of DUE. The current study provides new insights into the function of Bmp signaling at early stage for the initiation of GT outgrowth.

Involvement of proliferative and apoptotic factors in the development of hindgut in rat fetuses with ethylenethiourea-induced anorectal malformations

BACKGROUND

Anorectal malformations (ARMs) are common congenital malformations of the terminal digestive tract, but little is known regarding their pathogenesis. Aberrant cell proliferation/apoptosis are believed to be involved in ARMs. However, there are no studies on proliferation/apoptosis-related genes.

PURPOSE

We aimed to investigate the spatiotemporal expression patterns of two proliferation/apoptosis-related genes (MYC proto-oncogene and tumor protein p53) and explore their potential functions in the hindguts of ethylene thiourea-induced ARMs rat fetuses.

METHODS

MYC and p53 expression was evaluated using immunohistochemical staining, western blotting, and quantitative real-time polymerase chain reaction (RT-qPCR). Terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and p53 costaining were performed to assay the colocalization of apoptotic and p53-expressing cells.

RESULTS

Rat fetuses with ARMs displayed fusion failure of the urogenital septum and cloacal membrane. In the control group, MYC was persistently expressed from gestational day (GD)14 to GD16 and distributed throughout the hindgut, while p53 was weakly detected in the terminal segment of the urethra and hindgut; in the ARMs group, MYC expression was obviously reduced, while p53 was widely and highly expressed in the urethra and hindgut. Western blotting and RT-qPCR confirmed the decrease in MYC and increase in p53 expression in ARMs. TUNEL and p53 co-staining revealed considerable overlap between apoptotic and p53-expressing cells.

CONCLUSION

The expression patterns of c-myc and p53 were disrupted in ARMs rat embryos, and the downregulation of c-myc and upregulation of p53 might be related to the development of ARMs at the key time points of ARMs morphogenesis.

Feeder Cells Free Rabbit Oral Mucosa Epithelial Cell Sheet Engineering

The optimal cell culture method of autologous oral mucosal epithelial cell sheet is not well established for a safe transplantation on to the patients' ocular surface. Animal serum and 3T3 mouse feeder cells are currently being used to stimulate the growth of the epithelial cells. However, the use of animal compounds can have potential side effects for the patient after transplantation of the engineered cell sheet. In the present study, we focused on engineering a rabbit oral mucosal epithelial cell sheet without 3T3 mouse feeder cells using a mix of Dulbecco's Modified Eagle Medium/Bronchial Epithelial Cell Growth Medium culture media (DMEM/BEGM). Autologous oral mucosal epithelial cell sheets, engineered with DMEM/BEGM feeder cell free culture media, were compared to those cultured in presence of serum and feeder cells. Using a DMEM/BEGM mix culture media, feeder cell free culture condition, autologous oral mucosal epithelial cells reached confluence and formed a multilayered sheet. The phenotype of engineered cell sheets cultured with DMEM/BEGM were characterized and compared to those cultured with serum and feeder. Hematoxylin and eosin staining showed the formation of a similar stratified multilayer cell sheets, in both culture conditions. The expression of deltaN-p63, ABCG2, PCNA, E-cadherin, Beta-catenin, CK3, CK4, CK13, Muc5AC, was similar in both culture conditions. We demonstrated that rabbit autologous oral mucosal epithelial cell sheet can be engineered, in feeder cell free conditions. The use of the DMEM/BEGM culture media to engineer culture autologous oral mucosa epithelial cell sheet will help to identify key factors involved in the growth and differentiation of oral mucosal epithelial cells.

A review of genetic factors contributing to the etiopathogenesis of anorectal malformations

BACKGROUND

Anorectal malformation (ARM) is a common congenital anomaly with a wide clinical spectrum. Recently, many genetic and molecular studies have been conducted worldwide highlighting the contribution of genetic factors in its etiology. We summarize the current literature on such genetic factors.

MATERIALS AND METHODS

Literature search was done using different combinations of terms related to genetics in anorectal malformations. From 2012 to June 2017, articles published in the English literature and studies conducted on human population were included.

OBSERVATIONS AND RESULTS

A paradigm shift was observed from the earlier studies concentrating on genetic aberrations in specific pathways to genome wide arrays exploring single nucleotide polymorphisms (SNPs) and copy number variations (CNVs) in ARM patients. Rare CNVs (including 79 genes) and SNPs have been found to genetically contribute to ARM. Out of disrupted 79 genes one such putative gene is DKK4. Down regulation of CDX-1 gene has also been implicated in isolated ARM patients. In syndromic ARM de novo microdeletion at 17q12 and a few others have been identified.

CONCLUSION

Major genetic aberrations proposed in the pathogenesis of ARM affect members of the Wnt, Hox (homebox) genes, Sonic hedgehog (Shh) and Gli2, Bmp4, Fgf and CDX1 signalling pathways; probable targets of future molecular gene therapy.

Limbal stem cells: identity, developmental origin, and therapeutic potential

The cornea is our window to the world and our vision is critically dependent on corneal clarity and integrity. Its epithelium represents one of the most rapidly regenerating mammalian tissues, undergoing full-turnover over the course of approximately 1-2 weeks. This robust and efficient regenerative capacity is dependent on the function of stem cells residing in the limbus, a structure marking the border between the cornea and the conjunctiva. Limbal stem cells (LSC) represent a quiescent cell population with proliferative capacity residing in the basal epithelial layer of the limbus within a cellular niche. In addition to LSC, this niche consists of various cell populations such as limbal stromal fibroblasts, melanocytes and immune cells as well as a basement membrane, all of which are essential for LSC maintenance and LSC-driven regeneration. The LSC niche's components are of diverse developmental origin, a fact that had, until recently, prevented precise identification of molecularly defined LSC. The recent success in prospective LSC isolation based on ABCB5 expression and the capacity of this LSC population for long-term corneal restoration following transplantation in preclinical in vivo models of LSC deficiency underline the considerable potential of pure LSC formulations for clinical therapy. Additional studies, including genetic lineage tracing of the developmental origin of LSC will further improve our understanding of this critical cell population and its niche, with important implications for regenerative medicine. WIREs Dev Biol 2018, 7:e303. doi: 10.1002/wdev.303 This article is categorized under: Adult Stem Cells, Tissue Renewal, and Regeneration > Stem Cells and Disease Adult Stem Cells, Tissue Renewal, and Regeneration > Tissue Stem Cells and Niches Adult Stem Cells, Tissue Renewal, and Regeneration > Regeneration.

Keratin 17 Is a Prognostic Biomarker in Endocervical Glandular Neoplasia

OBJECTIVES

Previous work in our laboratory identified keratin 17 (K17) as a specific and sensitive biomarker for high-grade squamous intraepithelial lesions and cervical squamous cell carcinoma (SCC). K17, however, has not been previously evaluated in endocervical glandular neoplasia. Based on the similar pathogenesis of squamous and glandular lesions of the cervix, we hypothesized that K17 overexpression could also be a diagnostic and/or prognostic biomarker for endocervical neoplasia.

METHODS

Cases of endocervical adenocarcinoma (n = 90), adenocarcinoma in situ (AIS) (n = 32), benign glandular lesions (n = 36), and normal endocervical mucosa (n = 5) were selected from Stony Brook Medicine and the University of Massachusetts from 2002 to 2013. Immunohistochemical staining for K17 was performed by an indirect immunoperoxidase method and was scored based on the proportion of cells that showed strong (2+) staining.

RESULTS

K17 was highly expressed in 21 (65.6%) of 32 AIS and in 75 (83.0%) of 90 adenocarcinoma cases. In adenocarcinomas, K17 staining was detected in a mean of 33.9% of malignant cells. Staining tended to be strongest at the periphery of pseudoglandular groups and at the invasive front of tumors. K17 was not detected in the epithelial cells of benign glandular lesions, but groups of cuboidal cells, residing beneath the epithelial layer of benign glands, were frequently positive for K17, especially in cases of microglandular hyperplasia. High levels of K17 expression were significantly associated with decreased patient survival.

CONCLUSIONS

K17 is highly expressed in most cases of both invasive adenocarcinoma and in AIS and is a powerful, negative prognostic marker for patient survival.

Novel mutations in the TP63 gene are potentially associated with Müllerian duct anomalies

STUDY QUESTION

Are mutations and/or polymorphisms in the TP63 gene associated with human Müllerian duct anomalies (MDAs)?

SUMMARY ANSWER

The novel mutation c.*374 G > A in the TP63 gene resulted in decreased expression of TP63 by generating new binding sites with miR-1260a/miR-532-3p and revealed the potential association between TP63 and human MDAs.

WHAT IS KNOWN ALREADY

It has been shown that mice lacking Tp63 exhibit hypoplastic genitalia, a single cloacal opening, and persistence of columnar epithelium at lower genital tract sites. It has also been reported that a nonsense mutation in EMX2 results in decreased TP63 expression in a woman with MDAs. However, generally in humans the association between TP63 and MDAs is unknown.

STUDY DESIGN, SIZE, DURATION

A total of 200 unrelated Chinese women with MDAs and 200 unrelated Chinese women with a normal uterus and vagina, as controls, were recruited in the Center for Reproductive Medicine of Shandong University. All participants had a normal karyotype (46, XX).

PARTICIPANTS/MATERIALS, SETTING, METHODS

The 20 exons of the TP63 gene were sequenced in 200 cases and 200 controls. Putative binding sites for microRNAs were validated by dual luciferase activity assays. The role of microRNAs was further examined by western blot.

MAIN RESULTS AND THE ROLE OF CHANCE

Sequence analysis revealed 15 known single-nucleotide polymorphisms. Additionally, three novel heterozygous variants, c.387 G > C, c.*374 G > A and c.*749 G > A, were identified in three patients with MDAs, none of which were detected in controls. Variant c.*374 G > A, located in the 3' untranslated region, was highly conserved among mammals and predicted to create microRNAs binding sites, which was confirmed by dual luciferase activity assays. Western blot demonstrated that the binding with miR-1260a/miR-532-3p resulting from the variation c.*374 G > A decreased the expression of TP63.

LARGE SCALE DATA

N/A LIMITATIONS, REASONS FOR CAUTION: Further study is needed to uncover the role of the EMX2-TP63 pathway in the development of the Müllerian duct.

WIDER IMPLICATIONS OF THE FINDINGS

This study revealed the possible association between TP63 and MDAs and suggested a potential contribution of microRNA-regulated expression of genes in the etiology of MDAs.

STUDY FUNDING/COMPETING INTERESTS

This research was supported by National Basic Research Program of China (973 Program) (2012CB944700), the State Key Program of National Natural Science Foundation of China (81430029), the National Natural Science Foundation of China (81270662, 81471509), China Postdoctoral Science Foundation (2014M561939) and the Scientific Research Foundation of Shandong Province of Outstanding Young Scientists (BS2014YY013, 2014BSE27022). The authors have no competing interests.

Integration of the Transcription Factor-Regulated and Epigenetic Mechanisms in the Control of Keratinocyte Differentiation

The epidermal differentiation program is regulated at several levels including signaling pathways, lineage-specific transcription factors, and epigenetic regulators that establish well-coordinated process of terminal differentiation resulting in formation of the epidermal barrier. The epigenetic regulatory machinery operates at several levels including modulation of covalent DNA/histone modifications, as well as through higher-order chromatin remodeling to establish long-range topological interactions between the genes and their enhancer elements. Epigenetic regulators exhibit both activating and repressive effects on chromatin in keratinocytes (KCs): whereas some of them promote terminal differentiation, the others stimulate proliferation of progenitor cells, as well as inhibit premature activation of terminal differentiation-associated genes. Transcription factor-regulated and epigenetic mechanisms are highly connected, and the p63 transcription factor has an important role in the higher-order chromatin remodeling of the KC-specific gene loci via direct control of the genome organizer Satb1 and ATP-dependent chromatin remodeler Brg1. However, additional efforts are required to fully understand the complexity of interactions between distinct transcription factors and epigenetic regulators in the control of KC differentiation. Further understanding of these interactions and their alterations in different pathological skin conditions will help to progress toward the development of novel approaches for the treatment of skin disorders by targeting epigenetic regulators and modulating chromatin organization in KCs.

Recurrence of split hand/foot malformation, cleft lip/palate, and severe urogenital abnormalities due to germline mosaicism for TP63 mutation

We describe two sibling fetuses with urogenital abnormalities detected by prenatal ultrasound, in which post-delivery examination showed split hand and foot malformation, and bilateral cleft lip and palate. These findings are consistent with ectrodactyly-ectodermal dysplasia-cleft lip with or without cleft palate syndrome (EEC). Both fetuses were found to have the same missense mutation in TP63 (c.1051G > A; p.D351N). Parental clinical examinations and lymphocyte DNA analyses were normal. This report illustrates the potential severity of urogenital defects in TP63-related disorders, which may be detectable with fetal ultrasonography. It highlights the need to counsel for the possibility of germline mosaicism in TP63-associated disorders. © 2016 Wiley Periodicals, Inc.

Novel function of LHFPL2 in female and male distal reproductive tract development

Congenital reproductive tract anomalies could impair fertility. Female and male reproductive tracts are developed from Müllerian ducts and Wolffian ducts, respectively, involving initiation, elongation and differentiation. Genetic basis solely for distal reproductive tract development is largely unknown. Lhfpl2 (lipoma HMGIC fusion partner-like 2) encodes a tetra-transmembrane protein with unknown functions. It is expressed in follicle cells of ovary and epithelial cells of reproductive tracts. A spontaneous point mutation of Lhfpl2 (LHFPL2^G102E) leads to infertility in 100% female mice, which have normal ovarian development, ovulation, uterine development, and uterine response to exogenous estrogen stimulation, but abnormal upper longitudinal vaginal septum and lower vaginal agenesis. Infertility is also observed in ~70% mutant males, which have normal mating behavior and sperm counts, but abnormal distal vas deferens convolution resulting in complete and incomplete blockage of reproductive tract in infertile and fertile males, respectively. On embryonic day 15.5, mutant Müllerian ducts and Wolffian ducts have elongated but their duct tips are enlarged and fail to merge with the urogenital sinus. These findings provide a novel function of LHFPL2 and a novel genetic basis for distal reproductive tract development; they also emphasize the importance of an additional merging phase for proper reproductive tract development.

Pathogenesis of bladder exstrophy: A new hypothesis

Classical bladder exstrophy affects 1 in 30 000 live births. Results of surgical treatment from different institutions employing various surgical techniques are not uniform, thus there is a need for a consensus on the best technique for bladder exstrophy repair. Surgical correction in bladder exstrophy would be more effective if the exact pathogenetic mechanism was deduced and the procedure was directed to correct the cause, which is responsible for the defect. The anatomy of exstrophy shows that the infraumbilical abdominal wall, the anterior wall of the bladder, and the urethra are split, with splayed out genitalia and musculature along with pubic diastasis. There is no tissue loss and hence embryological defect is unlikely to be the cause of bladder exstrophy. Thus there is a need to examine pathogenesis of bladder exstrophy.

METHODS

A literature search was made of the various hypotheses for cause of bladder exstrophy, and attempts were made to propose a new hypothesis. The present hypothesis is also the basis for a technique of mobilization of pelvic musculature, done in two stages.

RESULTS

The functional outcomes of 38 children with bladder exstrophy managed over a period of 10 years were reviewed. At a mean follow-up of 4.5 years (range 2.5-8 years), 82% of patients were functionally continent.

CONCLUSIONS

The exact embryopathogenesis of bladder exstrophy is unknown. In this study a new hypothesis is proposed, with the aim of tailoring the surgical procedure to correct this defect. Bladder exstrophy epispadias complex (BEEC) is a deformative disruption occurring after embryogenic phase and pubic diastasis, and is central to exstrophy development. A working hypothesis can be formulated in line with our observation so that future experiments based this new hypothesis can aim to elucidate the exact pathogenesis.

Systematic stereoscopic analyses for cloacal development: The origin of anorectal malformations

The division of the embryonic cloaca is the most essential event for the formation of digestive and urinary tracts. The defective development of the cloaca results in anorectal malformations (ARMs; 2–5 per 10,000 live births). However, the developmental and pathogenic mechanisms of ARMs are unclear. In the current study, we visualized the epithelia in the developing cloaca and nephric ducts (NDs). Systemic stereoscopic analyses revealed that the ND-cloaca connection sites shifted from the lateral-middle to dorsal-anterior part of the cloaca during cloacal division from E10.5 to E11.5 in mouse embryos. Genetic cell labeling analyses revealed that the cells in the ventral cloacal epithelium in the early stages rarely contributed to the dorsal part. Moreover, we revealed the possible morphogenetic movement of endodermal cells within the anterior part of the urogenital sinus and hindgut. These results provide the basis for understanding both cloacal development and the ARM pathogenesis.

Anorectal malformation: the etiological factors

Anorectal malformation (ARM) is a congenital anomaly commonly encountered in pediatric surgery practice. Although surgical procedures correct the anatomical anomalies, the post-operative bowel function is not universally satisfactory. The etiology of ARM remains unclear. In this review, we summarize the current understanding of the genetic and epigenetic factors contributing to the pathogenesis of ARM, based on published animal models, human genetics and epidemiological researches. Appreciation of these factors may be helpful in the management of ARM in the future.

p53/p63/p73 in the epidermis in health and disease

Although p53 has long been known as the "guardian of the genome" with a role in tumor suppression in many tissues, the discovery of two p53 ancestral genes, p63 and p73, more than a decade ago has triggered a considerable amount of research into the role of these genes in skin development and diseases. In this review, we primarily focus on mechanisms of action of p53 and p63, which are the best-studied p53 family members in the skin. The existence of multiple isoforms and their roles as transcriptional activators and repressors are key to their function in multiple biological processes including the control of skin morphogenesis, regeneration, tumorigenesis, and response to chemotherapy. Last, we provide directions for further research on this family of genes in skin biology and pathology.

New advances in the pathophysiologic and radiologic basis of the exstrophy spectrum

The exstrophy-epispadias complex is a rare spectrum of anomalies affecting the genitourinary system, anterior abdominal wall, and pelvis. Recent advances in the repair of classic bladder exstrophy (CBE) and cloacal exstrophy (CE) have resulted in significant changes in outcomes of surgical management (including higher continence rate, fewer surgical complications, and better cosmesis) and health-related quality of life in these patients. These noteworthy changes resulted from advances in the pathophysiological and genetic backgrounds of this disease and better radiologic assessment of the three-dimensional anatomy of the bony pelvis and its musculature. A PubMed search was performed with the keyword exstrophy. The resulting literature pertaining to genetics, stem cells, imaging, tissue engineering, epidemiology, and endocrinology was reviewed. The following represents an overview of the advances in basic science understanding and imaging of the exstrophy-epispadias spectrum and discusses their possible and future effects on the management of CBE and CE.

Modern management of the exstrophy-epispadias complex

The exstrophy-epispadias complex is a rare spectrum of malformations affecting the genitourinary system, anterior abdominal wall, and pelvis. Historically, surgical outcomes were poor in patients with classic bladder exstrophy and cloacal exstrophy, the two more severe presentations. However, modern techniques to repair epispadias, classic bladder exstrophy, and cloacal exstrophy have increased the success of achieving urinary continence, satisfactory cosmesis, and quality of life. Unfortunately, these procedures are not without their own complications. This review provides readers with an overview of the management of the exstrophy-epispadias complex and potential surgical complications.

New insights into the pathogenesis of bladder exstrophy-epispadias complex

Bladder exstrophy-epispadias complex (BEEC) is a complex and debilitating congenital disease. Familial and twin studies suggest a possible genetic component in BEEC pathogenesis. Bladder mesenchyme (detrusor) development requires induction by a signal from bladder urothelium, and we and others have shown the Shh-Gli-Bmp4 signalling pathway is likely to be involved. P63 is a master regulator in epithelial stratification and is expressed in urothelium. We have shown that p63 knock-out mice undergo excessive urothelial apoptosis. Failure of mesenchymal induction by epithelium leads to BEEC. We further demonstrated that insertion/deletion (in/del) polymorphisms (1 base pair (bp) ins and 4 bp ins., and 12 bp del) in the ΔNP63 promoter reduce transcriptional efficiency, and are associated with a statistically significant increase in the risk of BEEC in humans. Furthermore, a Genome-Wide Expression Profiling (GWEP) study suggests possible involvement of PERP in human BEEC. Intriguingly, PERP is a direct target of p63 during development, and is also involved in epithelial stratification. PERP co-localizes with desmosome, and both PERP and desmosome are essential for maintaining tissue integrity by cellular adhesion and epithelial stratification. A recent study showed that PERP and desmosome expression levels are abnormal in human BEEC patients. This review describes the role of the P63 > PERP > desmosome pathway in the development of human bladder during embryogenesis. We hypothesize that disruption of this pathway may increase the risk of BEEC.

Through the glass darkly: intraepithelial neoplasia, top-down differentiation, and the road to ovarian cancer

It is currently hoped that deaths from extra-uterine high-grade serous cancer (HGSC) will be reduced via opportunistic salpingectomy in healthy women. Accumulated data implicate the fimbria as a site of origin and descriptive molecular pathology and experimental evidence strongly support a serous carcinogenic sequence in the Fallopian tube. Both direct and indirect ('surrogate') precursors suggest that the benign tube undergoes important biological changes after menopause, acquiring abnormalities in gene expression that are often shared with malignancy, including PAX2, ALDH1, LEF1, RCN1, RUNX2, beta-catenin, EZH2, and others. However, the tube can be linked to only some HGSCs, recharging arguments that nearby peritoneum/ovarian surface epithelium (POSE) also hosts progenitors to this malignancy. A major sticking point is the difference in immunophenotype between POSE and Müllerian epithelium, essentially requiring mesothelial to Müllerian differentiation prior to or during malignant transformation to HGSC. However, emerging evidence implicates an embryonic or progenitor phenotype in the adult female genital tract with the capacity to differentiate, normally or during neoplastic transformation. Recently, a putative cell of origin for cervical cancer has been identified in the squamo-columnar (SC) junction, projecting a model whereby Krt7+ embryonic progenitors give rise to immunophenotypically distinct progeny under stromal influences via 'top down' differentiation. Similar differentiation can be seen in the endometrium with a parallel in juxtaposed mesothelial and Müllerian differentiation in the ovary. Abrupt mesothelial-Müllerian transitions remain to be proven, but would explain the rapid evolution, short asymptomatic interval, and absence of a defined epithelial starting point in many HGSCs. Resolving this question will require accurately distinguishing progenitor from progeny tumour cells in HGSC and pinpointing where initial transformation and trans-differentiation occur, whether in the tube or POSE. Both will be critical to expectations from prophylactic salpingectomy and future approaches to pelvic serous cancer prevention.

Molecular characteristics of malignant ovarian germ cell tumors and comparison with testicular counterparts: implications for pathogenesis

This review focuses on the molecular characteristics and development of rare malignant ovarian germ cell tumors (mOGCTs). We provide an overview of the genomic aberrations assessed by ploidy, cytogenetic banding, and comparative genomic hybridization. We summarize and discuss the transcriptome profiles of mRNA and microRNA (miRNA), and biomarkers (DNA methylation, gene mutation, individual protein expression) for each mOGCT histological subtype. Parallels between the origin of mOGCT and their male counterpart testicular GCT (TGCT) are discussed from the perspective of germ cell development, endocrinological influences, and pathogenesis, as is the GCT origin in patients with disorders of sex development. Integrated molecular profiles of the 3 main histological subtypes, dysgerminoma (DG), yolk sac tumor (YST), and immature teratoma (IT), are presented. DGs show genomic aberrations comparable to TGCT. In contrast, the genome profiles of YST and IT are different both from each other and from DG/TGCT. Differences between DG and YST are underlined by their miRNA/mRNA expression patterns, suggesting preferential involvement of the WNT/β-catenin and TGF-β/bone morphogenetic protein signaling pathways among YSTs. Characteristic protein expression patterns are observed in DG, YST and IT. We propose that mOGCT develop through different developmental pathways, including one that is likely shared with TGCT and involves insufficient sexual differentiation of the germ cell niche. The molecular features of the mOGCTs underline their similarity to pluripotent precursor cells (primordial germ cells, PGCs) and other stem cells. This similarity combined with the process of ovary development, explain why mOGCTs present so early in life, and with greater histological complexity, than most somatic solid tumors.

Anorectal malformation associated with a mutation in the P63 gene in a family with split hand-foot malformation

PURPOSE

The aims of this study were to identify the mutation gene of a Chinese family with anorectal malformation (ARM) associated with split hand-foot malformation and to determine the spatiotemporal expression of the mutated gene during hindgut and anorectum development in human embryos.

METHOD

A Chinese family with intrafamilial clinically variable manifestation was analyzed and primers were designed for exons 3-14 of P63, DLX5, DLX6, DAC, and HOXD13 as candidate genes and direct sequence analysis of the exons was performed. Immunohistochemical study of mutated gene in the hindgut and anorectum of human embryos of 4th-10th weeks was performed.

RESULT

Affected individuals were found to have an Arg227Gln P63 gene mutation. From the 4th-10th weeks of gestation of the human embryo, the P63-positive cells were mainly located on the epithelium of the apical urorectal septum, hindgut, and cloacal membrane. After the anorectum ruptured during the 8th week, the P63 remained strongly immunoreactive on the epithelium of the anal canal and urethra, but the mucous membrane of the rectum exhibited no reaction.

CONCLUSIONS

The mutation identified strongly suggests a causal relationship between the ARM phenotype and P63. The expression of P63 was persistently active during the dynamic and incessant septation of the cloaca and hindgut, suggesting that P63 may play a pivotal role in the morphogenesis of the hindgut and anorectum.

Genetic Syndromes and Genes Involved in the Development of the Female Reproductive Tract: A Possible Role for Gene Therapy

Müllerian and vaginal anomalies are congenital malformations of the female reproductive tract resulting from alterations in the normal developmental pathway of the uterus, cervix, fallopian tubes, and vagina. The most common of the Müllerian anomalies affect the uterus and may adversely impact reproductive outcomes highlighting the importance of gaining understanding of the genetic mechanisms that govern normal and abnormal development of the female reproductive tract. Modern molecular genetics with study of knock out animal models as well as several genetic syndromes featuring abnormalities of the female reproductive tract have identified candidate genes significant to this developmental pathway. Further emphasizing the importance of understanding female reproductive tract development, recent evidence has demonstrated expression of embryologically significant genes in the endometrium of adult mice and humans. This recent work suggests that these genes not only play a role in the proper structural development of the female reproductive tract but also may persist in adults to regulate proper function of the endometrium of the uterus. As endometrial function is critical for successful implantation and pregnancy maintenance, these recent data suggest a target for gene therapy. Future research will be needed to determine if gene therapy may improve reproductive outcomes for patients with demonstrated deficient endometrial expression related to abnormal gene expression.

Human papillomavirus infections and cancer stem cells of tumors from the uterine cervix

Different rate of development of productive infections (as low grade cervical intraepithelial neoplasias), or high grade lesions and cervical malignant tumors associated with infections of the Transformation zone (TZ) by High-Risk Human Papillomavirus (HR-HPV), could suggest that different epithelial host target cells could exist. If there is more than one target cell, their differential infection by HR-HPV may play a central role in the development of cervical cancer. Recently, the concept that cancer might arise from a rare population of cells with stem cell-like properties has received support in several solid tumors, including cervical cancer (CC). According to the cancer stem cell (CSC) hypothesis, CC can now be considered a disease in which stem cells of the TZ are converted to cervical cancer stem cells by the interplay between HR-HPV viral oncogenes and cellular alterations that are thought to be finally responsible for tumor initiation and maintenance. Current studies of CSC could provide novel insights regarding tumor initiation and progression, their relation with viral proteins and interplay with the tumor micro-environment. This review will focus on the biology of cervical cancer stem cells, which might contribute to our understanding of the mechanisms responsible for cervical tumor development.

Insertion/deletion polymorphisms in the ΔNp63 promoter are a risk factor for bladder exstrophy epispadias complex

Bladder exstrophy epispadias complex (BEEC) is a severe congenital anomaly; however, the genetic and molecular mechanisms underlying the formation of BEEC remain unclear. TP63, a member of TP53 tumor suppressor gene family, is expressed in bladder urothelium and skin over the external genitalia during mammalian development. It plays a role in bladder development. We have previously shown that p63^−/− mouse embryos developed a bladder exstrophy phenotype identical to human BEEC. We hypothesised that TP63 is involved in human BEEC pathogenesis. RNA was extracted from BEEC foreskin specimens and, as in mice, ΔNp63 was the predominant p63 isoform. ΔNp63 expression in the foreskin and bladder epithelium of BEEC patients was reduced. DNA was sequenced from 163 BEEC patients and 285 ethnicity-matched controls. No exon mutations were detected. Sequencing of the ΔNp63 promoter showed 7 single nucleotide polymorphisms and 4 insertion/deletion (indel) polymorphisms. Indel polymorphisms were associated with an increased risk of BEEC. Significantly the sites of indel polymorphisms differed between Caucasian and non-Caucasian populations. A 12-base-pair deletion was associated with an increased risk with only Caucasian patients (p = 0.0052 Odds Ratio (OR) = 18.33), whereas a 4-base-pair insertion was only associated with non-Caucasian patients (p = 0.0259 OR = 4.583). We found a consistent and statistically significant reduction in transcriptional efficiencies of the promoter sequences containing indel polymorphisms in luciferase assays. These findings suggest that indel polymorphisms of the ΔNp63 promoter lead to a reduction in p63 expression, which could lead to BEEC.

Bladder exstrophy epispadias complex is a severe congenital abnormality. The affected babies' bladders are born open, leaking urine constantly. Treatment involves multiple major reconstructive surgeries and the need for lifelong care for the complications of the disease. Although a number of studies have suggested a genetic cause of the disease, the genetic and molecular mechanism underlying the formation of BEEC remains unknown. One gene, TP63, plays a crucial role in the early bladder development. Two different genetic promoters of TP63 produce different forms of the protein with opposing properties. We have shown mice lacking p63 displayed a deformity complex identical to human BEEC. There are no genetic mutations in the p63 protein in BEEC, so genetic variants in the promoter could alter protein expression. Our hypothesis was that loss of p63 expression due to sequence polymorphisms in a promoter is a risk factor for BEEC. We found promoter sequence variants that were statistically associated with the disease and the sequence variant location varied between Caucasian and non-Caucasian patients. This is particularly important as Caucasian populations have a higher risk of BEEC. These findings provide an explanation of BECC and a base for further study of TP63 related genes in this disease.

Barrett's metaplasia as a paradigm for understanding the development of cancer

The conversion of one cell type to another is defined as metaplasia (or sometimes it is referred to as transdifferentiation or cellular reprogramming). Metaplasia is important clinically and may predispose to the development of cancer. Barrett's metaplasia is one such example and is the focus of the present review. Barrett's is a pathological condition in which the normal oesophageal stratified squamous epithelium is replaced by intestinal-type columnar epithelium and is associated with gastro-oesophageal reflux disease. The appearance of columnar epithelium in the oesophagus predisposes to the development of adenocarcinoma. Herein we review the latest evidence on the cellular origin of Barrett's metaplasia. Until recently it was thought that the cellular origin of the columnar epithelium was from a pre-existing cell within the oesophagus. However, recent evidence suggests that this may not be the case. Instead two recent publications indicate that the columnar cells may migrate from a site distal to the oesophagus. These new data contravene our current understanding of metaplasia and raise important questions about the cellular origin of cancer.

Molecular mechanisms of external genitalia development

External genitalia development occurs through a combination of hormone independent, hormone dependent, and endocrine pathways. Perturbation of these pathways can lead to abnormal external genitalia development. We review human and animal mechanisms of normal and abnormal external genitalia development, and we evaluate abnormal mechanisms that lead to hypospadias. We also discuss recent laboratory findings that further our understanding of animal models of hypospadias.

Molecular characteristics and alterations during early development of the human vagina

Unresolved questions remain concerning the derivation of the vagina with respect to the relative contributions from the Müllerian ducts, the urogenital sinus, and the Wolffian ducts. Recent molecular and cellular studies in rodents have opened up a large gap between the level of understanding of vaginal development in mice and understanding of human vaginal development, which is based on histology. To compare the findings in mice with human vaginal development and to address this gap, we analysed molecular characteristics of the urogenital sinus, Wolffian ducts, and Müllerian ducts in 8-14-week-old human specimens using immunohistochemical methods. The monoclonal antibodies used were directed against cytokeratin (CK) 14, CK19, vimentin, laminin, p63, E-cadherin, caspase-3, Ki67, HOX A13, and BMP-4. The immunohistochemical analysis revealed that, during weeks 8-9, the epithelium of the Müllerian ducts became positive for p63 as p63-positive cells that originated from the sinus epithelium reached the caudal tip of the fused Müllerian ducts via the Wolffian ducts. The lumen of the fused Müllerian ducts was closed by an epithelial plug that contained both vimentin-positive and vimentin-negative cells. Subsequently, the resulting epithelial tube enlarged by proliferation of basal p63-positive cells. The first signs of squamous differentiation were detected during week 14, with the appearance of CK14-positive cells. According to our results, all three components, namely, the urogenital sinus, Wolffian ducts, and Müllerian ducts, interacted during the formation of the human vagina. The sinus epithelium provided p63-positive cells, the Wollfian ducts acted as a 'transporter', and the Müllerian ducts contributed the guiding structure for the vaginal anlagen. Epithelial differentiation began at the end of the period studied and extended in a caudo-cranial direction. The present study is one of the first to provide up-to-date molecular correlates for human vaginal development that can be compared with the results of cell biological studies in rodents.

p63 in epithelial survival, germ cell surveillance, and neoplasia

The p53homolog p63has emerged as a gene with an enormously complex function that is distinct from that of p53. It encodes two distinct transcript isoforms that have a dramatic impact on replenishment of cutaneous epithelial stem cells and on ovarian germ cell survival. However, although these two fundamental roles of p63 attest to its powerful place in development, its other functions-specifically the apparent capacity of p63, when induced, to supervise the emergence of new cell populations in the breast, prostate, cervix, and upper reproductive tract-are shared by embryo and adult. These observed functions may only scratch the surface of a repertoire that has been postulated to encompass a range of cellular activities, as evidenced by the fact that p63 proteins have been shown to potentially bind to over 5800 target sites. Whether tumorigenic pathways are also involved, and to what extent, is a subject of both promise and controversy that remains to be resolved.