Quantitative CT texture analysis for evaluating histologic grade of urothelial carcinoma

PURPOSE

To investigate the feasibility of using CT texture analysis (CTTA) to differentiate between low- versus high-grade urothelial carcinoma.

METHODS

A total of 105 patients with high-grade urothelial carcinoma (HGUC, n = 106) and low-grade urothelial carcinoma (LGUC, n = 18) were included in this retrospective study. Both unenhanced and enhanced CT images representing the largest cross-sectional area of the tumor were chosen for CTTA performed using TexRAD software. Comparison of texture parameters, mean gray-level intensity (Mean), standard deviation, entropy, mean of positive pixels (MPP), skewness, and kurtosis were made for the objective. Receiver operating characteristic (ROC) analysis was performed and the area under the ROC curve was calculated for texture parameters that were significantly different (P < 0.05) for the purpose. Sensitivity (Se), specificity (Sp), positive predictive value, negative predictive value, and accuracy were calculated using the cut-off value of texture parameter with the highest AUC.

RESULTS

Compared to HGUC, LGUC had significantly lower Mean (P = 0.001), Entropy (P = 0.002), and MPP (P < 0.001) on unenhanced and enhanced images and lower SD (P = 0.048) on enhanced images. There was no significant difference in skewness or kurtosis at any texture scale on unenhanced and enhanced images. A MPP <24.13 at fine texture scale on unenhanced images identified LGUC from HGUC with the highest AUC of 0.779 ± 0.065 (Se = 72.2%, Sp = 84.9%, PPV = 44.8%, NPV = 94.7%, and accuracy = 83.1%).

CONCLUSIONS

CTTA proved to be a feasible tool for differentiating LGUC from HGUC. MPP quantified from fine texture scale on unenhanced images was the optimal diagnostic parameter for estimating histologic grade of urothelial carcinoma.

Efficacy and influence factors of icotinib hydrochloride in treating advanced non-small cell lung cancer

OBJECTIVE

To evaluate the efficacy and safety of icotinib hydrochloride in the treatment of patients with advanced non-small cell lung cancer (NSCLC) and discuss the influence factors on efficacy.

PATIENTS AND METHODS

120 treatment-experienced patients confirmed by pathology or cytology with stage III B-IV non-small cell lung cancer took icotinib hydrochloride and erlotinib orally until the occurrence of disease progression or serious adverse reactions. Then, the efficacy of icotinib hydrochloride and the related influence factors were analyzed.

RESULTS

In icotinib hydrochloride group, the response rate and the disease control rate were 30.00% and 65.00%, and the median progression-free survival time was 179 days (95% CI: 103.21-254.78); in erlotinib group, the response rate and the disease control rate were 25.00% and 56.70%, and the median progression-free survival time was 121 days (95% CI: 95.05-146.94). Moreover, the objective response rate and the disease control rate of second-line therapy were both superior to the third-line and above therapy. The objective response rate of patients with complete response/partial response/stable disease after the first-line therapy was higher than that of patients without response after the first-line therapy (p<0.05), and the significant differences existed in the objective response rate and the disease control rate among mutant group, wild-type group, and unknown group (p<0.05). The response rate and the disease control rate of erythra group were higher than those of non-erythra group (p<0.05). It was showed in the univariate analysis that the progression-free survival was correlated with the smoking status and the epidermal growth factor receptor gene mutations.

CONCLUSIONS

The icotinib hydrochloride is effective and safe in treating the treatment-experienced patients with advanced NSCLC, especially for patients with sensitive mutations.

Rs12941170 at SOX9 gene associated with orofacial clefts in Chinese

OBJECTIVE

Non-syndromic orofacial cleftings (NSOCs) are considered as complex trait, which results from genetic and/or environmental modifiers. Current findings could only explain small portion of the NSOCs. SOX9 gene plays an important role during craniofacial development in animal models and the Pierre Robin sequence (PRS). However, its role in non-syndromic clefts remains unknown.

DESIGN

In this study, we selected eight SNPs in and around SOX9 gene to make maximum coverage, and genotyped them by using RFLP-PCR and ligase detection reaction (LDR) methods to test its associations among 151 NSOCs (53 NSCLP, 52 NSCLO and 46 NSCPO) from Western Han Chinese population.

RESULTS

Allelic TDT results showed that G allele at rs12941170 of SOX9 was under-transmitted among NSOCs (p=0.00014, OR=0.55 and 95%CI: 0.40-0.75), which could indicate that the G allele is protective against NSOCs; parent-of-origin effect analysis showed that G allele at rs12941170 was maternally under-transmitted (p=0.002), while there was no statistically difference between the maternal and paternal transmission of it. To test if the adjacent SNPs travel together from parents to the affected individual, we carried out the sliding window haplotype analysis, it is interesting to find that the haplotypes carrying the G allele at rs12941170 also was under-transmitted for NSOCs, NSCL/P, NSCLP and NSCPO (lowest p=0.00033).

CONCLUSIONS

This study suggested that G allele at rs12941170 was protective, which could decrease the risk for NSOCs from Western Han Chinese population, and it will provide new reference for future research and genetic counseling in NSOCs.

[The effect and mechanism investigation of intermedin on the apoptosis of bone marrow derived mesenchymal stem cells induced by hydrogen peroxide]

Objective: To investigate the effect and mechanism of intermedin (IMD)on the apoptosis of BMSCs induced by H₂O₂ and its mechanism. Methods: BMSCs being cultured in vitro. After 30 min pretreatment with 10^-6mol/L IMD, cells were cultured in presence of 100 μmol/L H₂O₂ for 2 hour, cell apoptosis was determined by flow cytometry; Apoptosis related protein expression was determined by Western blotting and immunofluorescence; Protein and phosphorylation of ERK1/2 was detected by Western blotting and observe the influence of IMD after pretreatment with inhibitor of ERK1/2. Results: IMD could increase phosphorylation of ERK1/2 pathway of BMSCs (P<0.01). Pretreatment of IMD could decrease BMSCs apoptosis induced by H₂O₂, and up regulation expression of Caspase-3 and Bax, down regulation expression of Bcl-2 (P<0.01), and the effect was abrogated by U0126. Conclusion: IMD can activate ERK1/2 signaling pathway of BMSCs, and can regulate the expression of apoptosis related proteins. Furthermore, it can protect BMSCs from apoptosis induced by H₂O₂. Activation of ERK1/2 pathway was involved in the effect of IMD on apoptosis.

1α,25(OH)2D3 Induces Actin Depolymerization in Endometrial Carcinoma Cells by Targeting RAC1 and PAK1

Background: Cell proliferation and motility require actin reorganization, which is under control of various signalling pathways including ras-related C3 botulinum toxin substrate 1 (RAC1), p21 protein-activated kinase 1 (PAK1) and actin related protein 2 (ARP2). Tumour cell proliferation is modified by 1α,25-Dihydroxy-Vitamin D3 (1α,25(OH)2D3), a steroid hormone predominantly known for its role in calcium and phosphorus metabolism. The present study explored whether 1α,25(OH)2D3 modifies actin cytoskeleton in Ishikawa cells, a well differentiated endometrial carcinoma cell line. Methods: To this end, actin cytoskeleton was visualized by confocal microscopy. Globular over filamentous actin ratio was determined utilizing Western blotting and flow cytometry, transcript levels by qRT-PCR and protein abundance by immunoblotting. Results: A 24 hour treatment with 1α,25(OH)2D3 (100 nM) significantly decreased RAC1 and PAK1 transcript levels and activity, decreased ARP2 protein levels and depolymerized actin. The effect of 1α,25(OH)2D3 on actin polymerization was mimicked by pharmacological inhibition of RAC1 and PAK1. Conclusions: 1α,25(OH)2D3 leads to disruption of RAC1 and PAK1 activity with subsequent actin depolymerization of endometrial carcinoma cells.

Translation and validation of a Chinese version of the Warwick-Edinburgh Mental Well-being Scale with undergraduate nursing trainees

WHAT IS KNOWN ON THE SUBJECT?: Warwick-Edinburgh Mental Well-being Scale (WEMWBS) which is a measurement of mental health and well-being, was translated into Chinese to assess the reliability and validity in a sample of undergraduate nursing trainees in Wenzhou. WHAT THIS PAPER ADDS TO EXISTING KNOWLEDGE?: Currently, there is no a reliable assessment tool to systematically evaluate mental well-being in mainland China. Therefore, we undertook the translation and cultural adaptation of the WEMWBS and tested the scale's reliability and validity. The reliability and validity of the Chinese version of the Short Warwick-Edinburgh Mental Well-being Scale have been demonstrated in Hong Kong, but the WEMWBS has not been validated in mainland China in either clinical or non-clinical settings. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: It might provide a reliable quantitative tool to evaluate mental well-being in non-clinical settings, which has important implications for mental health nursing. In future,it might be a reliable quantitative tool for evaluating mental well-being in other population such as hospitalized patients to improve their life quality.

ABSTRACT

Introduction There is growing interest worldwide in the evaluation of positive mental health and wellbeing. Aim This study was to translate the Warwick-Edinburgh Mental Well-being Scale (WEMWBS) into Chinese and assess the reliability and validity of this scale in a sample of undergraduate nursing trainees. Methods A forward and backward translation protocol was used to translate the scale into Chinese. The psychometric properties of the C-WEMWBS, such as internal consistency reliability, test-retest reliability and factorial validity, were analysed. Results All 14 items of the initial C-WEMWBS were rated as conceptually equivalent to those of the original version. Confirmatory factor analysis indicated the emergence of a single factor. The psychometric properties of the C-WEMWBS were satisfactory, with an internal consistency reliability of .94 and a test-retest reliability of .83. The item-total correlations ranged from .66 to .83. There was a moderate relationship (r = .52) between the C-WEMWBS and the WHO-5. Implications for practice This was the first Chinese version of the WEMWBS to be developed and psychometrically assessed with a sample of undergraduate nursing trainees. It provides a reliable quantitative tool to evaluate mental well-being in non-clinical settings, which has important implications for mental health nursing.

Parent satisfaction with primary repair of paediatric cleft lip in Southwest China

The purpose of this study was to investigate the key factors in relation to parent satisfaction with the primary repair of paediatric cleft lip. One hundred and ninety-five children born with cleft lip and/or palate aged between 3 months and 1 year were recruited, along with their caregivers. All patients underwent primary cleft lip repair, and a telephone interview was held with their main caregivers at 3 months postoperative. The level of satisfaction with each item included in a simplified Cleft Evaluation Profile was ascertained and recorded. Patient clinical data were obtained from the medical records. One hundred and thirty-eight (71%) parents reported satisfaction with the general outcome of surgery. Parents were satisfied with the appearance of the lip and profile of the face, but were dissatisfied with the appearance of the nose and teeth. Mothers of patients showed lower satisfaction levels than fathers and grandparents. Parental satisfaction with the appearance of the lip was lower for patients without a cleft palate than for those with a cleft palate. The results of this study suggest that most Chinese parents of children who undergo primary cleft lip repair express satisfaction with the surgical outcomes. Satisfaction with the appearance of the nose and teeth is low and this needs to be improved. Other factors are likely to influence expressions of satisfaction.

MiR-338-3p targets pyruvate kinase M2 and affects cell proliferation and metabolism of ovarian cancer

MiR-338-3p is down-regulated in cancer, which inhibits cancer cell proliferation, metastasis, and increases chemosensitivity, but its functions in ovarian cancer remains unknown. The present study aims to identify the miR-338-3p targeted genes and to investigate the associated regulatory mechanisms in ovarian cancer cell proliferation and metabolism. Our results demonstrated miR-338-3p expression was down-regulated in most of ovarian cancer tissues and cell lines. Restoration of miR-338-3p expression in ovarian cancer cells could inhibit cell proliferation, lactate production and lactate production of ovarian cancer cells. PKM2 was verified as a target gene of miR-338-3p by luciferase assay. Further study indicated miR-338-3p controlled ovarian cancer cell metabolism by inhibiting PKM2 expression. It is summarized that the regulatory role of miR-338-3p on PKM2 expression in ovarian cancer may play important roles in cell metabolism.

Infiltrating T-lymphocyte Receptor Vβ Gene Family Utilization in Autoimmune Thyroid Disease

The expression of T-cell antigen receptor (TCR) Vβ genes in autoimmune thyroid diseases (AITDs) was investigated. RNA was extracted from the thyroid tissue of 23 patients with early-stage Graves' disease, 19 patients with late-stage Graves' disease and 20 patients with Hashimoto's disease. Peripheral blood lymphocytes from patients and 20 normal subjects (controls) were analysed in parallel. AITD was found to be associated with diminished TCR Vβ gene family utilization. In addition, AITDs appeared to select for specific TCR Vβ families. The Vβ3, Vβ5 and Vβ8 families were expressed more frequently in thyroid-infiltrating T-lymphocytes of early-stage Graves' disease than other Vβ gene families. Selective expression was not observed in infiltrating T-lymphocytes obtained from thyroid tissue of patients with late-stage Graves' disease or Hashimoto's disease. Preferentially expressed TCR Vβ gene families may be useful as molecular targets for targeted immunotherapy of AITDs.

[Association study between candidate genes involved in cell-cell adhesion and non-syndromic cleft lip with or without cleft palate in Chinese population]

OBJECTIVE

To explore the association and gene-environment interaction between single nucleotide polymorphisms (SNPs) involved in cell-cell adhesion and non-syndromic cleft lip with or without cleft palate (NSCL/P) among Chinese population.

METHODS

A total of 806 NSCL/P trios were drawn by an international consortium, which conducted a genome-wide association study (GWAS) using a case-parent trio design to investigate genes affecting risks to NSCL/P. The transmission disequilibrium test (TDT) was used to explore the association between cell-cell adhesion genes, including CDH1, CTNNB1, PVRL1, PVRL2, PVRL3, ACTN1, VCL, LEF1, and NSCL/P. Conditional Logistic regression models were used to estimate effects on risk of exposed and unexposed children. Four common maternal exposures including maternal smoking, environmental tobacco smoke, alcohol consumption and multivitamin supplementation during pregnancy were included in this study.

RESULTS

A total of 226 SNP markers were tested after quality control in this study. Although 23 SNPs in three genes (CTNNB1, CDH1, ACTN1) showed nominal significant association with NSCL/P in the TDT (P<0.05).There were no significant evidence of linkage and association that remained in the transmission disequilibrium test after Bonferroni correction(P>0.000 2). Tests for gene-environment interaction yielded significant results between rs743127 in ACTN1 and environmental tobacco smoke (P=0.000 1) with an estimated OR (case|G and E)=2.00(95%CI: 1.23-3.26) and OR (case|G no E)=0.59 (95%CI: 0.38-0.90). Among the lower P value results in gene-environment tests, there were no significant results between rs1475034, rs370535, rs2273419 in ACTN1, rs106871 in CTNNB1 and environmental tobacco smoke interaction. There were also no significant results between rs7634000, rs2971366, rs2634553, rs1489032, rs7624812 in PVRL3 and multivitamin supplementation during pregnancy in gene-environment tests(P>0.000 2).

CONCLUSION

There is no association between cell-cell adhesion genes, including CDH1, CTNNB1, PVRL1, PVRL2, PVRL3, ACTN1, VCL, LEF1, and NSCL/P when the genes are considered alone. But our results suggest that SNPs in ACTN1 may influence the risk to NSCL/P through gene-environment interaction.

Systematic Analysis of Icotinib Treatment for Patients with Non-Small Cell Lung Cancer

PURPOSE

This analysis was conducted to evaluate the efficacy and safety of icotinib based regimens in treating patients with non-small cell lung cancer (NSCLC).

METHODS

Clinical studies evaluating the efficacy and safety of icotinib-based regimens with regard to response and safety for patients with NSCLC were identified using a predefined search strategy. Pooled response rates of treatment were calculated.

RESULTS

With icotinib-based regimens, 7 clinical studies which including 5,985 Chinese patients with NSCLC were considered eligible for inclusion. The pooled analysis suggested that, in all patients, the positive reponse rate was 30.1% (1,803/5,985) with icotinib-based regimens. Mild skin itching, rashes and diarrhea were the main side effects. No grade III or IV renal or liver toxicity was observed. No treatment-related death occurred in patients treated with icotinib-based regimens.

CONCLUSIONS

This evidence based analysis suggests that icotinib based regimens are associated with mild response rate and acceptable toxicity for treating Chinese patients with NSCLC.

Effects of cello-oligosaccharide on intestinal microbiota and epithelial barrier function of weanling pigs

A total of 144 piglets (Duroc × Landrace × Yorkshire; average initial weight of 6.13 kg weaned at 21 ± 1 d age) were allotted to 4 treatments for 2 wk, each of which had 6 pens with 6 pigs per pen. After the feeding experiment, 6 pigs per treatment were slaughtered to investigate the effects of cello-oligosaccharide (COS) on intestinal microbiota and epithelial barrier function. The COS was added to the basal diet at 0, 1.5, 3.0, and 4.5 g/kg diet at the expense of corn, respectively. Plasma -lactate, diamine oxidase (DAO), and the Ussing chamber technique were used to determine the intestinal barrier function. 16S rRNA-based methods were used for intestinal microbiota analysis. The results showed that incremental levels of COS had no effect ( > 0.05) on growth performance. Incremental levels of COS increased lactobacilli in jejunal and colonic contents ( < 0.05); decreased in jejunal contents ( < 0.05) and and in colonic contents ( < 0.05); reduced plasma DAO (linear, = 0.013, and quadratic, = 0.037); increased jejunal mucosa DAO (linear, = 0.003, and quadratic, = 0.008); decreased fluorescein isothiocyanate dextran 4 kDa flux of jejunum and colon ( < 0.05); and increased transepithelial electrical resistance (TER) in colon ( < 0.05), claudin-1 protein expression in jejunal mucosa (linear, = 0.001, and quadratic, = 0.003), and protein expressions of claudin-1 and zonula occludens-1 (ZO-1) in colonic mucosa linearly ( = 0.001 and = 0.001, respectively) and quadratically ( = 0.001 and = 0.002, respectively). The results indicated that the improved microbial ecosystem in the presence of COS might contribute to improvement in intestinal barrier function and tight junction proteins. Results also showed that the appropriate dietary COS supplementation level was 3.0 g/kg in weaned pig diets under our trial conditions.

Association study between Van der Woude Syndrome causative gene GRHL3 and nonsyndromic cleft lip with or without cleft palate in a Chinese cohort

Cleft lip with or without cleft palate (CL/P) is one of the most common birth defects worldwide and is characterized by abnormalities of the orofacial structure. Syndromic CL/P is mainly caused by Mendelian disorders such as Van der Woude Syndrome (VWS). However, >70% of CL/P cases are nonsyndromic, characterized by isolated orofacial cleft without any known syndrome. The etiology of nonsyndromic CL/P (NSCL/P) remains elusive, but it has been suggested that causative genes of syndromic CL/P might also contribute to NSCL/P. As such, the VWS causative gene IRF6 has been extensively studied in NSCL/P. Recently, GRHL3 was identified as another VWS causative gene. Thus, it may be a novel candidate gene for NSCL/P. In the present study, we genotyped 10 tag SNPs covering GRHL3 and performed association analysis with NSCL/P in 504 cases and 455 healthy controls. Our preliminary results identified rs10903078, rs4638975, and a haplotype rs10903078-rs6659209 of GRHL3 that exceeded the significance threshold (p<0.05), though none survived Bonferroni correction for multiple comparisons. As the first study between GRHL3 and NSCL/P, the contribution of this gene to NSCL/P etiology should be interpreted with caution based on existing evidence. Further, the robustness of association between GRHL3 and NSCL/P should be further validated in expanded cohorts.

Linezolid Induced Twice Pure Red Cell Aplasia in a Patient with Central Nervous System Infection after Allogeneic Stem Cell Transplantation

Linezolid (LZD), severed as the first oxazolidinone antibiotic, was active against multidrug-resistant gram-positive strains. LZD can induce thrombocytopenia, anemia and leukocytopenia. Currently, reports on pure red cell aplasia (PRCA) cases induced by LZD are relatively rare (4-7). In this paper, we reported a patient with PRCA twice induced by LZD. A 37-year-old man was diagnosed with myelodysplatic syndrome (MDS) and underwent allo-HSCT from an unrelated donor with ABO blood type and leukocyte antigen (HLA)-matching. After HSCT for 2 years, the patient suffered from refractory fever and headache. He was first treated with empirical antifungal agent and antibiotics for central nervous system (CNS) infection, but then changed to LZD therapy for little effect. Twenty-eight days after LZD treatment, the symptom improved significantly but the hemoglobin declined to 70 g/L and the reticulocyte level was only 0.23%. The LZD therapy was stopped and the fever and headache symptoms reoccurred 1 week latter. Then, erythropoietin (EPO) and halved dosage of LZD were used for treatment. The CNS infection and the anemia symptom relieved gradually and the level of hemoglobin and reticulocyte declined again. After blood transfusion, the half dose of LZD was sustained without anaemia recovery. In summary, patients with anemia, myelosuppressants history or potential abnormal proliferation of T cells may suffer PRCA with long term LZD treatment. The monitoring of complete blood count and reticulocyte count were necessary during LZD therapy. If the clinical condition permits, LZD dosage reduction and blood transfusion should be considered.

Disrupting the intrinsic growth potential of a suture contributes to midfacial hypoplasia

Children with unoperated cleft palates have nearly normal growth of their faces whereas patients who have had early surgical repair often exhibit midfacial hypoplasia. Surgical repair is responsible for the underlying bone growth arrest but the mechanisms responsible for these surgical sequelae are poorly understood. We simulated the effect of cleft palate repair by raising a mucoperiosteal flap in the murine palate. Three-dimensional micro-CT reconstructions of the palate along with histomorphometric measurements, finite element (FE) modeling, immunohistochemical analyses, and quantitative RT-PCR were employed to follow the skeletal healing process. Inflammatory bone resorption was observed during the first few days after denudation, which destroyed the midpalatal suture complex. FE modeling was used to predict and map the distribution of strains and their associated stresses in the area of denudation and the magnitude and location of hydrostatic and distortional strains corresponded to sites of skeletal tissue destruction. Once re-epithelialization was complete and wound contracture subsided, the midpalatal suture complex reformed. Despite this, growth at the midpalatal suture was reduced, which led to palatal constriction and a narrowing of the dental arch. Thus the simple act of raising a flap, here mimicked by denuding the mucoperiosteum, was sufficient to cause significant destruction to the midpalatal suture complex. Although the bone and cartilage growth plates were re-established, mediolateral skeletal growth was nonetheless compromised and the injured palate never reached its full growth potential. These data strongly suggest that disruption of suture complexes, which have intrinsic growth potential, should be avoided during surgical correction of congenital anomalies.

Effects of dietary supplementation of fulvic acid on lipid metabolism of finishing pigs

The experiment was conducted to investigate the effects of dietary supplementation of fulvic acid on lipid metabolism of finishing pigs. One hundred eighty crossbred barrows (Landrace × Yorkshire, 60 ± 2.5 kg) were randomly allotted to 5 dietary treatments (36 pigs/treatment) and fed a basal diet supplemented with 0, 0.2%, 0.4%, 0.6%, and 0.8% fulvic acid for 42 d. Thirty pigs (6 pigs/treatment) were slaughtered at the end of the experiment. Blood samples and adipose tissue were collected for determination of blood parameters and lipid metabolic enzymes. The results showed that compared with the control group, dietary supplementation of 0.2%, 0.4%, and 0.6% fulvic acid significantly reduced mean backfat thickness of pigs (P < 0.05). The serum concentrations of low-density lipoprotein, leptin, growth hormone, insulin, and triiodothyronine were significantly increased by adding fulvic acid in diets (P < 0.05). With the raised concentration of dietary fulvic acid, hormone sensitive lipase (HSL) activity was significantly increased (P < 0.05), and lipoprotein lipase (LPL) activity was significantly decreased (P < 0.05) in adipose tissue. In conclusion, dietary supplementation of fulvic acid reduced the mean backfat thickness of pigs. This change related to the increased activity of HSL and the decreased activity of LPL in adipose tissue.

Twist1 Is Essential for Tooth Morphogenesis and Odontoblast Differentiation

Twist1 is a basic helix-loop-helix-containing transcription factor that is expressed in the dental mesenchyme during the early stages of tooth development. To better delineate its roles in tooth development, we generated Twist1 conditional knockout embryos (Twist2(Cre) (/+);Twist1(fl/fl)) by breeding Twist1 floxed mice (Twist1(fl/fl)) with Twist2-Cre recombinase knockin mice (Twist2(Cre) (/+)). The Twist2(Cre) (/+);Twist1(fl/fl) embryos formed smaller tooth germs and abnormal cusps during early tooth morphogenesis. Molecular and histological analyses showed that the developing molars of the Twist2(Cre) (/+);Twist1(fl/fl) embryos had reduced cell proliferation and expression of fibroblast growth factors 3, 4, 9, and 10 and FGF receptors 1 and 2 in the dental epithelium and mesenchyme. In addition, 3-week-old renal capsular transplants of embryonic day 18.5 Twist2(Cre) (/+);Twist1(fl/fl) molars showed malformed crowns and cusps with defective crown dentin and enamel. Immunohistochemical analyses revealed that the implanted mutant molars had defects in odontoblast differentiation and delayed ameloblast differentiation. Furthermore, in vitro ChIP assays demonstrated that Twist1 was able to bind to a specific region of the Fgf10 promoter. In conclusion, our findings suggest that Twist1 plays crucial roles in regulating tooth development and that it may exert its functions through the FGF signaling pathway.