Genome sequencing of pancreatic cancer: differential expression by location

The results demonstrated that pancreatic ductal carcinoma (PDAC) of the body/tail was associated with more transcriptional and genomic changes, and correlated with worse prognosis, than PDAC of the pancreatic head. The different mutation types and gene expression of tumour locations provide deep insight into the carcinogenesis or metastasis of PDAC, and suggest different early diagnostic and therapeutic strategies. SNV, single-nucleotide variations; NLS, Nuclear localization sequence; MB, million base-pairs; UTR, untranslated region.

[Implication of enhanced recovery after surgery in the surgical management of hypopharyngeal squamous cell carcinoma]

Objective: To investigate the safety and efficacy of enhanced recovery after surgery (ERAS) in the clinical management of hypopharyngeal squamous cell carcinoma (HSCC). Methods: In this retrospective study, a total of 168 patients with pyriform sinus carcinoma in Qilu Hospital of Shandong University from January 2015 to January 2019 were divided into two groups, based on the different perioperative interventions that patients received, i.e. the ERAS group (n=64) and the conventional group (n=104), including 164 males and 4 females, whose ages ranged from 42 to 84 years old. The difference between two groups in the operative time, postoperative nutritional status, incidences of postoperative complications and postoperative hospitalization time were compared using the student's t test, Chi-squared test or Fisher's exact test. Results: Compared with the conventional group, patients in the ERAS group had significantly shorter operative time [(166.8±58.2) min vs. (183.3±39.9) min,t=-2.72, P=0.031], higher levels of postoperative serum albumin [(38.3±4.2) μmol/L vs. (36.6±3.3) μmol/L, t=2.73, P=0.007] and more body weight [(65.4±9.4) kg vs. (62.1±9.4) kg, t=2.22, P=0.028], lower incidences of postoperative subcutaneous infection [7.8% (5/64) vs. 20.2% (21/104), χ²=4.64, P=0.03] and severe pneumonia [4.7% (3/64) vs. 15.4% (16/104), χ²=4.52, P=0.03], and shorter postoperative hospitalization time [(16.5±3.9) d vs. (18.2±4.3) d, t=-2.65, P<0.05]. Conclusion: ERAS is effective and safe in the surgical management of HSCC, with benefits in reducing the operative stress via saving operation time, shortening the hospitalization time, ameliorating nutritional status and decreasing the incidences of complications.

The long non-coding RNA DDX11-AS1 facilitates cell progression and oxaliplatin resistance via regulating miR-326/IRS1 axis in gastric cancer

OBJECTIVE

The long non-coding RNA DDX11 antisense RNA 1 (DDX11-AS1) was found to be highly expressed in gastric cancer (GC). This study was to explore the role and molecular mechanism in oxaliplatin (OXA) resistance.

PATIENTS AND METHODS

The levels of DDX11-AS1, microRNA-326 (miR-326) and insulin receptor substrate 1 (IRS1) were measured by quantitative Real-time polymerase chain reaction (qRT-PCR). Cell proliferation, migration, invasion and apoptosis were examined by methylthiazolyldiphenyl-tetrazolium bromide (MTT), transwell and flow cytometry assays, respectively. Levels of all protein were detected using Western blot. The correlation between miR-326 and DDX11-AS1/IRS1 was confirmed by Dual-Luciferase reporter and RNA immunoprecipitation (RIP) assays. The xenograft model was constructed to explore the effect of DDX11-AS1 in vivo.

RESULTS

DDX11-AS1 was overexpressed in OXA-resistant GC tissues and cells, and DDX11-AS1 knockdown inhibited cell proliferation, migration, invasion and OXA resistance, and promoted apoptosis in OXA-resistant GC cells. Mechanically, DDX11-AS1 directly targeted miR-326 and miR-326 could bind to IRS1 in OXA-resistant GC cells. Functionally, silencing DDX11-AS1 repressed the progression and OXA resistance in OXA-resistant GC cells by down-modulating IRS1 expression via sponging miR-326 in vitro and in vivo.

CONCLUSIONS

DDX11-AS1 accelerated the progression and OXA chemoresistance of GC cells in vitro and in vivo by sponging miR-326, thus increasing the expression of IRS1, suggesting DDX11-AS1 might be a promising prognostic biomarker and therapeutic target in GC.

[Probability of premature mortality caused by four major non-communicable diseases and its impact on life expectancy in Wuxi, 2008-2018]

Objective: To analyze the trend of premature death of non-communicable diseases (NCDs) in Wuxi from 2008 to 2018 and evaluate the influence of premature mortality probability caused by four main NCDs on life expectancy. Methods: Based on the mortality data collected by Wuxi Mortality Registration System and the population data collected by Wuxi Public Security Bureau during 2008-2018, this study analyzes the trend of the probability of premature death on malignant tumors, cardiovascular and cerebrovascular diseases, chronic respiratory diseases, and diabetes. The impact on life expectancy was analyzed by using the methods of abridged life table, Joinpoint regression, and life expectancy contribution decomposition. Results: From 2008 to 2018, the total probability of premature death of four main NCDs in Wuxi were declined consistently from 11.25% to 9.25% (AAPC = -2.0%, 95%CI: -2.6--1.5), higher in female (from 7.74% to 5.91%) than that in male (from 14.49% to 12.51%). The Wuxi resident's life expectancy increased by 1.86 years (from 78.66 to 80.52 years), in males and 1.26 years (from 83.85 to 85.11 years) in females, respectively. The decline of premature death of malignant tumors, cardiovascular and cerebrovascular diseases and chronic respiratory system diseases had a positive contribution to life expectancy, which contributed 0.34 years (23.90%), 0.15 years (10.50%), and 0.03 years (2.36%) to the life expectancy growth, respectively. Among which, premature death of cardiovascular and cerebrovascular diseases in men aged 40-55y had a negative contribution to life expectancy (-0.04 years). The probability of premature death of males with diabetes was on the rise (AAPC = 7.1%, 95%CI: 2.8-11.6), which negatively contributed to life expectancy for both males and females, reducing life expectancy by 0.03 years (-2.14%) in Wuxi. Conclusion: The premature death probability of four main NCDs in Wuxi declined consistently from 2008 to 2018, which played a positive role in the growth of life expectancy. Compared with females, males had a higher premature death probability and a slower rate of decline. More intervention and health management of premature male death on cardiovascular and cerebrovascular diseases and diabetes should be conducted to improve life expectancy further.

Asymptomatic COVID-19 infection in patients with cancer at a cancer-specialized hospital in Wuhan, China - Preliminary results

OBJECTIVE

Patients with cancer are usually immunosuppressive and susceptible to COVID-19 infection. Asymptomatic COVID-19 cases are infective and cannot be identified by symptom-based screening. There is an urgent need to control virus spread by asymptomatic carriers at cancer centres. We aim to describe the characteristics, screening methods, and outcomes of cancer patients with asymptomatic COVID-19 infection and to further explore anti-tumour treatment for this population.

PATIENTS AND METHODS

We reviewed patients with cancer who were admitted to Hubei Cancer Hospital in Wuhan from February 1, 2020, to April 4, 2020. We collected demographic data, laboratory findings, treatment information, nucleic acid and serum test results, chest computed tomography (CT) information and survival status of cancer patients diagnosed with asymptomatic COVID-19 infection.

RESULTS

A total of 16 cancer patients with asymptomatic COVID-19 infection were confirmed. The most common cancer type was breast cancer. The blood cell counts of most patients were in the normal range. Lymphocytes of 100% of asymptomatic carriers were in the normal range. Thirteen (81.3%) patients were positive for virus-specific IgM antibodies, and three (18.8%) were positive by PCR; only one (6.3%) patient showed novel coronavirus pneumonia features on CT. Three (18.3%) patients died, and the cause of death was considered malignancy caused by delaying anti-tumour treatment.

CONCLUSIONS

Our study shows that the lymphocytes of 100% of asymptomatic carriers were in the normal range. This result indicates that the host immunity of asymptomatic carriers is not significantly disrupted by COVID-19. Single PCR detection is not sufficient to screen among asymptomatic individuals, and a combination of PCR tests, serological tests and CT is of great importance. Unless the tumour is life-threatening or rapidly progressing, we advise restarting active anti-tumour therapy after PCR tests become negative.

The importance of proper and prompt treatment of ocular syphilis: a lesson from permanent vision loss in 52 eyes

BACKGROUND

Ocular involvement can occur at any stage of syphilis. Prompt diagnosis and proper treatment of ocular syphilis are vital to avoid long-term consequences.

OBJECTIVES

To describe the risk factors for ocular syphilis and clinical features of blindness caused by syphilis.

METHODS

We report risk factors for ocular syphilis amongst patients seen at the Shanghai Skin Disease Hospital between October 2009 and October 2017. We identify patients with ocular syphilis resulting in blindness and report the clinical characteristics, laboratory findings and treatment outcomes of these patients.

RESULTS

A total of 8310 new cases of syphilis were seen, of which 213 patients had ocular disease and 50 patients had blindness due to syphilis. Increasing age and higher RPR titres were associated with ocular involvement but there was no association with HIV status. Blindness in syphilis was restricted predominantly to patients with optic nerve involvement and not patients with isolated uveitis. Fifty patients (and a total of 67 eyes) met the WHO definition of blindness prior to treatment for syphilis. At the end of follow-up, vision had improved in 24 of 67 eyes (35.8%) after treatment. Successful treatment of uveitis was associated with the best improvement in visual acuity, whilst patient with underlying optic atrophy prior to treatment had the worst visual outcome.

CONCLUSIONS

Ocular involvement is an important manifestation of syphilis which may result in blindness. Our data demonstrate outcomes for ocular syphilis are poor if detected late; early recognition and diagnosis is therefore vital to avoid permanent visual loss.

[Comparisons of clinical characteristics and prognosis between patients with primary and secondary thyroid lymphoma]

Objective: To compare clinical characteristics and prognosis between patients with primary (PTL) and secondary thyroid lymphoma (STL) . Methods: A retrospective analysis was performed on 46 patients with thyroid lymphoma (PTL 19, STL 27) from January 2002 to October 2018. Results: ①PTL group included 4 males and 15 females, with a median age of 57 years. The STL group included 10 males and 17 females, with a median age of 61 years. Diffuse large B-cell lymphoma (DLBCL) was the main pathological subtype in both PTL and STL groups, with 14 cases (73.7%) and 20 cases (74.1%) respectively. In terms of clinical manifestations, goiter was the most common symptom in PTL patients 100.0% (19/19) , while 29.6% (8/27) STL had goiter (P<0.001) . The incidences of increased thyroglobulin antibody (TRAb) /thyroid peroxidase antibody (TPO) were 81.3% (13/16) in PTL group and 43.8% (7/16) in STL group (P=0.028) respectively. Concerning the clinical features of patients, only two PTL patients (10.5%) with advanced Ann Arbor stage (Ⅲ/Ⅳ) , while 21 (77.8%) STL experienced advanced Ann Arbor stage (P<0.001) . Elevated serum β(2)-MG were appeared in 1 (7.1%) PTL and 9 (47.4%) STL patients (P=0.013) , and advanced IPI score (3-5) was more common in STL than PTL (59.3% vs 5.3%, P<0.001) . ②Among the 17 PTL patients who received treatments, 15 (88.2%) achieved remission; as for STL patients received treatments, 23/25 (92.0%) were in remission. The 5-year overall survival (OS) rates of PTL (n=17) and STL groups (n=25) were (87.4±8.4) % and (70.0±13.1) % (P=0.433) respectively. ③The 5-year OS rate in 41 patients with B-cell thyroid lymphoma was (81.1±7.5) %. Univariate analysis showed that IPI score of 3-5 (P=0.040) and high level of serum IL-8 (P=0.022) were significantly associated with poor outcome. Conclusion: DLBCL was the most common subtype in both PTL and STL, and goiter was the major symptom in PTL. IPI score of 3-5 and high level of serum IL-8 were unfavorable prognostic factors for patients with B-cell thyroid lymphoma.

SAT0175 IMPACT OF ANTIMALARIAL ADHERENCE ON MORTALITY AMONG PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS: A POPULATION-BASED COHORT STUDY

Background:

Evidence has consistently shown that adherence to AM is poor in systemic lupus erythematosus (SLE) patients. However, data on the impact of adherence to AM on mortality is scarce.

Objectives:

To assess the effect of AM adherence on all-cause mortality in SLE patients from the general population.

Methods:

This study used administrative databases from British Columbia, Canada. We created an incident SLE cohort between January 01, 1997, and March 31, 2015, using the physician billing data and a 7-year washout period. The inclusion criteria were at least two physician visits, at least two months apart, within two years, with an ICD-9 code (710.0) or ICD-10 code (M32.1, M32.8, M32.9) for SLE. Follow-up started at the first day of having both SLE and AM, i.e., at the SLE index date (second ICD code) for those whose first AM use occurred before the SLE index date, or the date of the first AM use if otherwise. Our outcome was all-cause mortality, obtained from the vital statistics registry. In the analysis, the follow-up time was divided into 30-days windows, for a total of 293,190 person-months. For each window, a measure of adherence, the proportion of days covered (PDC), was calculated and categorized as adherent (PDC≥0.90), non-adherent (0<PDC<0.90), and discontinuer (no drug or PDC = 0). We used both Cox’s proportional hazards models and marginal structural models (MSM) to estimate the effect of AM adherence on all-cause mortality. Both analysis controlled for baseline demographics (age, sex, residence, income quintile), as well as the following baseline and time-varying covariates: immunosuppressive and other medications, hospitalizations, impatient, and other visits, and Charlson comorbidity index. To account for the possibility of a few time-varying covariates being mediators in the causal pathway from AM adherence to mortality, which may cause the Cox model to yield biased estimates of the adherence effects, we conducted the MSM analysis that can produce valid estimates as it balances the distributions of time-varying confounders among the three adherence groups via inverse probability weighting.

Results:

We identified 3,385 individuals with incident SLE (mean age 47.3 years, 89% were women) who had at least one filled AM prescription. Over the mean follow-up of 6.66 years, 288 (8.5%) incident SLE patients died. The incidence rate (IR) of mortality for AM adherent, non-adherent, and discontinuer patients were 4.31, 11.86, and 19.51 per 1000 person-years, respectively. Using the Cox model, the adjusted hazard ratio (HRs) obtained for AM adherent and non-adherent SLE patients were 0.20 and 0.66, respectively, compared to discontinuer SLE patients (Table 1). Using MSM, those adjusted HRs were found as 0.18 and 0.64. Also, the adjusted HRs for adherers compared to the non-adherers were 0.30 (Cox) and 0.28 (MSM). A statistically significant linear trend in the HRs of mortality risk over the adherence levels was found (Table 1, Linear Trend).

Table 1.Adherence LevelsNo. of DeathsIR Ratios (95%CI)Adjusted Cox HRs (95%CI)Adjusted MSM HRs (95%CI)Discontinuer (Reference)198Non-adherent470.61(0.44-0.84)0.66(0.47-0.93)0.64(0.46-0.89)Adherent430.22(0.16-0.31)0.20(0.14-0.28)0.18(0.12-0.25)Contrast: Partial vs. Full0.36(0.24-0.55)0.30(0.19-0.46)0.28(0.18-0.42)Linear Trend0.32(0.25-0.41)0.29(0.23-0.37)

Conclusion:

SLE patients that adhere to AM therapy have a lower risk of death than patients who do not adhere or who discontinue AM (5 and 3 times, respectively) in both the MSM and Cox analysis. Our findings support the importance of AM adherence to prevent premature deaths in SLE patients.

Disclosure of Interests:

None declared

The quorum-sensing molecule 2-phenylethanol impaired conidial germination, hyphal membrane integrity and growth of Penicillium expansum and Penicillium nordicum

AIMS

The aim of the study was to investigate the antifungal effects of a quorum sensing-molecule, 2-phenylethanol, against the food spoilage moulds Penicillium expansum and Penicillium nordicum.

METHODS AND RESULTS

Conidial germination of the tested Penicillium spp. (three strains in total) were inhibited by treatments with 2-phenylethanol in a concentration-dependent manner. Germinated conidia was significantly reduced from 4·4-16·7% at 7·5 mmol l^-1 and completely inhibited at 15 mmol l^-1 2-phenylethanol. Integrity of conidial cell membranes was unaffected by 2-phenylethanol resulting in reversible inhibition pattern of germination. In contrast, membrane permeability of actively growing hyphae was severely compromised, showing 63·5 - 75·7% membrane damage upon treatment with 15 mmol l^-1 2-phenylethanol. The overall inhibitory effect of 2-phenylethanol on colony development and growth of P. expansum and P. nordicum was additionally confirmed.

CONCLUSIONS

2-phenylethanol inhibits conidial germination and growth of P. expansum and P. nordicum in a nonlethal, reversible and concentration-dependent manner.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study indicates that 2-phenylethanol can find potential application as an antifungal agent for biological control of moulds in the food industry.

The Nab experiment: A precision measurement of unpolarized neutron beta decay

Neutron beta decay is one of the most fundamental processes in nuclear physics and provides sensitive means to uncover the details of the weak interaction. Neutron beta decay can evaluate the ratio of axial-vector to vector coupling constants in the standard model, λ = gA/gV, through multiple decay correlations. The Nab experiment will carry out measurements of the electron-neutrino correlation parameter a with a precision of δa/a = 10−3 and the Fierz interference term b to δb = 3 × 10−3 in unpolarized free neutron beta decay. These results, along with a more precise measurement of the neutron lifetime, aim to deliver an independent determination of the ratio λ with a precision of δλ/λ = 0.03% that will allow an evaluation of Vud and sensitively test CKM unitarity, independent of nuclear models. Nab utilizes a novel, long asymmetric spectrometer that guides the decay electron and proton to two large area silicon detectors in order to precisely determine the electron energy and an estimation of the proton momentum from the proton time of flight. The Nab spectrometer is being commissioned at the Fundamental Neutron Physics Beamline at the Spallation Neutron Source at Oak Ridge National Lab. We present an overview of the Nab experiment and recent updates on the spectrometer, analysis, and systematic effects.

Liquid Chromatographic Determination of Maleic Hydrazide in Technical and Formulated Products: Collaborative Study

Fourteen collaborating laboratories assayed maleic hydrazide (MH), 6-hydroxypyridazin-3(2H)-one, in technical and formulated products by reversed-phase liquid chromatography (LC) with sulfanilic acid as an internal standard. The active MH in the samples (6 lots) ranged from 16% (expressed as the potassium salt) to 98% (MH in the technical). A small amount of 1 M KOH was added to the technical MH and analytical standards to create the potassium salt of the analyte which is soluble in water. Test samples and standards were extracted with water containing the internal standard before analysis by LC on a C8 column with an ion-pairing eluting solution and UV detection at 254 nm. The concentration of MH was calculated by comparing the peak area response ratios of the analyte and the internal standard with those in the analytical standard solution. Eleven laboratories weighed each test sample twice with single analysis. Three laboratories weighed each sample once and made duplicate injections on the LC system. The data were analyzed using the 11 laboratories' results. A second data analysis was done including all laboratory results using a Youden pair approach, selecting one of 2 duplicate assay values randomly for each laboratory and sample. In the first data analysis, the repeatability standard deviation ranged from 0.07 to 1.39%; reproducibility standard deviation ranged from 0.22 to 1.39%. In the second data analysis (using all laboratory data), repeatability standard deviation ranged from 0.09 to 0.86%; reproducibility standard deviation ranged from 0.22 to 1.31%.

Transcriptome analysis reveals corresponding genes and key pathways involved in heat stress in Hu sheep

Heat stress (HS) seriously affects animal performance. In view of global warming, it is essential to understand the regulatory mechanisms by which animals adapt to heat stress. In this study, our aim was to explore the genes and pathways involved in heat stress in sheep. To this end, we used transcriptome analysis to understand the molecular responses to heat stress and thereby identify means to protect sheep from heat shock. To obtain an overview of the effects of heat stress on sheep, we used the hypothalamus for transcriptome sequencing and identified differentially expressed genes (DEGs; false discovery rate (FDR) < 0.01; fold change > 2) during heat stress. A total of 1423 DEGs (1122 upregulated and 301 downregulated) were identified and classified into Gene Ontology (GO) categories and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Heat stress triggered dramatic and complex alterations in gene expression in the hypothalamus. We hypothesized that heat stress induced apoptosis and dysfunction in cells and vital organs and affected growth, development, reproduction, and circadian entrainment via the calcium signaling pathway, which influences ribosome assembly and function. Real-time PCR was used to evaluate the expression of the genes regulating important biological functions or whose expression profiles were significantly changed after acute heat stress (FDR < 0.01; fold change > 4), and the results showed that the expression patterns of these genes were consistent with the results of transcriptome sequencing, indicating that the credibility of the sequencing results. Our data indicated that heat stress induced calcium dyshomeostasis, blocked biogenesis, caused ROS accumulation, impaired the antioxidant system and innate defense, and induced apoptosis through the P53 signaling pathway activated by PEG3, decreased growth and development, and enhanced organ damage. These data is very important and helpful to elucidate the molecular mechanism of heat stress and finally to find ways to deal with heat stress damage in sheep.

Klinefelter's syndrome with systemic lupus erythematosus and atrial fibrillation

We describe a 65-year-old man who presented with arthralgia, reduced body hair and gynecomastia. He showed severe pancytopaenia. Laboratory examination revealed high follicle-stimulating hormone, low testosterone and oestradiol, elevated antinuclear antibodies, anti-dsDNA and ESR levels, as well as low complement levels. An electrocardiogram showed atrial fibrillation. Computed tomography and dual-energy x-ray absorptiometry showed pleural effusion and osteoporosis. Chromosome analysis revealed 47, XXY karyotype. The unifying diagnosis was therefore Klinefelter's syndrome (KS) with systemic lupus erythematosus (SLE), with manifestations of pancytopaenia, atrial fibrillation, serositis and osteoporosis. After immunosuppressive therapy, his physical condition and pancytopaenia improved. Sex hormones and gene escape from X chromosome inactivation may contribute to the pathogenesis of SLE. Clinicians should consider autoimmune processes when patients with KS present with pancytopaenia or additional features of a systemic autoimmune disorder.

[Surgical treatment in 184 patients with supraglottic carcinoma at a single institute]

Objective: To summarize clinical experience in surgical treatment of supraglottic carcinoma and reconstructive techniques. Methods: Medical files of 184 patients (173 men, 11 women) were collected and retrospectively analyzed, who underwent surgeries between January 2008 and December 2012 at Qilu Hospital of Shandong University. Among them, T1, T2, T3 and T4 staging tumors accounted respectively for 14.1% (26/184), 41.9%(77/184), 31.5%(58/184) and 12.5%(23/184). Cervical metastasis was histologically identified in 86 cases (98 for N0, 31 for N1 and 55 for N2). Advanced cases (56 cases at stage Ⅲ and 67 at stage Ⅳ), early cases (22 at stage Ⅰ and 39 at stage Ⅱ) accounted respectively for 66.8% and 33.2%. Supraglottic horizontal laryngectomy or total laryngectomy was performed to allow for tumor excision without compromising margins and the tongue flap or sternohyoidmyofascial flap was subsequently used for repairing the defect after removal of tumor. Survival rates were analyzed by the Kaplan-Meier method. Results: Patients receiving conservation laryngeal surgery accounted for 75.5% (139/184). The 3-year and 5-year survival rates for all cases were 84.2% and 70.7%, respectively. Log-rank test demonstrated that cervical lymph node metastasis, primary tumor staging and clinical TNM staging were significantly associated with prognoses of patients (P=0.003, 0.010, 0.035). Dysphagia was not observed in any case and speech function was maintained in petients with partial laryngectomy. Conclusion: Adequate pre-operative evaluation, individualized treatment, and comprehensive application of flaps for repair are critical to precise tumor excision and reconstruction of laryngeal functions.

Wnt Production in Dental Epithelium Is Crucial for Tooth Differentiation

The Wnt ligands display varied spatiotemporal expression in the epithelium and mesenchyme in the developing tooth. Thus far, the actions of these differentially expressed Wnt ligands on tooth development are not clear. Shh expression specifies the odontogenic epithelium during initiation and is consistently restricted to the dental epithelium during tooth development. In this study, we inactivate Wntless ( Wls), the key regulator for Wnt trafficking, by Shh-Cre to investigate how the Wnt ligands produced in the dental epithelium lineage act on tooth development. We find that conditional knockout of Wls by Shh-Cre leads to defective ameloblast and odontoblast differentiation. Wls^Shh-Cre teeth display reduced canonical Wnt signaling activity in the inner enamel epithelium and the underlying mesenchyme at the early bell stage, as exhibited by target gene expression and BAT-gal staining. The expression of Wnt5a and Wnt10b is not changed in Wls^Shh-Cre teeth. By contrast, Wnt10a expression is significantly increased in response to epithelial Wls deficiency. In addition, the expression of Hedgehog signaling pathway components Shh, Gli1, and Patched1 was greatly decreased in Wls^Shh-Cre teeth. Epithelial Wls loss of function in Shh lineage also leads to aberrant cell proliferation in dental epithelium and mesenchyme at embryonic day 16.5; however, the cell apoptosis is unaffected. Moreover, we find that Decorin and Col1a1, the key markers for odontoblast differentiation that are downregulated in Wls^Shh-Cre teeth, act as direct downstream targets of the canonical Wnt signaling pathway by chromatin immunoprecipitation analysis. Additionally, Decorin and Col1a1 expression can be increased by lithium chloride (LiCl) treatment in the in vitro tooth explants. Taken together, our results suggest that the spatial expression of Wnt ligands within the dental epithelial lineage regulates the differentiation of tooth structures in later stages.