Impact of chemotherapy on surgical outcomes in ileostomy reversal: a propensity score matching study from a single centre.

PURPOSE: In patients with chemotherapy, there is no consensus on the timing of ileostomy closure. Ileostomy reversal could improve the quality of life and minimise the long-term adverse events of delayed closure. In this study, we evaluated the impact of chemotherapy on ileostomy closure and searched for the predictive factors for complications. METHODS: We retrospectively analysed 212 patients with rectal cancer who underwent ileostomy closure surgery during and without chemotherapy and were consecutively enrolled between 2010 and 2016. As a result of the heterogeneity of the two groups, propensity score matching (PSM) was performed with a 1:1 PSM cohort. RESULTS: A total of 162 patients were included in the analysis. The overall stoma closure-related complications (12.4% vs. 11.1%, p = 1.00) and major complications (2.5% vs. 6.2%, p = 0.44) were not significantly different between the two groups. Multivariate analysis demonstrated that chronic kidney disease and bevacizumab use are risk factors for major complications. CONCLUSION: Patients with oral or intravenous chemotherapy can safely have ileostomy closure with an adequate time delay from chemotherapy. When patients use bevacizumab, major complications related to ileostomy closure should still be cautioned.

Infection risk in psoriatic patients receiving tumour necrosis factor inhibitors: a 20-year systematic review and meta-analysis of randomized controlled trials.

Tumour necrosis factor inhibitors (TNFis) are commonly used for treating psoriatic diseases; however, the risk of infection while receiving TNFis remains uncertain. The aim of this study was to investigate the infection risk in patients with psoriatic disease receiving TNFis. A prospectively registered systematic literature search was conducted in Medline (PubMed), Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE and the ClinicalTrials.gov databases from inception to December 31, 2021. We included double-blind randomized controlled trials that compared TNFis or other biologics with placebo in adults with psoriasis or psoriatic arthritis. The primary outcomes included overall and serious infection risks, and secondary outcomes included upper respiratory infections and nasopharyngitis risks. The risk ratio of the dichotomous outcome was calculated using the Mantel-Haenszel method with random effects, and heterogeneity was assessed using Cochran's Q statistic and quantified using the I-squared statistic. A total of 48 studies with 15 464 patients with psoriatic diseases were included. The meta-analysis demonstrated a slightly increased overall infection risk (risk ratio = 1.09; 95% confidence interval, 1.02-1.15) but not serious infection risk (risk ratio = 0.95; 95% confidence interval, 0.61-1.49) among patients receiving TNFis. There were also no increased risks of upper respiratory infections (risk ratio = 1.10; 95% confidence interval, 0.94-1.28) or nasopharyngitis (risk ratio = 1.14; 95% confidence interval, 1.00-1.30). In subgroup analyses using the fixed effects model, only etanercept and certolizumab pegol were, respectively, associated with an increased risk of overall infection (RR = 1.14, 95% CI, 1.03-1.27) and upper respiratory infections (RR = 1.42, 95% CI, 1.02-1.98). In conclusion, evidence to date suggests an increased overall infection risk that is generally tolerable in patients with psoriatic diseases receiving TNFis. There are no increased risks of serious infections, upper respiratory infections or nasopharyngitis.

[Minimally invasive surgery in the concept of enhanced recovery after surgery].

Enhanced recovery after surgery (ERAS) and minimally invasive surgery are two important development directions of modern surgery in the 21st century. They provide new clinical treatment methods and theoretical basis for the rapid recovery of surgical patients and more rational utilization of medical resources. They are two hot topics in clinical research and academic exchange of surgery-related subjects, and promote the rapid development and clinical application of surgery. ERAS covers a range of preoperative, intraoperative, and postoperative optimization measures, of which minimally invasive surgery is an important part of intraoperative optimization. The quality of surgery, especially minimally invasive surgery, plays a key role in postoperative recovery, which is the most important one of all ERAS measures. With good surgical quality and no postoperative complications, patients will recover quickly. Therefore, minimally invasive surgery plays a central role in the ERAS concept. The combination of ERAS with minimally invasive surgery is not only safe and feasible, but is also better than these two clinical therapies alone for postoperative recovery, and improves short-term and long-term outcome and accelerates the recovery of patients. For surgical diseases treated with minimally invasive surgery as far as possible, using the ERAS management for patients will result in reduced traumatic stress, better surgical tolerance, less postoperative pain, smaller incision, earlier ambulation, better organ function, and less morbidity of complications. In short, ERAS and minimally invasive surgery complement and promote each other. As two outstanding achievements of modern medicine, they are clinical treatments that provide sufficient theoretical basis for rapid recovery of patients and open a new chapter for the development of modern surgery.

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.

Transperineal minimally invasive APE: preliminary outcomes in a multicenter cohort.

BACKGROUND: Abdominoperineal excision (APE) for rectal cancer is associated with a relatively high risk of positive margins and postoperative morbidity, particularly related to perineal wound healing problems. It is unknown whether the use of a minimally invasive approach for the perineal part of these procedures can improve postoperative outcomes without oncological compromise. The aim of this study was to evaluate the feasibility of minimally invasive transperineal abdominoperineal excision (TpAPE) METHODS: This multicenter retrospective cohort study included all patients having TpAPE for primary low rectal cancer. The primary endpoint was the intraoperative complication rate. Secondary endpoints included major morbidity (Clavien-Dindo ≥ 3), histopathology results, and perineal wound healing. RESULTS: A total of 32 TpAPE procedures were performed in five centers. A bilateral extralevator APE (ELAPE) was performed in 17 patients (53%), a unilateral ELAPE in 7 (22%), and an APE in 8 (25%). Intraoperative complications occurred in five cases (16%) and severe postoperative morbidity in three cases (9%). There were no perioperative deaths. A positive margin (R1) was observed in four patients (13%) and specimen perforation occurred in two (6%). The unilateral extralevator TpAPE group had worse specimen quality and a higher proportion of R1 resections than the bilateral ELAPE or standard APE groups. The rate of uncomplicated perineal wound healing was 53% (n = 17) and three patients (9%) required surgical reintervention. CONCLUSIONS: TpAPE seems to be feasible with acceptable perioperative morbidity and a relatively low rate of perineal wound dehiscence, while histopathological outcomes remain suboptimal. Additional evaluation of the viability of this technique is needed in the form of a prospective trial with standardization of the procedure, indication, audit of outcomes and performed by surgeons with vast experience in transanal total mesorectal excision.

Phylogenetic placement of Paratrichaptum and reconsideration of Gloeophyllales.

Paratrichaptum accuratum is a large conspicuous polypore fungus growing on dead or living angiosperm trees in subtropical-boreal areas of China, Indonesia, Japan, and Taiwan. The present study places P. accuratum in the family Gloeophyllaceae that belongs to the order Gloeophyllales within Agaricomycetes (Basidiomycota), based on evidence derived from morphological and ecological characteristics, and phylogenetic analyses of sequences of nuclear rDNA regions (5.8S, nuc 18S, nuc 28S) and protein-coding genes (rpb1, rpb2, and tef1). The analyses presented in this study also give strong support for including Jaapia in Gloeophyllaceae and Gloeophyllales. Thus, the names Jaapiaceae and Jaapiales are considered here as synonyms of Gloeophyllaceae and Gloeophyllales. Since Paratrichaptum represents the earliest diverging lineage in Gloeophyllales, pileate basidiocarps and brown rot appear to be ancestral states of Gloeophyllales. Paratrichaptum accuratum may represent a relic species, according to its phylogenetic position, peculiar distribution pattern and rare occurrence.

Incompletely excised lentigo maligna melanoma is associated with unpredictable residual disease: clinical features and the emerging role of reflectance confocal microscopy.

BACKGROUND: Lentigo maligna/lentigo maligna melanoma (LM/LMM) poses a treatment and surgical challenge given unpredictable subclinical extension resulting in incomplete excision. OBJECTIVES: To describe the demographic, clinical and pathologic characteristics of incompletely excised LM/LMM. To evaluate the potential role of reflectance confocal microscopy (RCM). PATIENTS AND METHODS: A retrospective review of a melanoma database at a tertiary cancer centre for patients referred with 'incompletely excised LM/LMM' or 'incompletely excised melanoma' between October 2006 and July 2017. We recorded clinical and pathological data and surgical margins needed to clear the residual LM/LMM. The second part consisted of a prospective cohort of patients in which RCM was performed when presenting with incompletely excised LM/LMM. RESULTS: We included a total of 67 patients (retrospective + prospective cohort); mean age was 64.9 (standard deviation: 11.3) years and 52.2% were males. For the retrospective cohort (n = 53), the mean scar size was 3.4 cm. The average initial margins excised prior to presentation were 4.8 mm (range 3-7 mm). The average additional margin needed to clear the residual, incompletely excised LM/LMM was 7.8 mm. For the prospective cohort (n = 14), there were no differences in age, gender or size when compared to the retrospective cohort. RCM had a diagnostic accuracy of 78.6%, a sensitivity of 90.9%, a specificity of 33.3% and a positive predictive value of 83.3% for the detection of incompletely excised LM/LMM. CONCLUSIONS: Incompletely excised LM/LMM is a poorly characterized clinical-pathological scenario that may require considerable extra margins for microscopic clearance. RCM may emerge as a valuable tool for the evaluation of patients with incompletely excised LM/LMM.

Inpatient and outpatient treatment patterns of cancer-associated thrombosis in the United States.

Low molecular weight heparins (LMWHs) and direct oral anticoagulants (DOACs) are among the recommended treatment options for cancer-associated thrombosis (CAT) in the 2019 National Comprehensive Care Network guidelines. Little is known about the current utilization of DOACs in CAT patients, particularly on the inpatient to outpatient therapy transition. This study assessed real-world treatment patterns of CAT in hospital/ED in adult cancer patients (≥ 18 years) diagnosed with CAT during a hospital visit in IQVIA's Hospital Charge Data Master database between July 1, 2015 and April 30, 2018, and followed their outpatient medical and pharmacy claims to evaluate the initial inpatient/ED and outpatient anticoagulants received within 3 months post-discharge. Results showed that LMWH and unfractionated heparin (UFH) were the most common initial inpatient/ED CAT treatments (35.2% and 27.4%, respectively), followed by DOACs (9.6%); 20.8% of patients received no anticoagulants. Most DOAC patients remained on DOACs from inpatient/ED to outpatient settings (71.4%), while 24.1%, 43.5%, and 0.1% of patients treated with LMWH, warfarin, or UFH respectively, remained on the same therapy after discharge. In addition, DOACs were the most common initial post-discharge outpatient therapy. Outpatient treatment persistence and adherence appeared higher in patients using DOACs or warfarin versus LMWH or UFH. This study shows that DOACs are used as an inpatient/ED treatment option for CAT, and are associated with less post-discharge treatment switching and higher persistence and adherence. Further research generating real-world evidence on the role of DOACs to help inform the complex CAT clinical treatment decisions is warranted.

Reflectance confocal microscopy and dermoscopy aid in evaluating repigmentation within or adjacent to lentigo maligna melanoma surgical scars.

BACKGROUND: Determining whether repigmentation within or adjacent to lentigo maligna or lentigo maligna melanoma (LM/LMM) scars represents recurrence of melanoma is challenging. The use of reflectance confocal microscopy (RCM) and dermoscopy may aid in differentiating true melanoma recurrence from other causes of repigmentation. OBJECTIVES: To describe the characteristics of repigmentation within or adjacent to LM/LMM scars observable on RCM and dermoscopy. METHODS: We retrospectively analysed patients who presented with new pigmentation within or adjacent to scars from surgically treated LM/LMM between January 2014 and December 2018. Clinical and demographic characteristics and time to recurrence were recorded. RCM was used to evaluate areas of pigmentation before biopsy. If available, dermoscopic images were also evaluated. RESULTS: In total, 30 confocal studies in 29 patients were included in the study cohort. Twenty-one patients had biopsy-confirmed recurrent LM/LMM; the remainder had pigmented actinic keratosis (n = 4) or hyperpigmentation/solar lentigo (n = 5). RCM had sensitivity of 95.24% (95% CI, 76.18-99.88%), specificity of 77.7% (95% CI, 39.99-97.19%), positive predictive value of 90.91% (95% CI, 74.58-97.15%) and negative predictive value of 87.5% (95% CI, 50.04-98.0%). The most common dermoscopic feature observed among patients with recurrent LM/LMM was focal homogeneous or structureless areas of light-brown pigmentation (92.8% vs. 37.5% in patients with other diagnoses; P = 0.009). LM-specific dermoscopic criteria were present in only 28.5% of patients with recurrent LM/LMM. CONCLUSIONS: Reflectance confocal microscopy and dermoscopy are valuable tools for the comprehensive evaluation of repigmentation within or adjacent to LM scars.

Activation of the NLRP3 and AIM2 inflammasomes in a mouse model of Schistosoma mansoni infection.

Schistosomiasis is an inflammatory disease that occurs when schistosome species eggs are deposited in the liver, resulting in fibrosis and portal hypertension. Schistosomes can interact with host inflammasomes to elicit host immune responses, leading to mitochondrial damage, generation of high levels of reactive oxygen species (ROS) and activation of apoptosis during inflammation. This study aims to examine whether ROS and NF-κB (p65) expression elicited other types of inflammasome activation in Schistosoma mansoni-infected mouse livers. We examine the relationship between inflammasome activation, mitochondrial damage and ROS production in mouse livers infected with S. mansoni. We demonstrate a significant release of ROS and superoxides and increased NF-κB (p65) in S. mansoni-infected mouse livers. Moreover, activation of the NLRP3 and AIM2 inflammasomes was triggered by S. mansoni infection. Stimulation of HuH-7 hepatocellular carcinoma cells with soluble egg antigen induced activation of the AIM2 inflammasome pathway. In this study, we demonstrate that S. mansoni infection promotes both NLRP3 and AIM2 inflammasome activation.

[Clinical manifestations analysis of patients diagnosed with primary pulmonary mucosa-associated lymphoid tissue lymphoma].

Objective: To analyze the clinical features of pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma. Methods: A total of 14 cases diagnosed with primary pulmonary MALT lymphoma were collected from May 2007 to May 2017 in Zhongshan Hospital, Fudan University. The clinical features, pathological characteristics, diagnosis, treatment and prognosis were retrospectively analyzed. Results: All 14 cases were pathologically diagnosed with primary pulmonary MALT lymphoma. The biopsy tissues were obtained through the Video-assisted Thoracoscopic Surgery (VATS) (4 cases), percutaneous puncture (2 cases), and bronchoscopy (8 cases). Cell types of these tumors were centrocyte-like cells (10 cases), lymphocytoid cells (2 cases), and monocytoid B cells (2 cases). The B cell clonality was detected by IgH cloning test in 4 cases and 3 of them were demonstrated with monoclonal strips. MALT1 breakup gene was positive in 3 out of 6 examined cases using fluorescence in situ hybridization (FISH). As for the treatment, 8 patients underwent chemotherapy, 5 patients underwent surgical resection and 1 patient abandoned treatment. Twelve patients were followed up to 9 years. The tumor recurrence occurred in 2 patients and resulted their death. Conclusions: The clinical manifestations of primary pulmonary MALT lymphoma are lack of specificity. The pathology, immunohistochemistry, IgH cloning test and MALT1 breakup gene tested by FISH are the criteria for diagnosis.

Tumor-induced osteomalacia in association with PTEN-negative Cowden syndrome.

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic condition in which phosphaturic mesenchymal tumors (PMTs) secrete high levels of fibroblast growth factor 23 (FGF23) into the circulation. This results in renal phosphate wasting, hypophosphatemia, muscle weakness, bone pain, and pathological fractures. Recent studies suggest that fibronectin-fibroblast growth factor receptor 1 (FN1-FGFR1) translocations may be a driver of tumorigenesis. We present a patient with TIO who also exhibited clinical findings suggestive of Cowden syndrome (CS), a rare autosomal dominant disorder characterized by numerous benign hamartomas, as well as an increased risk for multiple malignancies, such as thyroid cancer. While CS is a clinical diagnosis, most, but not all, harbor a mutation in the tumor suppressor gene PTEN. Genetic testing revealed a somatic FN1-FGFR1 translocation in the FGF23-producing tumor causing TIO; however, a germline PTEN mutation was not identified. To our knowledge, this is the first reported case of concurrent TIO and CS.

Strongly exchange-coupled and surface-state-modulated magnetization dynamics in Bi2Se3/yttrium iron garnet heterostructures.

Harnessing the spin-momentum locking of topological surface states in conjunction with magnetic materials is the first step to realize novel topological insulator-based devices. Here, we report strong interfacial coupling in Bi2Se3/yttrium iron garnet (YIG) bilayers manifested as large interfacial in-plane magnetic anisotropy (IMA) and enhancement of damping probed by ferromagnetic resonance. The interfacial IMA and damping enhancement reaches a maximum when the Bi2Se3 film approaches its two-dimensional limit, indicating that topological surface states play an important role in the magnetization dynamics of YIG. Temperature-dependent ferromagnetic resonance of Bi2Se3/YIG reveals signatures of the magnetic proximity effect of TC as high as 180 K, an emerging low-temperature perpendicular magnetic anisotropy competing the high-temperature IMA, and an increasing exchange effective field of YIG steadily increasing toward low temperature. Our study sheds light on the effects of topological insulators on magnetization dynamics, essential for the development of topological insulator-based spintronic devices.

Acute myeloid leukemia transforms the bone marrow niche into a leukemia-permissive microenvironment through exosome secretion.

Little is known about how leukemia cells alter the bone marrow (BM) niche to facilitate their own growth and evade chemotherapy. Here, we provide evidence that acute myeloid leukemia (AML) blasts remodel the BM niche into a leukemia growth-permissive and normal hematopoiesis-suppressive microenvironment through exosome secretion. Either engrafted AML cells or AML-derived exosomes increased mesenchymal stromal progenitors and blocked osteolineage development and bone formation in vivo. Preconditioning with AML-derived exosomes 'primed' the animals for accelerated AML growth. Conversely, disruption of exosome secretion in AML cells through targeting Rab27a, an important regulator involved in exosome release, significantly delayed leukemia development. In BM stromal cells, AML-derived exosomes induced the expression of DKK1, a suppressor of normal hematopoiesis and osteogenesis, thereby contributing to osteoblast loss. Conversely, treatment with a DKK1 inhibitor delayed AML progression and prolonged survival in AML-engrafted mice. In addition, AML-derived exosomes induced a broad downregulation of hematopoietic stem cell-supporting factors (for example, CXCL12, KITL and IGF1) in BM stromal cells and reduced their ability to support normal hematopoiesis. Altogether, this study uncovers novel features of AML pathogenesis and unveils how AML cells create a self-strengthening leukemic niche that promotes leukemic cell proliferation and survival, while suppressing normal hematopoiesis through exosome secretion.

Cancer incidence in young and middle-aged people with schizophrenia: nationwide cohort study in Taiwan, 2000-2010.

AIMS: For nearly a century, the incidence of cancer in people with schizophrenia was lower than in the general population. In the recent decade, the relationship between cancer and schizophrenia has become obscured. Thus, we investigated the cancer risk among young and middle-aged patients with schizophrenia. METHODS: Records of newly admitted patients with schizophrenia (n = 32 731) from January 2000 through December 2008 were retrieved from the Psychiatric Inpatient Medical Claims database in Taiwan, and the first psychiatric admission of each patient during the same period was defined as the baseline. We obtained 514 incident cancer cases that were monitored until December 2010. Standardised incidence ratios (SIRs) were calculated to compare the risk of cancer between those with schizophrenia and the general population. Stratified analyses of cancer incidences were performed by gender, site of cancers and duration since baseline (first psychiatric admission). RESULTS: The incidence of cancer for all sites was slightly higher than that of the general population for the period (SIR = 1.15 [95% CI 1.06-1.26], p = 0.001). Men had a significantly higher incidence of colorectal cancer (SIR = 1.48 [95% CI 1.06-2.06], p = 0.019). Women had a higher incidence of breast cancer (SIR = 1.47 [95% CI 1.22-1.78], p < 0.001). Intriguingly, the risk for colorectal cancer was more pronounced 5 years after the first psychiatric admission rather than earlier (SIR = 1.94 [1.36-2.75], p < 0.001) and so was the risk for breast cancer (SIR = 1.85 [1.38-2.48], p < 0.001). The cancer incidence was higher in patients with schizophrenia contradicting the belief that schizophrenia was protective of cancers. CONCLUSIONS: Our analyses suggest that men and women with schizophrenia were more vulnerable to certain types of cancers, which indicates the need for gender-specific cancer screening programs. The fact that risk of colorectal cancer was more pronounced 5 years after the first psychiatric admission could imply the impact of unhealthy lifestyles or the possibility of delayed diagnoses.

The impact of hepatitis B virus infection and vaccination on the development of non-Hodgkin lymphoma.

Hepatitis B virus (HBV) infection has been documented as a risk factor for non-Hodgkin lymphoma (NHL). However, there are few large cohort studies, and there is no report about the impact of HBV vaccination. We conducted this study to evaluate these issues. We used the nationwide cohort of the Taiwan National Health Insurance Research Database for 1997-2013. We compared the incidence and the risk of developing NHL and CD20+ aggressive lymphoma between HBV and non-HBV cohorts. The hazard ratios (HRs) were computed using Cox proportional hazards models. We matched these two large cohorts to reconfirm the data. We also compared the incidence of NHL between cohorts born before and after the inception of universal HBV vaccination. We found that HBV infection increased the risk for developing NHL and CD20+ aggressive lymphoma, with HRs of 4.14 and 5.52, with a higher incidence of 17.07 and 13.9 per 100 000 person-years, respectively, compared to the non-HBV cohort. The incidence of NHL in the cohort born in the era before universal HBV vaccination was higher with 1.85 per 100 000 person-years compared to 0.74 in the cohort born later aged younger than 20. Our study confirms that HBV confers a greater risk for developing NHL, especially CD20+ aggressive lymphoma. The impact of HBV vaccination is protective against lymphoma development in the teenagers in an endemic area, but longer follow-up is needed for older age.

[Naked cuticle homolog 2 positively regulates the osteogenic differentiation of rat dental follicle cells].

Objective: To examine the expression of naked cuticle homolog 2 (Nkd2) in the process of root development and osteogenic differentiation of dental follicle cells of rat (rDFC), in order to explore the molecular mechanisms of Nkd2 on the osteoblast differentiation of rDFCs. Methods: Immunohistochemical analysis was used to detect the expression of Nkd2 in the base dental follicle of the mandibular first molar of rat at 1, 3, 5, 7, 9, 11 and 13 days postnatal. Mineralization nodule formation of rDFCs was detected by alizarin red staining and cetylpyridine. The change of Nkd2 during osteogenic differentiation of rDFCs was evaluated by Western blotting and the associations between Nkd2 and osteogenic cytokines of alkaline phosphatase (ALP), Runt-related transcription factor-2 (RUNX2) and osteocalcin (OCN) were examined. The rDFCs were transfected with small interfering RNA (siRNA) to knock down the expression of Nkd2 and Western blotting and quantitative real-time PCR (qPCR) were adopted to explore the effects of Nkd2 on osteogenic differentiation by detecting variations of Nkd2 and osteogenic factors ALP, RUNX2, OCN among silencing group (Si), negative control RNA group (Nc) and mock control group (Mock), respectively. Results: The expression of Nkd2 in the base dental follicle of the mandibular first molar of rat was time dependent. Mineralization nodules of rDFCs and absorbance of cetylpyridine after osteogenic induction increased gradually (the absorbances of cetylpyridine were 0 week: 0.017±0.005, 1 week: 0.702±0.044, 2 weeks: 1.812±0.531, 3 weeks: 2.767±0.253, respectively). Results of Western blotting showed that Nkd2 (1.60±0.23) of mineralization group was significantly higher than that of control group (1) (P<0.05) at the early stage of osteogenic differentiation along with the expression of other osteogenic factors. The protein and mRNA of Nkd2 and osteogenic factors were significantly decreased in Si group compared with Nc and Mock groups (P<0.05), and no changes between Nc and Mock groups were observed. The changes of protein in Si, Nc and Mock groups were Nkd2: 0.42±0.10, 1.12±0.07, 1, ALP: 0.70±0.15, 1.11±0.14, 1, RUNX2: 0.58±0.08, 0.93±0.08, 1 and OCN: 0.64±0.06, 0.99±0.02, 1, respectively. The mRNA variances in Si, Nc and Mock groups were Nkd2: 0.39±0.05, 0.96±0.10, 1, ALP: 0.15±0.13, 1.01±0.07, 1, RUNX2: 0.39±0.31, 0.97±0.13, 1, OCN: 0.17±0.08, 1.08±0.21, 1, respectively. Conclusions: Nkd2 participates in the root development process in rat and may acts as a positive role in the early stage of osteogenic differentiation of rDFCs in rat.