The Role of Pericyte Migration and Osteogenesis in Periodontitis.

A ligature-induced periodontitis model was established in wild-type and CD146CreERT2; RosatdTomato mice to explore the function of pericytes in alveolar bone formation. We found that during periodontitis progression and periodontal wound healing, CD146+/NG2+ pericytes were enriched in the periodontal tissue areas, which could migrate to the alveolar bone surface and colocalize with ALP+/OCN+ osteoblasts. Chemokine C-X-C motif receptor 4 (CXCR4) inhibition using AMD3100 blocked CD146-Cre+ pericyte migration and osteogenesis, as well as further exacerbated periodontitis-associated bone loss. Next, primary pericytes were sorted out by magnetic-activated cell sorting and demonstrated that C-X-C motif chemokine ligand 12 (CXCL12) promotes pericyte migration and osteogenesis via CXCL12-CXCR4-Rac1 signaling. Finally, the local administration of an adeno-associated virus for Rac1 overexpression in NG2+ pericytes promotes osteoblast differentiation of pericytes and increases alveolar bone volume in periodontitis. Thus, our results provided the evidence that pericytes may migrate and osteogenesis via the CXCL12-CXCR4-Rac1 axis during the pathological process of periodontitis.

[Analysis of symptoms and influencing factors of low back work-related musculoskeletal disorders among workers in a container manufacturing factory].

Objective: To investigate the occurrence of low back work-related musculoskeletal disorders (WMSDs) among workers in a container manufacturing factory, and to explore the influencing factors. Methods: In June 2022, 952 workers from a container factory were selected as the research objects by cluster random sampling. Through questionnaire survey, the incidence of low back WMSDs symptoms among workers in the past one year was collected, and the influencing factors of low back WMSDs were analyzed by logistic regression. Results: The incidence rate of low back WMSDs was 46.7% (445/952). The factors with higher exposure at work were frequent slight bending (77.0%, 733/952), frequent overtime (74.1%, 705/952), and the need to turn around while working (62.3%, 593/952). Multivariate logistic regression analysis showed that age over 40 years old, smoking, drinking, often bending over slightly, sitting for a long time, maintaining a large bending posture for a long time, often working overtime, limited operating space, and there was always a need to complete conflicting things in the container manufacturing factory workers were the risks of increasing the low back WMSDs (OR=1.68, 1.96, 2.47, 1.49, 1.84, 2.11, 1.90, 1.82, 2.00, P<0.05). Standing at work, always friendly colleagues, and always supportive and helpful leaders were protective factors for low back WMSDs (OR=0.60, 0.32, 0.40, P<0.05) . Conclusion: The incidence of low back WMSDs symptoms in container manufacturing workers is high, and work-related factors such as frequent slight bending, long time holding large bending posture and limited operating space are the focus of ergonomic intervention in container manufacturing enterprises.

B-Cell-Derived TGF-ß1 Inhibits Osteogenesis and Contributes to Bone Loss in Periodontitis.

B cells play a vital role in the elimination of periodontal pathogens, the regulation of the immune response, and the induction of tissue destruction. However, the role of B cells in the dysfunction of mesenchymal stem cell (MSC) differentiation to osteoblasts in periodontitis (PD) has been poorly studied. Here we show that the frequency of CD45-CD105+CD73+ MSCs in inflamed periodontal tissues is significantly decreased in patients with PD compared with that of healthy controls. CD19+ B cells dominate the infiltrated immune cells in periodontal tissues of patients with PD. Besides, B-cell depletion therapy reduces the alveolar bone loss in a ligature-induced murine PD model. B cells from PD mice express a high level of TGF-ß1 and inhibit osteoblast differentiation by upregulating p-Smad2/3 expression and downregulating Runx2 expression. The inhibitory effect of PD B cells on osteoblast differentiation is reduced by TGF-ß1 neutralization or Smad2/3 inhibitor. Importantly, B-cell-specific knockout of TGF-ß1 in PD mice significantly increases the number of CD45-CD105+Sca1+ MSCs, ALP-positive osteoblast activity, and alveolar bone volume but decreases TRAP-positive osteoclast activity compared with that from control littermates. Lastly, CD19+CD27+CD38- memory B cells dominate the B-cell infiltrates in periodontal tissues from both patients with PD and patients with PD after initial periodontal therapy. Memory B cells in periodontal tissues of patients with PD express a high level of TGF-ß1 and inhibit MSC differentiation to osteoblasts. Thus, TGF-ß1 produced by B cells may contribute to alveolar bone loss in periodontitis, in part, by suppressing osteoblast activity.

[Safety and efficacy of percutaneous mechanical thrombectomy through ipsilateral calf venous access in the treatment of entire-limb acute deep venous thrombosis].

Objective: To evaluate the safety and clinical efficacy of percutaneous mechanical thrombectomy (PMT) through ipsilateral calf venous access in the treatment of entire-limb acute deep vein thrombosis (DVT). Methods: From July 2017 to August 2020, the clinical data of patients with entire-limb acute DVT at Renji Hospital, School of Medicine, Shanghai Jiaotong University treated by AngioJet through ipsilateral calf venous access were analyzed retrospectively. All patients received rivaroxaban or warfarin anticoagulant therapy for at least 6 months after operation. Pressure gradient socks were given routinely after operation. All patients were followed up at 3, 6, 12 months and every year after operation. The primary end points were the 12-month primary patency rate and the incidence of post thrombotic syndrome (PTS). The secondary end points included the thrombus clearance rate, total complication rate, bleeding complication rate and the 12-month incidence of moderate to severe PTS. Results: A total of 31 patients were included in the study. The age ranged from 31 to 80 (63±14) years, including 16 males and 15 females, 23 left lower limb DVT and 8 right lower limb DVT. There were 15 cases treated through peroneal venous access, 6 cases through anterior tibial venous access and 10 cases through posterior tibial venous access. Moreover, 9 cases underwent combined catheter-directed thrombolysis, 25 cases underwent iliac vein percutaneous transluminal angioplasty (PTA), and 10 cases underwent iliac vein stenting. The thrombus clearance rate was grade Ⅱ in 19 cases (61.3%) and grade Ⅲ in 12 cases (38.7%). One patient (3.2%) with anterior tibial venous access developed hematoma at the puncture site, which was improved after pressure bandage, and there were no other bleeding and serious complications. All the 31 patients were followed up for at least 12 months, with an average follow-up period of (22±9) months. The 12-month primary patency rate was 77.4% (24/31). The 12-month incidence of PTS was 16.1% (5/31) and the incidence of moderate to severe PTS was 3.2% (1/31). Conclusions: PMT through ipsilateral calf venous access is safe and effective in the treatment of entire-limb acute DVT. Thrombus in the distal popliteal vein can be one-stage removed and the incidence of PTS is low. It is considered as the first choice of access for the endovascular treatment of entire-limb acute DVT.

Sentinel lymph node biopsy with carbon nanoparticle suspension after neoadjuvant chemotherapy for breast cancer patients.

INTRODUCTION: The aim of the study was to explore the feasibility of performing sentinel lymph node biopsy (SLNB) using a carbon nanoparticle suspension (CNPS) after neoadjuvant chemotherapy in breast cancer patients. METHODS: Some 152 patients diagnosed with primary breast cancer (cT1-3N0-2M0) were recruited. Patients were divided into two groups according to axillary lymph node (ALN) status after four to six cycles of neoadjuvant chemotherapy. All patients received a CNPS injection, after which SLNB and axillary lymph node dissection (ALND) were performed. RESULTS: Sentinel lymph nodes (SLN) of 143 patients were identified; with an accuracy rate of 94.4% and a false-negative rate of 9.9%. Group A included 67 patients, and the detection, accuracy and false-negative rates within this group were 95.5%, 96.9% and 6.7%, respectively. The corresponding rates for group B (85 patients) were 92.9%, 92.4% and 11.8%, respectively. CONCLUSIONS: CNPS is an ideal tracer for improving the detection rate of SLN and can be used to determine SLN status following neoadjuvant chemotherapy.

Factors associated with Scrub Typhus infection: A case-control study from Luhe, China.

INTRODUCTION: Scrub typhus (ST) is an acute febrile infection and remains a significant health problem globally. This study aimed to determine the factors associated with ST infection in Luhe District, China. MATERIAL AND METHODS: The case-control study was conducted among 116 cases identified through passive surveillance systems over three years.The control subjects were 232 living in the same village for more than six months without any history of ST infection were selected by matching to the age (within 5-years) and identified through active surveillance. Statistical analyses were performed using SPSS v. 25.0 for Windows (IBM SPSS, Chicago, IL, USA). RESULTS: The mean age of confirmed persons was 58.1(SD=10.15) years, while control subjects were 56.14 (11.57).There is no significant difference in gender, age, education, and occupations between case and control. Farmers had the most significant number of cases among occupational groups. The three factors that were significantly associated with an increased odds of having ST infection are bundling or moving waste straw (OR: 1.94, 95%CI; 0.99,381), morning exercise in the park or field (OR: 4.74 95%CI; 1.19, 18.95), and working as labourer in the vegetable field (OR:1.02, 95%CI:1.02,3.19). CONCLUSIONS: Our findings suggested establishing a prevention and control strategy for these groups to lower ST development risk.

[Analysis of the diagnosis of occupational radiogenic neoplasms in three cases of leukemia].

Objective: To analyze the diagnosis of 3 cases of leukemia applying for the diagnosis of occupational radiogenic neoplasms. Methods: Retrospective analysis the occupational history, the disease history and the probability of causation (PC value) information of 3 radiological workers. Results: Two cases' PC value of 95% confidence limit of were >50%, and they were diagnosed as radiogenic neoplasms. One case was <50% and diagnosed as nonoccupational radiogenic neoplasms. Conclusion: The probability of causation analysis has important guiding significance for the diagnosis of occupational radiogenic neoplasms. Radiological workers should improve their awareness of self-protection and reduce the occurrence of occupational diseases.

[Ultrasound-guided percutaneous transluminal angioplasty in the treatment of arteriovenous fistula immaturation: day surgery mode and clinical efficacy].

Objective: To summarize the clinical effect of ultrasound-guided percutaneous transluminal angioplasty (PTA) in the treatment of arteriovenous fistula (AVF) immaturation under day surgery mode. Methods: The clinical data was retrospective analyzed of patients with AVF immaturation who were treated by ultrasound-guided PTA under day surgery mode from November 2016 to June 2019 in Renji Hospital. The basic information, lesion location, puncture approach, number and diameter of balloon used were counted. The primary and secondary patency rates were calculated at 6 and 12 months after operation. Results: In all of the 21 patients, 11 patients were male and 10 patients were female. The mean age was (52.6±12.9) years old. There were 20 of the 21 patients who were treated successfully. One patient had AVF reconstruction with vascular rupture, and the complication rate was 4.8% (1/21). The length of hospitalization was (1.05±0.71) days, and the cost was (11 487.7±4 401.4) yuan. The follow-up time was (19.7±8.3) months. The 6-month and 12-month primary patency rate were 70% and 55%, and the 6-month and 12-month secondary patency rate were both 90%. Conclusion: Ultrasound-guided PTA in the treatment of AVF immaturation under day surgery mode is safe and effective, which has a high technical success rate and good patency rate for AVF maturation.

Age-related histological changes in rat tibia.

BACKGROUND: At present, studies on osteochondral morphogenesis only focus on a certain period of time or only provide a pattern diagram, but lack of dynamic tracking observation from the initiation of development to maturity. This study was aimed to dynamically observe the changes of skeleton morphology and structure from embryo to adult, to provide research data for enriching the knowledge of bone and cartilage tissue structure. MATERIALS AND METHODS: In the intrauterine experiment, 5 normal pregnant Wistar rats were sacrificed under anaesthesia at gestational day (GD) 14, 17, 20, respectively. One of their offspring was randomly selected, and a total of 5 offspring were obtained at each time point. In the postnatal experiment, on the 7th and 10th day after birth and at postnatal weeks (PW) 2, 3, 6, 12, 28, 5 offspring rats from 5 different pregnant Wistar rats were randomly selected and sacrificed under anaesthesia at each time point. After obtaining the above offspring, the soft tissue was removed, and the tibia of hind limbs was retained for paraffin-embedded section. After stained with Safranin-O-fast-green and haematoxylin, the morphological development of the tibia was observed under an optical microscope. RESULTS: At GD14, there was no obvious joint space, the whole hind limb was cartilage and bone tissue was not visible. At GD17, visible joint space was seen and the chondrocytes in the centre region appeared to hypertrophy. At GD20, the primary ossification centre was obvious, and a typical epiphysis growth plate structure could be seen. On the 7th day after birth, the chondrocytes in the centre of epiphysis cartilage were hypertrophic and differentiated, the cartilage canal grows from the cartilage surface toward the centre of the epiphysis cartilage, at postnatal day 14, the secondary ossification centre was formed. At this time, the tibia had typical morphological characteristics of the metaphysis, however, there was no obvious layered structure of articular cartilage; the stratified structure of articular cartilage could be seen at PW6, but its mature marker (tidemark) was still not visible; however, at PW12, typical 4 layers of articular cartilage appeared, and the tidemark was visible. The growth plates were clearly visible at PW2, 6 and 12. At PW28, growth plates could still be observed, but its morphology is abnormal. CONCLUSIONS: Our results, for the first time, dynamically observed the morphological changes of osteochondral at critical period of development from embryo to adult, especially the process of cartilage canal participating in the formation of secondary ossification centre.

The distinctive characteristics of the micro-vasculature and immune cell infiltration in cystic pancreatic neuroendocrine tumors.

PURPOSE: Hypervascularity is a main characteristic of pancreatic neuroendocrine tumors (PanNETs), and cystic PanNETs (CPanNETs) are unique type of PanNETs in which the microenvironment remains unknown. We aim to compare the micro-vasculature features and immune cell infiltration between CPanNETs and solid PanNETs (SPanNETs). METHODS: Data of 301 SPanNET and 36 CPanNET patients from a high-volume institution were evaluated. CD4, CD8, CD11c, CD15, CD20, CD68, CD34 and α-SMA expression levels were assessed by immunohistochemistry and immunofluorescent double staining. The microvessel density (MVD) and microvessel integrity (MVI) were examined. RESULTS: MVD and MVI expression levels in CPanNETs were significantly higher than those in SPanNETs (p = 0.025 and 0.0092, respectively). CPanNETs had higher proportions of T1 (p = 0.023) and G1 (p = 0.052) than SPanNETs. In SPanNETs, higher MVD occurred in stages T1, N0 and G1 than in the T2/T3, N1 and G2 subgroups. In CPanNETs, CD34-MVD was uncorrelated with the T stage or grade. Higher CD34-MVD, but not MVI, was associated with better DFS (HR 0.3209, 95% CI 0.1259-0.8176, p = 0.004). There were significantly more peritumoral infiltrating immune cells than their intratumoral counterparts (p < 0.001 for each) in CPanNETs and SPanNETs. The mean number of peritumoral CD68 + TAM in CPanNETs was significantly lower than that in SPanNETs (p = 0.008). The counts of other peritumoral immune cells did not significantly differ between CPanNETs and SPanNETs. CONCLUSIONS: CPanNETs had a microenvironment distinct from that of SPanNETs, including higher CD34-MVD, higher MVI and lower TAM. This specific microenvironment structure may partially help predicting the prognosis of patients with PanNET.

[Expression and clinical significance of LRFN4 in colorectal cancer tissue].

Objective: To investigate the expression and clinical significance of LRFN4 in colorectal cancer. Methods: A total of 210 cases of colorectal cancer tissues and 228 cases of corresponding surgical margin tissues were collected. Immunohistochemistry was employed to evaluate the expression of LRFN4 in colorectal cancer.The correlation between LRFN4 expression and clinicopathological features of colorectal cancer as well as patient outcome were analyzed. Results: The positive rate of LRFN4 in colorectal cancer and in non-cancer was 55.24%(116/210), and 37.28% (85/228) , respectively.The expression of LRFN4 in colorectal cancer tissues was higher than that in non-cancer tissues(χ(2)=14.196, P<0.001). High expression of LRFN4 was significantly correlated with tumor location(χ(2)=4.133,P=0.042), T staging(χ(2)=6.494,P=0.039), N staging(χ(2)=11.715,P=0.008), TNM staging(χ(2)=13.398,P=0.004), CEA (χ(2)=6.017, P=0.049), but without gender, age, degree of differentiation, M staging(P>0.05).The Kaplan-Meier survival curves indicated that high LRFN4 expression was associated with good survival (P<0.05). In addition, Cox proportional hazards model showed that the high expression of LRFN4(HR=0.585, P=0.018)was an independent risk factor for prognosis in patients with colorectal cancer. Conclusions: The expression of LRFN4 is up-regulated in colorectal cancer, which is significantly correlated with the clinicopathological features and prognosis. High expression of LRFN4 reduced the risk of death in patients with colorectal cancer.

Artificial Intelligence in the Management of Intracranial Aneurysms: Current Status and Future Perspectives.

Intracranial aneurysms with subarachnoid hemorrhage lead to high morbidity and mortality. It is of critical importance to detect aneurysms, identify risk factors of rupture, and predict treatment response of aneurysms to guide clinical interventions. Artificial intelligence has received worldwide attention for its impressive performance in image-based tasks. Artificial intelligence serves as an adjunct to physicians in a series of clinical settings, which substantially improves diagnostic accuracy while reducing physicians' workload. Computer-assisted diagnosis systems of aneurysms based on MRA and CTA using deep learning have been evaluated, and excellent performances have been reported. Artificial intelligence has also been used in automated morphologic calculation, rupture risk stratification, and outcomes prediction with the implementation of machine learning methods, which have exhibited incremental value. This review summarizes current advances of artificial intelligence in the management of aneurysms, including detection and prediction. The challenges and future directions of clinical implementations of artificial intelligence are briefly discussed.

[Expression and clinical significance of KIAA1199 in primary hepatocellular carcinoma].

Objective: To investigate the expression and clinical significance of KIAA1199 in primary hepatocellular carcinoma. Methods: A total of 136 cases of primary hepatocellular carcinoma tissues and paired adjacent tissues were collected. Immunohistochemistry and Western blot were used to detect the expression of KIAA1199 in primary hepatocellular carcinoma tissues and paired adjacent tissues. The relationship between KIAA1199 and clinicopathological parameter of primary hepatocellular carcinoma was analyzed. Results: The positive rate of KIAA1199 in primary hepatocellular carcinoma was 82.3% (112/136), which was higher than that in paired para-cancerous tissues (14.7%, 20/136). High expression of KIAA1199 was significantly correlated with age, cirrhosis history, tumor size, tumor number, degree of differentiation, TNM staging and microvenous invasion (MVI) (P<0.05), but without gender, drinking alcohol hobby, hepatitis history, family genetic history, tumor location (P>0.05). The Kaplan-Meier survival curves indicated that high KIAA1199 expression was associated with poor survival (P<0.01). In addition, Cox proportional hazards model showed that the expression of KIAA1199 was related to age, cirrhosis history, tumor size, tumor number, degree of differentiation, TNM staging and MVI (P<0.05). Conclusion: The expression of KIAA1199 is up-regulated in primary hepatocellular carcinoma, which is significantly correlated with the clinicopathological features and prognosis, high expression of KIAA1199 increased the risk of death in patients with primary hepatocellular carcinoma.

[The expression of LTBP2 in breast cancer and its clinical significance].

Objective: To explore the expression of latent transforming growth factor (TGF)-beta binding protein 2 (LTBP2) in breast cancer and its clinical significance. Methods: Immunohistochemistry was used to detect the expression of LTBP2 in 125 cases of breast cancer tissue and normal breast tissue. Relationship between the expression of LTBP2 and estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), Ki67, and its relationship with clinicopathological parameters of breast cancer were analyzed. Results: The positive expression of LTBP2 in breast cancer tissues (55.20%) was significantly higher than that in adjacent normal breast tissues (28.80%) (P<0.001). The expression of LTBP2 in breast cancer tissues was correlated with the clinical stage (χ(2)=4.516, P=0.034), over-expression of ER (χ(2)=7.112, P=0.008) and Ki67(χ(2)=4.024, P=0.045) and other adverse prognostic factors. Conclusion: Positive expression of LTBP2 in breast cancer plays an important role in the development and progression of breast cancer, and may be a marker of prognosis of patients.

Application of endoscopy to treat mandibular keratocystic odontogenic tumors.

The aim of this study was to evaluate the feasibility of endoscopy to remove keratocystic odontogenic tumors (KCOTs) with virtual 3D mandibular images. Fifteen patients (mean age, 40.27±14.58 years) who underwent endoscopic mandibular KCOT enucleation between May 2009 and October 2009 were included. Virtual 3D mandibular reconstructions derived from computed tomography (CT) imaging were generated for all patients. Recurrence and pathological fracture were evaluated as the primary outcome variables at 1 and 12 months after operation. Secondary infection and inferior alveolar nerve injury were evaluated as the secondary outcome variables at 1 and 6 months after operation. None of the 15 patients exhibited signs of recurrence or pathological fracture after operation. During long-term follow-up, no symptoms of inferior alveolar nerve injury or secondary infection were observed and no signs of recurrence were found in any of the patients. Endoscopy helps surgeons to remove mandibular KCOTs with small incisions. Moreover, endoscopy can provide clear and magnified views and help to avoid damage to the inferior alveolar neurovascular bundle. Therefore, under the support of preoperative virtual 3D mandibular images, the application of endoscopy to remove the tumors should be considered to be a treatment option for KCOTs.

Ten novel MHC-DPB1 alleles identified in Tibetan macaque (Macaca thibetana).

Ten novel MHC-DPB1 alleles of Tibetan macaque, were identified by cloning and sequencing.

[Individual dose monitoring and health status of radiation workers in some Three A hospitals of Zhejiang province].

Objective: To investigate the individual irridiateddose levelandhealth statusofoccupational externalexposureamong radiationworkers inThreeA hospitals ofZhejiangprovince,andprovideevidence for occupationalhealthmanagement. Methods: 367 different typesof radiationworkerswereexperienced thedose monitoring and health examination from January toDecember, 2015, according to the requirements of"SpecificationsofIndividualMonitoring forOccupationalExternalExposure"and"Specifications forOccupational healthsurveillance forradiationworkers".The resultsofdosemonitoring,chromosomeaberration rate, lensopacity rate,hemogramand thyroid functionwerestatisticallyanalyzed. Results: Theannualeffectivedoseamong radiation workers fromZhejiangprovince in2015was0.13mSv,98.91%of them less than1mSv,whichunder the limit standardofstate(20mSv/a).Thechromosomeaberration(dicentric)detection rateswere7.41%and4.35%, from nuclearmedicinegroupand interventionalgroup respectively,whichhigher thandiagnostic radiologygroup, the differencewasstatisticallysignificant(χ(2)=13.686,8.092,P<0.01).Besides,1caseofsuspiciouschronic radiation dermatitiswas found in the interventiongroup.Radiation lengthhadsignificanteffecton lensopacity rate(P<0.01), lensopacity increasedwith the increasing lengthof the linear trend (χ(2)trend=16.363,P<0.01),and the incidence ofabnormalthyroid function theabnormalrateof lymphocyte ratiohad significantdifferenceamong theagegroups (P<0.05). Conclusion: Although, theoccupationalexternalexposureamong radiationworkersinThreeAhospitals ofZhejiangprovince issafe, long-term lowdosesofionizing radiation stillhascertainhealtheffectson the fieldof nuclearmedicineand interventionalradiologystaff,suchaseye lens,cytogenetics,nailsandskin.

Infiltrating immune cells and gene mutations in pancreatic ductal adenocarcinoma.

BACKGROUND: The aim of this study was to assess the immune profile within the microenvironment of pancreatic ductal adenocarcinoma (PDAC), and to investigate the prognostic value of intratumoral infiltrating immune/inflammatory cells (IICs) in patients after surgery. METHODS: Eighteen phenotypic markers representing 11 types of IIC and the protein products of genes TP53, CDKN2A/p16 and SMAD4/DPC4 were assessed by immunohistochemistry of specimens from patients with pancreatic cancer. The expression of IICs and the mutational status of the genes were correlated with tumour recurrence and survival, and results were validated in an independent cohort. RESULTS: CD15+ neutrophils, CD20+ B cells and CD206+ tumour-associated macrophages were seen frequently in tumours, and their presence was associated with reduced survival in a cohort of 79 patients. Expression of CD4+ T helper cells, CD8+ cytotoxic T lymphocytes and CD117+ mast cells was associated with a favourable prognosis. A weighted Cox regression recurrence-predictive model was constructed that showed good correlation of IICs and gene mutations. A combination of CD15, CD206, CD117 and Smad4 expression was independently associated with overall (hazard ratio (HR) 3·63, 95 per cent c.i. 2·18 to 6·04; P < 0·001) and recurrence-free (HR 2·93, 1·81 to 4·75; P < 0·001) survival. These findings were validated in an independent cohort (151 patients) and in 54 tissue samples obtained by preoperative endoscopic ultrasound-guided fine-needle aspiration. CONCLUSION: PDAC has a unique immunosuppressive phenotype that is associated with characteristic gene mutations, disease recurrence and survival after pancreatectomy. Surgical relevance The immune microenvironment plays a critical role in the development of pancreatic ductal adenocarcinoma (PDAC). PDAC is associated with mutations in major driver genes, including KRAS, TP53, CDKN2A/p16 and SMAD4/DPC4. This study shows that the microenvironment of PDAC has a unique immunosuppressive phenotype, which may be driven by oncogene mutations. Patients with PDAC with a highly immunosuppressive profile tended to have poor postoperative survival. A model including three intratumoral infiltrating immune markers (CD15+, CD206+ and CD117+) and a SMAD4 mutation can be used to predict recurrence and survival in patients after surgery for PDAC.