Objective:To develop CNN-Dinov2, a deep learning-based automatic classification model for Gram-stained images, enabling rapid diagnosis of three prevalent Gram-negative bacilli in bloodstream infections: Escherichia coli ( E.coli), Klebsiella pneumoniae ( K.pneumoniae), and Pseudomonas aeruginosa ( P.aeruginosa). Methods:This evaluation study analyzed 1 425 Gram-stained microscopic images from patients with bloodstream infections at Houjie Hospital, in Dongguan City, collected between January 2023 and January 2024. The images, all positive for blood culture and identified as target strains, were categorized into Escherichia coli (419 images), Klebsiella pneumoniae (411 images), Pseudomonas aeruginosa (413 images), and other Gram-negative bacilli (182 images). They were randomly split into a training set (1 141 images), a validation set (141 images), and a test set (143 images) in an 8∶1∶1 ratio. A hybrid CNN-Dinov2 model was developed by integrating ResNet′s local feature extraction with Dinov2′s global pre-trained features, followed by a fully connected layer. The model was optimized by inputting the preprocessed images and adjusting parameters through loss calculation and backpropagation. AlexNet, Dinov2, and ResNet18 served as control models. The models′ classification performance was assessed using accuracy, precision, weighted F1 score, and recall rate, derived from the confusion matrix. The PR curve and AP value further evaluated each model′s classification capability across the four image categories. Results:The CNN-Dinov2 model achieved a training accuracy of 99.74%, a validation accuracy of 98.12%, and a validation loss of 0.070 6, demonstrating robust generalization without overfitting. Validation metrics revealed superior performance with an accuracy of 98.60%, precision of 98.65%, a weighted F1 score of 98.60%, and a recall rate of 98.60%, outperforming other models. The confusion matrix confirmed its strong classification capability, with the highest sum of diagonal values for identifying four types of bacteria. The macro average precision (AP) values under the precision-recall (PR) curves were all 1, indicating excellent discrimination across all categories. Overall, the CNN-Dinov2 model exhibited the best performance among the four models evaluated.Conclusion:This study successfully developed CNN-Dinov2, an automated classification model for Gram staining images. It offers valuable support for the rapid diagnosis of bloodstream infections caused by Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa, demonstrating practical utility.

Objective:To investigate, for multi-sensitized allergic rhinitis (AR) patients allergic to dust mites combined with other allergens (pollen, mold, animal dander, etc.), whether the single dust mite subcutaneous immunotherapy (SCIT) can improve the specific symptoms caused by other allergens in the patients, and to analyze the relationship between the effectiveness of symptom improvement in these patients and the type, quantity and severity of the allergens.Methods:A multicenter retrospective study was conducted to collect mul-sensitized AR patients from allergy or respiratory departments of 5 hospitals who received house dust mite allergen preparation SCIT for 12 to 36 months and met other inclusion and exclusion criteria from February to July 2024. General clinical data were collected and the perennial or seasonal symptoms before and after treatment were evaluated with visual analogue scale (VAS) to assess whether there was an perennial or allergen-specific symptom improvement (VAS score decrease ≥30%), by which the patients were divided into effective group and ineffective. R software was used to analyze the differences between groups by using Fisher′s exact test and Mann-Whitney U test. Results:A total of 62 patients were enrolled, and the treatment were effective in 39 of them, with an effective rate of 62.9%. For allergen-specific symptoms, the median age of the effective group was higher than that of the ineffective group (12 years old vs. 8 years old, P=0.039), and the effective rate in dust mite specific immunoglobin E (sIgE) grade ≤5 group was higher than that in sIgE grade >5 group (81.6% vs. 45.5%, P=0.008), and the effective rate of mold sIgE grade ≤2 group was higher than that of sIgE grade >2 group (83.3% vs. 28.6%, P=0.045), and there was no statistically significant correlation between the other allergen grades and the effective rate ( P>0.05). For perennial symptoms, the effective rate in the mold grade ≤2 group was higher than that in the sIgE grade >2 group (91.3% vs. 28.6%, P=0.010), and there was no statistically significant correlation between the other allergen grades and the effective rate ( P>0.05). There was no significant correlation between the treatment effectiveness of perennial or allergen-specific symptoms and the number of combined allergens, the grade of skin test, and the difference between the grade of combined allergens and that of dust mites ( P>0.05). Conclusion:Among the patients with multi-sensitized AR allergic to dust mites included in this study, single dust mite SCIT is effective in some of them, and for allergen-specific symptoms, the effective group was elder, and dust mite sIgE grade 6 and mold sIgE grade ≥2 was related to the low effective rate of SCIT. The present results are insufficient for selecting single or multiple AIT in any type of multi-sensitized patients.

Objective:To investigate the clinical demand for subcutaneous immunotherapy (SCIT) with pet allergens and explore the sensitization characteristics of patients undergoing pet SCIT.Methods:A cross-sectional retrospective analysis was conducted on patients diagnosed with pet allergies and treated with pet allergen SCIT in our outpatient clinic from January 2019 to December 2023. Patients were categorized into three groups based on the type of SCIT received: single-cat SCIT group, single-dog SCIT group, and combined cat-dog SCIT group.Results:A total of 931 patients were included, the age range was 5-65 years (median age of 30 years), with 283 male and 648 female. Among them, 67.7%( n=630) received single-cat SCIT, 10.9% ( n=102)received single-dog SCIT, and 21.4% ( n=199) received combined cat-dog SCIT. The number of patients receiving pet allergen SCIT increased annually. Patients in the single-dog SCIT group were significantly older than those in the other two groups ( H=41.329, P<0.001) and had a lower prevalence of allergic rhinitis (91.2% vs. 96.5% and 98.5%; χ2=10.400, P=0.006). In the combined cat-dog SCIT group, the allergy rate to mold allergens was significantly higher than in the single-cat SCIT group (12.6% vs. 4.9%, χ2=13.965, P=0.001). In the single-dog SCIT group, the allergy rate to spring pollen allergens was significantly higher than in the other two groups ( χ2=15.731, P<0.001), and the allergy rate to autumn pollen allergens was significantly higher than in the single-cat SCIT group ( χ2=13.459, P=0.001). There was no significant difference in the dust mite allergy rate among the three groups( χ2=4.117, P=0.129). In the single-dog SCIT group, patients with asthma were significantly older than those without asthma (41.2 vs. 35.2 years old, t=-2.073, P=0.041). In both the single-cat and single-dog SCIT groups, the proportion of allergic rhinitis in the asthma group(91.2%,78.3%) was significantly lower than that in the non-asthma group(97.4%,94.9%) ( χ2=8.863,6.158; P=0.008,0.026). In the single-cat SCIT group, non-asthmatic patients were significantly more likely to receive SCIT combined with spring pollen allergens compared to asthmatic patients (23.9% vs. 11.0%, χ2=7.586, P=0.006). Conclusions:The demand for pet allergen SCIT has steadily increased over the years, with a predominance of female patients. Sensitization profiles varied among patients receiving SCIT for different pet allergens. This study comprehensively elucidates the clinical demand and sensitization characteristics of patients undergoing pet allergen SCIT, providing valuable reference data for clinical diagnosis and treatment.

Objective To investigate the feasibility of parallel capillary bundle arrays for physiomimetic impedance modeling and establish a parametric quantification framework,thereby providing a customizable impedance characterization methodology for diverse in-vitro mock circulation researches.Methods Based on the parallel flow resistance and Poiseuille equation,a tube resistance element with multiple parallel-aligned capillary glass tubes was designed and fabricated.The resistance values of the capillary-bundle and a ball valve were measured through constant flow experiments analogous to electrical resistance measurement method.Moreover,a simple lumped-parameter mock circulation loop was constructed and the pressure and flow rate for each node of the loop were measured under different input flow waveforms.An 0D-Windkessel model corresponding to the experiment was developed.The impedance and compliance were adjusted to match the simulated and experimental pressure and flow waveforms.The accuracy of the capillary bundle impedance in pulsatile experiments was verified by using the computational resistance values.Results The constant-flow impedance calibration experiments revealed that the capillary bundle impedance remained unaffected by flow rate variations over a wide flow range.When the capillary bundle impedance was integrated into the pulsatile circulatory system and the same impedance value obtained from the constant-flow calibration was applied in the computational model,the resulting pressure and flow waveforms showed good agreement with those measured in the pulsatile experiments.However,when the ball valves with nominally identical impedance values were inserted in the pulsatile system,the calculated impedance exhibited a two-fold difference,and significant discrepancies were observed between the simulated and experimental terminal flow waveforms.Conclusions The capillary bundle impedance maintains a constant value regardless of flow rate variations.Once the calibrated resistance value is determined through constant flow experiments,it can be directly applied to pulsatile systems.This approach can provide quantitative pulsatile flow conditions for testing various medical devices.

Objective To investigate the feasibility of parallel capillary bundle arrays for physiomimetic impedance modeling and establish a parametric quantification framework,thereby providing a customizable impedance characterization methodology for diverse in-vitro mock circulation researches.Methods Based on the parallel flow resistance and Poiseuille equation,a tube resistance element with multiple parallel-aligned capillary glass tubes was designed and fabricated.The resistance values of the capillary-bundle and a ball valve were measured through constant flow experiments analogous to electrical resistance measurement method.Moreover,a simple lumped-parameter mock circulation loop was constructed and the pressure and flow rate for each node of the loop were measured under different input flow waveforms.An 0D-Windkessel model corresponding to the experiment was developed.The impedance and compliance were adjusted to match the simulated and experimental pressure and flow waveforms.The accuracy of the capillary bundle impedance in pulsatile experiments was verified by using the computational resistance values.Results The constant-flow impedance calibration experiments revealed that the capillary bundle impedance remained unaffected by flow rate variations over a wide flow range.When the capillary bundle impedance was integrated into the pulsatile circulatory system and the same impedance value obtained from the constant-flow calibration was applied in the computational model,the resulting pressure and flow waveforms showed good agreement with those measured in the pulsatile experiments.However,when the ball valves with nominally identical impedance values were inserted in the pulsatile system,the calculated impedance exhibited a two-fold difference,and significant discrepancies were observed between the simulated and experimental terminal flow waveforms.Conclusions The capillary bundle impedance maintains a constant value regardless of flow rate variations.Once the calibrated resistance value is determined through constant flow experiments,it can be directly applied to pulsatile systems.This approach can provide quantitative pulsatile flow conditions for testing various medical devices.

Objective:To investigate, for multi-sensitized allergic rhinitis (AR) patients allergic to dust mites combined with other allergens (pollen, mold, animal dander, etc.), whether the single dust mite subcutaneous immunotherapy (SCIT) can improve the specific symptoms caused by other allergens in the patients, and to analyze the relationship between the effectiveness of symptom improvement in these patients and the type, quantity and severity of the allergens.Methods:A multicenter retrospective study was conducted to collect mul-sensitized AR patients from allergy or respiratory departments of 5 hospitals who received house dust mite allergen preparation SCIT for 12 to 36 months and met other inclusion and exclusion criteria from February to July 2024. General clinical data were collected and the perennial or seasonal symptoms before and after treatment were evaluated with visual analogue scale (VAS) to assess whether there was an perennial or allergen-specific symptom improvement (VAS score decrease ≥30%), by which the patients were divided into effective group and ineffective. R software was used to analyze the differences between groups by using Fisher′s exact test and Mann-Whitney U test. Results:A total of 62 patients were enrolled, and the treatment were effective in 39 of them, with an effective rate of 62.9%. For allergen-specific symptoms, the median age of the effective group was higher than that of the ineffective group (12 years old vs. 8 years old, P=0.039), and the effective rate in dust mite specific immunoglobin E (sIgE) grade ≤5 group was higher than that in sIgE grade >5 group (81.6% vs. 45.5%, P=0.008), and the effective rate of mold sIgE grade ≤2 group was higher than that of sIgE grade >2 group (83.3% vs. 28.6%, P=0.045), and there was no statistically significant correlation between the other allergen grades and the effective rate ( P>0.05). For perennial symptoms, the effective rate in the mold grade ≤2 group was higher than that in the sIgE grade >2 group (91.3% vs. 28.6%, P=0.010), and there was no statistically significant correlation between the other allergen grades and the effective rate ( P>0.05). There was no significant correlation between the treatment effectiveness of perennial or allergen-specific symptoms and the number of combined allergens, the grade of skin test, and the difference between the grade of combined allergens and that of dust mites ( P>0.05). Conclusion:Among the patients with multi-sensitized AR allergic to dust mites included in this study, single dust mite SCIT is effective in some of them, and for allergen-specific symptoms, the effective group was elder, and dust mite sIgE grade 6 and mold sIgE grade ≥2 was related to the low effective rate of SCIT. The present results are insufficient for selecting single or multiple AIT in any type of multi-sensitized patients.

Objective:To investigate the clinical demand for subcutaneous immunotherapy (SCIT) with pet allergens and explore the sensitization characteristics of patients undergoing pet SCIT.Methods:A cross-sectional retrospective analysis was conducted on patients diagnosed with pet allergies and treated with pet allergen SCIT in our outpatient clinic from January 2019 to December 2023. Patients were categorized into three groups based on the type of SCIT received: single-cat SCIT group, single-dog SCIT group, and combined cat-dog SCIT group.Results:A total of 931 patients were included, the age range was 5-65 years (median age of 30 years), with 283 male and 648 female. Among them, 67.7%( n=630) received single-cat SCIT, 10.9% ( n=102)received single-dog SCIT, and 21.4% ( n=199) received combined cat-dog SCIT. The number of patients receiving pet allergen SCIT increased annually. Patients in the single-dog SCIT group were significantly older than those in the other two groups ( H=41.329, P<0.001) and had a lower prevalence of allergic rhinitis (91.2% vs. 96.5% and 98.5%; χ2=10.400, P=0.006). In the combined cat-dog SCIT group, the allergy rate to mold allergens was significantly higher than in the single-cat SCIT group (12.6% vs. 4.9%, χ2=13.965, P=0.001). In the single-dog SCIT group, the allergy rate to spring pollen allergens was significantly higher than in the other two groups ( χ2=15.731, P<0.001), and the allergy rate to autumn pollen allergens was significantly higher than in the single-cat SCIT group ( χ2=13.459, P=0.001). There was no significant difference in the dust mite allergy rate among the three groups( χ2=4.117, P=0.129). In the single-dog SCIT group, patients with asthma were significantly older than those without asthma (41.2 vs. 35.2 years old, t=-2.073, P=0.041). In both the single-cat and single-dog SCIT groups, the proportion of allergic rhinitis in the asthma group(91.2%,78.3%) was significantly lower than that in the non-asthma group(97.4%,94.9%) ( χ2=8.863,6.158; P=0.008,0.026). In the single-cat SCIT group, non-asthmatic patients were significantly more likely to receive SCIT combined with spring pollen allergens compared to asthmatic patients (23.9% vs. 11.0%, χ2=7.586, P=0.006). Conclusions:The demand for pet allergen SCIT has steadily increased over the years, with a predominance of female patients. Sensitization profiles varied among patients receiving SCIT for different pet allergens. This study comprehensively elucidates the clinical demand and sensitization characteristics of patients undergoing pet allergen SCIT, providing valuable reference data for clinical diagnosis and treatment.

Objective:To develop CNN-Dinov2, a deep learning-based automatic classification model for Gram-stained images, enabling rapid diagnosis of three prevalent Gram-negative bacilli in bloodstream infections: Escherichia coli ( E.coli), Klebsiella pneumoniae ( K.pneumoniae), and Pseudomonas aeruginosa ( P.aeruginosa). Methods:This evaluation study analyzed 1 425 Gram-stained microscopic images from patients with bloodstream infections at Houjie Hospital, in Dongguan City, collected between January 2023 and January 2024. The images, all positive for blood culture and identified as target strains, were categorized into Escherichia coli (419 images), Klebsiella pneumoniae (411 images), Pseudomonas aeruginosa (413 images), and other Gram-negative bacilli (182 images). They were randomly split into a training set (1 141 images), a validation set (141 images), and a test set (143 images) in an 8∶1∶1 ratio. A hybrid CNN-Dinov2 model was developed by integrating ResNet′s local feature extraction with Dinov2′s global pre-trained features, followed by a fully connected layer. The model was optimized by inputting the preprocessed images and adjusting parameters through loss calculation and backpropagation. AlexNet, Dinov2, and ResNet18 served as control models. The models′ classification performance was assessed using accuracy, precision, weighted F1 score, and recall rate, derived from the confusion matrix. The PR curve and AP value further evaluated each model′s classification capability across the four image categories. Results:The CNN-Dinov2 model achieved a training accuracy of 99.74%, a validation accuracy of 98.12%, and a validation loss of 0.070 6, demonstrating robust generalization without overfitting. Validation metrics revealed superior performance with an accuracy of 98.60%, precision of 98.65%, a weighted F1 score of 98.60%, and a recall rate of 98.60%, outperforming other models. The confusion matrix confirmed its strong classification capability, with the highest sum of diagonal values for identifying four types of bacteria. The macro average precision (AP) values under the precision-recall (PR) curves were all 1, indicating excellent discrimination across all categories. Overall, the CNN-Dinov2 model exhibited the best performance among the four models evaluated.Conclusion:This study successfully developed CNN-Dinov2, an automated classification model for Gram staining images. It offers valuable support for the rapid diagnosis of bloodstream infections caused by Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa, demonstrating practical utility.

Objective:To analyze the expression of FAT1 gene in pancreatic adenocarcinoma and its relationship with clinicopathological features, prognosis, and immunotherapy for pancreatic adenocarcinoma.Methods:(1) Bioinformatics analysis: based on FAT1 mRNA expression and clinical data of 179 cases of pancreatic adenocarcinoma in the TCGA database, and FAT1 mRNA expression data of 328 cases of normal pancreatic tissues in the GTEx database. We analyzed the differences in FAT1 mRNA expression in pancreatic adenocarcinoma and normal pancreatic tissues and the relationship between FAT1 mRNA expression and the degree of differentiation, clinical stage, prognosis, immune cell infiltration, and immune checkpoint-associated genes in pancreatic adenocarcinoma. FAT1-related differentially expressed genes were analyzed by applying Limma 3.40.2 software package, and GO and KEGG enrichment analysis was performed on the differentially expressed genes. Immunohistochemical (IHC) of FAT1 in pancreatic adenocarcinoma and normal pancreatic tissues was analyzed by HPA database. (2) Validation of own tissue samples: tissue samples and clinical and prognostic data of 192 patients with pancreatic ductal adenocarcinoma admitted to Zhejiang Cancer Hospital from March 8, 2010 to September 30, 2020 were collected. IHC was performed on the tissue samples to verify the protein expression of FAT1 in pancreatic adenocarcinoma and its relationship with immune-related proteins, the degree of differentiation of pancreatic adenocarcinoma, clinical staging, and prognosis.Results:(1) Bioinformatics analysis: the FAT1 mRNA expression of 179 pancreatic adenocarcinoma tissues from the TCGA database was 5.55±1.04, which was higher than that of 328 normal pancreatic tissues with FAT1 mRNA from the GTEx database (2.95±0.53, P＜0.001). FAT1-specific IHC images showed that FAT1 expression was generally high in pancreatic adenocarcinoma tissues, and FAT1 expression shifted from the cell membrane to the cytoplasm. The FAT1 mRNA expression in the highly differentiated group (31 cases), the moderately differentiated group (96 cases), and the lowly differentiated group (52 cases) were 4.99±1.46, 5.51±0.80, and 5.68±1.08, the expression of pancreatic adenocarcinoma tissues were all higher than that of normal pancreatic tissues (all P＜0.001), and the FAT1 mRNA expression of the moderately differentiated group and the poorly differentiated group were all higher than that of the highly differentiated group (all P＜0.001). The median progression-free survival time (PFS) and median overall survival time (OS) of the 90 patients in the FAT1 mRNA low-expression group were 16.5 and 24 months, respectively, which were longer than those of the 89 patients in the FAT1 mRNA high-expression group (median PFS and OS were 13 and 18 months, respectively; P-values were 0.011 and 0.005, respectively). Multifactorial Cox regression analysis showed that FAT1 mRNA expression level was an independent influencing factor for OS in pancreatic adenocarcinoma patients ( HR=1.47, 95% CI: 1.09-1.99). Correlation analysis showed that FAT1 mRNA expression in pancreatic adenocarcinoma was positively correlated with B-cell infiltration, CD8+ T-cell infiltration, neutrophil infiltration, macrophage infiltration, and myeloid dendritic cell infiltration ( ρ=0.27, P＜0.001; ρ=0.28, P＜0.001; ρ=0.32, P＜0.001; ρ=0.21, P=0.004; ρ=0.32, P＜0.001), and also positively correlated with mRNA expression of CD274, HAVCR2, and PDCD1LG2 ( r=0.327, P＜0.001; r=0.231, P=0.002; r=0.258, P＜0.001). GO and KEGG enrichment analyses showed that FAT1 mRNA expression levels were associated with activation of the Wnt signaling pathway ( P=0.029), the PI3K/Akt pathway ( P<0.001), and other tumor microenvironment-related pathways. (2) Validation of own tissue samples: among 192 pancreatic adenocarcinoma tissues, FAT1 was highly expressed in 58 cases (30.21%), and the proportion of FAT1-expressing positive tumor cells was positively correlated with the combined positive score of PD-L1 and the number of CD3+ T-cells infiltration ( r=0.154, P=0.032; r=0.287, P＜0.001), and the protein expression of FAT1 had no correlation with the differentiation degree of pancreatic adenocarcinoma ( ρ=0.082, P=0.254). The median OS of 58 patients in the FAT1 high-expression group and 134 patients in the FAT1 low-expression group were 18.89 and 25.84 months, respectively, and the difference was not statistically significant (χ2=1.93, P=0.165). Conclusion:FAT1 gene is highly expressed in pancreatic adenocarcinoma tissues, may play an oncogenic role in pancreatic adenocarcinoma, may be an adverse influence on overall survival and progression-free survival of patients; FAT1 gene may be involved in multiple immune-related pathways and promote tumor immune escape.

Objective:To analyze the expression of FAT1 gene in pancreatic adenocarcinoma and its relationship with clinicopathological features, prognosis, and immunotherapy for pancreatic adenocarcinoma.Methods:(1) Bioinformatics analysis: based on FAT1 mRNA expression and clinical data of 179 cases of pancreatic adenocarcinoma in the TCGA database, and FAT1 mRNA expression data of 328 cases of normal pancreatic tissues in the GTEx database. We analyzed the differences in FAT1 mRNA expression in pancreatic adenocarcinoma and normal pancreatic tissues and the relationship between FAT1 mRNA expression and the degree of differentiation, clinical stage, prognosis, immune cell infiltration, and immune checkpoint-associated genes in pancreatic adenocarcinoma. FAT1-related differentially expressed genes were analyzed by applying Limma 3.40.2 software package, and GO and KEGG enrichment analysis was performed on the differentially expressed genes. Immunohistochemical (IHC) of FAT1 in pancreatic adenocarcinoma and normal pancreatic tissues was analyzed by HPA database. (2) Validation of own tissue samples: tissue samples and clinical and prognostic data of 192 patients with pancreatic ductal adenocarcinoma admitted to Zhejiang Cancer Hospital from March 8, 2010 to September 30, 2020 were collected. IHC was performed on the tissue samples to verify the protein expression of FAT1 in pancreatic adenocarcinoma and its relationship with immune-related proteins, the degree of differentiation of pancreatic adenocarcinoma, clinical staging, and prognosis.Results:(1) Bioinformatics analysis: the FAT1 mRNA expression of 179 pancreatic adenocarcinoma tissues from the TCGA database was 5.55±1.04, which was higher than that of 328 normal pancreatic tissues with FAT1 mRNA from the GTEx database (2.95±0.53, P＜0.001). FAT1-specific IHC images showed that FAT1 expression was generally high in pancreatic adenocarcinoma tissues, and FAT1 expression shifted from the cell membrane to the cytoplasm. The FAT1 mRNA expression in the highly differentiated group (31 cases), the moderately differentiated group (96 cases), and the lowly differentiated group (52 cases) were 4.99±1.46, 5.51±0.80, and 5.68±1.08, the expression of pancreatic adenocarcinoma tissues were all higher than that of normal pancreatic tissues (all P＜0.001), and the FAT1 mRNA expression of the moderately differentiated group and the poorly differentiated group were all higher than that of the highly differentiated group (all P＜0.001). The median progression-free survival time (PFS) and median overall survival time (OS) of the 90 patients in the FAT1 mRNA low-expression group were 16.5 and 24 months, respectively, which were longer than those of the 89 patients in the FAT1 mRNA high-expression group (median PFS and OS were 13 and 18 months, respectively; P-values were 0.011 and 0.005, respectively). Multifactorial Cox regression analysis showed that FAT1 mRNA expression level was an independent influencing factor for OS in pancreatic adenocarcinoma patients ( HR=1.47, 95% CI: 1.09-1.99). Correlation analysis showed that FAT1 mRNA expression in pancreatic adenocarcinoma was positively correlated with B-cell infiltration, CD8+ T-cell infiltration, neutrophil infiltration, macrophage infiltration, and myeloid dendritic cell infiltration ( ρ=0.27, P＜0.001; ρ=0.28, P＜0.001; ρ=0.32, P＜0.001; ρ=0.21, P=0.004; ρ=0.32, P＜0.001), and also positively correlated with mRNA expression of CD274, HAVCR2, and PDCD1LG2 ( r=0.327, P＜0.001; r=0.231, P=0.002; r=0.258, P＜0.001). GO and KEGG enrichment analyses showed that FAT1 mRNA expression levels were associated with activation of the Wnt signaling pathway ( P=0.029), the PI3K/Akt pathway ( P<0.001), and other tumor microenvironment-related pathways. (2) Validation of own tissue samples: among 192 pancreatic adenocarcinoma tissues, FAT1 was highly expressed in 58 cases (30.21%), and the proportion of FAT1-expressing positive tumor cells was positively correlated with the combined positive score of PD-L1 and the number of CD3+ T-cells infiltration ( r=0.154, P=0.032; r=0.287, P＜0.001), and the protein expression of FAT1 had no correlation with the differentiation degree of pancreatic adenocarcinoma ( ρ=0.082, P=0.254). The median OS of 58 patients in the FAT1 high-expression group and 134 patients in the FAT1 low-expression group were 18.89 and 25.84 months, respectively, and the difference was not statistically significant (χ2=1.93, P=0.165). Conclusion:FAT1 gene is highly expressed in pancreatic adenocarcinoma tissues, may play an oncogenic role in pancreatic adenocarcinoma, may be an adverse influence on overall survival and progression-free survival of patients; FAT1 gene may be involved in multiple immune-related pathways and promote tumor immune escape.