The combination of exon sequencing and metabolomics to establish a molecular typing system for gastric cancer.

Background: Gastric cancer (GC) is one of the most common malignant tumors in the world. It has become increasingly difficult to meet the needs of precision therapy using the existing molecular typing system. Therefore, developing a more effective molecular typing system for GC is urgent. Methods: In this study, 100 Chinese GC patients were included. Whole-exome sequencing (WES) and metabolomics analysis were performed to reveal the characteristics of genomic and metabolic changes. Results: In WES, nonsynonymous mutations accounted for the majority. Based on metabolomics, GC has been divided into three subtypes with distinct metabolic features. Importantly, we ultimately divided GC into four subtypes with different metabolic characteristics, genomic alterations, and clinical prognoses by incorporating biomics analysis. Conclusions: Integrating biological features, we constructed a novel molecular system for GC that was closely related to genetics and metabolism, providing new insights for further understanding the heterogeneity and formulating precise treatment strategies.

Screening chondrocyte necroptosis-related genes in the diagnosis and treatment of osteoarthritis.

Background: Osteoarthritis (OA) is the most common form of joint diseases, with hallmark of cartilage degeneration. Recent studies have shown that the pathogenesis of OA is associated with chondrocyte necroptosis. Methods: In this study, we used single-cell RNA sequencing (scRNA-seq) and bulk RNA sequencing data to analyze necroptosis regulation in OA chondrocytes. We performed enrichment analysis, carried out experimental validation, constructed machine learning models, and docked drug molecules. Results: After least absolute shrinkage and selection operator (LASSO) algorithm screening, 4 hub genes (RIPK3, CYBB, HSP90AB1, and TRAF5) with diagnostic characteristics were obtained. Following the comparison of multiple models, the Bayesian model with an average area under curve (AUC) value of 0.944 was finally selected. We found that nimesulide exhibited strong binding affinity to CYBB and HSP90AB1, and experimentally verified that nimesulide reduced the expression of RIPK3 and CYBB, suggesting its potential as an inhibitor of chondrocyte necroptosis. Furthermore, scRNA-seq results showed that necroptosis in OA was significantly upregulated on regulatory chondrocytes (RegC) compared to other chondrocyte subtypes. Conclusions: The results indicate that nimesulide might be used to treat OA by inhibiting chondrocyte necroptosis through down-regulation of RIK3 and CYBB genes. This study reveals the role of chondrocyte necroptosis in OA, and suggests a potential therapeutic strategy by regulating necroptosis with nimesulide.

High-yield extracellular vesicle production from HEK293T cells encapsulated in 3D auxetic scaffolds with cyclic mechanical stimulation for effective drug carrier systems.

Extracellular vesicles (EVs) show promise in drug loading and delivery for medical applications. However, the lack of scalable manufacturing processes hinders the generation of clinically suitable quantities, thereby impeding the translation of EV-based therapies. Current EV production relies heavily on non-physiological 2D cell culture or bioreactors, requiring significant resources. Additionally, EV-derived ribonucleic acid cargo in 3D and 2D culture environments remains largely unknown. In this study, we optimized the biofabrication of 3D auxetic scaffolds encapsulated with human embryonic kidney 293T (HEK293T) cells, focusing on enhancing the mechanical properties of the scaffolds to significantly boost EV production through tensile stimulation in bioreactors. The proposed platform increased EV yields approximately 115-fold compared to conventional 2D culture, possessing properties that inhibit tumor progression. Further mechanistic examinations revealed that this effect was mediated by the mechanosensitivity of YAP/TAZ. EVs derived from tensile-stimulated HEK293T cells on 3D auxetic scaffolds demonstrated superior capability for loading doxorubicin compared to their 2D counterparts for cancer therapy. Our results underscore the potential of this strategy for scaling up EV production and optimizing functional performance for clinical translation.

Long-term trend forecast of chlorophyll-a concentration over eutrophic lakes based on time series decomposition and deep learning algorithm.

Long-term trend forecast of chlorophyll-a concentration (Chla) holds significant implications for eutrophication management and pollution control planning on lakes, especially under the background of climate change. However, it is a challenging task due to the mixture of trend, seasonal and residual components in time series and the nonlinear relationships between Chla and the hydro-environmental factors. Here we developed a hybrid approach for long-term trend forecast of Chla in lakes, taking the Lake Taihu as an instantiation case, by the integration of Seasonal and Trend decomposition using Loess (STL), wavelet coherence, and Convolutional Neural Network with Bidirectional Long Short-Term Memory (CNN-BiLSTM). The results showed that long-term trends of Chla and the hydro-environmental factors could be effectively separated from the seasonal and residual terms by STL method, thereby enhancing the characterization of long-term variation. The resonance pattern and time lag between Chla and the hydro-environmental factors in the time-frequency domain were accurately identified by wavelet coherence. Chla responded quickly to variations in TP, but showed a time lag response to variations in WT in Lake Taihu. The forecasting method using multivariate and CNN-BiLSTM largely outperformed the other methods for Lake Taihu with regards to R2, RMSE, IOA and peak capture capability, owning to the combination of CNN for extracting local features and the integration of bidirectional propagation mechanism for the acquisition of higher-level features. The proposed hybrid deep learning approach offers an effective solution for the long-term trend forecast of algal blooms in eutrophic lakes and is capable of addressing the complex attributes of hydro-environmental data.

Retinal microvascular changes in patients with pancreatitis and their clinical significance.

Acute pancreatitis, a common exocrine inflammatory disease affecting the pancreas, is characterized by intense abdominal pain and multiple organ dysfunction. However, the alterations in retinal blood vessels among individuals with acute pancreatitis remain poorly understood. This study employed optical coherence tomography angiography (OCTA) to examine the superficial and deep retinal blood vessels in patients with pancreatitis. Sixteen patients diagnosed with pancreatitis (32 eyes) and 16 healthy controls (32 eyes) were recruited from the First Affiliated Hospital of Nanchang University for participation in the study. Various ophthalmic parameters, such as visual acuity, intraocular pressure, and OCTA image for retina consisting of the superficial retinal layer (SRL) and the deep retinal layer (DRL), were recorded for each eye. The study observed the superficial and deep retinal microvascular ring (MIR), macrovascular ring (MAR), and total microvessels (TMI) were observed. Changes in retinal vascular density in the macula through annular partitioning (C1-C6), hemispheric quadrant partitioning (SR, SL, IL, and IR), and early diabetic retinopathy treatment studies (ETDRS) partitioning methods (R, S, L, and I). Correlation analysis was employed to investigate the relationship between retinal capillary density and clinical indicators. Our study revealed that in the superficial retinal layer, the vascular density of TMI, MIR, MAR, SR, IR, S, C2, C3 regions were significantly decreased in patients group compared with the normal group. For the deep retinal layer, the vascular density of MIR, SR, S, C1, C2 regions also reduced in patient group. The ROC analysis demonstrated that OCTA possesses significant diagnostic performance for pancreatitis. In conclusion, patients with pancreatitis may have retinal microvascular dysfunction, and OCTA can be a valuable tool for detecting alterations in ocular microcirculation in pancreatitis patients in clinical practice.

Engineering ZnIn2S4 with efficient charge separation and utilization for synergistic accelerate dual-function photocatalysis.

Combining photocatalytic reduction with organic synthetic oxidation in the same photocatalytic redox system can effectively utilize photoexcited electrons and holes from solar to chemical energy. Here, we stabilized 0D Au clusters on the substrate surface of Zn vacancies modified 2D ZnIn2S4 (ZIS-V) nanosheets by chemically bonding Au-S interaction, forming surfactant functionalized Au/ZIS-V photocatalyst, which can not only synergistic accelerate the selective oxidation of phenylcarbinol to value-added products coupled with clean energy hydrogen production but also further drive photocatalytic CO2-to-CO conversion. An internal electric field of Au/ZIS-V ohmic junction and Zn vacancies synchronously promote the photoexcited charge carrier separation and transfer to optimized active sites for redox reactions. Compared with CO2 reduction in water and the pristine ZnIn2S4, the reaction thermodynamics and kinetics of CO2 reduction over the Au/ZIS-V were simultaneously improved about 11.09 and 45.51 times, respectively. Moreover, the photocatalytic redox mechanisms were also profoundly studied by 13CO2 isotope tracing tests, in situ electron paramagnetic resonance (in situ EPR), in situ X-ray photoelectron spectroscopy (in situ XPS), in situ diffuse reflection infrared Fourier transform spectroscopy (in situ DRIFTS) and density functional theory (DFT) characterizations, etc. These results demonstrate the advantages of vacancies coupled with metal clusters in the synergetic enhancement of photocatalytic redox performance and have great potential applications in a wide range of environments and energy.

An in situ bioadhesive foam as a large intestinal delivery platform for antibody fragment to treat inflammatory bowel disease.

Biologics have been widely used as injectables in the treatment of inflammatory bowel disease (IBD). Different local treatment attempts have been developed in recent years. However, maintaining systemic levels of biologics is still crucial for achieving colitis remission. An equilibrium between systemic and local concentrations of biologics is therefore essential for treatment of colitis. Current formulations struggle to create optimal balance between drug concentrations in plasma and the colonic wall. Addressing this challenge, we developed a rectally delivered in situ foam that generates CO2via a reaction between potassium bicarbonate (PB) and citric acid (CA) without the aid of an external device. An anti-TNF-α antibody fragment (Fab) was loaded into the foam formulation, which promoted prolonged colon retention and improved Fab distribution up to proximal colon following rectal administration to mice. In addition, we observed increased plasma Fab concentrations in mice receiving the rectal Fab foam compared to a Fab solution. In a non-everted rat gut ex vivo model, a single exposure to the CO2-containing foam improved macromolecule transepithelial flux across colonic tissue by over ten-fold. Foam efficacy for Fab was investigated in a range of colitis mouse models, from acute to chronic. This non-invasive formulation platform demonstrates potential to overcome existing limitations in delivering biologics to inflamed colonic tissue.

Associations of 24-Hour Central Systolic Blood Pressure With Multiorgan Damage in Nondialysis Patients With Chronic Kidney Disease.

BACKGROUND: Multiple target-organ damages (TODs) in the same patient are common and further increase the risk of cardiovascular disease. However, the relationship between ambulatory central systolic blood pressure (SBP) and multiple TODs has yet to be explored. METHODS AND RESULTS: MobilO-Graph PWA was used to monitor the participants' ambulatory blood pressure, and the presence of left ventricular hypertrophy, carotid hypertrophy, and kidney injury were used to define TOD. Logistic regression analyses and receiver operating characteristic analyses were used to explore the correlation between SBP and TOD. Overall, 2018 nondialysis patients with chronic kidney disease were included and 580 (28.74%) had multiple TODs. Twenty-four-hour central SBP with c2 calibration exhibited a stronger correlation with the increasing number of TOD compared with 24-hour brachial SBP in ordinal logistic regression analyses. In the multivariable analyses with the presence of multiple TODs, the odds ratios were 1.786 (95% CI, 1.474-2.165; P<0.001) for 24-hour brachial SBP and 1.949 (95% CI, 1.605-2.366; P<0.001) for 24-hour central SBP with c2 calibration. The receiver operating characteristic analyses also showed that 24-hour central SBP with c2 calibration had higher discrimination than 24-hour brachial SBP regarding multiple TODs (P<0.001). In addition, using 130/135 mm Hg as the threshold for 24-hour brachial SBP/central SBP with c2 calibration to cross-classify, the prevalence of multiple TODs was greater in cases of concordant hypertension compared with cases of isolated brachial hypertension and concordant normotension, with no difference between the latter 2 conditions. CONCLUSIONS: Twenty-four-hour central SBP with c2 calibration was more associated with the presence of multiple TODs compared with 24-hour brachial SBP and was helpful in risk classification of multiple TODs among nondialysis patients with chronic kidney disease.

STING coordinates resolution of inflammation during wound repair by modulating macrophage trafficking through STAT3.

Efficient cutaneous wound healing requires a coordinated transition between inflammatory phases mediated by dynamic changes in leukocyte subset populations. Here, we identify STING as a key innate immune mediator governing timely resolution of inflammation by regulating macrophage dynamics during skin repair. Using a mouse model, we show STING deficiency caused delayed wound closure associated with abnormal persistence of TNF-α+ leukocytes. This resulted from the impaired macrophage recruitment. STING controlled the trafficking of bone marrow myeloid cells into blood and wounds, intrinsically enhancing macrophage migratory capacity through STAT3 activation. Specifically, STING modulated the production of monocyte chemokines and their receptors CCR2/CCR5 to enable efficient egress and wound infiltration. Consequently, disrupted systemic and local STING-STAT3-chemokine signaling combine to delay macrophage influx. This study elucidates STING as a critical rheostat tuning macrophage responses through STAT3 to orchestrate inflammatory resolution necessary for efficient wound healing. Our findings have broad implications for targeting STING therapeutically in both regenerative medicine and inflammatory disease contexts. STING regulates the macrophage trafficking through STAT3 in wound healing.

Case report: Cytokine and miRNA profiling in multisystem inflammatory syndrome in children.

Multisystem inflammatory syndrome in children (MIS-C) is an imperative pediatric inflammatory condition closely linked to COVID-19, which garners substantial attention since the onset of the pandemic. Like Kawasaki illness, this condition is characterized by an overactive immune response, leading to symptoms including pyrexia, cardiac and renal complications. To elucidate the pathogenesis of MIS-C and identify potential biomarkers, we conducted an extensive examination of specific cytokines (IL-6, IL-1ß, IL-6R, IL-10, and TNF-α) and microRNA (miRNA) expression profiles at various intervals (ranging from 3 to 20 days) in the peripheral blood sample of a severely affected MIS-C patient. Our investigation revealed a gradual decline in circulating levels of IL-6, IL-1ß, IL-10, and TNF-α following intravenous immune globulin (IVIG) therapy. Notably, IL-6 exhibited a significant reduction from 74.30 to 1.49 pg./mL, while IL-6R levels remained consistently stable throughout the disease course. Furthermore, we observed an inverse correlation between the expression of hsa-miR-596 and hsa-miR-224-5p and the aforementioned cytokines. Our findings underscore a robust association between blood cytokine and miRNA concentrations and the severity of MIS-C. These insights enhance our understanding of the genetic regulatory mechanisms implicated in MIS-C pathogenesis, offering potential avenues for early biomarker detection and therapy monitoring through miRNA analysis.

Investigating the impact of supply voltage fluctuations on phase noise in quartz crystal oscillators.

The impact of power supply voltage fluctuations on the phase noise of quartz crystal oscillators (XOs) remains an open issue. Currently, there is a lack of comprehensive analysis on this matter. This work presents a novel phase-noise drive sensitivity (PNDS) model for the XO to reveal its mechanism. This model based on five noise modulation processes demonstrates the distribution of the PNDS in the frequency domain clearly, and there exists a PNDS bandwidth fS that limits the supply voltage fluctuation, which is similar to the effect of the noise bandwidth of the classical Leeson model. Using the PNDS, we successfully predict the phase noise of a 10 MHz oscillator under different supply voltage noises. In addition, experimental results show that the PNDS floor is determined by the phase modulation of the sustaining amplifier, while the amplitude-frequency effect of the resonator and the tuning of the diode often play crucial roles in the near-carrier PNDS.

Molecular investigation of Treponema pallidum strains associated with ocular syphilis in the United States, 2016-2020.

Ocular syphilis is a serious complication of Treponema pallidum infection that can occur at any stage of syphilis and affect any eye structure. It remains unknown if certain T. pallidum strains are associated with ocular infections; therefore, we performed genotyping and whole genome sequencing (WGS) to characterize strains from patients with ocular syphilis. Seventy-five ocular or non-ocular specimens from 55 ocular syphilis patients in 14 states within the United States were collected between February 2016 and November 2020. Sufficient T. pallidum DNA was available from nine patients for genotyping and three for WGS. Genotyping was done using the augmented Centers for Disease Control and Prevention typing scheme, and WGS was performed on Illumina platforms. Multilocus sequence typing allelic profiles were predicted from whole genome sequence data. T. pallidum DNA was detected in various specimens from 17 (30.9%) of the 55 patients, and typing was done on samples from 9 patients. Four complete strain types (14d10/g, 14b9/g, 14d9/g, and 14e9/f) and five partial types were identified. WGS was successful on samples from three patients and all three strains belonged to the SS14 clade of T. pallidum. Our data reveal that multiple strain types are associated with ocular manifestations of syphilis. While genotyping and WGS were challenging due to low amounts of T. pallidum DNA in specimens, we successfully performed WGS on cerebrospinal fluid, vitreous fluid, and whole blood.IMPORTANCESyphilis is caused by the spirochete Treponema pallidum. Total syphilis rates have increased significantly over the past two decades in the United States, and the disease remains a public health concern. In addition, ocular syphilis cases has also been on the rise, coinciding with the overall increase in syphilis rates. We conducted a molecular investigation utilizing traditional genotyping and whole genome sequencing over a 5-year period to ascertain if specific T. pallidum strains are associated with ocular syphilis. Genotyping and phylogenetic analysis show that multiple T. pallidum strain types are associated with ocular syphilis in the United States.

Thermal-Driven Cobalt Intercalation Enhances Thermoelectric ZT of n-Type Bi2Te2.7Se0.3.

Layered materials have emerged as stars in the realm of nanomaterials, showcasing exceptional versatility in various fields. This investigation employed a thermally driven method to intercalate cobalt (Co) into the van der Waals gaps of (CuI)0.002Bi2Te2.7Se0.3 crystals and investigated the mechanism by which the intercalated Co enhances the thermoelectric performance of the material. Co intercalation decreases the carrier concentration, thereby improving the Seebeck coefficient and decreasing both the mobility and the electrical conductivity. These effects result in a significant enhancement of the power factor above 400 K. Theoretical electronic structure calculations provide insights into the role of Co in this material. Additionally, the presence of intercalated Co significantly enhances phonon scattering, thereby boosting the thermoelectric figure-of-merit, ZT to 1.33 at 350 K for 0.17% Co intercalation. These findings highlight the potential of Co incorporation for improving the thermoelectric energy efficiency of n-type Bi2Te2.7Se0.3, offering avenues for further optimization in thermoelectric applications.

Anthraquinones-based photocatalysis: A comprehensive review.

In recent years, there has been significant interest in photocatalytic technologies utilizing semiconductors and photosensitizers responsive to solar light, owing to their potential for energy and environmental applications. Current efforts are focused on enhancing existing photocatalysts and developing new ones tailored for environmental uses. Anthraquinones (AQs) serve as redox-active electron transfer mediators and photochemically active organic photosensitizers, effectively addressing common issues such as low light utilization and carrier separation efficiency found in conventional semiconductors. AQs offer advantages such as abundant raw materials, controlled preparation, excellent electron transfer capabilities, and photosensitivity, with applications spanning the energy, medical, and environmental sectors. Despite their utility, comprehensive reviews on AQs-based photocatalytic systems in environmental contexts are lacking. In this review, we thoroughly describe the photochemical properties of AQs and their potential applications in photocatalysis, particularly in addressing key environmental challenges like clean energy production, antibacterial action, and pollutant degradation. However, AQs face limitations in practical photocatalytic applications due to their low electrical conductivity and solubility-related secondary contamination. To mitigate these issues, the design and synthesis of graphene-immobilized AQs are highlighted as a solution to enhance practical photocatalytic applications. Additionally, future research directions are proposed to deepen the understanding of AQs' theoretical mechanisms and to provide practical applications for wastewater treatment. This review aims to facilitate mechanistic studies and practical applications of AQs-based photocatalytic technologies and to improve understanding of these technologies.

Acoustic black hole ultrasonic scalpel.

Ultrasonic scalpels (USs), as the preferred energy instruments, are facing a growing need to exhibit enhanced performance with the diversification of modern surgical challenges. Hence, we proposed an acoustic black hole ultrasonic scalpel (ABHUS) in longitudinal-bending coupled vibration for efficient surgical cutting. By incorporating an acoustic black hole profile, the local bending wave velocity is reduced and the amplitude is amplified cumulatively, thus creating a high-energy region near the blade tip to enhance the cutting performance of the ABHUS. The precise physical analysis model is established for systematic design of the ABHUS and quick estimation of its frequency characteristics. The vibration simulation and experiments demonstrate that compared with the conventional ultrasonic scalpel (CUS), the output amplitude of the ABHUS significantly increases, particularly a 425% increase in bending vibration displacement. The in-vitro cutting experiment confirms that ABHUS exhibits superior cutting performance. Our design presents vast possibilities and potential for the development of high-performance ultrasonic surgical instruments, serving as an innovative supplement with extraordinary significance for application of acoustic black holes.

Discovery of a Highly Promising Disulfide Derivative Scaffold as Inhibitor of SARS-CoV-2 main protease.

The main protease (Mpro) of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) represents a promising target for antiviral drugs aimed at combating COVID-19. Consequently, the development of Mpro inhibitor  is an ideal strategy for combating the virus. In this study, we identified twenty-two dithiocarbamates (1a-h), dithiocarbamate-Cu(II) complexes (2a-hCu) and disulfide derivatives (2a-e, 2i) as potent inhibitors of Mpro, with IC50 value range of 0.09-0.72, 0.9-24.7 and 15.1-111 µM, respectively, through FRET screening. The enzyme kinetics, inhibition mode, jump dilution, and DTT assay revealed that 1g may be a partial reversible inhibitor, while 2d and 2f-Cu are the irreversible and dose- and time-dependent inhibitors, potentially covalently binding to the target. Binding of 2d, 2f-Cu and 1g to Mpro was found to decrease the stability of the protein. Additionally, DTT assays and thermal shift assays indicated that 2f-Cu and 2d are the nonspecific and promiscuous cysteine protease inhibitor. ICP-MS implied that the inhibitory activity of 2f-Cu may stem from the uptake of Cu(II) by the enzyme. Cytotoxicity assays demonstrated that 2d and 1g exhibit low cytotoxicity, whereas 2f-Cu show certain cytotoxicity in L929 cells. Overall, this work presents two promising scaffolds for the development of Mpro inhibitors to combat COVID-19.

Knowledge, Attitude, and Practice Toward Varicocele in Patients with Varicoceles: A Cross-Sectional Study in Chinese Patients.

Objective: To explore patients' knowledge, attitude, and practice (KAP) toward varicocele in China and the relationship between treatment selection and KAP. Methods: This cross-sectional study enrolled varicocele patients at the Third Affiliated Hospital of Soochow University (September to October 2023). Structural equation modeling (SEM) was used to explore the relationship between clinical factors and KAP. A score >mean score for each dimension was defined as adequate knowledge, positive attitude, and proactive practice. The patients were grouped according to varicocelectomy vs no surgery. Univariable and multivariable logistic regression analyses were used to identify the factors independently associated with KAP. A structural equation modeling (SEM) analysis was performed to examine how the KAP dimensions influenced each other. Results: Among 502 patients, 44.02%, 35.86%, and 20.12% were ≤30, 31-40, and >40 years old, respectively. Those who underwent varicocelectomy (n=407) had significantly higher knowledge (20 (15-22) vs 0 (0-6), P<0.001), attitude (26 (24-26) vs 14 (10-18), P<0.001), and practice (20 (17-24) vs 8 (6-16), P<0.001) than those who did not. A higher proportion of patients with varicocelectomy were <40 years old, more educated, had higher income, and were unmarried compared with those without surgery (all P<0.001). High school or higher education level and varicocelectomy (irrespective of type) were independently associated with adequate knowledge (all P<0.001). Knowledge, college/bachelor's degree education, and varicocelectomy type (irrespective of type) were associated with positive attitudes (all P<0.05). In the SEM, knowledge directly influenced attitude, knowledge directly influenced practice, and attitude directly influenced practice (all P<0.001). Having knowledge of the subject may direct varicocele patients to varicocelectomy. Conclusion: Chinese patients who underwent varicocelectomy exhibit appropriate KAP regarding varicocele, while non-surgery patients have poorer KAP. These results suggest that patients who did not undergo surgery should nevertheless be properly informed about their disease.

The impact of tumor size on the prognosis and chemotherapy efficacy in stage I/II colon cancer patients.

Background: The impact of tumor size on the survival and chemotherapy reponse of early-stage colon cancer remains unclear. Our study explored the effect of tumor size on overall survival (OS) and postoperative chemotherapy efficacy in patients with stage I/II colon cancer. Methods: Stage I/II colon cancer patients from the Surveillance, Epidemiology and End Results (SEER) database and a China center were extracted as two cohorts respectively. X-tile program was adopted to acquire optimal cutoff points of tumor size (16mm and 49mm). Harrell's concordance index (c-index) and time-dependent receiver operating characteristic curve (ROC) were used to indicate discrimination ability of prognostic factors. Results: Overall, 104,908 and 168 stage I/II postoperative colon cancer patients from SEER database and a China center were eligible, respectively. Kaplan-Meier analysis showed that large tumor size was associated with poor OS in two cohorts. The effect of tumor size on OS gradually decreased as the T stage increased both before PSM (c-index 0.535 for T1N0M0 and 0.506 for T4N0M0, p<0.05) and after PSM (c-index 0.543 for T1N0M0, p<0.05; c-index 0.543 for T4N0M0, p>0.05). Stratified analyses showed that chemotherapy improved the OS rate by 9.5% (chemotherapy vs. non-chemotherapy: 83.5% vs. 73.0%) or 12.8% (chemotherapy vs. non-chemotherapy: 85.7% vs. 72.9%) before and after PSM in T2N0M0 patients with tumor size >49 mm, but not in T1N0M0. The survival benefit provided by chemotherapy for T2N0M0 patients with large tumor was also validated in the Chinese cohort. Conclusions: Large tumor size was a risk factor for stage I/II colon cancer, especially for T1N0M0. Tumor size could serve as a complementary factor guiding postoperative chemotherapy for T2N0M0 patients.