BACKGROUND:Inhibition of osteoclast activity by bisphosphonates slows the progression of osteoporosis.However,serious complications of bisphosphonates,such as osteonecrosis of the jaw and atypical femur fracture,limit the clinical application of bisphosphonates.Effective alternative therapies need to be sought to improve existing clinical dilemmas. OBJECTIVE:To prepare strontium-containing mesoporous bioactive glass nanoparticles loaded with bisphosphonates(BPS@Sr-MBG)and analyze its activity against bone loss. METHODS:Strontium-containing mesoporous bioactive glass nanoparticles(Sr-MBG)were prepared by sol-gel method and added to alendronate saturated solution for the preparation of BPS@Sr-MBG.(1)Cell experiment:Mouse bone marrow macrophages were inoculated in 96-well plates and supplemented with ɑ-MEM complete culture medium containing macrophage colony stimulating factor and activator-ligand of nuclear factor κB receptor for osteoclast induced differentiation experiment.Meanwhile,they were cultured in three groups.The blank group was added with PBS.The control group was added with bisphosphonate,and the experimental group was added with BPS@Sr-MBG.After 5 days of culture,the differentiation of osteoclasts was observed by F-actin ring staining.(2)Animal experiments:Twenty-four female C57/BL mice were randomly divided into four groups with six mice in each group.Except sham operation group,ovariectomy group,BPS group and BPS@Sr-MBG group were used to construct osteoporosis model.One week after model establishment,mice in BPS group and BPS@Sr-MBG group were intraperitoneally injected with bisphosphonate solution and BPS@Sr-MBG solution,respectively.Mice in the sham operation group and ovariectomy group were intraperitoneally injected with PBS once a week.After 8 weeks of continuous injection,mouse femurs were taken for Micro-CT scanning and hematoxylin-eosin staining. RESULTS AND CONCLUSION:(1)Cell experiment:F-actin ring-formation staining demonstrated that compared with blank group,the area proportion and number of osteoclasts in the control group were decreased(P<0.01).Compared with the control group,the area proportion of osteoclasts and the number of osteoclasts in the experimental group were decreased(P<0.01).(2)Animal experiments:Micro-CT scanning results of femur showed that compared with the sham operation group,bone density,trabecular bone volume fraction,trabecular thickness and trabecular number of mice in the ovariectomy group were decreased(P<0.05,P<0.01),while trabecular distance and structural model index were increased(P<0.01).Compared with the ovariectomy group,the above bone parameters in the BPS group and BPS@Sr-MBG group were significantly improved(P<0.01),and the improvement in the BPS@Sr-MBG group was more obvious.The Micro-CT scanning results were further confirmed by hematoxylin-eosin staining of the femur.(3)The results show that BPS@Sr-MBG can exert anti-osteoporosis activity through anti-osteoclastic effect and promoting bone formation.

【Objective】 To establish an effective quality indicator monitoring system, scientifically and objectively evaluate the quality management level of blood banks, and achieve continuous improvement of quality management in blood bank. 【Methods】 A quality monitoring indicator system that covers the whole process of blood collection and supply was established, the questionnaire of Quality Monitoring Indicators for Blood Collection and Supply Process with clear definition of indicators and calculation formulas was distributed to 17 blood banks in Shandong. Statistical analysis of 21 quality monitoring indicators in terms of blood donation service (10 indicators), blood component preparation (7 indicators ), and blood supply (4 indicators) from each blood bank from January to December 2022 were conducted using SPSS25.0 software The differences in quality monitoring indicators of blood banks of different scales were analyzed. 【Results】 The average values of quality monitoring indicators for blood donation service process of 17 blood banks were as follows: 44.66% (2 233/5 000) of regular donors proportion, 0.22% (11/50) of adverse reactions incidence, 0.46% (23/5 000) of non-standard whole blood collection rate, 0.052% (13/25 000) of missed HBsAg screening rate, 99.42% (4 971/5 000) of first, puncture successful rate, 86.49% (173/200) of double platelet collection rate, 66.50% (133/200) of 400 mL whole blood collection rate, 99.25% (397/400) of donor satisfaction rate, 82.68% (2 067/2 500) of use rate of whole blood collection bags with bypass system with sample tube, and 1 case of occupational exposure in blood collection.There was a strong positive correlation between the proportion of regular blood donors and the collection rate of 400 mL whole blood (P<0.05). The platelet collection rate, incidence of adverse reactions to blood donation, and non-standard whole blood collection rate in large blood banks were significantly lower than those in medium and small blood banks (P<0.05). The average quality monitoring indicators for blood component preparation process of 17 blood banks were as follows: the leakage rate of blood component preparation bags was 0.03% (3/10 000), the discarding rate of lipemic blood was 3.05% (61/2 000), the discarding rate of hemolysis blood was 0.13%(13/10 000). 0.06 case had labeling errors, 8 bags had blood catheter leaks, 2.76 bags had blood puncture/connection leaks, and 0.59 cases had non-conforming consumables. The discarding rate of hemolysis blood of large blood banks was significantly lower than that of medium and small blood banks (P<0.05), and the discarding rate of lipemic blood of large and medium blood banks was significantly lower than that of small blood banks (P<0.05). The average values of quality monitoring indicators for blood supply process of 17 blood banks were as follows: the discarding rate of expired blood was 0.023% (23/100 000), the leakage rate during storage and distribution was of 0.009%(9/100 000), the discarding rate of returned blood was 0.106% (53/50 000), the service satisfaction of hospitals was 99.16% (2 479/2 500). The leakage rate of blood components during storage and distribution was statistically different with that of blood component preparation bags between different blood banks (P<0.05). There were statistically significant differences in the proportion of regular blood donors, incidence of adverse reactions, non-standard whole blood collection rate, 400 mL whole blood collection rate, double platelet collection rate, the blood bag leakage rate during preparation process, the blood components leakage rate during storage and distribution as well as the discarding rate of lipemic blood, hemolysis blood, expired blood and returned blood among large, medium and small blood banks (all P<0.05). 【Conclusion】 The establishment of a quality monitoring indicator system for blood donation services, blood component preparation and blood supply processes in Shandong has good applicability, feasibility and effectiveness. It can objectively evaluate the quality management level, facilitate the continuous improvement of the quality management system, promote the homogenization of blood management in the province and lay the foundation for future comprehensive evaluation of blood banks.

Objective:To understand the incidence trend of meningococcal meningitis from 1990 to 2023 and major pathogenic serogroups of Neisseria ( N.) meningitidis from 2006 to 2023 in China and the time trend of the incidence of meningococcal meningitis caused by main pathogenic serogroups, and provide reference for the prevention and control of meningococcal meningitis. Methods:The study used the data from "National Epidemic Data Compile" from 1990 to 2003 and the data from China Notifiable Infectious Disease Reporting System from 2004 to 2023 to analyze the incidence trend of meningococcal meningitis in China from 1990 to 2023 by Joinpoint regression method. Based on the data of the national meningococcal meningitis surveillance information reporting and management system from 2006 to 2023, the incidence of meningococcal meningitis caused by different serogroups of N. meningitidis was described and analyzed, and the trend χ2 test was performed to analyze the change of the incidence of meningococcal meningitis caused by N. meningitidis A, B, and C. Results:The overall incidence of meningococcal meningitis in China showed a downward trend from 1990 to 2023 [average annual percent change (AAPC)=-14.80%, P<0.001], with the most obvious decline from 2005 to 2012 [annual percent change (APC)=-31.01%, P<0.001]. The incidence of meningococcal meningitis decreased in both men and women (AAPC=-14.69% and -15.05%, both P<0.001). A total of 1 178 serogroup specific cases of meningococcal meningitis were reported in China from 2006 to 2023, the proportion of serogroup C was highest (32.5%), followed by unclassified (22.3%), B (20.1%), A (18.4%), W (4.5%), Y (2.0%) and X (0.2%). The results of trend χ2 test indicated that the incidence of meningococcal meningitis caused by N. meningitidis A and C showed downward trends (both P<0.001) and the incidence of meningococcal meningitis caused by N. meningitidis B showed an upward trend in general population and young children (0-4 years old group) from 2006 to 2023 (both P<0.05). Conclusion:The incidence of meningococcal meningitis showed a downward trend in China from 1990 to 2023, but it is still necessary to pay more attention to the incidence of meningococcal meningitis caused by N. meningitidis B in age group aged 0-4 years and by multi serogroups at same time in general population.

Objective:To investigate the current status of endoscopic treatment for gastroesophageal varices in portal hypertension in China, and to provide supporting data and reference for the development of endoscopic treatment.Methods:In this study, initiated by the Liver Health Consortium in China (CHESS), a questionnaire was designed and distributed online to investigate the basic condition of endoscopic treatment for gastroesophageal varices in portal hypertension in 2022 in China. Questions included annual number and indication of endoscopic procedures, adherence to guideline for preventing esophagogastric variceal bleeding (EGVB), management and timing of emergent EGVB, management of gastric and isolated varices, and improvement of endoscopic treatment. Proportions of hospitals concerning therapeutic choices to all participant hospitals were calculated. Guideline adherence between secondary and tertiary hospitals were compared by using Chi-square test.Results:A total of 836 hospitals from 31 provinces (anotomous regions and municipalities) participated in the survey. According to the survey, the control of acute EGVB (49.3%, 412/836) and the prevention of recurrent bleeding (38.3%, 320/836) were major indications of endoscopic treatment. For primary [non-selective β-blocker (NSBB) or endoscopic therapies] and secondary prophylaxis (NSBB and endoscopic therapies) of EGVB, adherence to domestic guideline was 72.5% (606/836) and 39.2% (328/836), respectively. There were significant differences in the adherence between secondary and tertiary hospitals in primary prophylaxis of EGVB [71.0% (495/697) VS 79.9% (111/139), χ2=4.11, P=0.033] and secondary prophylaxis of EGVB [41.6% (290/697) VS 27.3% (38/139), χ2=9.31, P=0.002]. A total of 78.2% (654/836) hospitals preferred endoscopic therapies treating acute EGVB, and endoscopic therapy was more likely to be the first choice for treating acute EGVB in tertiary hospitals (82.6%, 576/697) than secondary hospitals [56.1% (78/139), χ2=46.33, P<0.001]. The optimal timing was usually within 12 hours (48.5%, 317/654) and 12-24 hours (36.9%, 241/654) after the bleeding. Regarding the management of gastroesophageal varices type 2 and isolated gastric varices type 1, most hospitals used cyanoacrylate injection in combination with sclerotherapy [48.2% (403/836) and 29.9% (250/836), respectively], but substantial proportions of hospitals preferred clip-assisted therapies [12.4% (104/836) and 26.4% (221/836), respectively]. Improving the skills of endoscopic doctors (84.2%, 704/836), and enhancing the precision of pre-procedure evaluation and quality of multidisciplinary team (78.9%, 660/836) were considered urgent needs in the development of endoscopic treatment. Conclusion:A variety of endoscopic treatments for gastroesophageal varices in portal hypertension are implemented nationwide. Participant hospitals are active to perform emergent endoscopy for acute EGVB, but are inadequate in following recommendations regarding primary and secondary prophylaxis of EGVB. Moreover, the selection of endoscopic procedures for gastric varices differs greatly among hospitals.

【Objective】 To analyze the predictive value of serum β-defensin-3 (HBD-3) and decoy receptor 3 (DCR3) for urinary tract infection after percutaneous nephrolithotomy (PCNL) in patients with complex kidney calculi. 【Methods】 A prospective study was conducted on 112 patients treated with PCNL at our hospital during Jan.2020 and Dec.2022.The patients were divided into the non-infection group (52 cases) and infection group (60 cases).The general data, HBD-3 and DCR3 levels of the two groups were compared.Receiver operating characteristic (ROC) curve was drawn to analyze the predictive value of C reactive protein (CRP), procalcitonin (PCT), HBD-3 and DCR3 levels for postoperative urinary tract infection. 【Results】 Compared with the non-infection group, the infection group had higher levels of HBD-3 [(0.77±0.08) ng/mL vs. (1.36±0.25) ng/mL, P=0.001] and DCR3 [(4.68±0.53) ng/mL vs.(13.21±0.28) ng/mL, P=0.001].Multivariate logistic regression showed that a history of urinary tract surgery, preoperative urinary tract infection, operation time, catheterization time, stone load, type of antibiotics, concomitant renal dysfunction, intraoperative channel type, CRP, PCT, HBD-3 and DCR3 were risk factors of postoperative urinary tract infection (P<0.05).The ROC curve showed that the accuracy of CRP, PCT, and CRP plus PCT were 70.54%, 72.32%, and 78.57%, respectively; the accuracy of HBD-3, DCR3, and HBD-3 plus DCR3 were 69.64%, 75.89%, and 86.61%, respectively. 【Conclusion】 Postoperative urinary tract infection in patients with complex kidney calculi is associated with multiple factors, especially high expression levels of HBD-3 and DCR3.Combined detection has high predictive value.

Objective To investigate the value of combined serum levels of neutrophil gelatinase-associated lipocalin(NGAL)and growth differentiation factor 15(GDF-15)in diagnosis of renal injury in elderly patients with H-type hypertension.Methods A total of 177 patients with H-type hypertension admitted to Department of Neurology and Department of General Medicine of the Affiliated Hospital of Chengde Medical College from April 2021 to June 2022 were enrolled,and based on their estimated glomerular filtration rate(eGFR),they were divided into the renal im-pairment group(81 cases)and normal renal function group(96 cases).General data and laboratory indicators were collected in the two groups.ROC curve analysis was used to evaluate the diagnos-tic value of combined NGAL and GDF-15 levels for renal injury in the elderly patients with H-type hypertension,and Pearson correlation analysis was performed to analyze the correlation between serum NGAL and GDF-15 levels and renal injury in the patients.Results SBP level was significantly higher in the renal impairment group than the normal renal function group[148.53±14.62 mm Hg(1 mm Hg=0.133 kPa)vs 138.75±13.36 mm Hg,P＜0.01],but no such difference was observed in DBP level between the two groups(P＞0.05).The levels of creatinine(Cr),urea nitrogen(BUN),β2-microglobulin(β2-MG),cystatin C(Cys C),urinary microalbumin(MA),NGAL and GDF-15 levels were obviously higher in the renal impairment group than the group with normal renal function(P＜0.01).ROC curve analysis showed that the combined detection of NGAL and GDF-15 levels was significantly higher than that of the two indicators alone(P＜0.01).Pearson correlation analysis indicated that serum NGAL and GDF-15 levels were positively correlated with Cr,BUN,β2-MG,Cys C and MA levels(P＜0.01).Conclusion Serum NGAL and GDF-15 levels are elevated in elderly H-type hypertension patients.Combined detection of the two indicators has higher value in the diagnosis of renal injury in elderly H-type hypertension patients.

Objective:To investigate the protective effect of quercetin (QR) on acute liver injury induced by diquat (DQ) poisoning in mice and its mechanism.Methods:Eighty healthy male C57BL/6 mice with SPF grade were randomly divided into control group, DQ model group, QR treatment group, and QR control group, with 20 mice in each group. The DQ poisoning model was established by a one-time intraperitoneal injection of DQ solution (40 mg/kg); the control and QR control groups received equivalent amounts of distilled water through intraperitoneal injection. Four hours after modeling, the QR treatment group and the QR control group received 0.5 mL QR solution (50 mg/kg) through gavage. Meanwhile, an equivalent amount of distilled water was given orally to the control group and the DQ model group. The treatments above were administered once daily for seven consecutive days. Afterwards, the mice were anesthetized, blood and liver tissues were collected for following tests: changes in the structure of mice liver tissue were observed using transmission electron microscopy; the levels of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were detected using enzyme linked immunosorbent assay (ELISA); the levels of glutathione (GSH), superoxide dismutase (SOD), and malondialdehyde (MDA) in liver tissues were measured using the water-soluble tetrazolium-1 (WST-1) method, the thiobarbituric acid (TBA) method, and enzymatic methods, respectively; the protein expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), Kelch-like ECH-associated protein 1 (Keap1), and activated caspase-9 in liver tissues were detected using Western blotting.Results:Severe mitochondrial damage was observed in the liver tissues of mice in the DQ model group using transmission electron microscopy, yet mitochondrial damage in the QR treatment group showed significant alleviation. Compared to the control group, the DQ model group had significantly increased levels of MDA in liver tissue, serum AST, and ALT, yet had significantly decreased levels of GSH and SOD in liver tissue. In comparison to the DQ model group, the QR treatment group exhibited significant reductions in serum levels of ALT and AST, as well as MDA levels in liver tissue [ALT (U/L): 52.60±6.44 vs. 95.70±8.00, AST (U/L): 170.45±19.33 vs. 251.10±13.09, MDA (nmol/mg): 12.63±3.41 vs. 18.04±3.72], and notable increases in GSH and SOD levels in liver tissue [GSH (μmol/mg): 39.49±6.33 vs. 20.26±3.96, SOD (U/mg): 121.40±11.75 vs. 81.67±10.01], all the differences were statistically significant (all P < 0.01). Western blotting results indicated that the protein expressions of Nrf2 and HO-1 in liver tissues of the DQ model group were significantly decreased compared to the control group. On the other hand, the protein expressions of Keap1 and activated caspase-9 were conspicuously higher when compared to the control group. In comparison to the DQ model group, the QR treatment group showed a significant increase in the protein expressions of Nrf2 and HO-1 in liver tissues (Nrf2/β-actin: 1.17±0.08 vs. 0.92±0.45, HO-1/β-actin: 1.53±0.17 vs. 0.84±0.09). By contrast, there was a notable decrease in the protein expressions of Keap1 and activated caspase-9 (Keap1/β-actin: 0.48±0.06 vs. 1.22±0.09, activated caspase-9/β-actin: 1.17±0.12 vs. 1.59±0.30), the differences were statistically significant (all P < 0.01). Conclusion:QR may reduce acute liver injury induced by DQ poisoning in mice via activating Keap1/Nrf2 signaling pathway.

[Purpose]To analyze the incidence trend and age at diagnosis of thyroid cancer in can-cer registration areas of Jiangsu Province from 2009 to 2019.[Methods]The continuous and com-plete cancer data from 2009 to 2019 meeting quality control requirements were collected from 16 registries in Jiangsu Province.Thyroid cancer was coded as C73 according to ICD-10.The crude incidence rate,age-standardized incidence rate by Chinese standard population(ASIRC),the mean diagnostic age and adjusted mean diagnostic age of thyroid cancer were calculated by sex,age groups and regions.The trends of above indicators were analyzed and the average annual per-centage change(AAPC)was calculated.[Results]The crude incidence rate and ASIRC of thyroid cancer for men in Jiangsu cancer registration areas in 2009 and 2019 were 1.25/105,1.00/105 and 7.32/105,6.48/105,respectively.For women those were 3.64/105,3.06/105 and 24.91/105,20.94/105,respectively.The AAPC of crude incidence rate and ASIRC of thyroid cancer from 2009 to 2019 were 22.05％(95％CI:19.70％～24.45％)and 22.55％(95％CI:20.06％～25.08％),respectively.The adjusted mean diagnostic age of thyroid cancer declined from 46.27 years old in 2009 to 43.03 years old in 2019(β=-0.243,P＜0.001).[Conclusion]The incidence rate of thyroid cancer showed an increasing trend in cancer registration areas of Jiangsu Province from 2009 to 2019,while the diagnostic age showed a downward trend during the same period.

Objective:To investigate the effect of nuclear factor-erythroid 2-related factor 2 (Nrf2) gene on the proliferation and apoptosis of colorectal adenocarcinoma cells in vitro, and the role of Nrf2 gene in regulation of epithelial-mesenchymal transition (EMT) pathway.Methods:Three Nrf2 small interfering RNA (siRNA) sequences were designed and synthesized, namely siRNA-223, siRNA-538 and siRNA-756, and the unrelated sequences were designed and synthesized. The plasmids carrying various siRNA sequences of Nrf2 were constructed, and the plasmids carrying siRNA sequences and the plasmids carrying unrelated sequences were transfected into human colorectal adenocarcinoma Caco-2 cells, namely interference group and empty vector group, respectively. Additionally, Caco-2 cells without any treatment were used as the control group. Real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) and Western blotting (WB) methods were used to detect the relative expression of Nrf2 gene in transcription and translation levels in each group of cells, in order to verify the interference effect of Nrf2; the siRNA with the best interference effect was selected for subsequent experiments. CCK-8 method was used to detect the proliferation ability of each group of cells (expressed as absorbance value); RT-qPCR was used to detect the relative expression of EMT pathway-related factors [vimentin (Vim), N-cadherin (N-cad) and E-cadherin (E-cad)] in transcription level in each group of cells; WB method was used to detect the expression of pro-apoptotic protein Bax in each group of cells.Results:The results of RT-qPCR and WB methods showed that compared with the control group and the empty group, the relative expression of Nrf2 gene in transcription and translation levels in Caco-2 cells of the siRNA-756 interference group were the lowest, and the differences were statistically significant (all P < 0.05). The CCK-8 results showed that the absorbance values of Caco-2 cells in the control group, empty group and siRNA-756 interference group after 48 hours of culture were (100±5)%, (94±4)% and (82±5)%, respectively; compared with the control group and the empty group, the siRNA-756 interference group had lower absorbance value, and the differences were statistically significant (all P < 0.05). The results of RT-qPCR method showed that the relative expression of Vim and N-cad in transcription level in the siRNA-756 interference group were higher than those in the control group and the empty vector group, and the differences were statistically significant (all P < 0.05); the relative expression of E-cad in transcription level was lower than those in the control group and the empty vector group, and the differences were statistically significant (both P < 0.05). The results of WB method showed that the relative expression of Bax protein in the siRNA-756 interference group was higher than that in the control group, and the difference was statistically significant ( P < 0.05). Conclusions:Interference with Nrf2 expression in vitro can weaken the proliferation and anti-apoptotic abilities of human colorectal adenocarcinoma Caco-2 cells. The mechanism may be that Nrf2 regulates the expression of Vim, N-cad and E-Cad in the EMT pathway to enhance the EMT ability of tumor cells.

Objective:To investigate the clinicopathological characteristics of early-onset colorectal cancer.Methods:The retrospective and descriptive study was conducted. The clincopatholo-gical data of 59 206 patients with colorectal cancer in the Surveillance, Epidemiology, and End Results Program of the United States of America From January 1,2010 to December 31,2019 were collected. There were 33 213 males, 25 993 males, aged (50±7)years. Observation indicators: (1) demographic and oncological characteristics of colorectal cancer patients; (2) comparison of clinico-pathological characteristics between early-onset and late-onset colorectal cancer. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was conducted using the t test. Measurement data with skewed distribution were represented as M( Q1, Q3), and comparison among groups was conducted using the Kruskal-Wallis H test. Count data were described as absolute numbers, and comparison among groups was conducted using the chi-square test. Comparison of ordinal data was conducted using the non-parameter H test. Patients with early-onset colorectal cancer were segmented by age, and missing data for categorical variables is set as unknown. Results:(1) Demographic and oncological characteristics of colorectal cancer patients. Of 59 206 patients, there were 23 104 cases with early-onset colorectal cancer and 36 102 cases with late-onset colorectal cancer, and cases aged 13-29 years, cases aged 30-34 years, cases aged 35-39 years, cases aged 40-44 years, cases aged 45-49 years, cases aged 55-59 years were 1 041, 1 740, 3 288, 6 050, 10 985, 15 303,20 799, respectively. (2) Comparison of clinicopathological charac-teristics between early-onset and late-onset colorectal cancer. ① There were significant differences in gender, tumor location, degree of tumor differentiation, tumor histological type, tumor TNM staging, tumor T staging, tumor N staging, tumor M staging, preoperative carcinoembryonic antigen (CEA), perineural invasion, cancer nodule, tumor diameter between patients with early-onset and late-onset colorectal cancer ( P<0.01). Results of further analysis showed that cases with tumor located in ileocecal region, ascending colon, colon liver region, transverse colon were 2 329, 2 139, 579, 1 303 in the 6 350 patients with early-onset right colon cancer. The above indicators were 4 563, 3 945, 902, 1 951 in the 11 361 patients with late-onset right colon cancer. There was a significant difference in the above indicators between the two groups of patients ( χ2=114.27, P<0.01). Cases with tumor located in splenic region of the colon, descending colon, sigmoid colon, rectum sigmoid junction were 553, 1 354, 6 404, 2 431 in the 10 742 patients with early-onset left colon cancer. The above indicators were 865, 1 798, 9 668, 3 610 in the 15 941 patients with late-onset left colon cancer. There was a significant difference in the above indicators between the two groups of patients ( χ2=35.60, P<0.01). ②Of 23 104 patients with early-onset colorectal cancer, cases aged 13-29 years, cases aged 30-34 years, cases aged 35-39 years, cases aged 40-44 years, cases aged 45-49 years were 1 041, 1 740, 3 288, 6 050, 10 985, respectively. There were significant differences in gender, degree of tumor differentiation, tumor histological type, tumor TNM staging, tumor T staging, tumor N staging, pre-operative CEA, perineural invasion, cancer nodule, tumor diameter among patients of different age groups ( P<0.01). Results of further analysis showed that cases with tumor located in ileocecal region, ascending colon, colon liver region, and transverse colon were 91, 117, 45, 69 in the 6 350 early-onset right colorectal cancer patients aged 13-29 years. The above indicators were 165, 136, 47, 115, 304, 313, 93,201, 614, 535, 151, 330, 1 155, 1 038, 243, 588 in early-onset right colorectal cancer patients aged 30-34, 35-39, 40-44, 45-49 years, respectively. There was a significant difference in the above indicators among the five groups of patients ( H=36.63, P<0.01). Cases with tumor located in splenic region of the colon, descending colon, sigmoid colon, rectum sigmoid junction were 32, 83, 260, 95 in the 10 742 early-onset left colorectal cancer patients aged 13-29 years. The above indica-tors were 53, 112, 452, 171, 95, 230, 867, 342, 149, 337, 1 702, 665, 224, 592, 3 123, 1 158 in the 10 742 early-onset left colorectal cancer patients aged 30-34, 35-39, 40-44, 45-49 years, respectively. There was a significant difference in the above indicators among the five groups of patients ( H=47.84, P<0.01). Conclusions:Compared with late-onset colorectal cancer, early-onset colorectal cancer are more likely to occur in the left colon and rectum, with poorly differentiated and undifferentiated tumors, histological type of mucinous adenocarcinoma, TNM staging of stage Ⅲ and Ⅳ, higher proportion of nerve infiltration and cancer nodules, and larger tumor diameter. There are significant differences in clinicopathological characteristics of tumors among patients with early-onset colorectal cancer of different age groups.