Background: Retroperitoneal liposarcoma (RPLS) is a critical malignant disease with various clinical outcomes. However, the molecular heterogeneity of RPLS was poorly elucidated, and few biomarkers were proposed to monitor its progression. Methods: RNA sequencing was performed on a training cohort of 88 RPLS patients to identify dysregulated genes and pathways using clusterProfiler. The GSVA algorithm was utilized to assess signaling pathway levels in each sample, and unsupervised clustering was employed to distinguish RPLS subtypes. Differentially expressed genes (DEGs) between RPLS subtypes were identified to construct a simplified dichotomous clustering via nonnegative matrix factorization. The feasibility of this classification was validated in a separate validation cohort (n=241) using immunohistochemistry (IHC) from the REtroperitoneal SArcoma Registry (RESAR). The study is registered with https://clinicaltrials.gov/ under number NCT03838718. Results: Cell cycle, DNA damage and repair, and metabolism were identified as the most aberrant biological processes in RPLS, enabling the division of RPLS patients into two distinct subtypes with unique molecular signatures, tumor microenvironment, clinical features, and outcomes (overall survival [OS] and disease-free survival [DFS]). A simplified RPLS classification based on representative biomarkers (LEP and PTTG1) demonstrated high accuracy (area under the curve [AUC]>0.99), with patients classified as LEP+ and PTTG1-, showing lower aggressive pathological composition ratio and fewer surgery times, along with better OS (HR = 0.41, p<0.001) and DFS (HR = 0.60, p=0.005). Conclusions: Our study provided an ever-largest gene expression landscape of RPLS and established an IHC-based molecular classification that was clinically relevant and cost-effective for guiding treatment decisions. Funding: This work was supported by grants from the Beijing Municipal Science and Technology Project (Z191100006619081), National Natural Science Foundation of China (82073390), and Young Elite Scientists Sponsorship Program (2023QNRC001). The study sponsors had no role in the design and preparation of this manuscript. Clinical trial number: NCT03838718

11563 Background: Retroperitoneal liposarcoma (RPLS) is a rare type of mesenchymal tumor characterized by difficult surgical management, immune desert, poor response to immunotherapy and high local recurrence rate. However, how tertiary lymphoid structures (TLS) dictates complex biological processes such as antitumor immunity remains unknown. Thus, we aimed to investigate the spatio-temporal heterogeneity of TLS formation, maturation, and functional involvement in TIME, and the clinical value of TLS in multiple retrospective RPLS clinical cohorts. Methods: 330 patients were retrospectively enrolled into five independent cohorts from the two largest retroperitoneal tumor research centers in China and the TCGA database. Single-cell RNA sequencing (sc-RNA seq) (n=4) and spatial transcriptome seq (n=2) were performed for the estimation of TIME based on treatment-naive RPLS. Transcriptomic profiles of 309 cases in five cohorts were obtained from the ZSFD, GEO, and TCGA databases. TLS was quantified in three different anatomic subregions (intra-tumor, invasion margin and peri-tumor) and correlated with overall survival (OS) and disease-free survival (DFS) by Cox regression and Kaplan-Meier analysis. Multiplex immunohistochemistry (mIHC) was performed to characterize and validate the spatial composition of TLS in another treatment-naive RPLS cohort (n=16), neoadjuvant chemotherapy (n=12) and neoadjuvant radiotherapy (n=20) RPLS cohorts. Results: The joint scoring system of T and P scores stratified RPLS into four immune classes with different TLS distribution patterns and prognoses (p<0.001). The immune class C-index was significantly higher than the TNM staging system (0.798 vs. 0.62, p=0.005). Importantly, mIHC revealed that regulatory T cells (Tregs) and M2 phenotype tumor-associated macrophages (TAMs) were significantly increased in intra-tumoral TLS in DDLPS compared to WDLPS, showing an immunosuppressive pattern. Strikingly, neoadjuvant chemotherapy and radiotherapy could block this status of immunosuppressive, induced TLS formation and restore the antitumor immune balance with significantly more CD38+IgG+ plasma cells (PCs) in responsive RPLS, whereas non-responsive RPLS deteriorated into a more suppressive one. Sc-RNA Seq and ST analysis further revealed significant intra- and inter-tumoral TIME heterogeneity and identified the underlying transcriptomic programs driving each phenotype. Conclusions: Our study provides a high-resolution map of TIME in treatment-naive and neoadjuvant chemotherapy/radiotherapy RPLS. Effective neoadjuvant chemotherapy and radiotherapy can induce TLS formation and restore the antitumor immune balance in RPLS.

ObjectiveGiven high risks of major bleeding during retroperitoneal sarcoma(RPS) surgeries, severe complications and deaths are common to see perioperatively. Thus, effective anesthetic management is the key point to ensuring the safety of patients. This study aimed to introduce anesthesia management and mortalities in RPS patients receiving massive blood transfusions during surgeries.MethodsRecords of RPS surgeries under general anesthesia from January 2016 through December 2021 were retrospectively retrieved from our database. Patients who received massive blood transfusions (MBT) exceeding 20 units in 24h duration of operations were finally included in this study. Demographics, modalities of anesthesia management, blood loss, transfusion, peri-anesthesia biochemical tests as well as morbidities and mortalities were collected. Risk factors of postoperative 60d mortality were determined through logistic regression in uni-and multi-variety analysis using the statistics software STATA 17.0.ResultsA total of 70 patients (male 31) were included. The mean age was 50.1 ± 15.8 years. All patients received combined resections of sarcoma with involved organs under general anesthesia. Mean operation time and anesthesia time were 491.7 ± 131.1mins and 553.9 ± 132.6mins, respectively. The median intraoperative blood loss was 7000ml (IQR 5500,10000ml). Median red blood cells (RBC) and fresh frozen plasma (FFP) transfusion were 25.3u (IQR 20,28u), and 2400ml (IQR 2000,3000ml), respectively. Other blood products infusions included prothrombin complex concentrate (PCCs), fibrinogen concentrate (FC), platelet(plt) and albumin(alb) in 82.9% (58/70), 88.6% (62/70), 81.4% (57/70) and 12.9% (9/70) of patients. The postoperative severe complication rate(Clavien-Dindo grade≥3a) was 35.7%(25/70). A total of 7 patients (10%) died during the postoperative 60-day period. BMI, volumes of crystalloid infusion in anesthesia, and hemoglobin and lactate levels at the termination of operation were found significantly associated with postoperative occurrence of death in univariate analysis. In logistic multivariate analysis, extended anesthesia duration was found associated with postoperative venous thrombosis embolism (VTE) and severe complication. The lactate level at the immediate termination of the operation was the only risk factor related to perioperative death (p<0.05).ConclusionRPS patients who endure MBT in surgeries face higher risks of death postoperatively, which needs precise and effective anesthesia management in high-volume RPS centers. Increased blood lactate levels might be predictors of postoperative deaths which should be noted.

Objective:The Transatlantic Australasian Retroperitoneal Sarcoma Working Group conducted a retrospective study on the disease course and clinical management of ganglioneuromas. Background:Ganglioneuromas are rare tumors derived from neural crest cells. Data on these tumors remain limited to case reports and single-institution case series. Methods:Patients of all ages with pathologically confirmed primary retroperitoneal, intra-abdominal, and pelvic ganglioneuromas between January 1, 2000, and January 1, 2020, were included. We examined demographic, clinicopathologic, and radiologic characteristics, as well as clinical management. Results:Overall, 328 patients from 29 institutions were included. The median age at diagnosis was 37 years with 59.1% of patients being female. Symptomatic presentation comprised 40.9% of cases, and tumors were often located in the extra-adrenal retroperitoneum (67.1%). At baseline, the median maximum tumor diameter was 7.2 cm. One hundred sixteen (35.4%) patients underwent active surveillance, whereas 212 (64.6%) patients underwent resection with 74.5% of operative cases achieving an R0/R1 resection. Serial tumor evaluations showed that malignant transformation to neuroblastoma was rare (0.9%, N=3). Tumors undergoing surveillance had a median follow-up of 1.9 years, with 92.2% of ganglioneuromas stable in size. With a median follow-up of 3.0 years for resected tumors, 84.4% of patients were disease free after resections, whereas recurrences were observed in 4 (1.9%) patients. Conclusions:Most ganglioneuromas have indolent disease courses and rarely transform to neuroblastoma. Thus, active surveillance may be appropriate for benign and asymptomatic tumors particularly when the risks of surgery outweigh the benefits. For symptomatic or growing tumors, resection may be curative.

Abstract Background Aggressive angiomyxoma (AAM) is a rare mesenchymal tumor that mostly arises from the pelvic and perineal soft tissues. Few studies reported its characteristics and outcomes previously due to its rarity and challenges of treatments. This study aimed to investigate the clinical characteristics as well as surgical and short-term survival outcomes of primary abdominopelvic AAM. Methods Medical records of patients who were admitted to surgery with pathological confirmation of primary abdominopelvic AAM at Peking University International Hospital from January 2016 through December 2021 were retrospectively retrieved from our retroperitoneal tumor database. Demographics, operative outcomes and pathological findings were collected. Patients received followed-up routinely after the surgery. Survival probabilities were calculated and determined through Kaplan–Meier analysis. Results A total of 12 consecutive patients (male/female 4:8) were included in this study. The median age was 45 years old. The clinical presentation varied among individuals, consisting of 2 abdominal discomforts, 4 constipations, 1 lumbago, 1 prolonged menstruation, and 1 buttock swelling. R0/R1 resection was achieved in 100% of patients. Postoperatively, 50% of patients developed various complications including 3 fistulas and 3 wound infections. No operative mortality was observed. Histopathology of all patients was suggestive of AAM. Immunohistochemistry was done with a 91.7% positive rate for estrogen and progesterone receptors. The median recurrence-free survival time was 38 months. There were no cases of deceased or presented with distal metastasis during a median of 42 months’ follow-up. Conclusions The clinical manifestations of abdominopelvic AAM are mostly atypical. Surgical resection with curative intents remains the mainstay treatment of this disease, which was strongly suggested in experienced sarcoma centers due to the high probability of severe postoperative complications. In addition, long-term follow-up is necessary due to the high rate of local recurrences.

Background Complete resection (CR) serves as the standard of surgical treatment for retroperitoneal liposarcoma (RPLS). Unfortunately, even at referral centers, recurrence rates are high, and CR may not address multifocal diseases, which are a common phenomenon in RPLS. We sought to retrospectively compare the clinical outcomes of RPLS patients treated with total (ipsilateral) retroperitoneal lipectomy (TRL) and CR. Because TRL remove potentially multifocal tumors in the fat, patients may have a better prognosis than CR. Methods Patients with primary/first-recurrent RPLS who had been treated at 5 referral centers were recruited from December 2014 to June 2018. Multivariable Cox regression analyses were conducted to determine the effects of demographic, operative, and clinicopathological variables on the following primary endpoints: local recurrence (LR), local recurrence-free survival (LRFS), and overall survival (OS). Results A total of 134 patients were enrolled in this retrospective study, 53 of whom underwent TRL, and 81 of whom underwent CR. The 2 groups were comparable in terms of age, gender, presentation (primary vs. first-recurrent RPLS), number of tumors (unifocal vs. multifocal) at presentation, and Fédération Nationale des Centres de Lutte Contre le Cancer (FNCLCC) grade. The TRL group had higher levels of preoperative hemoglobin (Hb) (13 vs. 12.5 g/dL; P=0.008) and a lower amount of intraoperative blood loss (400 vs. 500 mL; P=0.034), but there were no significant differences in the length of hospital stay (23 vs. 22 d; P=0.47) or complications (32 vs. 30; P=0.82) between the 2 groups. In a subset of patients with multifocal tumors at initial presentation, OS was more prolonged in those treated with TRL than those treated with CR (P=0.0272). Based on the multivariable analysis, primary liposarcoma and a low FNCLCC grade were associated with decreased LR and improved OS. Conclusions TRL is a safe procedure that positively affects the OS of patients with multifocal RPLS. This novel strategy deserves further investigation in prospective studies.

Background: Prophylactic ureteral catheters placement (PUCP) was advocated as an effective strategy for decreasing ureteral morbidities in colorectal surgeries. However, whether it should be routinely used prior to primary retroperitoneal liposarcoma (PRLS) surgeries remains unknown. Methods: It was a retrospective study, conducted at a tertiary sarcoma center. Medical records of patients with PRLS undergoing surgeries from January 2015 through December 2018 were reviewed. Primary endpoint was the rate of ureteral morbidities during and after retroperitoneal liposarcoma resection procedures. Univariate and multivariate analyses determined risk factors associated with ureteral injury (UI) in patients undergoing surgeries. Results: A total of 55 patients of PRLS were included. Fourteen (25.5%) patients underwent PUCP, with 1 UI (7.1%) identified. In 41 patients with no PUCP, 15 (36.6%) exhibited UIs during and post surgeries. There were significant improvements of UIs in group PUCP, compared with patients without PUCP (P < .05). Resection surgeries combined with colectomy and tumor-ureter relationship were 2 risk factors significantly associated to UIs (P < .01). Conclusions: PUCP might be an effective way of preventing UIs in patients with PRLS. It could be suggested especially in patients with ureter encased by tumor or anticipated colectomy during the surgical process.

Objective: The Transatlantic Australasian Retroperitoneal Sarcoma Working Group conducted a retrospective study on the disease course and clinical management of ganglioneuromas. Background: Ganglioneuromas are rare tumors derived from neural crest cells. Data on these tumors remain limited to case reports and single-institution case series. Methods: Patients of all ages with pathologically confirmed primary retroperitoneal, intra-abdominal, and pelvic ganglioneuromas between January 1, 2000, and January 1, 2020, were included. We examined demographic, clinicopathologic, and radiologic characteristics, as well as clinical management. Results: Overall, 328 patients from 29 institutions were included. The median age at diagnosis was 37 years with 59.1% of patients being female. Symptomatic presentation comprised 40.9% of cases, and tumors were often located in the extra-adrenal retroperitoneum (67.1%). At baseline, the median maximum tumor diameter was 7.2 cm. One hundred sixteen (35.4%) patients underwent active surveillance, whereas 212 (64.6%) patients underwent resection with 74.5% of operative cases achieving an R0/R1 resection. Serial tumor evaluations showed that malignant transformation to neuroblastoma was rare (0.9%, N=3). Tumors undergoing surveillance had a median follow-up of 1.9 years, with 92.2% of ganglioneuromas stable in size. With a median follow-up of 3.0 years for resected tumors, 84.4% of patients were disease free after resections, whereas recurrences were observed in 4 (1.9%) patients. Conclusions: Most ganglioneuromas have indolent disease courses and rarely transform to neuroblastoma. Thus, active surveillance may be appropriate for benign and asymptomatic tumors particularly when the risks of surgery outweigh the benefits. For symptomatic or growing tumors, resection may be curative.

Objective:To investigate the pathogeny, diagnosis and treatment of solitary fibrous tumors of the abdomen and pelvis.Methods:Retrospective analysis was made on the clinical data of 12 SFT patients undergoing surgical resection in Peking University International Hospital from Jul 2015 to Jul 2019.Results:All patients underwent radical resection. After operation, complications in clued pelvic hemorrhage in 1 case and ureteral fistula in 1 case, all improved after conservative treatment.According to pathological and immunohistochemical results, 7 cases were MSFT and 5 cases were SFT. All patients were followed up for 2-53 months. 5 cases were recurrent, among which 1 case died of intestinal obstruction caused by tumor compression.Conclusion:The clinical manifestations of solitary fibrous tumors are mostly nonspecific.Imaging examination and puncture pathology are of great significance for preoperative diagnosis. Radical resection is an important means to improve the prognosis of patients.

Transanal minimally invasive surgery (TAMIS) is mainly used for benign tumors of the rectum, but there are few reports on treating malignant tumors of the rectum with a large volume. The aim of this study was to evaluate the feasibility and safety of TAMIS for resection of rectal malignant tumors. A 57-year-old patient was pathologically diagnosed as rectal malignancy before surgery. Computed tomography (CT), magnetic resonance imaging (MRI), fludeoxyglucose-18F (18F-FDG), and endoscopic mucosal biopsy were performed to assess the tumor location and preoperative size. There were no contraindications in all preoperative examinations. We applied TAMIS technology to perform the operation on this patient, And the operative time, the amount of blood loss, the length of hospital stay, the cost of hospital stay, surgical complications, postoperative complications and other relevant data were all collected. The operation was successful, the operation time was 45 min, 10 mL of intraoperative blood loss, and the length of stay was 3 days, a tumor of a maximum diameter of 4 cm being completely removed. There were no related complications or recurrence during postoperative follow-up. The pathological results were tubular villous adenoma with low-grade intraepithelial neoplasia, and a focal area of high-grade intraepithelial neoplasia. The pathological stage was T1N0M0. At 3-month follow-up there were no signs of recurrence. The patient was followed up for 5 years after the operation and there was no tumor recurrence or metastasis in other parts and no other discomfort. TAMIS is less commonly used in rectal malignancies, especially for tumors with larger diameters. We successfully performed complete resection of a 4-cm rectal malignant tumor with TAMIS. Given its low risk, low cost, simple operation, and few complications, TAMIS can be used for more indications of rectum diseases.

Background Polyethylene glycol solution (PEG) is widely used for bowel preparation prior to colonoscopies. However, patients often exhibited adverse events as nausea, vomit and distention due to its uncomfortable tastes and potential side affects. This study aimed to evaluate the effectiveness and safety of concomitant use of green tea (GT) with PEG in bowel preparation prior to colonoscopy. Methods This was a prospective, randomized controlled study. It was conducted at an outpatient setting of colorectal surgery in a tertiary hospital. Patients aged 18 through 80 who were scheduled to undergo colonoscopy between August 2015 and February 2016 were randomly assigned into two groups, admitting either 2 L-PEG solutions with 1 L GT liquids or 2 L-PEG solutions only for bowel preparation. Admitted doses of PEG solutions, taste evaluation, adverse reactions (nausea and vomiting, distention and abdominal pain) were investigated by questionnaires. The bowel cleanliness of each patient was evaluated according to the Aronchick indicators. Results A total of 116 patients were enrolled in this study (PEG+GT 59, PEG 57). Full compliances were achieved in 93.2% patients of group PEG+GT and 59.6% of group PEG ( p < 0.001). Mean Aronchick scale between two groups were 2.0 ± 0.9 versus 2.2 ± 0.7 respectively (PEG+GT vs PEG, p = 0.296). Rates of adverse events as nausea and vomiting, abdominal pain in bowel preparation were significantly different between two groups (55.9% vs 77.2%, p = 0.015 and 13.6% vs 33.3%, p = 0.012). Patients in group PEG+GT who have probabilities to receive repeating colonoscopy had a higher willingness to accept PEG+GT again for bowel preparation, compared with PEG group (94.9% vs 57.9%, p < 0.001). Conclusions Concomitant use of green tea and polyethylene glycol may effectively reduce incidence of adverse events, increase compliances, with comparable bowel cleanliness in bowel preparation. Trial registration This trial was retrospectively registered on Feb 1st, 2019 ( ChiCTR1900021178 ).

Objective:To evaluate primary retroperitoneal liposarcoma surgeries in combination with involved bowel resection .Methods:Clinical data of primary retroperitoneal liposarcoma patients admitted for surgery at Peking University International Hospital from Jan 2015 to July 2019 were retrospectively reviewed.Results:Twenty-four patients undergoing resectional surgeries combining with bowel resection were included for the study, of which 6 cases underwent right hemicolectomy, 8 did left hemicolectomy, 6 did sigmoidectomy, 2 did proctectomy and 8 did small bowel resection. The post operative morbidity was 38%. 2 of 24 had anastomotic fistula. There was no mortality. Final pathology disclosed well differentiated liposarcoma in 13 and dedifferentiated liposarcoma in 11 cases. 18 cases were confirmed with bowel infiltration pathologically. All patients were followed up after the surgery. After a median of 25 months following up, 8 cases developed recurrences and 3 deceased. Two-year overall survival and progression free survival probability were 91% and 71% respectively. Dedifferentiated liposarcoma as a pathological type was found as the only risk factor associated to poor progression free survival ( Z=2.02, P=0.042). Conclusion:Combining resection of primary retroperitoneal liposarcoma with involved bowel was relatively safe, with low morbidity, increasing tumor clearance. Dedifferentiated liposarcoma is associated wth poor prognosis.

Liposarcoma is a malignancy of fat that commonly develops in the retroperitoneum (1,2). In this anatomic location, tumors can be low grade, well differentiated (WD) or have an additional high grade, dedifferentiated (DD) component. Entirely WD tumors are typically indolent and do not metastasize, while tumors with a DD component are more aggressive and have distant metastatic potential. WD and DD liposarcoma can be regarded as opposite ends of a spectrum of disease aggressiveness (e.g., lipoma-like WD to rhabdomyoblastic DD) (3). For patients with retroperitoneal (RP) liposarcoma, high resolution, contrast enhanced CT of the abdomen and pelvis is critical as part of the initial evaluation (4). This should be performed if not done already at the time of referral. WD liposarcomas are well-defined round or lobulated masses predominantly composed of macroscopic fat with few, thin septations (5). Non-fatty, soft tissue density areas with a ground glass appearance can occur and typically constitute less than 25% of the tumor (6). DD areas manifest as discrete nodular soft tissue density areas often with good demarcation from surrounding fat and show variable contrast enhancement. Internal septations are thicker (>2 mm) in DD. Calcifications may also be seen and would suggest DD liposarcoma if found in the nonfatty areas. For patients with suspected DD disease, CT of the chest should be obtained as part of staging to rule out distant metastasis to the lungs (4). To confirm the diagnosis of RP liposarcoma, percutaneous core needle biopsy can be performed. Biopsy may not always be necessary, especially in cases in which the radiologic features highly suggest the diagnosis. On histopathologic examination, WD liposarcoma consists of adipocytes of varying size with fibrous septae and interspersed hyperchromatic cells (7). DD areas are typically juxtaposed next to WD areas with an abrupt transition from the adipocytic (WD) to non-adipocytic, high grade appearing areas containing prominent mitotic figures (DD). Both WD and DD liposarcoma have amplification of 12q13-15 which includes several important genes such as MDM2 and CDK4. This molecular feature is considered pathognomonic and can be used for the definitive diagnosis if the histologic features alone are unclear. For all patients with nonmetastatic retroperitoneal liposarcoma, surgery is the mainstay of treatment. However, in the retroperitoneum, tumors are frequently massive in size and can potentially invade critical organs and major blood vessels, making surgery very difficult. Whether due to technical factors (e.g., “positive” margins) or disease biology [e.g., “field defect” (8)], recurrence rates after resection are high and do not plateau over time (9). Radiation therapy may offer improved local control, but the true benefit for retroperitoneal liposarcoma remains controversial (10). Sarcoma MDT Series

Objective:To evaluate the clinicopathological features of primary retroperitoneal paragangliomas.Methods:Data of 24 patients with retroperitoneal paragangliomas who underwent surgical treatment in our hospital from Jan 2015 to Dec 2018 was collected and analyzed.Results:Hypertension, abdominal pain/discomfort and headache were the most common complaints while 10 patients were asymptomatic and were diagnosed accidently in routine body examination. Tumor size ranged from 3.4-13.0 cm (6.9±2.5) cm, and all the tumors were located in the vicinity of abdominal aorta and inferior vena cava. All the patients received surgical treatment. Intraoperative blood pressure fluctuations were significantly correlated with prolonged operation time, more blood loss, more blood transfusion and prolonged length of stay (all P<0.05). The median follow-up time was 29 months and 1 patient died from tumor recurrence and progression. The other patients have had a tumor free survival. Conclusions:Surgical resection was the principal treatment of primary paraganglioma. Preoperative assessment was very important for perioperative safety.

Objective To investigate the expression of Aspartate Beta-Hydroxylase (ASPH) in retroperitoneal liposarcoma (RL)and evaluate its clinical significances.Methods Relevant clinical data of 69 RL cases after surgical resection were collected.The expression of ASPH in tumor tissues was detected by immunohistochemistry.The CTL epitopes of ASPH protein HLA-A2 were predicted by SYFPEITHI and NetMHCpan software.Results The overall positive rate of ASPH expression for the whole group was 81％,that for well-differentiated liposarcoma was 73％,dedifferentiated liposarcoma was 87％ (P ＜ 0.05).ASPH expression was positively correlated with the postoperative recurrence free survival rate (P ＜ 0.05).Five HLA-A2 restricted CTL epitopes (9 peptides) were screened with the method of motif prediction.Conclusions ASPH expression is positively correlated with the degree of malignancy of RL,and the ASPH expression is an independent risk factor for postoperative recurrence free survival rate of RL.Moreover,ASPH was found to have 5 HLA-A2 restricted CTL epitopes,which are expected to be used for the immunotherapy of RL.

AIM To investigate the effect of epigallocatechin gallate (EGCG) on structural changes of gut microbiota in colorectal carcinogenesis. METHODS An azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced colitis mouse model was established. Forty-two female FVB/N mice were randomly divided into the following three groups: group 1 (10 mice, negative control) was treated with vehicle, group 2 (16 mice, positive control) was treated with AOM plus vehicle, and group 3 (16 mice, EG) was treated with AOM plus EGCG. For aberrant crypt foci (ACF) evaluation, the colons were rapidly took out after sacrifice, rinsed with saline, opened longitudinally, laid flat on a polystyrene board, and fixed with 10% buffered formaldehyde solution before being stained with 0.2% methylene blue in saline. For tumor evaluation, the colon was macroscopically inspected and photographed, then the total number of tumors was enumerated and tumor size measured. For histological examination, the fixed tissues were paraffin-embedded and sectioned at 5 mm thickness. Microbial genomic DNA was extracted from fecal and intestinal content samples using a commercial kit. The V4 hypervariable regions of 16S rRNA were PCR-amplified with the barcoded fusion primers. Using the best hit classification option, the sequences from each sample were aligned to the RDP 16S rRNA training set to classify the taxonomic abundance in QIIME. Statistical analyses were then performed. RESULTS Treatment of mice with 1% EGCG caused a significant decrease in the mean number of ACF per mouse, when compared with the model mice treated with AOM/DSS (5.38 ± 4.24 vs 13.13 ± 3.02, P < 0.01). Compared with the positive control group, 1% EGCG treatment dependently decreased tumor load per mouse by 85% (33.96 ± 6.10 vs 2.96 ± 2.86, respectively, P < 0.01). All revealed that EGCG could inhibit colon carcinogenesis by decreasing the number of precancerous lesions as well as solid tumors, with reduced tumor load and delayed histological progression of CRC. During the cancerization, the diversity of gut microbiota increased, potential carcinogenic bacteria such as Bacteroides were enriched, and the abundance of butyrate-producing bacteria (Clostridiaceae, Ruminococcus, etc.) decreased continuously. In contrast, the structure of gut microbiota was relatively stable during the intervention of EGCG on colon carcinogenesis. Enrichment of probiotics (Bifidobacterium, Lactobacillu, etc.) might be a potential mechanism for EGCG’s effects on tumor suppression. Via bioinformatics analysis, principal coordinate analysis and cluster analysis of the tumor formation process, we found that the diversity of gut microbiota increased in the tumor model group while that in the EGCG interfered group (EG) remained relatively stable. CONCLUSION Gut microbiota imbalance might be a potential mechanism for the prevention of malignant transformation by EGCG, which is significant for diagnosis, treatment, prognosis evaluation, and prevention of colorectal cancer.

AIM:To observe the protective effect of glucagon-like peptide-2 (GLP-2) on the intestinal barrier of rats with obstructive jaundice and determine the possible mechanisms of action involved in the protective effect.METHODS:Thirty-six Sprague-Dawley rats were randomly divided into a sham operation group, an obstructive jaundice group, and a GLP-2 group; each group consisted of 12 rats. The GLP-2 group was treated with GLP-2 after the day of surgery, whereas the other two groups were treated with the same concentration of normal saline. Alanine aminotransferase (ALT), total bilirubin, and endotoxin levels were recorded at 1, 3, 7, 10 and 14 d. Furthermore, on the 14(th) day, body weight, the wet weight of the small intestine, pathological changes of the small intestine and the immunoglobulin A (IgA) expressed by plasma cells located in the small intestinal lamina propria were recorded for each group.RESULTS:In the rat model, jaundice was obvious, and the rats' activity decreased 4-6 d post bile duct ligation. Compared with the sham operation group, the obstructive jaundice group displayed increased yellow staining of abdominal visceral serosa, decreased small intestine wet weight, thinning of the intestinal muscle layer and villi, villous atrophy, uneven height, fusion, partial villous epithelial cell shedding, substantial inflammatory cell infiltration and significantly reduced IgA expression. However, no significant gross changes were noted between the GLP-2 and sham groups. With time, the levels of ALT, endotoxin and bilirubin in the GLP-2 group were significantly increased compared with the sham group (P < 0.01). The increasing levels of the aforementioned markers were more significant in the obstructive jaundice group than in the GLP-2 group (P < 0.01).CONCLUSION:GLP-2 reduces intestinal mucosal injuries in obstructive jaundice rats, which might be attributed to increased intestinal IgA and reduced bilirubin and endotoxin.