The application of biological technology and the deepening of tumor research have effectively improved the level of tumor diagnosis, treatment and clinical outcome prediction. However, the specific mechanisms of tumorigenesis and development are still unclear, and tumor drug resistance has also become an urgent problem that needs to be solved to improve the clinical outcome of patients. Considerable studies have shown that the extrachromosomal DNA (ecDNA) can promote tumorigenesis, development and drug resistance. EcDNA is a looser, rounded form of DNA with unique genetic properties that carry specific genes and regulatory elements. This paper will discuss the biological characteristics, tumor-promoting mechanisms and drug resistance-facilitating of ecDNA.

Objective To investigate the efficacy and safety of modified endoscopic submucosal dissection (ESD) and rubber band ligation assisted endoscopic dissection for treatment of small gastric submucosal tumors (SMT) originating from the muscularis propria layer. Methods A total of ninety-two patients diagnosed as gastric SMT (6 mm≤diameter≤13 mm) originating from the muscularis propria layer by EUS in our hospital were enrolled in this study. With intravenous anesthesia and tracheal intubation in all patients, modified ESD was performed firstly to stripe the small tumors. After being exposed to a certain extent, the tumors were ligated by rubber band and snared for endoscopic dissection. The situation of bleeding, perforation in both intraoperative and postoperative, the integrity and size of the resected specimens were observed and recorded. The resected specimens were identified with histopathological detection and immunohistochemistry assay. At the 6-month and 12-month after the operation, all patients were reviewed by gastroscopy and EUS in our hospital. Results All the 92 tumors were resected completely and successfully. The mean operating time was (19.2±2.3) min and the mean blood loss in operation was (2.6±0.5) mL. Perforation after resection occurred in 3 cases, which were closed with metal hemostatic clips and nylon ropes. No delayed bleeding and perforation occurred in one week after the operation. The tumor sizes ranged from 6 mm × 5 mm to 13 mm × 12 mm. Seventy-three gastric stromal tumors (risk classification:all were very low risk), 18 gastric leiomyomas and 1 gastric neurofibroma were identified. There were no residue or recurrence in all cases during the 12-month follow-up period. Conclusion The modified ESD and rubber band ligation assisted endoscopic dissection are effective and safe for treatment of small gastric submucosal tumors originating from the muscularis propria layer. The tumors are resected completely and successfully, showing certain significance to assess the nature, degree of malignancy of the tumor and prognosis of the patients.

Glioma is one of the most common and invasive malignant tumors in the central nervous system. The Wnt-β-catenin signaling pathway is a classical Wnt pathway, which is involved in the occurrence and development of glioma and other tumors. Long non-coding RNA (LncRNA) is a functional RNA molecule without protein coding function, which plays a regulatory role in the occurrence and development of various tumors. Recent studies have shown that LncRNA and Wnt-β-catenin signaling pathways are jointly involved in glioma growth, invasion, migration and other processes, but the complex mechanism has not been thoroughly elaborated. In this paper, the influence of Wnt-β-catenin signaling pathway and its related LncRNA on glioma was reviewed, and the pathogenesis of glioma was deeply understood, so as to find a better way for the diagnosis and treatment of glioma.

Objective To construct and identify a patient-derived organoid model,and to investigate the sensitivity of chemotherapy drugs using this model.Methods Pancreatic cancer cells were obtained from the surgical specimens of two female patients with a confirmed diagnosis of pancreatic cancer after tumor tissue digestion,and then the cells were inoculated into a culture dish using matrigel for three-dimensional culture.Paraffin sections were prepared for HE staining and immunohistochemical staining and were compared with the parent tumor tissue to determine whether the histopathological features of the tumor in vivo were preserved.The pancreatic cancer organoids were treated with seven chemotherapy drugs at different concentrations;Cell Titer-Glo?3D reagent was used to measure cell viability,and the results of drug sensitivity were analyzed.Results Two patient-derived pancreatic cancer organoids were successfully constructed,and HE staining and immunohistochemical staining showed that the pancreatic cancer organoids had consistent histopathological features with the tumors of the corresponding patient.Both pancreatic cancer organoids were more sensitive to gemcitabine monotherapy and the combination of oxaliplatin+SN38+fluorouracil,and patient 1 was more sensitive than patient 2.There were individual differences in the response to drugs between the organoids from different patients.Conclusion The pancreatic cancer organoid model successfully constructed in this study can reflect the histological classification of parent pancreatic tumors and can be used for in vitro chemotherapy drug sensitivity test,which is expected to provide a reference for clinical medication.