Organoids are three‐dimensional (3D) miniaturized versions of organs or tissues that are derived from cells with stem potential and can self‐organize and differentiate into 3D cell masses, recapitulating the morphology and functions of their in vivo counterparts. Organoid culture is an emerging 3D culture technology, and organoids derived from various organs and tissues, such as the brain, lung, heart, liver, and kidney, have been generated. Compared with traditional bidimensional culture, organoid culture systems have the unique advantage of conserving parental gene expression and mutation characteristics, as well as long‐term maintenance of the function and biological characteristics of the parental cells in vitro. All these features of organoids open up new opportunities for drug discovery, large‐scale drug screening, and precision medicine. Another major application of organoids is disease modeling, and especially various hereditary diseases that are difficult to model in vitro have been modeled with organoids by combining genome editing technologies. Herein, we introduce the development and current advances in the organoid technology field. We focus on the applications of organoids in basic biology and clinical research, and also highlight their limitations and future perspectives. We hope that this review can provide a valuable reference for the developments and applications of organoids.

AIM: To evaluate the prognostic factors of hilar cholangiocarcinoma in a large series of patients in a single institution. METHODS: Eight hundred and fourteen patients with a diagnosis of hilar cholangiocarcinoma that were evaluated and treated between 1990 and 2014, of which 381 patients underwent curative surgery, were included in this study. Potential factors associated with overall survival (OS) and disease-free survival (DFS) were evaluated by univariate and multivariate analyses. RESULTS: Curative surgery provided the best long-term survival with a median OS of 26.3 mo. The median DFS was 18.1 mo. Multivariate analysis showed that patients with tumor size > 3 cm [hazard ratio (HR) = 1.482, 95%CI: 1.127-1.949; P = 0.005], positive nodal disease (HR = 1.701, 95%CI: 1.346-2.149; P < 0.001), poor differentiation (HR = 2.535, 95%CI: 1.839-3.493; P < 0.001), vascular invasion (HR = 1.542, 95%CI: 1.082-2.197; P = 0.017), and positive margins (HR = 1.798, 95%CI: 1.314-2.461; P < 0.001) had poor OS outcome. The independent factors for DFS were positive nodal disease (HR = 3.383, 95%CI: 2.633-4.348; P < 0.001), poor differentiation (HR = 2.774, 95%CI: 2.012-3.823; P < 0.001), vascular invasion (HR = 2.136, 95%CI: 1.658-3.236; P < 0.001), and positive margins (HR = 1.835, 95%CI: 1.256-2.679; P < 0.001). Multiple logistic regression analysis showed that caudate lobectomy [odds ratio (OR) = 9.771, 95%CI: 4.672-20.433; P < 0.001], tumor diameter (OR = 3.772, 95%CI: 1.914-7.434; P < 0.001), surgical procedures (OR = 10.236, 95%CI: 4.738-22.116; P < 0.001), American Joint Committee On Cancer T stage (OR = 2.010, 95%CI: 1.043-3.870; P = 0.037), and vascular invasion (OR = 2.278, 95%CI: 0.997-5.207; P = 0.051) were independently associated with tumor-free margin, and surgical procedures could indirectly affect survival outcome by influencing the tumor resection margin. CONCLUSION: Tumor margin, tumor differentiation, vascular invasion, and lymph node status were independent factors for OS and DFS. Surgical procedures can indirectly affect survival outcome by influencing the tumor resection margin.

Background: Abnormal angiogenesis is crucial for gallbladder cancer (GBC) tumor growth and invasion, highlighting the importance of elucidating the mechanisms underlying this process. LncRNA (long non-coding RNA) is widely involved in the malignancy of GBC. However, conclusive evidence confirming the correlation between lncRNAs and angiogenesis in GBC is lacking. Methods: LncRNA sequencing was performed to identify the differentially expressed lncRNAs. RT-qPCR, western blot, FISH, and immunofluorescence were used to measure TRPM2-AS and NOTCH1 signaling pathway expression in vitro. Mouse xenograft and lung metastasis models were used to evaluate the biological function of TRPM2-AS during angiogenesis in vivo. EDU, transwell, and tube formation assays were used to detect the angiogenic ability of HUVECs. RIP, RAP, RNA pull-down, dual-luciferase reporter system, and mass spectrometry were used to confirm the interaction between TRPM2-AS, IGF2BP2, NUMB, and PABPC1. Results: TRPM2-AS was upregulated in GBC tissues and was closely related to angiogenesis and poor prognosis in patients with GBC. The high expression level and stability of TRPM2-AS benefited from m⁶A modification, which is recognized by IGF2BP2. In terms of exerting pro-angiogenic effects, TRPM2-AS loaded with exosomes transported from GBC cells to HUVECs enhanced PABPC1-mediated NUMB expression inhibition, ultimately promoting the activation of the NOTCH1 signaling pathway. PABPC1 inhibited NUMB mRNA expression through interacting with AGO2 and promoted miR-31-5p and miR-146a-5p-mediated the degradation of NUMB mRNA. The NOTCH signaling pathway inhibitor DAPT inhibited GBC tumor angiogenesis, and TRPM2-AS knockdown enhanced this effect. Conclusions: TRPM2-AS is a novel and promising biomarker for GBC angiogenesis that promotes angiogenesis by facilitating the activation of the NOTCH1 signaling pathway. Targeting TRPM2-AS opens further opportunities for future GBC treatments.

Prediction of early postoperative recurrence is of great significance for follow‐up treatment. However, there are few studies available that focus on high‐risk factors of early postoperative recurrence or even the definition the exact time of early recurrence for hilar cholangiocarcinoma. Thus, we aimed to examine the optimal cut‐off value for defining the early in patients with R0 resection of hilar cholangiocarcinoma and to investigate prognostic factors associated with early recurrence. Two hundred and fifty‐eight patients with R0 resection of hilar cholangiocarcinoma between 2000 and 2015 were included. The minimum P value approach was used to define the optimal cut‐off of early recurrence. The prognostic factors associated with early recurrence were investigated. The optimal cut‐off value for dividing patients into early and non‐early recurrence groups after R0 resection of hilar cholangiocarcinoma was 12 months. Sixty‐two patients were recorded as early recurrence, and the remaining 196 patients were labeled as non‐early recurrence. Multivariate logistic regression analysis indicated lymph node metastasis (OR = 2.756, 95% CI 1.409‐5.393; P = 0.003), poor differentiation (OR = 1.653; 95% CI 1.040‐2.632; P = 0.034), increased postoperative CA 19‐9 levels (OR = 1.965, 95% CI 1.282‐3.013; P = 0.002), neutrophil‐to‐lymphocyte ratio > 3.41 (OR = 5.125, 95% CI 2.419‐10.857; P < 0.001) and age > 60 years (OR = 2.018, 95% CI 1.032‐3.947; P = 0.040) were independent determinants of early and non‐early recurrence. Poor differentiation (HR = 2.609, 95% CI 1.600‐4.252; P < 0.001), Bismuth classification type III/IV (HR = 2.510, 95% CI 1.298‐4.852; P = 0.006) and perineural invasion (HR=2.380, 95% CI 1.271‐4.457; P = 0.007) were independent factors of overall survival in the subgroup of patients who developed early recurrence. The optimal cut‐off value for dividing early recurrence after R0 resection of hilar cholangiocarcinoma was 12 months. Tumor differentiation, Bismuth classification, and perineural invasion were independent factors of overall survival in the subgroup of patients with early recurrence. Patients with risk factors should be monitored closely after curative surgery.

Cholangiocarcinoma (CCA) is a highly heterogeneous malignancy originating from the epithelial system of the bile ducts, and its incidence in recent years is steadily increasing. The immune microenvironment of CCA is characterized by diversity and complexity, with a substantial presence of cancer‑associated fibroblasts and immune cell infiltration, which plays a key role in regulating the distinctive biological behavior of cholangiocarcinoma, including tumor growth, angiogenesis, lymphangiogenesis, invasion and metastasis. Despite the notable success of immunotherapy in the treatment of solid tumors in recent years, patients with CCA have responded poorly to immune checkpoint inhibitor therapy. The interaction of tumor cells with cellular components of the immune microenvironment can regulate the activity and function of immune cells and form an immunosuppressive microenvironment, which may cause ineffective immunotherapy. Therefore, the components of the tumor immune microenvironment appear to be novel targets for immune therapies. Combination therapy focusing on immune checkpoint inhibitors is a promising and valuable first‑line or translational treatment approach for intractable biliary tract malignancies. The present review discusses the compositional characteristics and regulatory factors of the CCA immune microenvironment and the possible immune escape mechanisms. In addition, a summary of the advances in immunotherapy for CCA is also provided. It is hoped that the present review may function as a valuable reference for the development of novel immunotherapeutic strategies for CCA.