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Background: Gallbladder cancer (GC) is a malignant disease characterized with highly cellular heterogeneity and poor prognosis. Determining the intratumoral heterogeneity and microenvironment (TME) can provide novel therapeutic strategies for GC. Methods: We performed the single‐cell RNA sequencing on the primary and lymph node metastatic gallbladder tumors and the adjacent normal tissues of five patients. The transcriptomic atlas and ligand–receptor‐based intercellular communication networks of the single cells were characterized. Results: The transcriptomic landscape of 24,887 single cells was obtained and characterized as 10 cellular clusters, including epithelial, neuroendocrine tumor cells, T&NK cells, B cells, RGS5+ fibroblasts, POSTN+ fibroblasts, PDGFRA+ fibroblasts, endothelial, myeloid cells, and mast cells. Different types of GC harbored distinct epithelial tumor subpopulations, and squamous cell carcinoma could be differentiated from adenocarcinoma cells. Abundant immune cells infiltrated into adenocarcinoma and squamous cell carcinoma, rather than neuroendocrine neoplasms, which showed significant enrichment of stromal cells. CD4+/FOXP3+ T‐reg and CD4+/CXCL13+ T helper cells with higher exhausting biomarkers, as well as a dynamic lineage transition of tumor‐associated macrophages from CCL20hi/CD163lo, CCL20lo/CD163hi to APOE+, were identified in GC tissues, suggesting the immunosuppressive and tumor‐promoting status of immune cells in TME. Two distinct endothelial cells (KDR+ and ACKR1+), which were involved in angiogenesis and lymphangiogenesis, showed remarkable ligand–receptor interactions with primary GC cells and macrophages in gallbladder tumors. Conclusions: This study reveals a widespread reprogramming across multiple cell populations in GC progression, dissects the cellular heterogeneity and interactions in gallbladder TME, and provides potential therapeutic targets for GC. [ABSTRACT FROM AUTHOR]

The 8th edition of the American Joint Commission on Cancer (AJCC) Staging System for gallbladder cancer (GBC) has been used in clinical practice, but we have found some deficiencies in this edition. Survival analyses were performed to evaluate the application of various editions of the AJCC staging systems using the Surveillance, Epidemiology, and End Results (SEER) database (N = 9616 patients) and Fudan University Zhongshan Hospital (FUZH) database (N = 327 patients). A modified staging system was proposed based on the 8th edition of the AJCC Staging System. Although all N2 diseases were grouped into stage IVB as M1 in the 8th edition, some patients with N2 diseases could undergo R0 resection, and had longer survival than patients with M1 diseases had in both cohorts (p < 0.001 in SEER, p = 0.041 in FUZH). Furthermore, in the SEER database, stage IIIA patients aberrantly had poorer survival than stage IIIB patients had (p < 0.001). Therefore, we proposed a modified staging system by rearranging the substages. N2 disease was subdivided and reappraised according to T stage, and the aberrant survival reversal of stage IIIA and stage IIIB disease was also corrected. Through our modification, the C-index of the 8th AJCC Staging System was elevated from 0.596 [95% confidence interval (CI): 0.585–0.607] to 0.623 (95% CI: 0.612–0.634) for local disease in the SEER cohort. Similar findings were also observed in the FUZH cohort. Our modified 8th AJCC Staging System is more suitable for GBC and could be adopted for clinical practice. [ABSTRACT FROM AUTHOR]

Gallbladder carcinoma (GBC) is a highly lethal malignancy of the gastrointestinal tract. Despite extensive research, the underlying molecular mechanism of GBC remains largely unclear. Deleted in malignant brain tumors 1 (DMBT1) is low-expression during cancer progression and as a potential tumor-suppressor gene in various types of cancer. However, its role in Gallbladder cancer remains poorly understood. Here, we found that DMBT1 was significantly low-expression and deletion of copy number in GBC tissues by qRT-PCR and Western blot. Overexpression of DMBT1 impaired survival, promoted apoptosis in GBC cells in vitro, and inhibited tumor progression in vivo. Further study of underlying mechanisms demonstrated that DMBT1 combined with PTEN which could stabilize PTEN protein, resulting in inhibiting the activation of PI3K/AKT signaling pathway. Our study revealed a new sight of DMBT1 as a tumor-suppressor gene on the PI3K/AKT pathway in GBC, which may be a potential therapeutic target for improving treatment. Down-regulation of DMBT1 suppresses progression of gallbladder carcinoma through PI3K/AKT signaling pathway activation by targeting PTEN. [ABSTRACT FROM AUTHOR]

B Introduction: b The 8 SP th sp edition of the AJCC staging system for gallbladder cancer (GBC) has been used in clinical practice, but we have found some deficiencies in the new edition. In our modified edition, N2 disease obtained a significant subdivision and reappraisal according to T stage, and the aberrant survival reversal of stage IIIA and stage IIIB was also corrected. [Extracted from the article]