The impact of the gut microbiome on tumor immunotherapy: from mechanism to application strategies

Immunotherapy is one of the fastest developing areas in the field of oncology. Many immunological treatment strategies for refractory tumors have been approved and marketed. Nevertheless, much clinical and preclinical experimental evidence has shown that the efficacy of immunotherapy in tumor treatment varies markedly among individuals. The commensal microbiome mainly colonizes the intestinal lumen in humans, is affected by a variety of factors and exhibits individual variation. Moreover, the gut is considered the largest immune organ of the body due to its influence on the immune system. In the last few decades, with the development of next-generation sequencing (NGS) techniques and in-depth research, the view that the gut microbiota intervenes in antitumor immunotherapy through the immune system has been gradually confirmed. Here, we review important studies published in recent years focusing on the influences of microbiota on immune system and the progression of malignancy. Furthermore, we discuss the mechanism by which microbiota affect tumor immunotherapy, including immune checkpoint blockade (ICB) and adoptive T-cell therapy (ACT), and strategies for modulating the microbial composition to facilitate the antitumor immune response. Finally, opportunity and some challenges are mentioned to enable a more systematic understanding of tumor treatment in the future and promote basic research and clinical application in related fields.

A novel approach for the analysis of single-cell RNA sequencing identifies TMEM14B as a novel poor prognostic marker in hepatocellular carcinoma

A fundamental goal in cancer-associated genome sequencing is to identify the key genes. Protein-protein interactions (PPIs) play a crucially important role in this goal. Here, human reference interactome (HuRI) map was generated and 64,006 PPIs involving 9094 proteins were identified. Here, we developed a physical link and co-expression combinatory network construction (PLACE) method for genes of interest, which provides a rapid way to analyze genome sequencing datasets. Next, Kaplan‒Meier survival analysis, CCK8 assays, scratch wound assays and Transwell assays were applied to confirm the results. In this study, we selected single-cell sequencing data from patients with hepatocellular carcinoma (HCC) in GSE149614. The PLACE method constructs a protein connection network for genes of interest, and a large fraction (80%) of the genes (screened by the PLACE method) were associated with survival. Then, PLACE discovered that transmembrane protein 14B (TMEM14B) was the most significant prognostic key gene, and target genes of TMEM14B were predicted. The TMEM14B-target gene regulatory network was constructed by PLACE. We also detected that TMEM14B-knockdown inhibited proliferation and migration. The results demonstrate that we proposed a new effective method for identifying key genes. The PLACE method can be used widely and make outstanding contributions to the tumor research field.

To cut or not to cut? A prospective randomized controlled trial on short-term outcomes of the uncut Roux-en-Y reconstruction for gastric cancer

BACKGROUND

Roux-en-Y (R-Y) anastomoses have been widely used in distal gastrectomy, while the incidence of Roux stasis syndrome remains common. Uncut R-Y anastomosis maintains the neuromuscular continuity, thus avoiding the ectopic pacemaker of the Roux limb and reducing the occurrence of Roux stasis. However, retrospective studies of Uncut R-Y anastomosis remain scarce and randomized controlled trials have not been reported.

METHODS

We conducted a randomized controlled trial to compare the surgical safety, nutritional status, and postoperative quality of life (QOL) between uncut and classic Roux-en-Y (R-Y) reconstruction patients. Patients with Stage I gastric cancer were randomly enrolled and underwent laparoscopic distal gastrectomy followed by uncut or classic R-Y reconstruction. Body mass index and blood test were used to evaluate the nutritional status. QOL was evaluated using European Organization for Research and Treatment of Cancer QOL Questionnaire (STO22) and laboratory examinations at postoperative month (POM) 3, 6, 9, and 12. Computed tomography scanning was used to evaluate the skeletal muscle index (SMI) at POM 6 and 12. Endoscopy was performed at POM 12.

RESULTS

Operation time, blood loss, time to recovery, complication morbidities, and overall survival were similar between the two groups. Compared with the classic R-Y group, the uncut R-Y group displayed a significantly decreased QOL at POM 9, possibly due to loop recanalization, determined to be occupied 34.2% of the uncut R-Y group. Post-exclusion of recanalization, the QOL was still higher in the classic R-Y group than in the uncut R-Y group, despite their hemoglobin and total protein levels being better than those in the classic R-Y group. Preoperative pre-albumin level and impaired fasting glycemia significantly correlated with the postoperative recanalization.

CONCLUSION

We found no significant benefit of uncut over classic R-Y reconstruction which challenges the superiority of the uncut R-Y reconstruction.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02644148.