Analysis of BGN and pan-cancer correlations: based a Mendelian randomisation and bioinformatics study

Background/Objectives: To preliminarily explore the significance of BGN in various cancers using pan-cancer analysis. Methods: Transcriptome data of 33 cancers were downloaded from TCGA database, and the expression levels of BGN in 33 cancers were extracted using Perl software. The limma package of R software was used to identify differential genes in some tumour types (paraneoplastic samples ≥5), and the clinical prognostic significance of BGN was analysed using Kaplan-Meier and Cox in conjunction with clinical information from TCGA. Mendelian randomisation was used to test for causal associations between BGN and multiple malignancies. The correlation between BGN and the tumour immune infiltration microenvironment was explored by ESTIMATE package, and the relationship between BGN and immune subtypes, clinical stage and tumour immune infiltration microenvironment were analysed in conjunction with TCGA-GTEx data. Analysis of clinical data of 180 patients with gastric cancer and immunohistochemical verification of the poor prognosis of BGN in gastric cancer. Results: BGN was significantly differentially expressed in most of the tumours, and MR analysis revealed potential causal associations with colorectal, lung and cervical cancers, etc. BGN showed prognostic correlations with a variety of cancers in survival analyses (P < 0.05). Single-tumour analyses showed correlations between BGN and TNM staging, immune subtypes, and the tumour microenvironment. BGN expression promotes immune cell infiltration and expression of immune checkpoint-associated genes in the tumour microenvironment, and the higher the level of expression, the greater the stromal component and the less the immune component.BGN may be expressed via ECM receptor interaction, BGN may be involved in the process of tumour immune and inflammatory responses through ECM receptor interaction, ascorbate and aldarate metabolism, and other signalling pathways. Conclusion: BGN plays an important role in tumour development and is expected to become a new prognostic marker and a potential target for immunotherapy in many types of cancers.