Evaluation of ENG/CD105 expression, methylation, immuno-response, and cordycepin (CD) regulation as a novel biomarker of breast invasive carcinoma (BRCA).

ENG/CD105 encodes a vascular endothelial glycoprotein and plays a crucial role in modulating angiogenesis. However, the significance of ENG expression, DNA methylation, immuno-response, and cordycepin (CD) regulation as diagnostic, prognostic, and therapeutic markers for breast invasive carcinoma (BRCA) remains unclear. As a result, ENG is decreased in BRCA tissues compared with corresponding healthy tissues. Five isoforms were found, and the utilization for isoform (ENG-002) was the highest, suggesting its potential involvement in important roles in BRCA. DNA was frequently altered in most types of cancer, and overall survival (OS) for mutant was significantly longer than for wild-type cases. High expressions of remarkably correlate with long relapse-free survival (RFS) for breast cancer (BC). Additionally, the methylation level was higher in BRCA tissues compared with matched healthy tissues. The expression and DNA methylation showed a significantly reverse correlation, demonstrating that methylation may be a regulatory mechanism. By constructing diagnostic and prognostic models of methylation for BRCA, we found four CpGs (CpG sites) that ranked with high importance. High methylation for cg14185922 of ENG in BRCA tissues showed shorter OS (high risk), indicating that CpGs' methylation has potential as a diagnostic and prognostic biomarker for BRCA. Moreover, ENG might be a novel target for tumor immune response and immunotherapy in pancancer, including BC. CD, an adenosine analog and anti-cancer agent, increased ENG levels in a dose-dependent manner in animal models. This suggests that CD repressed BC growth and metastasis, at least partially through increasing the expression of the tumor suppressor gene ENG. Thus, our study successfully evaluated ENG/CD105 expression, DNA methylation, immune response, and CD regulation, which act as a novel diagnostic, prognostic, and therapeutic biomarker for BRCA. This research also fills critical knowledge gaps in this ENG/cancer field and highlights ENG's potential importance for the diagnosis, prognosis, and treatment of BRCA.