The role and regulation mechanisms of APOD in prognosis and subtyping of breast cancer.

Background: Breast cancer is the most common cancer, and abnormal lipid metabolism is associated with cancer. APOD expression is negatively correlated with various cancers related to tumor prognosis. DNA methylation may affect APOD expression. Therefore, this paper aims to investigate the significance of APOD expression and APOD DNA methylation in breast cancer. Methods: This study utilized comprehensive bioinformatics analysis of APOD using Gene Expression database of Normal and Tumor tissues 2, UCSC Xena, etc. Clinical and survival information obtained from the The Cancer Genome Atlas and Gene Expression Omnibus datasets were extracted for data mining. Results: The correlation between APOD and breast cancer was examined, along with the connection between APOD DNA methylation and APOD expression. In the The Cancer Genome Atlas cohort, as well as GSE31448 and GSE65194 datasets, APOD expression decreased in breast cancer (P < 0.0001). Clinical feature analysis results showed that APOD expression was correlated with the PAM50 subtype, with the lowest expression in the Basal subtype (P < 0.0001). High APOD expression is a good prognostic marker for breast cancer (HR = 0.71, P = 0.037). APOD methylation level was significantly negatively correlated with expression level (R = -0.4770, P < 0.001), and cg15231202, cg23720929, and cg05624196 were important regulatory targets. High APOD expression was associated with higher metabolism and extracellular matrix scores. Conclusion: APOD is an independent prognostic marker for breast cancer and is regulated by DNA methylation to modulate mRNA expression. [ABSTRACT FROM AUTHOR]