Background: Breast cancer (BC) is the leading cause of malignancy death in females worldwide. While intense efforts have been made to elucidate the pathogeny, the molecular mechanism of BC remains elusive. Thus, this study aimed to investigate the role of PPEF1  in the progression of BC and further explore the better clinical significance.
Methods: The diagnostic and prognostic values of elevated PPEF1  expression in BC were unveiled via public databases analysis. In addition, Gene Ontology (GO), Gene Set Enrichment Analysis (GSEA) and Protein–protein interaction (PPI) analysis were performed to explore the potential functions and molecular mechanisms of PPEF1  in BC progression. Experimentally, transwell and CCK-8 assays were carried out to estimate the effects of PPEF1  on the BC metastasis. Meanwhile, the differential expressions of PPEF1  in paraffin-embedded tissues and serum samples were, respectively, analyzed by Immunohistochemical (IHC) analysis and enzyme-linked immunosorbent assay (ELISA) kit.
Results: The transcriptional levels of PPEF1  were higher in BC than in normal breast tissues or adjacent normal tissues. Moreover, survival analysis revealed that higher PPEF1  expression was negatively associated with overall survival (OS), all events-free (AE-free) and metastatic recurrence-free (MR-free) survival, and further was an independent risk factor of unfavorable prognosis in BC patients. Additionally, the present study provided the first evidence that PPEF1  participated in multiple biological processes and underly signaling pathways involving in tumorigenesis and development of BC. Furthermore, PPEF1  promotes the BC progression and can be used as a noninvasive diagnostic marker. Noteworthy, the combined determination of serum PPEF1  and traditional tumor markers can enhance diagnostic accuracy thus is of vital importance in the early diagnosis of BC.
Conclusion: PPEF1  exerted a tumorigenic role and involved in molecular mechanism of tumorigenesis in BC which served as a promising biomarker for prognosis and diagnosis.
Keywords: PPEF1 , breast cancer, biomarker, molecular function, signaling pathway