Integrative Analysis of Periostin in Primary and Advanced Prostate Cancer

Periostin (POSTN) is an extracellular matrix protein associated with tumor progression and shorter survival in prostate cancer (PCa). Here, we performed an integrative analysis of POSTN's role in patients with PCa. Clinical and POSTN data from large-scale datasets were analyzed. POSTN cutoffs were identified with X-Tile, and STRING was used for protein-protein interaction analysis. In a cohort of 48 patients with metastatic castration-resistant prostate cancer (mCRPC), we used the AdnaTest platform to isolate circulating tumor cells and extract POSTN mRNA. Plasma samples were also tested for POSTN protein expression by dot blot assay. Data from large-scale datasets did not reveal any association between POSTN genetic alterations and outcome. In primary tumors, we found a significant correlation be-tween POSTN mRNA overexpression, worse baseline prognostic features, and shorter disease-free survival. POSTN was overexpressed in mCRPC and correlated with aggressive features. In our cohort of mCRPC patients, we found a positive correlation between POSTN plasma levels and androgen-receptor variant 7 positivity and an association with shorter overall survival. Our integrative analysis shows that POSTN is associated with poor clinical features and worse outcome in patients with PCa. Further studies are warranted to uncover the function of POSTN in PCa progression and to validate the prognostic significance of POSTN in mCRPC.