The Role of Exosomes in Prostate Field Cancerization

Field cancerization is formally defined as the presence of molecular alterations in structurally normal tissues adjacent to tumors. Currently, the etiology of prostate field cancerization is still unknown. We hypothesize that exosomes (vesicles excreted by cells that may contain protein, lipids, or RNA) are released by tumors and are endocytosed by adjacent normal cells converting them into abnormal cells, thereby aiding cancer progression. The following biomarkers have been associated with field cancerization: MIC-1, PDGF-A, FASN, and EGR-1, while markers for exosomes are CD-9, CD-63, and PSMA. To test this hypothesis, exosomes were isolated from human prostate cancer cell models LNCaP and PC-3 and were used to treat human non-cancerous RWPE-1 cells. Quantitative reverse transcriptase polymerase chain reaction and Western blotting were used to determine mRNA and protein expression levels of the biomarkers, respectively. The future implications of this study are to utilize biomarkers to indicate pro-cancer development in normal cells, allowing for patient intervention before cancer development by inhibiting exosome release from tumor cells. In addition, knowledge of molecular mechanisms of field cancerization may lead to the development of preventative measures to inhibit tumorigenesis and tumor multifocality