Investigating the clinical significance of E2F5 expression in circulating extracellular vesicles in prostate...

Prostate-specific antigen (PSA) based screening strategy has caused a marked improvement in prostate cancer detection and reduction in associated mortality. However, its specificity and sensitivity is not optimal for differentiating different forms of prostate cancer, resulting in overtreatment of indolent tumors. E2F5, a member of the family of transcription factors plays essential roles during many cellular processes. E2F5 amplification is a major event in PCa. A liquid biopsy is a minimally invasive procedure to investigate the cancer-related molecules in circulating tumor cells (CTCs), cell-free DNA, and extracellular vesicles (EVs). Serum and plasma are attractive sources of EV-based biomarkers as blood sample acquisition is a minimally invasive procedure. Given, the shortcomings of PSA as a serum marker, the suitability of E2F5 expression and chemical properties of EVs can be used for the diagnosis of clinically significant prostate cancer.

To technically refine the current histopathology-based diagnosis of PCa by adding it to the molecular readouts specific to disease states and biochemical fingerprints of EVs.

The study included 100 TRUS-biopsied tissues, 50 representing 4 Gleason grades and another 50 representing BPH. Expression of E2F5 was studied in all the qualified tissues by Immunohistochemistry (IHC). Blood from patients was collected and EVs were isolated and characterized.

E2F5 was highly upregulated through all Gleason grades, the maximum being in Gleason 10(5 + 5) and the minimum in Gleason 7(3 + 4), as compared to BPH. The EVs isolated from blood plasma were within 30-200 nm in size.

E2F5, being a transcription factor, is highly overexpressed in malignant biopsy tissues, through all Gleason grades. BPH tissues served as control samples. EVs from blood plasma might serve as a potential liquid biopsy marker for predicting disease progression and better prognosis.