FLNA and posterior cortical atrophy: Specific protein biomarkers were identified for PCa patients in each ethnic group when compared to healthy individuals, but Filamin A was not confirmed as an African American specific biomarker, possibly because most proteins identified in plasma/serum exosomes are high abundance proteins in plasma/serum (e.g., albumin, macroglobulin, apolipoproteins, complement component, fibrinogen, haptoglobin, and immunoglobulin G (IgG)), an indication of potential issues in exosome purity.