CD81 and posterior cortical atrophy: PCa-associated exosomes under hypoxic conditions contain nearly three times as much protein (CD63, CD81, HSP90, HSP70, Annexin II, TGF-β2, TNF1α, IL6, TSG101, Akt, ILK1, and β-catenin) as exosomes in normoxic conditions, which ultimately promotes CAF formation [91].