CD9 and posterior cortical atrophy: Consequently, these data establish RAB1A as a key regulator of EV biogenesis in PCa, likely acting through the coordinated suppression of a network of essential Rab GTPases (RAB27A, RAB7A, RAB5A, RAB11A, RAB35) and EV cargo-sorting/scaffolding factors (ALIX, TSG101, SNAP23, CD9).