KRT18 and posterior cortical atrophy: In PBMC scRNA-seq from M1-stage metastatic PCa patients, KP_Pos T cells exhibited a distinct expression profile marked by KRT18 and multiple ribosomal genes (RPS12, RPS13, RPL30, RPS3A, RPL11, RPL32, RPS8, RPS23, RPS14, RPL5), indicating partial epithelial-like reprogramming possibly driven by tumor-derived factors or extracellular vesicle-mediated transcript transfer 33.