CD28 and posterior cortical atrophy: Premised on reports that T-cell-mediated anticancer immune response is regulated by a cascade of co-stimulatory and co-inhibitory signals, with PCa cells exploiting the co-inhibitory signals for evasion of immunosurveillance [27], our present study results indicate that, unlike PSA/KLK3 which is upregulated, AIM/CD5L is concomitantly suppressed with markers of T-cell activation CD8A, CD28, TNFRSF9, CD69, PTPRC, SELL, and CCR7 mRNA in primary localized and castration-resistant bone metastatic PCa, but markedly enhanced in normal samples.