AKT1 and posterior cortical atrophy: Notably, siRNA knockdown of PIK3CD-S has shown superior inhibition of AKT/mTOR signaling (i.e. significant reduction of pAKT and pS6 levels) in 22Rv1 and MDA PCa 2b, reflecting the higher sensitivities upon siPIK3CD-S due to their higher S/L ratios (1.45 and 2.24, respectively).