SMAD2 and posterior cortical atrophy: To determine the clinical correlation of miR-133b with TGFBRI, TGFBRII, REST expression, and TGF-β signaling activity in clinical PCa tissues, the miR-133b expression and protein levels of TGFBRI, TGFBRII, REST and nuclear SMAD2/3 expression were examined in four bone metastatic and four non-bone metastatic PCa tissues.