SMAD2 and cancer: Brodin et al. (1999) suggested that activation of SMAD family member 2 (Smad2) and upregulation of SMAD family member 3, 4, 6 and 7 (Snad3, Smad4, Smad6 and Smad7) are associated with induction of apoptosis in both normal and cancer prostate cells.