The genes SMAD family member 3 (SMAD3), trans-activation-responsive RNA-binding protein (TRBP) and double-stranded RNA-specific endoribonuclease (DROSHA) play a crucial roles in microRNA processing [137] and SNPs in these genes (rs745103, rs744910 and rs1722821 for SMAD3; rs6088619 for TRBP; and rs10719 for DROSHA) were significantly associated with nCRT response in 265 rectal cancer patients [138]. This evidence concerns the gene SMAD3 and rectal cancer.