SMAD4 and neoplasm: The following tumour suppressor genes were identified: 37% of studies (n=17) identified TP53 mutations, 30% (n=14) identified SMAD4 mutations, 24% (n=11) identified APC mutations, 9% (n=4) identified ATM mutations, 9% identified RNF43 mutations, and 7% (n=3) identified RB1 mutations.