SMAD4 and neoplasm: As the TCGA mutations were determined using paired tumour/normal data, which is the more precise method for determining somatic mutations, we restricted our attention to the remaining 17 genes that had similar mutation frequencies in the TCGA data set (KRAS, TP53, APC, SMAD4, FBXW7, BRAF, TCF7L2, PIK3CA, GNAS, CBX4, ADAMTS18, TAF1L, FAM123B, CSMD3, ITGB4, LRP1B and SYNE1, given in decreasing order of mutation rate).