As shown by the Venn diagrams for each CRC case in Fig. 3, generally few distinct mutations (maximum of 3, including APC, KRAS, NRAS, PIK3CA, SMAD4 and/or TP53) were shared between all case-matched DNA samples (primary tumour, synchronous and/or metachronous liver and/or lung metastases) of an individual CRC case (Table 2). This evidence concerns the gene NRAS and neoplasm.