When the discordance rates of the KRAS status between primary tumors and respective metastatic sites (lung, peritoneum, distant LN or ovary) were compared with the discordance rate between primary tumors and hepatic metastatic tissues (10.6%), pulmonary metastasis only showed a significantly higher discordance rate of KRAS mutation status (32.4%; P = 0.014). Here, KRAS is linked to metastasis.