Differential Mutations In Matched Primary and Metastatic Colorectal Cancers

This study compares DNA mutations detected in matched primary and metastatic colorectal cancer samples from 18 individuals across 1,321 genes. We found many more mutations were shared between tumor pairs (avg. 33.3 mutations/tumor) than were discordant (avg. 2.3 mutations / tumor). Nearly all tumors showed at least one discordance, and these were observed in genes known to be involved in colorectal cancer progression. Therefore, although primary and metastatic colorectal tumors are highly genetically concordant, evidence exists for discordance, which has clinical implications especially in situations of chemotherapy resistance or insensitivity.