Introduction: The treatment for advanced colorectal cancer (CRC) is getting better owing to the progression of molecular target drugs and one of the targets is Epidermal Growth Factor Receptor (EGFR). To detect the gene mutation, we used circulating tumor DNA (ctDNA) in the blood to confirm whether we can identify KRAS mutations from serums.

Materials and Methods: We gathered serum samples from 20 patients (2013-2015) who had undergone colon cancer operations. We abstracted ctDNA from the serum samples, examined the existence of KRAS mutations, and then compared them to the biopsy specimen.

Results and Discussion: 8 cases are wild type and 7 cases are mutation type for both (biopsy specimen and serum), however 5 cases are mutation type for biopsy specimen and wild type for serum. We show here that the sensitivity of this study for testing KRAS mutations is 83.3%.

Conclusion: This study suggests that the possibility of using the ctDNA in serum samples to check for the KRAS mutation.