Unresectable Colon Cancer with Charles Fuchs, MD and Tanios Bekaii-Saab, MD: Case 2 - Episode 10

Charles Fuchs, MD: Clinical Importance of RAS Mutations

What is the clinical importance of RAS mutations in treatment of metastatic CRC?

The RAS mutation, it predicts resistance to EGFR antibody, and that makes sense because we realize that the receptor signals through RAS to actually affect growth of the cancer cell. So whereas the antibody that hits the receptor might impair the growth of the cell in a RAS wild type where the signaling pathway is appropriately functioning, if you have the mutation in that downstream event of RAS, which by the way that mutation turns the gene on permanently, so because that downstream event is switched on no matter what, whether you affect the upstream receptor with the antibody or not, you realize the antibody won't work. Even if you turn the receptor off, the next step is turned on by the mutation.

Unresectable Colon Cancer: Case 2

52-year-old woman newly diagnosed with metastatic CRC and is genotyped as part of her initial work up.