Mutations - 1256493

Hi Gail,

The answer is probably not well known at this time. For example, EGFR mutations are thought to be mutually exclusive with both ALK rearrangements and KRAS mutations, but there are rare exceptions. Since the field is so new, the coexistence of various mutations is still being determined and they may be less rare than previously thought. Also, at present there few targeted therapies aside from TKIs for EGFR and Xalkori for ALK, so other mutations are mostly relevant only in clinical trials. Multiplex molecular testing will likely clarify this issue in the future:

http://cancergrace.org/lung/2013/04/28/sequist-multiplex-next-generatio…
http://cancergrace.org/lung/2013/04/13/riely-multiplex-next-generation-…

JimC
Forum moderator

Yes. At this point, the evidence has generally shown that "driver mutations" like EGFR mutations or ALK or ROS1 mutations are mutually exclusive, or nearly so. So in general, there isn't a high yield to doing additional mutation testing after finding a driver mutation.

-Dr. West

Thanks again Jim for pointing that out. I'd never looked at these in this format before, so didn't realize I could search and find more. Take care, Judy

Hi Gail (I feel I am seeing quite a lot of you elsewhere!) I had some extra tests on my original biopsies recently: these included ALK, HER2, BRAF, and KRAS. All they could find was EGFR, which is nice of course but we already knew about that. Makes Dr West's point nicely ...
Where the presence of another mutation becomes useful/interesting would be when a post-progression re-biopsy shows something new that explains or plays a role in resistance, of which the most common for people with EGFR seems to be the T790M mutation.
We have been thwarted in our holiday plans but I am still hopeful!