Such a thing as a good mutation in CRC?

I am stage 4 metastatic colon cancer, spread to skull and also have bone mets on spine and pelvis. I went through surgery, radiation and chemo and finished all treatment about 6 weeks ago. Had my sans throughout June and early July and everything has continued to shrink. My oncologist has been on vacation and his colleague, who handled my radiation, saw me to discuss the scan results. During the conversation, he mentioned that my dr. told him I had a mutation, but that they were characterizing it as a good thing. Apparently, he assumed I knew about it (I did not, though I knew my dr. was taking extra blood for genetic testing). I have been searching the internet to find some sort of information about a "good" mutation in terms of CRC, and I have to say, I've found nothing but bad news. Has anyone ever heard of or have knowledge of any mutations in CRC being beneficial? My oncologist doesn't get back from vacation for another week or so and I'm going a little crazy. Thanks.