Mutation testing questions

[JerryfromFauq]

Catherine, I am trying to figure out where to post some general questions that relates to genetics genomics, nomenclature. etc. http://forum.melanomainternational.org/mif/posting.php?mode=post&f=54# one question there has been debate about is how the Term “Wild Type” is used. By definition it seems this is the most common form of gene and is considered “unmutated” as far as being cancerous after being tested. I have seen the term such as BRAF and c-kit negative used to mean “unmutated”. From my reading it appears that neither is quite accurate without a further qualifyier. Do any of the tests actually show nonmutated” or do they just test for specific mutations and say negative for those and then say “WT”? How do the cases of oncoprotein over expressiom and ___mutation Negative fit in? IS this because a known carcinogenic mutation wasn’t found, vice saying that there is no mutations in the genes? :ugeek:

[Keith Flaherty]

Regarding the question about mutation testing for the mutated oncogenes that we now consider to be the critical ones for which therapies are either validated or in clinical trials, I would put it this way:

Certain melanoma oncogenes, such as BRAF and NRAS, are analyzed using tests that are specifically designed to detect the most common mutations that can occur in those genes that result in a constantly active form of the resulting molecule. These tests come out as either positive or negative. Positive means that the specific mutation being probed was found, negative means that it was not. The gene most certainly exists in its wild type (nonmutated) form in those cases that are reported as negative. CKIT and, on occasion, BRAF and NRAS can be analyzed by “sequencing” in which case the result will not be positive or negative, but rather indicate whether the elements of the gene being sequenced are mutated or nonmutated and, if mutated, where those mutations are found. This is especially important in the case of CKIT since we know that there are several different mutations that can affect the gene and activate the resulting molecule.

[JerryfromFauq]

Thanks Doc. I have been having a disagreement on Facebook with a patient that is telling others that BRAF WT is a segment of the BRAF Positive mutations.

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