kras mutation. best method for detection - (Jul/17/2008 )

hello hello hello

i've a question...

I'm sequencing Kras for the detection of mutation in colorectal cancer pacients, but I've had some problems with the doctors, they say that the test that swould be make is Real Time... does somebody could help me with this???? it is true that sequencing is not as good as Real Time????

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I would not say that there is good and bad. It really depends on your particular question.
As a rule of the thumb, if you need to asses a lot of samples over and over, for a limited set of mutations, then you should consider sequencing. However, if you are more interested in screening, or to detect various mutations, then you should consider real-time (we are talking price-wise here).

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Sequencing has only limited ability to quantify mutation status, that's probably why doctors call for real-time.

As Pallas wrote, it's quite simple:
screen for many or unknown mutations -> sequencing (must be at least 10% of affected in sample), cons: you miss a low quantity mutation
look for one or a few known mutations with high sensitivity -> real-time assay for each of the mutations, cons: you miss all other mutations

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Thanks, i'm working with metastatic colon cancer and the volume of cells is big... so i'm doing ok usin sequencing

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Both sequencing and real-time have their advantages as stated above.

I have had similar problems finding the appropriate test to use for KRAS testing in my lab. You may want to check out a recently released product from Trimgen. Last week they announced a new KRAS test (modified sequencing method) for KRAS screening.

I only know of two kits currently on the market, Trimgen's and DxS's. Do you know of any others? I rather not develop the test myself but will if necessary.

In my research, DxS screens 7 KRAS mutations and Trimgen screens 12 KRAS mutations. I read in a paper that 7 mutations occur in approx. 90%-95% of patients with the KRAS mutations. I plan on ordering a kit from Trimgen to see if it really can detect 1% mutations on a sequencer.

Please reply if you know of any other platforms or have suggestions for designing the test on my own.

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