Hi Jessie,

I did start studying genetics at university prior to getting ill and having to quit uni so my basic understanding of the subject isn't too bad (as an identical twin I still read a lot of genetics).  However, please note that I'm not qualified in any way on the subject and can really only speak from my own experience of genetic testing.

Apologies if you know this already, but the cells in our body will usually have 2 copies of each gene.  One copy is inherited from our mother, the other from our father.  Our body has genes whose job it is to suppress tumours (the proteins of those genes repair DNA).  If one of those genes is mutated (basically has errors on it) then it won't do its job properly and tumours aren't suppressed. If one of your parents has a mutated gene then you have a 50-50 chance of it being passed on to you (remember they also have two copies of each gene so they may pass on to you the healthy copy or the mutated copy).

So for me all they had to do was take a blood sample, they then tested it for mutations on the BRCA1, BRCA2, PAL-B and CHEK2 genes. With different cancers it's different genes, so there will be a list of genes that fall under the banner of 'Lynch Syndrome' that they will look at, and a mutation in one or more of those genes would indicate Lynch syndrome.  I realise with some cancers they do testing on the tumour and that can suggest if a condition is likely, but there will be other genes not included in that syndrome that can increase your risk of certain cancers.

So they've ruled out Lynch Syndrome for you which is great.  My recollection is that Lynch Syndrome is relatively common so with your type of cancer (colorectal?) it makes sense they would test the genes that fall under that banned first.  And it looks like now they are going to test to see if you have mutated copies of other genes that don't fall under that banner.

I'm not sure where you are at with your bowel surgery (sorry I've probably missed other posts) but as a general rule having a mutated gene can mean you are eligible for prophylactic surgery.  This is where body tissue (in my case it would be the unaffected breast and my ovaries) can be removed as these are the most likely places for cancer to develop, it's a preventative measure.  So if they find you have a mutated copy of a gene and that increases your risk of breast cancer they may say you can opt for a double mastectomy, for example.  Obviously some organs can't just be removed cause we need them.

If you have bowel surgery planned I cannot see how the genetic testing would affect that but I don't know much about that area.  However, it could alter other treatments as some chemical treatments have a better effect on genetically-driven cancers.

My example is that I my breast cancer was initially treated with FEC-T chemotherapy.  This is very much the standard for breast cancer.  However, the type of chemotherapy I'm about to start (Platinum) is a very common general chemotherapy, but it is known to be more effective on breast cancers where there is BRCA2 mutation involvement than on non-genetic breast cancers.

Sorry I'm rambling as always.  Not long woken up and obviously I don't know what level your knowledge of this area is at, and when we start talking genetics it's a complex area.

Hope that helps somewhat though.  Feel free to message me if I can explain anything further, just remember I am not medically qualified, but I promise I will make it clear if I am presuming something or just making an educated guess.  That said you don't know me from Adam so the usual warnings of being careful where you get your information from apply.

LJx