Genetics Testing

At my oncology appointment on Monday, my doctor had asked me if I was ready to meet with a genetics counselor.  When I was first diagnosed, she had mentioned this to me but I never really researched it. I qualified for genetics testing because the type of cancer that I have (diffuse gastric cancer with signet ring cells) is rare and because of my age.  So on Tuesday I got a call from the genetics counselor I would be working with.  She asked me about my family history and I had to name off not only my siblings but my parents siblings.  I had to provide age and any history of cancer.

I felt dumb because I could not remember how many siblings my parents each have.  Unfortunately, I do not know most of my family.  My dads parents are deceased but my mothers are still alive.  I have visited Mexico 3 times to meet my family (at ages 10, 15, and 17).  My dad has a couple of brothers in the Los Angeles area and luckily I know some of my cousins from there.  Other than that, I don't know my family.  Some of my other siblings do visit Mexico more frequently and know my family better than I do.  I'm jealous of everyone around me.  I feel like I missed out on getting to know my grandparents. I wish I had that relationship with my extended family that everyone around me seems to have.  And figuring out my medical family history has also been tough.  In Mexico, access to healthcare is limited and my family is not rich.  And when someone dies, there is no autopsy.  You just kinda bury them in a couple of days.

After we went over my family history, we made an appointment for me to come in and submit a blood sample.  She suggested I bring any family I could so I chose to come in on Thursday (3/22/12) so that my sister could take the day off and come with me.

Thursday came and we headed into San Francisco for my appointment.  I just remember sitting in the car, staring out the window, thinking about my life.  Genetics testing?  Why?  Why are we making a big deal out of this?  I'm no one.  I constantly struggle with the emotions that come running through my head about the value of my life and why it's worth saving.  We arrived at Kaiser and I registered for my appointment.  Shortly afterwards, the genetics counselor and the genetics doctor came out and brought us into an office.  We sat at a round table and again, we went over a little bit on my family history.  My sister was able to elaborate some more about family members who possibly had cancer.  Because they were my "mothers dads sisters daughters daughter," it made no significant link to my cancer.  We next got a little lesson in genetics.  Basically, my cancer is rare.  We are not sure why I got it and why I got it so young.  The importance of this genetic testing is to see if I have a mutation in my genes that caused this cancer.  If I do have a mutation in the CDH1 gene and we find that this is hereditary, it can help my family.  My siblings can then get tested also to see if they carry the gene.  If they do, they will be told the probability of them developing gastric cancer, which can often be anywhere from a 60-80% chance.  With that said, some family members may choose to have their stomach removed, which sounds drastic but in comparison to cancer, it doesn't sound that bad.  You can have periodic endoscopies done with biopsies but the thing about it is that precancerous tissue might not be biopsied.  You just don't know if the tissue being sampled will have cancer cells.  My stomach, apparently has cancer everywhere, hence the stage IV.

One website that has been a great source of information for me is www.nostomachforcancer.org.  Rather than trying to give you a genetics lesson, here is what the site has to say:

GENETICS

The CDH1 gene, located on chromosome 16, normally encodes for a protein called E-cadherin. The normal function of E-cadherin is to allow cells and tissues to adhere to one another. ⁴

The structure of the E-cadherin protein chain bends and turns. The normal function of E-cadherin is to allow cells and tissues to adhere to one another in a normal fashion.

When there is a mutation in the CDH1 gene, the function of the E-cadherin protein is disrupted, and cancer often results.^3,4 The exact mechanism by which this mutation ultimately causes gastric cancer is not entirely known. ⁴

Inheritance of the CDH1 gene mutation follows an autosomal dominant pattern, meaning that offspring of mutation carriers have a 50% chance of inheriting the mutant gene.^3,4 It is estimated that three out of every four CDH1 gene mutation carriers will go on to develop gastric cancer,³ with an average age at diagnosis of 38.^5,6

It is important to note, however, that not all HDGC families have a mutation in the CDH1 gene. Other genes that may lead to HDGC are not known at this time.

The results of my genetic testing will come back in about 3-6 weeks.  They may find that this is hereditary, they may not.  But it's worth a shot to check.  Anything to help my family out.  I would't want them to go through this.  The last part of my appointment was spent down in the lab, where they collected my blood to send off to the laboratory who does the actual decoding of my DNA.  It was a simple little blood draw but the next day, I developed a lovely bruise.  

I am eager to learn the results of the testing.  I asked the genetics counselor to give me a call when the results were ready and that I would come in so we can discuss them.  

So far my week off of chemo has been good. I noticed that I started developing a cough and some wheezing.  This is similar to the cough that I had before diagnosis (which was pleural effusion).  I basically have fluid that collects in my left lung and it makes it hard for me to breath.  This time around, it's very mild and taking codeine pills helps manage it.  I'm also back on Lasix (my diuretic) to see if I can remove the fluid in my lung and belly.  Monday I am headed back to the lab for blood work. If everything comes back normal, we will resume chemotherapy infusion #3 on Tuesday.  Keep your fingers crossed for me!

If you're interested in learning about my specific type of cancer, I encourage you to visit this link below.  It breaks it down very nicely.

http://www.nostomachforcancer.org/gastric-cancer/hereditary-diffuse-gastric-cancer