New Poster: Possible to Test Tumor Samples for BRCA Mutations?

BlueBunny

Hi, does anybody know if it's possible to test saved tumor samples for BRCA mutations?

My mother died of breast cancer in 2014, and after she died, I did a lot of family research. My grandmother and her grandmother died of breast cancer at 80 and 48 respectively, and my grandmother's sister died of pancreatic cancer at 27. My mother was an only child, so I have no maternal aunts or cousins. My mother was diagnosed age 55 but the oncologist said he thought it had been growing for ten years.

I have been tested for BRCA 1 and 2 and was negative. However, now I don't know if my mother would have tested positive and I am truly in the clear, or if she also would have been negative and I therefore might have an undiscovered mutation.

So, I'm trying to get her doctors to test one of her saved samples for the BRCA mutations, and they are being unhelpful.

My question is, does anyone know if testing a saved sample for mutations is even possible? And do you know if your oncologists store blood samples? I do know that her samples are saved in paraffin blocks, as is the norm. If they want to analyse them for future use, why not for this? I'm trying to get an accurate picture of what's saved and the kinds of tests that can be carried out on samples before I come down on her hospital.

I wouldn't have thought it was uncommon to realise about a family history after someone has died and to want to then test their samples. If anyone has had this done, I would LOVE to hear from you.

Thank you!

BB.

farmerlucy

I ask about DNA testing lipstick I.e. saliva and the genetic company said they can’t do it on saliva, and also they are prohibited from genetic testing someone who is not alive to give their permission.

SimoneRC

Hi BlueBunny!

I do not know about testing tumor samples.

I am curious if you only tested for BRCA or if you tested for all of the known breast cancer gene mutations? For instance, I am ATM mutated and that one is linked to breast, ovarian, pancreatic, colorectal and possibly other cancers. BRCA gets a lot of attention, but unfortunately there are a bunch of other gene mutations that result in elevated cancer risk.

Good luck and keep us posted!

Moderators

Hi there, BlueBunny! Welcome to BCO, we hope you find some helpful information and support here!

According to the National Society of Genetic Counselors, postmortem testing is an option in some cases, but it sounds like samples have to be stored in a very specific way to preserve them for testing (particularly if the samples are months to years old). So that's something you would have to verify, and testing would be done at your expense at a center of your choosing. But SimoneRC raises a good point about being tested for other mutations - there are several that can increase your risk of breast cancer, so it might be prudent for you to undergo more thorough genetic testing before pursuing postmortem testing from your mom's samples.

Please keep us posted on what you learn!

The Mods

ShetlandPony

I agree that doing a multi-gene cancer panel on you is a good way to go. You are trying to figure out why this family history, and what that means for you and your living relatives. Maybe a gene other than BRCA is implicated. To use myself as an example, I was able to obtain BRCA testing when I was first diagnosed, not because there was a lot of breast and ovarian cancer in the family, but because there were few female relatives on one side. I was premenopausal. The test came back negative — no BRCA mutation. About four years later I had a multi-gene generic cancer panel done(Ambry). It showed a mutation in a gene that would account for the direct line of four relatives with skin, colon, and breast cancer (me being the breast cancer case). My intuition had been correct. So then another relative was able to get tested for that mutation and take proper prevention and screening measures for the various cancers associated with that particular mutation.

NancyHB

Maybe I’m misunderstanding, but isn’t genetic testing done on blood samples and not tumors? Would testing a tumor - rather than a blood sample - give genetic panel results?

MelissaDallas

My Geneticist was surprised by my negative results and had suggested that the next time my Dad had a colonoscopy his doc arrange to send any polyps removed to UTSW for both pathology and gene tests, since he didn’t want to do direct genetic testing

santabarbarian

I had my tumor tested as well as my blood.

Blood will give you "germline" mutations... mutations that are part of you from birth. The tumor will have those mutations as all the cells in your body have them. BUT the tumor may have FURTHER mutated. In my case my germline mutation is a TP-53 mutation of unknown significance, likely to be benign. But my tumor had 2 TP-53 mutations... the one from my germline and one from the tumor itself having mutated. The second one, when I looked it up, is associated with cancer.

BlueBunny

Thank you, everyone.

Yes, I had the full breast cancer panel test from Ambry Genetics. It included all the genes mentioned in this thread. Ones I remember are PTEN, CHEK2, PALB2, NBN, NF1, VHL, MUTYH, and more.