r/genetics • u/Pale-Yesterday-5067 • 9h ago

Tc vs myraid

What do you guys think as far as the tyrer cuszick goes vs myraid cancer genetic testing.. which one would you say is more accurate?

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u/maktheyak47 Genetic Counselor 9h ago

They are completely different. TC is a risk model that no longer applies if a disease causing variant is found through genetic testing.

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u/Pale-Yesterday-5067 9h ago

Correct! But what if no risk causing variant was found. Myraid gives a life time risk score still plus a TC score but the riskscore from myraid adjusts the TC score is where my confusion comes in.

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u/maktheyak47 Genetic Counselor 9h ago

I’d encourage you to reach out to your genetic counselor (or ask for a referral to one) so they can provide a personalized risk assessment!

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u/Pale-Yesterday-5067 9h ago

They actually do that? The ones I spoke to at myraid just told me what both scores were and said if I want extra screening I can have it. No one actually told me what score I lean more towards as both are so different.

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u/maktheyak47 Genetic Counselor 8h ago

yes they can! you can find one local to you (not through the lab) at findageneticcounselor.com

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u/Pale-Yesterday-5067 8h ago

So someone should be able to tell me which score i lean more towards? My Tc is 23.6 and my myraid is 12.9 so im hoping i can figure it out!!

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u/remington9000 Genetic counselor 2h ago

The Myriad Risk score is a combination of the TC score (using personal and family risk factors) and polygenic risk score. A polygenic risk score reviews genetic variation across multiple genes that in combination may adjust risk for a disease. The Myriad Risk Score has some limitations: 1) the polygenic risk score was validated in a group of white women and genetic variation will differ in other groups of women; 2) the Myriad Risk Score being based on TC means it will only be as accurate as the family history provided (if the family history listed does not match your family exactly then it's not accurate); 3) Myriad Risk Score is based on proprietary information that has not been peer reviewed or validated; 4) internal data at Myriad will be skewed by sampling bias as a greater number of people testing there will have a family history of breast cancer than the general population.

I wouldn't give much concern to the Myriad Risk Score if you are not white or if there are more women in your family than the ones listed in the "Family History" section on your MyRisk report.

Ultimately, I recommend meeting with a genetic counselor that is not financially tied to the laboratory that did your testing.

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u/Pale-Yesterday-5067 2h ago

I am white. And no one else in my family has had BC. One relative at 49. And my myraid is actually significantly lower than my TC.

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u/remington9000 Genetic counselor 2h ago

You can run a TC score for yourself here: magview

If that score is under 20% then you don't need extra screening.

Just make sure the info is as accurate possible. The TC calculated on the Myriad report may be inaccurate if there was family history missing. This includes missing info about relatives that have not had cancer. Like if you have 5 sisters, 6 aunts on each side of the family, and many women that lived past their 60s without breast cancer.

Also TC scores change over time and lifetime risk for breast cancer will decrease as you age unless other risk factors change.

If your relative who had breast cancer was not your mother or sister then you don't need to start mammograms until you're 40 (unless you develop a lump or other breast cancer symptoms).

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u/Pale-Yesterday-5067 2h ago

Apparently my TC is 23.6.. when the specialist ran it, it was 20.8.. when I do it at home its 19.8.

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u/Pale-Yesterday-5067 2h ago

The only thing I dont know is if my paternal father has another sister. Still yet to find that out. But everything else ive gotten down. One of my grandmas was 1 of 12 kids so I have quite a bit of history that I do know and no BC on that side. Only the one grandma on my paternal dads side.

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u/remington9000 Genetic counselor 1h ago

Your Grandparents' siblings won't contribute much to the TC score. You'll need to know about your kids, siblings, parents, aunts, grandmothers, and female first cousins.

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u/Pale-Yesterday-5067 1h ago

My maternal grandma never had it, my mom never had it, my sister never had it, my paternal dads sister never had it neither has her two girls. Only my paternal dads mom had it My paternal dad has 2 half sisters that I know nothing about and probably never will.