Thyroid hormones in cancer progression and regression
I recently learned that the thyroid pro-hormone T4 is a cancer-promoting hormone. While the active thyroid hormone T3 is in charge of your cellular metabolism, T4 may be up to no good. Not only can it drive cancer cell proliferation, it also opposes the effects of natural anti-cancer compounds, such as resveratrol.
“The physiological circulating concentration of free T3 is about 10−11 M and we have found this level of T3 to have no effect on resveratrol-induced antiproliferation. In contrast, circulating levels of free T4 do oppose the anticancer effects of resveratrol.” (Ho et al. (2017) Nutrients 9(10):1046)
But Mother Nature gave us a solution to the T4 problem. The solution is another thyroid hormone derivative called Tetrac. Tetrac keeps T4 in check and the serum levels of Tetrac may determine whether T4 does or does not achieve its nefarious potential.
In the video below, I summarize the science on T4 and Tetrac: how they compete for thyrointegrin on the surface of cancer cells and how Tetrac could tip the balance toward spontaneous cancer regression.
Obviously, I am interested with metastatic thyroid cancer & its complexities/complications. Readings that suggest complete thyroidectomy - as was done in the case of which I am concerned - specifically employed T4 to suppress TSH. I am unsure of the role of tetrac, but I have read it is employed in metastatic cases with "inhibiting angiogenesis and disrupting cancer cell proliferation through non-genomic pathways." While I understand that with thyroidectomy, it necessitates synthetic T4 supplementation, is this also true of tetrac? Below are the two studies I read to reach the (perhaps dubious?) conclusion that I did.
Davis, PJ, Davis, FB, Mousa, SA, Luidens, MK, Lin, HY. Membrane receptor for thyroid hormone: physiologic and pharmacologic implications. Annu Rev Pharmacol Toxicol. 2011:51:99-115. https://doi.org/10.1146/annurev-pharmtox-010510-100512.
Glinskii, GV, Huxley, VH, Glinsky, GV, Pienta, KJ, Raz, A, Glinsky, VV. Mechanical entrapment is insufficient and intercellular