Hypothyroid and Melanoma
Jacob Schor, ND FABNO
October 3, 2008

Thyroid Medication and Malignant Melanoma; a good idea

Way back in August 2004, one of those obscure little papers was published that I don’t notice until years later. J. Ellerhost and colleagues at MD Anderson Cancer Center in Texas had a paper appear in Clinical Cancer Research titled, “Expression of thyrotropin-releasing hormone by human melanoma and nevi.”

OK, the title still doesn’t leap out and say read me. But let me explain what these guys figured out.

Thyrotropin-releasing hormone (TRH) is a hormone produced by the hypothalamus, the little thing in the brain, in response to a perceived deficiency in thyroid hormone in the blood. It gets carried to the anterior pituitary gland by the superior hypophyseal artery, there it increases Thyroid Stimulating Hormone (TSH) production and release.

Anyway Ellerhorst and colleagues tested various skin cooties and found that melanoms (the nasty skin cancers) were sensitive to TRH which acted to stimulate their growth. The also tested nevi and dysplastic nevi. Nevi (the plural) or nevus for just one of them is the medical term for ‘sharply-circumscribed and chronic lesions of the skin.’ These are the things we commonly call birthmarks and moles. By definition, nevi are benign. If the mole starts to look ugly, that is not the like your ordinary mole, it’s called dysplatic.

Dysplastic nevi are generally larger than ordinary moles and have irregular and indistinct borders. Their color frequently is not uniform and ranges from pink to dark brown; they usually are flat, but parts may be raised above the skin surface.

Dysplastic nevi can be found anywhere, but are most common on the trunk in men, and on the calves in women. In 1992, the NIH recommended that the term "dysplastic nevus" be avoided in favor of more descriptive language.

So when these guys tested all these various skin lesions for reaction to TRH , reactivity was, “observed in 12 of 19 melanomas (63%), 23 of 33 (69.7%) dysplastic nevi, and 14 of 27 (51.9%) benign nevi”. About half reacted though the dysplastic ones and cancerous growths were a little more sensitive. When they tested nevi from patients who also had melanoma there was a much greater chance they would be TRH sensitive. This provides an interesting angle for testing skin lesions and predicting who might get a malignant melanoma down the road even if the current lump being biopsied appears benign. Only trouble of course with all of this is where do you find a lab capable of testing little snipped off skin lesions for TRH sensitivity? This is all very fine for MD Anderson to do but what do we do with this?

Ellerhorst has a follow up paper published in 2006 that is more interesting and more useful. Instead of looking at TRH they looked at TSH. Admitting that they had observed that people with melanoma were often hypothyroid, they set out in this study, “…. to test the hypothesis that TSH, which circulates at elevated levels in hypothyroid individuals, stimulates the growth of melanoma cells.” They found that all of these skin lesions, moles or nevi etc had a good chance of having receptors for TSH and the percentages increased as the moles became dysplastic and malignant. What is more, TSH when it hooked on to these receptors stimulated cell growth. “Taken together, these data support the hypothesis that TSH is a growth factor for human melanoma.”

In English, TSH makes skin cancer grow faster.

They conclude their summary; “Our findings have broad clinical implications for the prevention of melanoma and the management of established disease.”

My daughter has an expression for statements like this that refers to the literary figure Sherlock Holmes and the absence of fecal material, but that is not appropriate for this venue.

If TSH makes skin cancer grow faster, than this would seem to be a no brainer.

If you increase thyroid hormone levels in the blood, TSH goes down. With enough hormone you can lower TSH to nearly zero.

The first is treat people with hypothyroid disease to prevent elevated TSH. Avoiding high levels of TSH more sense than wallowing in sunscreen if you are trying to prevent skin cancer.

The second thing it suggests should again be obvious. For people with skin cancer or a history of cancer, keeping them on a dose of supplemental thyroid hormone that is a little on the high side can suppress TSH production. Keeping TSH low, may prevent it from acting as ‘growth factor’ and stimulating skin cancer cell proliferation.

[note: Thank you to Michael Traub, ND, FABNO who practices in Hawaii, author of the book Naturopathic Dermatology, former president of the AANP, and all around most excellent person, who pointed out Ellerhorst’s work to me]

Clin Cancer Res. 2004 Aug 15;10(16):5531-6.Click here to read Links
Expression of thyrotropin-releasing hormone by human melanoma and nevi.
Ellerhorst JA, Naderi AA, Johnson MK, Pelletier P, Prieto VG, Diwan AH, Johnson MM, Gunn DC, Yekell S, Grimm EA.

Endocr Relat Cancer. 2006 Dec;13(4):1269-77.Click here to read Links
Human melanoma cells express functional receptors for thyroid-stimulating hormone.
Ellerhorst JA, Sendi-Naderi A, Johnson MK, Cooke CP, Dang SM, Diwan AH.