Cancer Thyroid hormone

Liu R, Li Z, Bai S, et al. Mechanism of cancer cell adaptation to metabolic stress proteomics identification of a novel thyroid hormone-mediated gastric carcinogenic signaling pathway. Mol. Cell. Proteomics 2009 8 70-85. 

A low RAIU indicates the excess thyroid hormone is not a consequence of thyroid gland hyperfunction. This may be seen in painful subacute thyroiditis, painless thyroiditis, struma ovarii, follicular cancer, and factitious ingestion of exogenous thyroid hormone. 

Monden T, Wondisford FE, Hollenberg AN (1997) Isolation and characterization of a novel ligand-dependent thyroid hormone receptor-coactivating protein. J Biol Chem 272 29834-29841 Moore SD, Herrick SR, Ince TA, Kleinman MS, Cin PD, Morton CC, Quade BJ (2004) Uterine leiomyomata with t(10 17) disrupt the histone acetyltransferase MORF. Cancer Res 64 5570-5577... 

A number of medical conditions are associated with high rates of depression (see Table 3.4). In some instances, the distinction between MDD and depression due to a general medical condition is largely academic with little bearing on treatment selection. For example, pancreatic cancer may induce depression directly through the release of tumor-secreted substances however, depression in the pancreatic cancer patient is treated with conventional antidepressant medications. In other cases, the diagnostic distinction bears important treatment implications. One commonly cited example is depression occurring in association with hypothyroidism. Patients with depression and hypothyroidism do not respond to antidepressant treatment alone but require a thyroid hormone supplement. 

Yamada-Okabe T, Sakai H, Kashima Y, Yamada-Okabe H (2005) Modulation at a cellular level of the thyroid hormone receptormediated gene expression by 1,2,5,6,9,10-hexabromocyclodo-decane (HBCD), 4,4 -diiodobiphenyl (DIB), and nitrofen (NIP). Toxicol Lett 55 127-133 Zahm SH, Blair A (1993) Cancer among migrant and seasonal farmworkers An epidemiologic review and research agenda. Am J Ind Med 24 753-766 Zahm SH, Ward MH (1998) Pesticides and childhood cancer. Environ Health Perspect 106 893-908... 

The lARC has determined that there is sufficient evidence for the carcinogenicity of amitrole to experimental animals and inadequate evidence for carcinogenicity to humans. It was noted that amitrole produces thyroid tumors in rodents by a nongenotoxic mechanism that involves interference with the functioning of the thyroid peroxidase, resulting in a reduction in circulating thyroid hormone concentration and an increase secretion of thyroid-stimulating hormone. Amitrole would not be expected to produce thyroid cancer in humans exposed to concentrations that do not alter thyroid hormone homeostasis. 

Thyroid cancer Exogenous thyroid hormone may produce regression of metastases from follicular and papillary carcinoma of the thyroid and is used as ancillary therapy of these conditions with radioactive iodine. Larger doses than those used for replacement therapy are required. 

Thyroid cancer Larger amounts of thyroid hormone than those used for replacement therapy are required. 

TSH is approved for medical use as a diagnostic aid in the detection of thyroid cancer/thyroid remnants in post-thyroidectomy patients. Thyroid cancer is relatively rare, exhibiting the highest incidence in adults, particularly females. First-line treatment is surgical removal of all or most of the thyroid gland (thyroidectomy). This is followed by thyroid hormone suppression therapy, which entails administration of T3 or T4 at levels sufficient to maintain low seum TSH levels through the negative feedback mechanism mentioned earlier. TSH suppression is required... 

Liothyronine sodium (Cytomel) is the sodium salt of the naturally occurring levorotatory isomer of T3. Liothyronine is generally not used for maintenance thyroid hormone replacement therapy because of its short plasma half-life and duration of action. The use of T3 alone is recommended only in special situations, such as in the initial therapy of myxedema and myxedema coma and the short-term suppression of TSH in patients undergoing surgery for thyroid cancer. The use of T3 alone may also be useful in patients with the rare condition of 5 -deiodinase deficiency who cannot convert T4 to T3. 

Levothyroxine is taken orally or intravenously and is normally prescribed to treat hypothyroidism or to suppress the release of thyroid hormone so as to manage cancerous thyroid nodules (i.e., thyroid cancer) and growth of goiters. Other less frequently prescribed thyroid and parathyroid drugs include methimazole (Tapazole), various iodides, lithioronine (Triostat), and liotrix (Thyrolar). 

A possible link between breast cancer in women and thyroid hormone therapy was suggested on the basis of a retrospective study of patients with breast cancer (SEDA-3, 340). A subsequent statistical re-analysis of the original data failed, as did later studies, to confirm such a relation (SEDA-3, 340 SEDA-4, 294 57). 

Thyrotropin stimulates iodine uptake, and this facilitates the diagnosis and treatment of recurrent disease or metastases in the follow-up of differentiated thyroid cancer. It is used as an alternative to thyroid hormone withdrawal, to avoid symptomatic hypothyroidism (1). Headache and nausea occur in 6-40% of patients after intramuscular administration, but are usually mild and transient (2,3). 

Haugen BR, Pacini F, Reiners C, Schlumberger M, Ladenson PW, Sherman SI, Cooper DS, Graham KE, Braverman LE, Skarulis MC, Davies TF, DeGroot LJ, Mazzaferri EL, Daniels GH, Ross DS, Luster M, Samuels MH, Becker DV, Maxon HR 3rd, Cavalieri RR, Spencer CA, McEllin K, Weintraub BD, Ridgway EC. A comparison of recombinant human thyrotropin and thyroid hormone withdrawal for the detection of thyroid remnant or cancer. J Clin Endocrinol Metab 1999 84(11) 3877—85. 

Martin, V., Cortes, M.L., de Fehpe, P., Farsetti, A., Calcaterra, N.B. and Izquierdo, M. (2000) Cancer gene therapy by thyroid hormone-mediated expression of toxin genes. Cancer Res., 60, 3218-3224. 

Thyrotropin alpha has the biologic properties of pituitary TSH. It binds to TSH receptors on both normal thyroid and differentiated thyroid cancer cells. The TSH-activated receptor stimulates intracellular adenylyl cyclase activity. Increased cAMP production causes increased iodine uptake and increased production of thyroid hormones and thyroglobulin. 

Treatment of metastatic differentiated thyroid cancer requires the administration of large doses of 131I (30-200 mCi) in the presence of persistently high serum levels of TSH (see Chapter 38 Thyroid Antithyroid Drugs). Patients must withdraw from thyroid hormone replacement in order to achieve this. For treatment purposes, thyrotropin alpha administration cannot substitute for thyroid hormone withdrawal. 

Several lines of evidence indicate that macromolecules of as yet unidentified chemical nature, produced by cancers and released into the systemic circulation, are responsible for the biochemical alterations in the liver and other host organs. In view of the diverse regulatory properties of the many different enzymes that increase or decrease towards their immature level (see Table III), a deficiency or excess in any given endocrine or dietary factor can clearly not explain the phenomenon. Nor has it been possible to implicate reductions in the efficacy of these factors. Subnormal concentration of the nuclear thyroid hormone receptor has been noted in the liver of tumor-bearing animals(24) however, since losses in the T3-inducible catalysts of the same liver occurred at much earlier stages of tumor-bearing,(24) the subnormal receptor concentration could clearly not be the cause of these losses but was probably another, and rather late, reflection of the process of biochemical undifferentiation. 

In contrast to arsenic, trace concentrations of selenium are essential for human and animal health. Until the late 1980s, the only known metabolic role for selenium in mammals was as a component of the enzyme glutathione peroxidase (GSH-Px), an anti-oxidant that prevents cell degeneration. There is now growing evidence, however, that a seleno-enzyme is involved in the synthesis of thyroid hormones (Arthur and Beckett, 1989 G. F. Combs and S. B. Combs, 1986). Selenium dehciency has been linked to cancer, AIDS, heart disease, muscular dystrophy, multiple sclerosis, osteoarthropathy, immune system and reproductive disorders in humans, and white muscle disease in animals (Levander,... 

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