Thyroid follicular carcinoma

Spontaneous thyroid tumors derived from the thyroid follicular cell occur in l%-3% of laboratory rats (adenomas and carcinomas combined in a variety of strains of rats aged 2 or more years). 

At dosages above 30mg/kg in the diet, chlordane interfered with reproduction in rats and mice, but this effect was reversible after exposure ceased." Pre- and postnatal exposures to chlordane altered the development of the immune system in rodents. A dose-related increase in the incidence of hepatocellular carcinomas was found in male and female mice fed approximately 60mg/k chlordane for 80 weeks. In rats, increases in the incidences of thyroid follicular cell neoplasms were observed. ... 

Chronic oral exposure of rats and mice to MDA and its dihydrochloride is carcinogenic. Treatment-related increases in the incidences of thyroid follicular cell adenomas and hepatocellular neoplasms were observed in mice after chronic ingestion of MDA in drinking water. In rats, increases in the incidences of thyroid follicular cell carcinoma and hepatic nodules were observed in males and thyroid follicular cell ademonas occurred in females. Although not statistically significant, certain uncommon tumors such as bile duct adenomas, papillomas of the urinary bladder, and granulosa cell tumors of the ovary also were reported. These tumors are of low incidence in historical controls. In another report, MDA acted as a promoter of thyroid tumors in rats. °... 

M (CEL increased incidence of NTP 1982b thyroid follicular cell adenoma or carcinoma)... 

Fig. 2. Human thyroid biopsies. 1D >H MR spectra (8.5 T, 37°C) residual water suppressed by selective gated irradiation, sweep width 3957 Hz, using 8192 data points, 128 accumulations, and acquisition time of 1.14 s and relaxation delay of 2 s. (a) Normal thyroid tissue, (b) Known follicular carcinoma, (c) Thyroid follicular neoplasm predicted by MRS to be normal—confirmed by histopathology. (d) Thyroid follicular neoplasm predicted by MRS to be cancer and confirmed by histopathology—the presence of capsular invasion. Reprinted with permission from the National Research Council, Canada.

Carcinogenic response was observed after exposure to nitrobenzene in rats and mice mammary adenocarcinomas were observed in female B6C3Ei mice, liver carcinomas in male Fischer-344 rats and thyroid follicular cell adenocarcinomas in male Fischer-344 rats. Benign tumors were observed in five organs. 

Potential carcinogenicity of PEGS has been examined in a dietary 2 year bioassay with rats. In male and female rats exposed to 20 mg kg there was a significant increase in the incidence of hepatocellular adenomas while in females there was also an increase in hepatocellular carcinomas. In addition, there was a significant increase in thyroid follicular cell adenomas and carcinomas in males in a recovery group treatment group. 

Cancer Rat (Fischer-344) 2 yr 5 d/wk 1 x/d (GW) 3.7 (CEL forestomach squamous cell papillomas in males and females thyroid follicular cell carcinomas in males) NTP 1993 MC... 

Tg is primarily used as a tumor marker in patients carrying a diagnosis of differentiated thyroid carcinoma (DTC). Although serum Tg is elevated in patients with thyroid cancer, including thyroid follicular and papillary carcinoma, elevations are also are seen in nonneoplastic conditions such as thyroid adenoma, subacute thyroiditis, Hashimoto s thyroiditis, and Graves disease. Serum Tg concentrations are not increased in patients with medullary thyroid carcinoma. 

Nikiforova MN, Lynch RA, Biddinger PW, et al. RAS point mutations and PAX8-PPAR gamma rearrangement in thyroid tumors evidence for distinct molecular pathways in thyroid follicular carcinoma. J Clin Endocrinol Metab. 2003 88 2318-2326. 

The t(2 3)(ql3 p25) translocation, found in a subset of thyroid follicular carcinomas, results in fusion of the DNA binding domains of the thyroid transcription factor PAX-8 to domains A-F of the peroxisome proliferation-activated receptor (PPAR) y 1 (Hg. 10.13). Studies using PCR and immunohistochemistry demonstrated that most follicular carcinomas positive for PPAR Y were widely invasive while tumors lacking the rearrangement were PPAR y negative. Papillary carcinomas and Hurthle cell tumors were negative. Other studies, however, have reported positivity both in follicular carcinomas and adenomas. 

CA 15-3 and CA 19-9 are variably expressed in thyroid follicular tumors. Both follicular and papillary carcinomas reveal CA 15-3 positivity in 100% of cases, whereas CA 19-9 is present in 70% of papillary tumors but in no follicular carcinomas.CA 125 immunoreactivity has been reported in approximately 40% of papillary carcinomas.The distribution of mucin-related antigens (MUC) has also been analyzed in thyroid tumors.These studies have demonstrated that MUCl plays a key role in the glycosylation of well-differentiated thyroid carcinomas. However, there are no consistent differences between papillary and follicular carcinomas with respect to the expression of mucins. 

Steroid hormone receptors (estrogen, progesterone, androgen) are variably expressed in thyroid tumors. Bur and associates reported estrogen receptor positivity in 8 of 39 (21%) papillary carcinomas, while follicular... 

Schelfhout LJDM, van Muijen GN, Fleuren GJ. Expression of keratin 19 distinguishes papillary thyroid carcinoma from follicular carcinomas and follicular thyroid adenoma. Am J Clin Pathol. 1989 92 654-658. 

Dorion P, Shi J, Zhang K, et al. Utility of SlOO protein in differentiating adenocarcinoma of the lung from papillary carcinoma and follicular carcinoma of the thyroid. Modern Pathol. 2008 21 340. 

There is sufficient evidence for the carcinogenicity of ETU in experimental animals. When administrated in the diet, ETU induced increased incidences of thyroid follicular cell carcinomas and papillary carcinomas with some metastases and liver hyperplastic nodules in rats of both sexes. There is inadequate evidence fw the carcinogenicity of ETU in humans [42]. ETU is used primarily as an accelerator for vulcanizing polychloropene and polyacrylate rubbers. The primary routes of potential human exposure to ETU are inhalation, ingestion and dermal contact. Potential occupational exposure also occurs during the manufacture of Cumulation and rqrplication of fungicides and insecticides prepmed from ETU. Residues of the compound have been found in 28 different commercial ethylenebisdithiocarbamates products [59]. 

Note-. PC, papillary carcinoma FC, follicular carcinoma UC, undifferentiated carcinoma MC, medullary carcinomas TL, thyroid lymphoma NA, not applicable (TL none in males and before salt iodination, MC two and three cases before and after prophylaxis, respectively). Thyroid cancer by type, mean age and gender before (1958-1972) (I) and after (1985-2003) (II) salt iodization in the province of Salta, Argentina. 

Thyroid transcription factor-1 (TTF-1) Lung cancer (adenocarcinoma, small cell carcinoma), thyroid tumors Small cell carcinoma of different locations Type II pneumocytes and Clara cells of lung, thyroid follicular and parafollicular C cells, diencephalon... 

Despite few controversial studies reporting the detection of RET/PTC rearrangements in benign or non-papillaty thyroid lesions such as Hashimoto thyroiditis, follicular and Hiirthel cell adenoma, the RET rearrangements seems to be characteristic for papillary thyroid carcinoma and not reported in any other thyroid carcinoma. The reported positive results in other thyroid lesion are possibly due to the presence of microfocus of papillary microcarcinoma, latent carcinoma or atypical follicular cells in transformation. 

Papillary thyroid carcinoma is a tumor of thyroid follicular epithelium with papillary and follicular growth pattern and the characteristic nuclear features. Papillary thyroid carcinoma makes about 70% of all thyroid carcinomas, often associated with radiation exposure or high iodine intake, and mainly metastasizes by invasion of lymph vessels. Papillary thyroid carcinoma frequently associated with different rearrangements mainly involving the RET/PTC gene discussed in a previous section. 

Follicular thyroid carcinoma is also a tumor of thyroid follicular epithelium exhibiting pure follicular differentiation and lacking the nuclear features charac-... 

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