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The aim of the study was to describe the spontaneous TSH level variations and levothyroxine dose adjustments in athyreotic patients with differentiated thyroid cancer (DTC) in real-life practice. Patients with DTC were retrospectively evaluated at a tertiary referral center between October 2006 and November 2013. Hormone measurements (TSH and FT4 serum levels), L-T4 prescription information (dose per kg per day) and other medications were recorded at 1 month and 3, 12, 24, 36 and 48 months after primary treatment (surgery ± radioiodine therapy). The cohort was composed of 452 patients; about 20% of patients with stable levothyroxine dose have clinically meaningful spontaneous TSH variations (defined as ΔTSH > 2 mcUI/mL) at yearly follow-up visit. Furthermore, about 25% of athyreotic DTC patients with stable dose have a ΔTSH > 1.5 mcUI/mL and about 40% a ΔTSH > 1 mcUI/mL during each follow-up visit. We further investigated whether this TSH variation would lead to subsequent dose changes. About 19.9–37.7% of DTC patients on stable LT4 dose on the previous visit had their levothyroxine dose reduced, while 7.8–14.9% increased due to TSH variations. We further evaluated the decision to change the dose in relation with the age-specific TSH range. Up to 77.2% of patients had their dose adjusted due to TSH falling below the age-specific range. Spontaneous serum TSH variations determine levothyroxine replacement therapy in athyreotic patients with DTC, requiring multiple dose changes.

Background: Agents capable of increasing radioiodine concentration by stimulating the sodium/iodide symporter (NIS) expression have been extensively investigated for the treatment of certain well-differentiated breast cancers. Aim: In this study, we analyzed the regulation of the NIS and lactoperoxidase (LPO) gene expression in 4 different human breast cancer cell lines, representative of different histotypes of breast cancer. Methods: MCF-7, T-47D, MDA-MB231, and HCC-1937 (the latter carrying the BRCA-1 mutation) were exposed to different stimulators and the levels of NIS and LPO mRNA measured by a quantitative RT-PCR. Results: AII-trans-Retinoic Acid (RA), Dexamethasone (DEX), Trichostatin A (TSA), and Sodium Butyrate (NaB) induced the expression of NIS mRNA in MCF-7 and T-47D cell lines, whereas HCC-1937 and MBA-MB231 were slightly responsive only to the histone-deacetylase inhibitors TSA and NaB. Minor stimulatory effects were detected on LPO mRNA in MCF-7 and T-47D treated with TSA and NaB or RA only in MCF-7, while no effect was detectable in the other two cell lines. Conclusions: These data indicate that retinoic acid, alone or in combination with DEX, as well as HDAC-inhibitors are very promising agents for a radioiodine-based therapy in a large spectrum of breast cancers, including neoplasms from both basal and ductal cells, especially for the well-differentiated estrogen-dependent tumors. Other molecules or other drug combinations should be tested to extend the same strategy to the less differentiated and more aggressive tumor cells, including those carrying the BRCA mutation.

TSH data from the congenital hypothyroidism screening program were analyzed in a mild to moderate iodine deficiency region. Neonatal TSH levels were measured at day 4-5 of life in 22,384 infants (99% coverage; 51.1% males, 48.9% females). The cut off TSH value for recall was established at 20 microUl/ml whole blood. TSH values20 microUl/ml were excluded from further analysis of the data. The frequency distribution analysis showed that the median neonatal TSH level was 2 microUl/ml and the mode (28% of newborns) corresponded to neonatal TSH values1 microUl/ml. TSH levels above 5 microUl/ml were observed in 14.4% children and the 97% cut off was 11 microUl/ml. When examined in relation to the areas of newborn origin, the individual 97% cut off values varied from 8 to 14 microUl/ml. Accordingly, the frequency of TSH levels above the 97% cut off value calculated for the entire newborn series (11 microUl/ml) ranged from 2.1% to 4.6%. A significant correlation was found between the frequency of neonatal TSH levels11 microUl/ml and both goiter prevalence (r2 = 0.88; p = 0.0019) and median urinary iodine excretion (r2 = 0.86; p = 0.0077) observed in those areas for which epidemiological data were available (n = 7). The results indicate that neonatal TSH data from the congenital hypothyroidism screening programs can be used for monitoring mild to moderate iodine deficiency regions.

For its DNA repair, transcription factor regulation and anti-apoptotic activity, the apurinic/apirimidinic Ape1/Ref-1 endonuclease is thought to play a relevant role in human tumorigenesis. In human thyroid tumors, we demonstrated an altered nuclear/cytoplasmic ratio in all the carcinomas examined but not in follicular adenomas. In this study, Ref-1 expression and cellular localization were analyzed in a series of human thyroid carcinoma cell lines. We found a reduced nuclear/cytoplasmic ratio in BCPAP, TPC1 and ARO cells and not in WRO cells. Such a pattern of expression corresponds to that observed in thyroid tumoral tissues except for the WRO cells which behave as the follicular adenomas rather than carcinomas. Thus, these cell lines represent an excellent in vitro model to analyze the molecular mechanisms involved in Ref-1 regulation and activity and clarify its role in thyroid tumorigenesis.

We studied the cAMP response and radioiodinated TSH binding in the FRTL5 rat thyroid cell line after chronic exposure to TSH. In parallel experiments, continuous exposure to TSH induced both a decrease in the cellular cAMP responsiveness to a second acute stimulation by thyrotropin (desensitization) and a reduction in 125I-TSH cellular binding (down-regulation). These two processes appeared to differ in that: a) cAMP desensitization was maximal (45-55% inhibition in comparison to control cells) after 24 h of preexposure to TSH; on the contrary, a loss of the TSH binding to thyroid cells was detected only after 24 h and was maximal (55-65% lower than control cells) after 48 h of preexposure to TSH; b) a different dependence on the TSH dose was observed for cAMP desensitization and TSH down-regulation: the former was maximal at 10 microU/ml of TSH, the latter only at 10 mU/ml of TSH; c) recovery from cAMP desensitization was detected 3 h after TSH withdrawal and was fully achieved at 24 h, whereas the recovery from the TSH receptor down-regulation was not evident for up to 24 h and a full recovery obtained only at 72 h; d) the use of cAMP analogues proved that, unlike desensitization, TSH receptor down-regulation is a cAMP dependent process. These findings support the concept that different patterns of response to prolonged stimulation with TSH, an earlier and cAMP-independent process (desensitization) and a later cAMP-dependent mechanism (down-regulation), occur in the rat thyroid cell.

Differential protein arrays between nuclear extracts of human thyroid cell lines obtained from tumors with different degree of differentiation were exploited to define molecular alterations occurring during thyroid tumor progression. Nuclear extracts from the well differentiated TPC-1 (from papillary carcinoma) and the poorly differentiated ARO (from anaplastic carcinoma) cells showed an overall similar pattern of protein expression as revealed by two-dimensional gel electrophoresis analysis. However, manganese-superoxide dismutase (Mn-SOD) was clearly identified by mass spectrometry procedures as significantly less expressed in ARO compared to TPC-1 cells. A reduced expression of Mn-SOD in the nuclear compartment was confirmed by Western blot and immunofluorescence analysis. A similar expression pattern of nuclear Mn-SOD was detected by immunohistochemistry in human thyroid tumors, with the lowest or absent detection in anaplastic carcinomas. Moreover, the levels of nuclear Mn-SOD in tumor cells were lower than in the normal thyrocytes. These data indicate that an altered nuclear expression of Mn-SOD parallels, together with changes in other elements of the antioxidant protective system, the loss of differentiation occurring during the progression of thyroid tumors.

The functional role of the sodium iodide symporter (NIS) in extrathyroidal tissues was investigated by examining its mRNA and protein expression, together with the evidence of radioiodine (131)I uptake in 302 patients who underwent (131)I total body scanning, following the administration of high doses of (131)I for a papillary or follicular thyroid carcinoma. By using a real-time kinetic quantitative RT-PCR and immunohistochemistry, the expression of NIS protein was detected mainly in secretory tissues. In parallel, 1311 uptake was evidenced in the majority of patients in the salivary glands (in 39%) and stomach (in 78%), but was found in breast in only 4 young female patients. These data demonstrate a strong correlation between the organ radioactivity distribution, as observed in vivo, and NIS protein expression. Interestingly, (131)I is rarely concentrated by mammary glands, even when large doses are administered. Moreover, a (131)I transfer in secretion fluids may represent a potential source of contamination responsible for false positive images and diagnostic pitfalls.

A case of a patient with an uncommon thyroid carcinoma, showing histological and immunohistochemical features of both follicular and parafollicular cells is described. Somatic point mutation (ATG to ACG heterozygotic mutation at codon 918) of the RET proto-oncogene was detected in tumor tissue, as confirmed by immunohistochemical expression of RET oncoprotein. Our findings suggest that constitutive RET proto-oncogene activation may be involved in the development of mixed medullary-follicular thyroid carcinoma.

We investigated the molecular mechanisms by which TSH, insulin and IGF-1 modulate the glucose transport system in FRTL5 cells. We found that TSH, insulin and IGF-1 increased the glucose transporter Glut-1 specific mRNA levels 6, 8 and 5 fold over control, respectively. The effect on Glut-1 mRNA was evident after 2 hours, followed by an increased Glut-1 protein expression in whole cells, as judged by western blot analysis, after 5 hours of stimulation with all the hormones studied. In contrast, plasma membrane Glut-1 increased (300-400% over control) after 2 hours of stimulation with TSH (10 mU/ml), dibutyryl-cAMP (1mM), IGF-1 (10 ng/ml) and insulin (10 nM). These data indicate that the glucose transport system is under multihormonal control in FRTL5 cells. Two different mechanisms are involved in TSH, IGF-1 and insulin stimulation of the glucose transport: a) neosynthesis of Glut-1 by activation of gene expression; b) recruitment of carriers from the intracellular pool to the plasma membrane.