Intense expression of the b7-2 antigen presentation coactivator is an unfavorable prognostic indicator for differentiated thyroid carcinoma of children and adolescents

Previous observations suggest that an immune response against thyroid carcinoma could be important for long-term survival. We recently found that infiltration of thyroid carcinoma by proliferating lymphocytes is associated with improved disease-free survival, but the factors that control lymphocytic infiltration and proliferation are largely unknown. We hypothesized that the antigen presentation coactivators (B7-1 and B7-2), which are important in other immune-mediated thyroid diseases, might be important in lymphocytic infiltration of thyroid carcinoma. To test this, we determined B7-1 and B7-2 expression by immunohistochemistry [absent (grade 0) to intense (grade 3)] in 27 papillary (PTC) and 8 follicular (FTC) thyroid carcinomas and 9 benign thyroid lesions. B7-1 and B7-2 were expressed by the majority of PTC and FTC (78% of PTC and 100% of FTC expressed B7-1; 88% of PTC and 88% of FTC expressed B7-2). B7-1 expression was more intense in PTC (1.4 +/- 0.2; P = 0.01) and FTC (2.6 +/- 0.2; P < 0.001) than in benign tumors (0.57 +/- 0.30) or presumably normal adjacent thyroid (0.07 +/- 0.07) and was more intense in carcinoma that contained lymphocytes (1.95 +/- 0.21) than in carcinoma that did not (1.08 +/- 0.26; P = 0.016). B7-2 expression was of similar intensity in benign and malignant tumors (PTC, 1.6 +/- 0.2; FTC, 2.1 +/- 0.4; benign, 1.86 +/- 0.4), but was more intense than in presumably normal adjacent thyroid (0.64 +/- 0.25; P 相似文献   

Nitrotyrosine,inducible nitric oxide synthase (iNOS), and endothelial nitric oxide synthase (eNOS) are increased in thyroid tumors from children and adolescents

Nitric oxide (NO) is a reactive cell signal that controls vascular tone and is generated by inducible (iNOS), endothelial (eNOS) and neuronal (nNOS) NO synthase (NOS). We hypothesized that NO could be important for growth of thyroid tumors and tested this hypothesis, by staining 41 papillary thyroid carcinoma (PTC), 9 follicular thyroid carcinoma (FTC), and 15 benign thyroid lesions for iNOS, eNOS and nitrotyrosine (N-TYR). Staining intensity was determined by 2 blinded, independent examiners, and quantified from grade 1 (absent) to grade 4 (intense). Average N-TYR staining of benign adenomas (2.5+/-0.42, p=0.009), PTC (3.10+/-0.12, p=0.001), FTC (2.44+/-0.30, p=0.001), and autoimmune lesions (3.25+/-0.48, p=0.019) were greater than that of multinodular goiter (1.0 for all 3) and surrounding normal thyroid (1.1+/-0.1). Average iNOS staining of benign adenomas (2.6+/-0.37), PTC (2.7+/-0.16), FTC (2.4+/-0.26) and autoimmune lesions (3.5+/-0.29) were all greater than that of surrounding normal thyroid (1.1+/-0.1, p<0.008), but there were too few multinodular goiters to achieve a significant difference (no.=2, 3.0+/-1.0). Average eNOS staining of benign adenomas (2.9+/-0.40), multinodular goiters (3.5+/-0.5), PTC (3.24+/-0.18), FTC (3.5+/-0.50), and autoimmune lesions (2.8+/-0.6) were also greater than that of surrounding normal thyroid (mean=1.4+/-0.2, p<0.001). N-TYR staining correlated with that of vascular endothelial growth factor (VEGF, r=0.36, p=0.007) and the number of lymphocytes/high power field (r=0.39, p=0.004). Recurrent disease developed only from carcinoma with moderate-intense N-TYR staining, but there were too few recurrent tumors to achieve statistical significance (p=0.08). We conclude that NO is produced by benign adenomas, PTC and FTC suggesting that NO could be important in vascularization of thyroid tumors and autoimmune thyroid diseases.     

The expression of vascular endothelial growth factor and the type 1 vascular endothelial growth factor receptor correlate with the size of papillary thyroid carcinoma in children and young adults.

Vascular endothelial growth factor (VEGF) is essential for the growth of many solid tumors, but there are little data regarding VEGH in childhood thyroid cancers. We examined the relationships between VEGF, the type 1 VEGF receptor (FLT-1) and clinical outcome for a group of thyroid cancers in children and young adults. The expression of VEGF and FLT-1 were determined by immunohistochemistry using archival, paraffin-embedded thyroid tissue blocks and compared with the retrospective clinical outcome for each patient. The study included 67 children and young adults with papillary thyroid carcinoma (PTC, n = 42), follicular thyroid carcinoma (FTC, n = 8), benign lesions (n = 15), or controls (n = 2). VEGF expression was greater in PTC (mean intensity 2.23 +/- 0.25, p = 0.002) and FTC (2.8 +/- 0.73, p = 0.01) than benign lesions (1.0 +/- 0.27), and correlated with PTC size (r = 0.42, p = 0.008). FLT-1 expression was greater in PTC (mean intensity 2.8 +/- 0.17) than FTC (1.9 +/- 0.25, p = 0.015) and benign lesions (1.7 +/- 0.32, p = 0.002); and correlated with PTC size (r = 0.41, p = 0.01) as well as VEGF expression (r = 0.52, p = 0.002). Recurrent disease developed exclusively in patients with PTC which expressed VEGF (7/28, 95% CI 10.6%-44.2%). PTC that did not express VEGF (0/8, 95% CI = 0%-31.2%) did not recur; however, the difference was not statistically significant (p = 0.15). We conclude that the expression of VEGF and FLT-1 are directly correlated with the size of PTC in children and young adults.     

Thyroid carcinomas that express telomerase follow a more aggressive clinical course in children and adolescents

With each cell division, DNA is lost from the telomeres, limiting the number of divisions, and leading to senescence. Malignant tumors maintain immortality by expressing a specific DNA repair enzyme, telomerase, that replaces this DNA. We hypothesized that tumors which express telomerase would have the highest recurrence risk and we tested this by determining telomerase expression in 27 papillary thyroid carcinomas (PTC), 5 follicular thyroid carcinomas (FTC) and 13 benign thyroid lesions from children and adolescents. Patients were 6-21 yr of age (mean+/-SE=16.6+/-4.1 yr) and followed from 0-14.1 yr (mean+/-SE=4.71+/-3.5 yr). Original tumors were sectioned, and immunostained for telomerase. Telomerase-specific staining was determined by two independent, blind examiners and graded from absent (Grade 0) to intense (Grade 3). Telomerase was detected in a similar majority of benign (11/13, 85%) and malignant tumors (24/32, 75%). However, the intensity of telomerase expression was greater among FTC (mean+/-SE=2.4+/-0.5 relative intensity) followed by PTC (mean+/-SE=1.9+/-1.0 relative intensity) and benign tumors (mean+/-SE=1.8+/-1.0 relative intensity). Autoimmune lesions had lower telomerase expression (mean+/-SE=1.25+/-0.5 relative intensity) compared to FTC (p=0.01), PTC (p=0.06) and benign lesions (p=0.15). Among PTC, 19 (70%) expressed telomerase, and 8 (30%) did not. Direct invasion (no.=4, 21%), distant metastasis (no.=2, 10%) and recurrence (no.=7, 37%) developed exclusively in PTC that expressed telomerase (p=0.02). Disease-free survival was also shorter for PTC that expressed telomerase (p=0.06). Recurrence developed in 1/2 (50%) FTC that expressed telomerase. We conclude that childhood thyroid cancers which express telomerase have an increased risk of tissue invasion, metastasis, and recurrence.     

Characterisation of DEHAL1 expression in thyroid pathologies

Iodotyrosine dehalogenase 1 (DEHAL1) is a transmembrane protein involved in the recycling of iodide in the human thyroid. The aim of the present study was (I) to investigate whether DEHAL1 expression is different in differentially functioning thyroid pathologies and (II) to evaluate DEHAL1 as a possible marker of thyroid cell differentiation. DESIGN AND METHODS: Real-time PCR for DEHAL1 and its isoform DEHAL1B was performed in a series of 105 thyroid specimens, including toxic thyroid nodules (TTN), Graves' disease (GD) thyroids, benign cold thyroid nodules (CTN), normal thyroid tissues and thyroid cancers (follicular thyroid carcinomas (FTC), papillary thyroid carcinomas (PTC), partially differentiated thyroid cancers (PDTC) and anaplastic thyroid carcinomas (ATC)). In addition, DEHAL1 protein expression was studied by immunohistochemistry in 163 benign and malignant thyroid pathologies and normal thyroids. RESULTS: (I) The highest DEHAL1 mRNA levels were found in GD thyroids, while downregulation of DEHAL1 and DEHAL1B mRNA occurred in PTC and ATC (P<0.001 and <0.05 respectively); (II) DEHAL1 protein was overexpressed in TTNs and GD thyroids with predominant apical staining in all samples; (III) a weaker and patchy staining pattern was found in CTNs and normal thyroids; (IV) in differentiated thyroid cancers (FTC and PTC), a diffuse cytoplasmic DEHAL1 expression was found; and (V) in PDTC and ATC, DEHAL1 expression was faint or absent. CONCLUSION: Upregulation of DEHAL1 protein expression and sublocalisation of DEHAL1 at the apical cell pole in TTNs and GD thyroids is consistent with increased thyroid hormone turnover during thyrotoxicosis. Diffuse cytoplasmatic localisation or downregulation of DEHAL1 expression in thyroid cancers suggests alteration or loss of DEHAL1 function during thyroid cell dedifferentiation.     

Evaluation of insulin-like growth factor II, cyclooxygenase-2, ets-1 and thyroid-specific thyroglobulin mRNA expression in benign and malignant thyroid tumours

OBJECTIVE: We evaluated three markers (insulin-like growth factor II (IGF-II), cyclooxygenase-2 (COX-2) and ets-1) of thyroid growth stimulation and cell transformation together with a thyroid-specific marker (thyroglobulin (Tg)) for their potential to differentiate benign and malignant follicular thyroid neoplasia (FN). DESIGN AND METHODS: mRNA expression levels were determined by real-time PCR in 100 snap-frozen thyroid samples: 36 benign thyroid nodules with different histology and function (19 cold (CTN) and 17 toxic thyroid nodules (TTN)), 36 corresponding normal thyroid tissues of the same patients, eight Graves' disease (GD) thyroids, 10 follicular thyroid carcinomas (FTC) and 10 papillary thyroid carcinomas (PTC). RESULTS: Mean IGF-II and COX-2 levels were not significantly altered between benign and malignant thyroid nodules (IGF-II) or nodular (FTC, TTN, CTN) and normal thyroid tissues (COX-2). In contrast, eight- to tenfold upregulation of ets-1 was observed in PTC and three- to fourfold upregulation of ets-1 was observed in FTC (and GD) compared with benign thyroid nodules and normal thyroid tissues. In addition, thyroglobulin mRNA expression was markedly downregulated (50- to 100-fold) in FTC, PTC and GD samples compared with benign nodular and normal thyroid tissues. Hence an ets-1/Tg ratio >20 distinguished differentiated thyroid cancer from benign nodular or normal thyroid tissue. We then studied ets1- and Tg mRNA expression levels in fine needle aspiration cytology (FNAC) samples. However, in a consecutive series of 40 FNAC samples only equivocal results were obtained on 38 benign and two malignant (FTC) thyroid tumour samples. CONCLUSIONS: Upregulation of ets-1 and downregulation of Tg mRNA expression occur in differentiated thyroid cancer and may facilitate pre-operative identification of thyroid malignancy depending on further evaluation of these potentially promising markers in a larger series of benign and malignant thyroid tumours and their FNAC samples.     

Matrix metalloproteinase (MMP) expression by differentiated thyroid carcinoma of children and adolescents

The factor(s) that control metastasis of thyroid carcinoma are unknown, but the matrix metalloproteinases (MMPs) are excellent candidates. MMP-1, membrane-type-1 MMP (MT1-MMP), and tissue inhibitor of MMP-1 (TIMP-1) have all been implicated, but the site of production and importance are disputed. In vitro, normal thyroid cells secrete TIMP-1, while thyroid cancer cells secrete TIMP-1 and MMP-1. However, previous pathological studies identified MMP-1 and TIMP-1 only in the stroma surrounding thyroid carcinoma. These data suggest that thyroid carcinoma or tumor-associated inflammatory cells might secrete a factor(s) which stimulates MMP-1 or TIMP-1 expression by surrounding tissues. We hypothesized that MMP-1, MT1-MMP, and TIMP-1 would be directly expressed by thyroid carcinoma and might promote invasion or metastasis. We used immunohistochemistry to determine the expression of MMP-1, MT1-MMP, and TIMP-1 in 32 papillary thyroid carcinoma (PTC), 10 follicular thyroid carcinoma (FTC) and 13 benign thyroid lesions from children and adolescents. The intensity of staining was graded from absent (grade 0) to intense (grade 3). Average MMP-1 expression (mean relative intensity units+/-SE) was significantly greater among PTC (1.97+/-0.15; p=0.004) and FTC (2.2+/-0.25; p=0.006) compared to benign lesions (1.30+/-0.15); but there was no relationship between MMP-1 expression and invasion, metastasis, or recurrence. Expression of MT1-MMP and TIMP-1 was similar for benign and malignant lesions; but recurrent PTC expressed lower levels of TIMP-1 when compared to non-recurrent PTC (p=0.049). Only the expression of TIMP-1 correlated with the presence of tumor-associated lymphocytes (r=0.35, p=0.032). We conclude that MMP-1, MT1-MMP and TIMP-1 are all expressed by thyroid carcinoma and could be important in promoting recurrence.     

Thyroid cancers express CD-40 and CD-40 ligand: cancers that express CD-40 ligand may have a greater risk of recurrence in young patients.

The immune response might suppress thyroid cancer recurrence. Although the factors that control this are unknown, CD-40 and CD-40 ligand might be important. To test this, we stained 36 papillary (PTC) and four follicular (FTC) thyroid carcinomas for CD-40 (n = 37) and CD-40 ligand (n = 36) and graded staining from absent (grade 0) to intense (grade 3). Follicular cells of the majority of thyroid tumors expressed CD-40 (30/37, 81%) and CD-40 ligand (15/24, 69%). Cancers from young patients (< or =21 years of age) that expressed CD-40 contained more numerous lymphocytes/high-power field (36 +/- 11) than cancers that failed to express CD-40 (4 +/- 3, p = 0.01), but there was no correlation with clinical outcome. Among young patients, CD-40 ligand expression was more intense in multifocal (1.1 +/- 0.2 vs. 0.45 +/- 0.2, p = 0.037), aggressive (1.14 +/- 0.14 vs. 0.65 +/- 0.2, p = 0.05) and recurrent tumors (1.2 +/- 0.2 vs. 0.65 +/- 0.2, p = 0.05) and associated with reduced disease-free survival (p = 0.03). We conclude that the majority of thyroid cancers express CD-40 and CD-40 ligand. In patients < or =21 years of age, tumors with intense expression of CD-40 ligand are more often multifocal, aggressive, and recurrent.     

Co-expression of interleukin-6 (IL-6) and interleukin-6 receptor (IL-6R) in thyroid nodules is associated with co-expression of CD30 ligand/CD30 receptor

Data on the expression of interleukin 6 (IL-6)/interleukin 6 receptor (IL-6R) in thyroid nodules is scarce. Based on our recent data of CD30 ligand (CD30L)/CD30 receptor (CD30) in these nodules and on the knowledge that this signal stimulates IL-6 production in non-thyroid neoplasms, we wanted to evaluate the immunocytochemical expression of these 2 ligand/receptor systems in a large archival series of paraffin-embedded specimens. These specimens included 6 normal thyroids and 130 thyroid nodules. Co-expression of IL-6 and IL-6R in the epithelial (follicular) cells was observed solely in CD30L/CD30 positive nodules: 5/15 (33%) oncocytic adenomas; 6/30 (20%) follicular adenomas which belonged to 2 variants (4/4 microfollicular toxic and 2/2 hyalinizing trabecular); 9/30 (30%) papillary thyroid cancers (PTC), all belonging to the conventional variant. In PTC the proportion of tumor epithelial cells that were IL6 positive was inversely correlated with the pTNM staging (r=-0.549, p=0.01). All 15 follicular cancers (FTC), all 6 anaplastic cancers (ATC) were IL-6/lL-6R negative; 14/15 FTC and 5/6 ATC were CD30L/CD30 negative. In another oncocytic adenoma, another 4 conventional PTC and another 7 non-conventional PTC CD30L/CD30 expression was associated to expression of IL-6 only. IL-6 staining associated to absent expression of CD30L and CD30 was observed in 7 follicular adenomas (all belonging to variants different from toxic and hyalinizing trabecular), 2 oncocytic adenomas, 5 of the 30 colloid nodules and 2 normal thyroids. Of the 6 tumors arising from the parafollicular C cells (medullary thyroid cancer, MTC), all 3 that had metastasized were CD30L/CD30/IL-6 positive and IL-6R negative; only IL-6 expression was lost in both the local and distant metastases. This finding matched the loss of IL-6 expression in one PTC metastasis. All 3 non-metastasized MTC were IL-6/IL-6R negative, and 1/3 was CD30L positive/CD30 negative. We conclude that only in a subset of both benign and malignant thyroid nodules the IL-6/IL-6R signal could be induced by the CD30L/CD30. IL-6 expression is related with aggressiveness in both PTC and MTC. In the normal thyroid tissue, colloid nodules, and another subset of benign and malignant thyroid nodules, IL-6 expression is under control of signals other than CD30L/CD30.     

Loss of heterozygosity of the long arm of chromosome 7 in follicular and anaplastic thyroid cancer, but not in papillary thyroid cancer.

Papillary thyroid cancer (PTC), but neither the follicular nor the anaplastic histotype [follicular thyroid cancer (FTC), anaplastic thyroid cancer (ATC)], overexpresses simultaneously the protooncogene HGF (hepatocyte growth factor) and its receptor HGF-R (or c-met). Because 1) HGF and c-met map to chromosome 7q21 and 7q31, respectively, 2) FTC loses genetic material at multiple loci with a frequency much higher than PTC, and 3) loss of heterozygosity (LOH) on 7q has been previously found in various tumors, we tested the hypothesis that both FTC and ATC, but not PTC, could harbor LOH in segments of 7q encompassing the loci for HGF and c-met. We screened 6 normal thyroids, 10 colloid nodules, 10 follicular hyperplasias, 10 oncocytic adenomas, 10 follicular adenomas (FA), 10 FTC, 6 ATC, 12 PTC using two microsatellite markers for HGF, and two for c-met. LOH for all 4 markers was found in 100% of FTC, 100% of ATC, and (for only 1 or 2 markers) in 10-29% of FA. This is the first demonstration of an LOH that separates both FTC and ATC from PTC, in the best possible manner: 100% vs. 0%. Clearly, each of the two segments we have probed contains at least one tumor suppressor gene, whose inactivation is crucial for the establishment of the FTC (and ATC) phenotype. This loss of genetic material explains why FTC and ATC, but not PTC, fail to express both HGF and c-met. Our findings may also have immediate diagnostic application, in the context of assisting pathologists in the often difficult task of distinguishing FA from FTC.     

Infiltration of differentiated thyroid carcinoma by proliferating lymphocytes is associated with improved disease-free survival for children and young adults

An immune response directed against thyroid cancer might be important in preventing metastasis and recurrence. This idea is supported by previous observations showing that adults with autoimmune thyroiditis or lymphocytic infiltration surrounding papillary thyroid carcinoma (PTC) have improved disease-free survival. The long-term outcome for differentiated thyroid cancer is even more favorable for children and young adults. If the immune response is important, we hypothesized that tumor-associated lymphocytes with a high proliferation index would be found in thyroid cancers from children and young adults and would be associated with improved disease-free survival. Using immunohistochemistry, we examined 39 childhood PTC, 9 follicular thyroid carcinomas, 2 medullary thyroid carcinomas, 11 benign thyroid lesions, and 2 normal thyroid glands for the presence of lymphocytes (leukocyte common antigen) and lymphocyte proliferation (proliferating cell nuclear antigen, Ki-67). The majority of PTC (65%) and follicular thyroid carcinomas (75%) from children and young adults contained lymphocytes in the immediate vicinity of thyroid cancers, but only 7 (18%) patients with PTC also had a diagnosis of autoimmune thyroiditis. Disease-free survival did not correlate with the presence or number of lymphocytes per high power field. In contrast, disease-free survival was significantly improved (P = 0.01) for thyroid cancers with the greatest number of Ki-67-positive lymphocytes per high power field. The number of lymphocytes per high powered field was greater for multifocal PTC (P: = 0.023), and the number of proliferating lymphocytes was greatest for PTC with regional lymph node involvement (30.5 +/- 12.3 vs. 6.8 +/- 5.0; P = 0.047). We conclude that proliferation of tumor-associated lymphocytes is associated with improved disease-free survival for children and young adults with thyroid cancer.     

Neutralizing monoclonal antibodies to hepatocyte growth factor/scatter factor (HGF/SF) display antitumor activity in animal models

The hepatocyte growth factor (HGF/SF) receptor, Met, regulates mitogenesis, motility, and morphogenesis in a cell type-dependent fashion. Activation of Met via autocrine, paracrine, or mutational mechanisms can lead to tumorigenesis and metastasis and numerous studies have linked inappropriate expression of this ligand-receptor pair to most types of human solid tumors. To prepare mAbs to human HGF/SF, mice were immunized with native and denatured preparations of the ligand. Recloned mAbs were tested in vitro for blocking activity against scattering and branching morphogenesis. Our results show that no single mAb was capable of neutralizing the in vitro activity of HGF/SF, and that the ligand possesses a minimum of three epitopes that must be blocked to prevent Met tyrosine kinase activation. In vivo, the neutralizing mAb combination inhibited s.c. growth in athymic nu/nu mice of tumors dependent on an autocrine Met-HGF/SF loop. Importantly, growth of human glioblastoma multiforme xenografts expressing Met and HGF/SF were markedly reduced in the presence of HGF/SF-neutralizing mAbs. These results suggest interrupting autocrine and/or paracrine Met-HGF/SF signaling in tumors dependent on this pathway is a possible intervention strategy.     

Activation of the hepatocyte growth factor (HGF)-Met system in papillary thyroid cancer: biological effects of HGF in thyroid cancer cells depend on Met expression levels

Met, the receptor for hepatocyte growth factor (HGF), is overexpressed in approximately 90% papillary thyroid carcinomas. To investigate the role of the HGF-Met system in these tumors, we examined HGF and Met expression in a variety of primary cultures, normal or malignant thyroid cells, and tissue specimens and analyzed the different HGF effects (promotion of mitogenesis, branching morphogenesis, and cell motility and invasion). In cancer specimens, HGF was produced at high levels by tumor stromal cells, and Met was constitutively phosphorylated in malignant cells. No HGF production was found in a panel of malignant thyroid cancer cells. Biological effects of HGF were examined in papillary cancer cell cultures with either high or low Met expression. High-Met cells were more sensitive to the growth effect of HGF (ED50 = 3-5 ng/ml and 10-15 ng/ml in high- or low-Met cells, respectively). Moreover, only high-Met cells underwent branching morphogenesis in response to HGF. In contrast, high-Met cells showed a reduced migration. Met down-regulation by small interfering RNAs resulted in enhanced cell migration and abrogation of branching morphogenesis in response to HGF. Conversely, Met overexpression impaired cell migration while favoring branching morphogenesis and cell adherence to substrate. These data suggest that both Met and HGF are overexpressed in papillary thyroid carcinomas, that Met is frequently activated in these carcinomas and may favor tumor growth, and that the abundance of Met expression may differently regulate cell growth, morphogenesis, and migration in response to HGF.     

Expression of PAX8-PPAR gamma 1 rearrangements in both follicular thyroid carcinomas and adenomas

Recently, a translocation t(2;3)(q13;p25), leading to the formation of a chimeric PAX8-peroxisome proliferator-activated receptor (PPAR)gamma 1 oncogene, was detected in follicular thyroid carcinomas (FTC), but not in follicular thyroid adenomas (FTA), papillary thyroid carcinomas (PTC), or multinodular hyperplasias. However, previous cytogenetic studies have identified the t(2;3)(q13;p25) translocation also in some cases of FTA. In this study, we have combined RT-PCR with primers in exons 4-8 of PAX8 and in exon 1 of PPAR gamma 1 with PPAR gamma immunohistochemistry to study PAX8-PPAR gamma 1 oncogene activation in FTC (n = 9), FTA (n = 16), PTC (n = 9), anaplastic thyroid carcinomas (n = 4), and multinodular hyperplasias (n = 2). PAX8-PPAR gamma 1 rearrangements were detected by RT-PCR in 5 of 9 (56%) FTC and in 2 of 16 (13%) FTA. By contrast, all cases of PTC, anaplastic thyroid carcinomas, and multinodular hyperplasia were RT-PCR-negative. Diffuse nuclear immunoreactivity for PPAR gamma was observed in 7 of 9 (78%) FTC, 5 of 16 FTA (31%), and 1 of 9 PTC (11%). Positivity was focal in 3 cases (1 FTC, 1 PTC, and 1 multinodular hyperplasia). Diffuse nuclear staining for PPAR gamma was present in RT-PCR- negative cases of FTC (n = 3), FTA (n = 3), and PTC (n = 1), suggesting that a different PAX8-PPAR gamma 1 breakpoint, a rearrangement between PPAR gamma 1 and a non-PAX8 partner, or overexpression of the native protein might be present. Our findings that PAX8-PPAR gamma 1 rearrangements are present in both follicular carcinomas and adenomas suggest that this oncogene is not a reliable marker to differentiate between FTC and FTA in fine-needle aspiration biopsies of follicular neoplasms of the thyroid.     

RET/PTC rearrangements in thyroid nodules: studies in irradiated and not irradiated, malignant and benign thyroid lesions in children and adults.

Rearrangements of the RET proto-oncogene may occur in both naturally occurring and radiation-induced papillary thyroid carcinomas. Conflicting results on the frequency and type of RET/PTC rearrangements have been reported in relation to age, radiation exposure, and histological tumor variant. We designed the present study to evaluate in a single laboratory, using the same methodologies, the pattern of RET/PTC activation in thyroid tumors from different groups of patients (exposed or not exposed to radiation, children or adults, with benign or malignant tumors) in relationship to the above mentioned variables. We studied 154 patients with benign nodules (n = 65) or papillary thyroid cancer (n = 89). In the last group, 25 were Belarus children exposed to the post-Chernobyl radioactive fallout, 17 were Italian adults exposed to external radiotherapy for benign diseases, and 47 were Italian subjects (25 children and 22 adults) with no history of radiation exposure. Among patients with benign thyroid nodules, 21 were Belarus subjects (18 children and 3 adults) exposed to the post-Chernobyl radioactive fallout, 8 were Italian adults exposed to external radiation on the head and neck, and 36 were Italian adults with naturally occurring benign nodules. The overall frequency of RET/PTC rearrangements in papillary thyroid cancer was 55%. The highest frequency was found in post-Chernobyl children and was significantly higher (P = 0.02) than that found in Italian children not exposed to radiation, but not significantly higher than that found in adults exposed to external radiation. No difference of RET/PTC rearrangements was found between samples from irradiated (external x-ray) or not irradiated adult patients, as well as between children and adults with naturally occurring, not irradiated, thyroid cancer. When analyzing the type of RET/PTC rearrangement (RET/PTC1 or RET/PTC3), no major difference was apparent. In addition, eight cases with an unknown RET/PTC rearrangement and three cases with the concomitant expression of RET/PTC1 and RET/PTC3 were found. No significant correlation was observed between the frequency and/or the type of RET/PTC rearrangement and clinical-epidemiological features of the patients such as age at diagnosis, age at exposure, histological variant, gender and tumor-node-metastasis (TNM) categories. RET/PTC rearrangements were also found in 52.4% of post-Chernobyl benign nodules, in 37.5% of benign nodules exposed to external radiation and in 13.9% of naturally occurring nodules (P = 0.005, between benign post-Chernobyl nodules and naturally occurring nodules). The relative frequency of RET/PTC1 and RET/PTC3 in rearranged benign tumors showed no major difference. In conclusion, our results indicate that the presence of RET/PTC rearrangements in thyroid tumors is not restricted to the malignant phenotype, is not higher in radiation-induced tumors compared with those naturally occurring, is not different after exposure to radioiodine or external radiation, and is not dependent from young age. Other factors, probably influenced by ethnic or genetic background, may act independently from or in cooperation with radiation, to trigger the DNA damage leading to RET proto-oncogene activation.     

Cytoplasmic localization of the paired box gene, Pax-8, is found in pediatric thyroid cancer and may be associated with a greater risk of recurrence.

The paired box-8 protein (Pax-8) has been observed in the nucleus of normal adult thyroids, follicular adenomas, follicular thyroid cancers, and papillary thyroid cancers (PTC) but not undifferentiated thyroid cancers. To our knowledge, Pax-8 has not been studied in pediatric thyroid cancer. Because of the more favorable prognosis for PTC in children compared to young patients, we hypothesized that Pax-8 expression might be different in pediatric thyroid cancers. To test this, we stained 47 thyroid lesions from children and young patients for Pax-8. Pax-8 was located in the cytoplasm (cPAX) or nucleus (nPAX) in the majority of samples. There was no significant difference in nPAX between benign and malignant lesions. However, cPAX was more commonly seen in PTC than autoimmune diseases (p = 0.01) and the intensity of cPAX staining correlated with tumor size (p = 0.041), metastasis, age, completeness of resection, local invasion, and tumor size (MACIS) scores (p = 0.045), and the presence of invasion, metastasis, recurrence, or persistence (p = 0.012). Disease-free survival was significantly reduced for cancers with intense cPAX staining (p = 0.0003). These data show that cPAX is common in PTC, and although limited by small sample size, suggest an association with higher MACIS scores, an aggressive clinical course, and an increased risk of clinically evident recurrence for children and young patients.     

Association of HLA DQ4-DR8 haplotype with papillary thyroid carcinomas

OBJECTIVE: The association of the human leucocyte antigen (HLA) system with thyroid carcinomas is not clear. We sought to relate HLA alleles to susceptibility to papillary thyroid carcinoma (PTC) and also to clinical and pathological characteristics of PTC patients. DESIGN AND PATIENTS: The distribution of HLA in 181 unrelated Caucasian patients with PTC was compared to the HLA distribution in 315 normal controls, 31 patients with follicular carcinoma (FTC), 29 patients with lymphocytic thyroiditis (LT) and 50 patients with multinodular goitre (MNG), using a microlymphocytotoxicity assay. RESULTS: Compared to normal controls, patients with PTC showed a significantly increased frequency of HLA-DQ4 [12.8%vs. 3.5%, P=0.0005, P(corrected) (P(c))=0.0032, odds ratio (OR)=4.058, 95% confidence interval (95% CI)=1.820-9.045] and HLA-DR8 (10.9%vs. 4.3%, P=0.013, P(c) > 0.05, OR=2.752, 95% CI=1.275-5.940). DQ4 and DR8 were also significantly increased in patients with MNG (DQ4, 16.3%; DR8, 16.3%) compared to controls (DQ4, P=0.0019, P(c)=0.011, OR=5.420, 95% CI=1.978-14.852; DR8, P=0.0044, P(c)=0.062). Linkage disequilibrium (LD) for these two alleles was present in controls (D=0.0130, P=9.7e-57) and in MNG patients (D=0.0730, P=4.6e-19) but not in PTC patients (D=0.038, P>0.05). In the subgroup of PTC subjects with concomitant 0thyroidal neoplasias (n=27), there was a significant (P< 0.05) increase in the frequency of B57 (18.5%), DR11 (56.5%) and DQ3 (81.8%) compared to PTC patients without coexistent neoplasias (2.0%, 21% and 47%, respectively). No significant differences of HLA allele distribution was found in relation to PTC histology, age at diagnosis (> 45 or 相似文献