Cytogenetic and molecular genetic characterization of papillary thyroid carcinomas.

A combined cytogenetic and molecular analysis was performed on 11 cases of papillary thyroid carcinoma. A simple karyotypic abnormality was detected in five tumors, whereas six had no apparent chromosome change. In four of five rearranged cases the presence of a specific chromosomal abnormality involving chromosome 10 (cases 1 and 2) and chromosome 1 (cases 3 and 4) was associated with the rearrangement of two protooncogenes: RET and NTRKI (formerly trk), respectively, with different donor genes. Moreover, the chromosomal localization of the involved genes and the type of chromosomal change observed suggested that RET and NTRKI activation occurred by intrachromosomal rearrangements. The six cases with normal karyotype did not show RET or NTRKI activation. These findings suggest that a combined cytogenetic and molecular approach would be useful in understanding the pathogenesis of thyroid neoplasia.     

The contributions of oestrogen receptor isoforms to the development of papillary and anaplastic thyroid carcinomas

Oestrogen (E2) is known to promote the proliferation of thyroid papillary carcinoma cells (KAT5). However, the molecular mechanism responsible is not well understood. In the study reported herein, the localization of ER alpha (ERalpha) and beta (ERbeta) in KAT5 and anaplastic carcinoma cells (FRO) was studied by immunofluorescence staining and by immunoblotting the proteins in subcellular fractions. Cell proliferation and apoptosis were also determined together with the expression of relevant proteins. The pattern of the subcellular localization of ERalpha and ERbeta differed between papillary and anaplastic cancer. Upon E2 treatment, the level of ERalpha increased in the nuclei of papillary cancer cells but ERbeta remained unchanged. The level of mitochondrial ERbeta surpassed that of ERalpha in anaplastic cancer cells. The different locations of ERalpha and ERbeta in KAT5 and FRO agreed with the finding that E2 promoted the proliferation of KAT5 but inhibited or did not affect that of FRO cells, and with the proposed functions of these two receptors. E2 inhibited the level of Bax in the mitochondria of papillary cancer, followed by a decrease of cytochrome c and/or apoptosis-inducing factor (AIF) release from the mitochondria into the cytosol. However, in anaplastic cancer, E2 promoted the expression of Bax in the mitochondria and the release of cytochrome c and/or AIF from mitochondria into the cytosol. Our results may explain the differences in epidemiology and responses to anti-tumour therapy between papillary and anaplastic cancer in terms of the subcellular localization of ER isoforms. In conclusion, the findings provide evidence to support the observation that E2 is an important factor in the development of thyroid cancer. The subcellular localization of ERalpha and ERbeta may account for the different pathogenesis of thyroid papillary and anaplastic cancers.     

Pathologic features of Hashimoto's-associated papillary thyroid carcinomas

Some investigators have found an increased incidence of papillary carcinoma (PC) of the thyroid in patients with Hashimoto's (autoimmune) thyroiditis (HT), which raises the possibility that there may be more than an incidental association between these 2 diseases. In this study, we analyzed the pathology of Hashimoto's-associated thyroid carcinomas to see if these tumors showed any distinctive features. The possible significance of solid cellular nodules as preneoplastic lesions in patients with HT was investigated. A review of all the cases of HT during a 16-year period yielded 30 PC and 3 follicular carcinomas (FC). Within the PC there were 7 (23%) follicular variants. Twenty (67%) of the PC showed various degree of intratumoral fibrosis, ranging from thick fibrous septa separating tumor nodules to almost complete obliteration of the tumor by the fibrosis, with only microscopic residual tumor nests. In most of the cases, the desmoplastic response within the tumors was of the fibromatosis-like type with dense hyalinized collagen and bland-appearing spindle cells. All the tumors, independently of the degree of fibrosis, showed the nuclear features of PC. No correlation was found between the degree of fibrosis in the tumors and the thyroid gland outside the tumors. There were tumors with marked fibrosis without fibrosis outside the tumors. Four cases of PC (13%) showed a growth pattern characterized by cystic spaces with thick hyalinized walls and focal papillary hyperplasia lined by flat and cuboidal epithelium, reminiscent of a vascular neoplasm. There were 4 atypical solid microscopic nodules with confluent cellularity; 2 of them associated with a PC and the other 2 with diffuse HT without PC. These nodules were composed of cells with clear nuclei and occasional grooves without nuclear pseudoinclusions. By immunohistochemistry, 2 of 3 nodules showed cytoplasmic reactivity for cytokeratin 19, and 2 of 3 nodules were positive for the RET/PTC (rearranged during transfection, papillary thyroid carcinoma) antibody. In summary, HT-associated PC may frequently display prominent stromal desmoplasia and a pseudovascular pattern, both of which can present diagnostic difficulties if the cytologic features of PC are not recognized because of the marked obliteration of the tumor by the fibrosis. Atypical nodules may represent a precursor lesion of PC in patients with HT.     

Loss of heterozygosity in follicular and papillary thyroid carcinomas

In this study we aimed at investigating the incidence and the role of 3p deletions, particularly at the 3p25 approximately pter region, in follicle cell-derived thyroid neoplasms, by using loss of heterozygosity (LOH) analysis. We analyzed 12 follicular adenomas (FA), 13 follicular thyroid carcinomas (FTC), and 15 papillary thyroid carcinomas (PTC) with 11 microsatellite markers for chromosome 3. One additional marker on 3q25.2 was also investigated for assessment of deletion extent on 3q. Microsatellite instability was detected at one locus in 1 of 15 PTC (7%) and at four loci in 1 of 13 FTC (8%). Loss of heterozygosity was found in 8 of 12 cases of FTC (67%), in 6 of 15 cases of PTC (40%), and in 2 of 12 FA (17%). We identified three minimal common deleted regions (CDR) involving significant sites of LOH: two in FTC (a new terminal region, of approximately 8 cM distal to D3S1620 at 3p25.3 approximately pter and the D3S1573-D3S1595 region at 3p21.2 approximately p12) and one in PTC (D3S1304-D3S1263 region at 3p25.3 approximately p24.2). The newly identified 3p25.3 approximately pter CDR seems to be specific for FTC. Our results suggest the existence of at least three distinct regions on 3p that might harbor tumor suppressor genes involved in the carcinogenesis processes of FTC and PTC.     

CA125 and thyroglobulin staining in papillary carcinomas of thyroid and ovarian origin is not completely specific for site of origin

AIMS: A 70-year-old woman presented with metastatic psammoma body-rich papillary carcinoma in a supraclavicular lymph node. No primary site was evident. The tumour showed strong staining for CA125 and weak staining for thyroglobulin. Prompted by this case we aimed to assess the reliability of immunostaining for CA125 and thyroglobulin in making the distinction between thyroid and ovarian papillary carcinoma. METHODS AND RESULTS: Nine papillary carcinomas of the thyroid and 17 serous papillary carcinomas of the ovary were stained for CA125 and thyroglobulin, as well as CAM 5.2, LP 34, carcinoembryonic antigen (CEA), S100 and diastase/periodic acid-Schiff. Nine of nine thyroid carcinomas stained for thyroglobulin; in addition CA125 was positive in four of nine. Normal surrounding thyroid also showed some reaction. Seventeen of 17 ovarian serous carcinomas were positive for CA125; in addition one case showed moderately strong staining for thyroglobulin. Mucin stains were positive in 14/17 ovarian serous carcinomas, but negative in all thyroid carcinomas. The other antibodies assessed showed no useful differences in staining frequency. Conclusion: Many cases of papillary carcinoma of the thyroid show CA125 staining, and this feature therefore has little positive predictive value for an ovarian origin. Occasional cases of ovarian papillary carcinoma may show staining for thyroglobulin, and this result should therefore be interpreted cautiously.     

Evaluation of adult papillary thyroid carcinomas by comparative genomic hybridization and microsatellite instability analysis

To clarify the mechanism of tumorigenesis in papillary thyroid carcinoma (PTC) and ascertain whether genomic changes correlate with histologic features, we conducted a comprehensive molecular evaluation of PTC using comparative genomic hybridization (CGH) and microsatellite instability (MSI) analysis in a set of 17 histologically well-characterized PTC specimens. To our knowledge, this is the first study that evaluates chromosomal and nucleotide instability in the same PTC tumor specimens. Four of 15 samples (27%) had aberrations detected by CGH. All four had a partial or complete gain of chromosome 20, and 3 of 4 had a partial or complete loss of chromosome 13. No MSI was detected in any of the PTC samples (n=16), and all samples examined by immunohistochemistry (n=9) expressed the DNA repair enzymes hmlh1 and hmsh2. All PTC samples with abnormal CGH had vascular invasion or invasion of the thyroid capsule, and there was a significant correlation between the presence of chromosomal aberrations and capsular/vascular invasion (P=0.026). We conclude that although chromosomal and microsatellite instability are uncommon in PTC, tumors with chromosomal aberrations are more likely to be associated with invasion.     

Cytological detection of papillary thyroid carcinomas by nuclear membrane decoration with emerin staining

Decoration of the nuclear membrane by emerin staining enhances detection of nuclear irregularities typical of papillary thyroid carcinoma (PTC). Our study aims to verify whether staining with emerin is a helpful diagnostic marker in fine-needle aspiration (FNA) cytology. We first designed a prospective study on smears, Thin Prep, and cell block specimens to prove the feasibility of the procedure; subsequently, we designed a retrospective study of 78 FNA cell blocks from cases that, after surgery, turned out to be either benign (34 cases) or malignant lesions (44, of which 31 PTC). From each sample, we obtained two slides, one stained with hematoxylin and eosin (H&E) and the other with emerin. In cases classified as Thy3, HBME-1 and galectin 3 (Gal3) stains had also been performed. Two blinded observers made the judgment concerning Thy categories (as proposed by the British Thyroid Association), first on H&E, then on emerin, HBME-1, and Gal3 stained slides. On cytological preparation, emerin staining represents an effective tool for the detection of nuclear irregularities, allowing for the identification of cases of PTC. In Thy3 cases, emerin staining's sensitivity and specificity (64% and 96%) proved higher than HBME-1's (60% and 88%) and Gal3's (61% and 68%). In conclusion, the immunohistochemical definition of the nuclear membrane, as determined by emerin stain, is a useful tool in the cytological diagnosis of thyroid lesions and can help to solve inconclusive cases by highlighting nuclear irregularities typical of PTC.     

Immunophenotypic and genomic characterization of papillary carcinomas of the breast

Papillary carcinomas are a special histological type of breast cancer and have a relatively good outcome. We characterized the genomic and phenotypic characteristics of papillary carcinomas to determine whether they would constitute an entity distinct from grade- and oestrogen receptor (ER)-matched invasive ductal carcinomas of no special type (IDC-NSTs). The phenotype of 63 papillary carcinomas of the breast and grade- and ER-matched IDC-NSTs was determined by immunohistochemistry. DNA of sufficient quality was extracted from 49 microdissected papillary carcinomas and 49 microdissected grade- and ER-matched IDC-NSTs. These samples were subjected to high-resolution microarray-based comparative genomic hybridization (aCGH) and Sequenom MassARRAY sequencing analysis of 19 known oncogenes. Papillary carcinomas were predominantly of low histological grade, expressed immunohistochemical markers consistent with a luminal phenotype, and a lower rate of lymph node metastasis and p53 expression than grade- and ER-matched IDC-NSTs. Papillary carcinomas displayed less genomic aberrations than grade- and ER-matched IDC-NSTs; however, the patterns of gene copy number aberrations found in papillary carcinomas were similar to those of ER- and grade-matched IDC-NSTs, including 16q losses. Furthermore, PIK3CA mutations were found in 43% and 29% of papillary carcinomas and grade- and ER-matched IDC-NSTs, respectively. The genomic profiles of encapsulated, solid and invasive papillary carcinomas, the three morphological subtypes, were remarkably similar. Our results demonstrate that papillary carcinomas are a homogeneous special histological type of breast cancer. The similarities in the genomic profiles of papillary carcinomas and grade- and ER-matched IDC-NSTs suggest that papillary carcinomas may be best positioned as part of the spectrum of ER-positive breast cancers, rather than as a distinct entity. Furthermore, the good prognosis of papillary carcinomas may stem from the low rates of lymph node metastasis and p53 expression, low number of gene copy number aberrations and high prevalence of PIK3CA mutations.     

BRAF mutation and AKAP9 expression in sporadic papillary thyroid carcinomas

AIM: We aimed to determine the BRAF mutation and AKAP9 expression in papillary thyroid carcinomas (PTCs). METHODS AND RESULTS: In this study, we analysed 100 sporadic PTC specimens and we detected mutation in 62.2% of the conventional type PTCs (51/82), in 50% of the follicular variant type PTCs (3/6), in 50% of the diffuse sclerosing variant type PTCs (1/2), and in 30% of the microcarcinomas (3/10). All mutations involved a T-->A transversion at the nucleotide 1796. The cases with BRAF mutation were significantly associated with extrathyroidal extension. We also evaluated the expression of AKAP9 protein by immunohistochemistry. The AKAP9 protein was seen as a single perinuclear dot in all the PTCs. Therefore, 58% of the specimens harboured the BRAF mutation and no case had AKAP9-BRAF fusion in the sporadic PTCs. CONCLUSION: Our results suggest that the BRAF mutation can be a useful diagnostic and prognostic marker and a target for exploring novel cancer therapies to treat PTCs. AKAP9-BRAF fusion may be a very rare event in sporadic PTCs.     

Expression of keratin 19 distinguishes papillary thyroid carcinoma from follicular carcinomas and follicular thyroid adenoma

Keratin expression with the use of chain-specific monoclonal antikeratin antibodies was investigated in normal thyroid tissue (n = 4), colloid nodules (n = 19), follicular thyroid adenomas (n = 18), follicular carcinomas (n = 10), and papillary carcinomas (n = 12). Frozen sections were stained with monoclonal antibodies M20 (keratin 8), M9 (keratin 18), and LP2K (keratin 19) with the use of the indirect immunoperoxidase technique. The immunohistochemical findings showed that the expression of keratins 8 and 18 was equally extensive in all normal, benign, and malignant lesions tested. In contrast, different staining patterns were observed with the use of monoclonal antibody to keratin 19. Follicular carcinomas were only focally stained with this antibody or were not reactive at all. Keratin 19, however, was present in all the tumor cells of papillary tissues and in a moderate amount of cells of nonneoplastic thyroid lesions and follicular adenomas. In papillary carcinoma, an identical homogeneous expression of keratin 19 was observed in both papillary and follicular structures, which suggests a common cellular origin. These results show that immunohistochemical staining with the use of monoclonal antibody against keratin 19 is useful to distinguish papillary thyroid carcinomas from follicular adenomas and follicular thyroid carcinomas.     

Follicular,papillary, and "hybrid" carcinomas of the thyroid

The existence of well-differentiated thyroid tumors sharing the clinicopathologic features of follicular and papillary carcinoma is discussed using the so-called diffuse (multinodular) form of the follicular variant of papillary carcinoma as a paradigm. Although the concept of a “hybrid carcinoma” of the thyroid is intellectuall very appealing, we conclude that there is not (yet) enough reliable genotypic or phenotypic evidence to support utilization of such a term.     

甲状腺乳头状癌中EphA7和ANXA1的表达及其意义

目的探讨受体酪氨酸激酶A7(Ephrin A7,Eph A7)和重组人膜联蛋白A1(Annexin A1,ANXA1)在甲状腺乳头状癌(papillary thyroid carcinoma,PTC)中的表达及其相关性。方法应用免疫组化En Vision两步法检测65例PTC、19例结节性甲状腺肿、19例癌旁甲状腺组织中Eph A7和ANXA1蛋白的表达,并分析二者与PTC临床病理特征的关系。结果 Eph A7和ANXA1在PTC组中的阳性率(64.6%、61.5%)高于结节性甲状腺肿组(26.3%、21.1%)以及癌旁甲状腺组(31.6%、26.3%,P均0.05)。Eph A7蛋白和ANXA1蛋白在PTC伴淋巴结转移组中的表达高于不伴淋巴结转移组(P0.05)。PTC组中ANXA1蛋白表达与患者淋巴结转移和临床分期相关(P均0.05),ANXA1蛋白与患者性别、年龄、部位、肿瘤大小、TG-Ab值和TPO-Ab值无关(P均0.05)。Eph A7蛋白表达与PTC淋巴结转移、临床分期、TG-Ab值和TPO-Ab值相关,与患者性别、年龄、肿瘤大小和部位无关(P均0.05)。Eph A7与ANXA1表达呈正相关(P0.01)。结论 Eph A7与ANXA1可能参与PTC的发生、发展,促进肿瘤淋巴结转移。     

Cytogenetic analyses of three papillary carcinomas and a follicular adenoma of the thyroid

Cytogenetic data of three papillary carcinomas and a follicular adenoma using direct preparations or cell cultures or both after 7 to 60 days in vitro are presented. Although karyotype of the follicular adenoma proved completely normal, in each of the three papillary carcinomas a modal chromosome number in the diploid range and a deleted 11q were observed. In case 1 the del(11)(q23) was associated with rearrangement of chromosome 1 and other marker chromosomes. Our results suggest that 11q deletion may be specific for papillary carcinoma of the thyroid.     

Twist基因蛋白表达在甲状腺乳头状癌诊断与鉴别诊断中的意义

目的探讨Twist基因蛋白在甲状腺乳头状癌中的表达状况,寻找更特异的标记物,用于甲状腺乳头状癌（PTC）与滤泡状腺瘤（FA）和良性乳头病变（BPL）的鉴别诊断。方法以50例PTC为研究组,以48例FA和47例BPL作对照组。在自制组织芯片上行免疫组织化学（SP法）标记,检测Twist基因蛋白和HBME-1,并以CK19进行对照。结果3种指标（Twist、HBME-1、CK19）阳性表达率：在PTC组分别为100％（48／48）、94．0％（47／50）和78．0％（39／50）;在FA组分别为0、6．7％（3／45）和0;在BPL组分别为7．0％（3／43）、2．1％（1／47）和0。PTC组分别与FA和BPL组比较差异均有统计学意义（P=0．000）。3种指标在鉴别诊断甲状腺良、恶性病变的灵敏度分别为：100％、96．4％和97．7％,特异度分别为：94．0％、95．7％和95．1％,准确度分别为：78．0％、100％和91．9％。结论Twist可应用于辅助诊断PTC,并可应用在对FA或BPL的鉴别诊断。     

Prevalence of RET/PTC rearrangements in Hashimoto's thyroiditis and papillary thyroid carcinomas

The relationship between Hashimoto's thyroiditis (HT) and follicular cell-derived thyroid cancer remains unclear. Recently, 2 studies reported a 95% prevalence of RET/PTC rearrangements in histologically benign tissue affected by HT, suggesting that multiple occult tumors exist in HT patients with high frequency. We tested the prevalence of RET/PTC rearrangements in 26 HT, in 6 papillary carcinomas arising in the background of HT, and in 27 papillary carcinomas not associated with HT. We detected no RET/PTC rearrangements in HT or papillary carcinomas arising in the background of HT, in contrast to a 33% prevalence among papillary carcinomas not associated with HT. However, the expression of wild-type RET was found in more than half of papillary carcinomas. These results suggest that, if the association between HT and thyroid cancer exists, its molecular basis is different from RET/PTC rearrangement.     

Expression of the sodium iodide symporter and thyroglobulin genes are reduced in papillary thyroid cancer.

Altered expression of the gene encoding the sodium iodine symporter (NIS) may be an important factor that leads to the reduced iodine accumulation characteristic of most benign and malignant thyroid nodules. Both up- and down-regulation of NIS gene expression have been reported in thyroid cancer using several different methods. The goal of the present study was to accurately identify alterations in NIS gene expression in benign and malignant thyroid nodules using an accurate real-time quantitative RT-PCR assay system. Total RNA was prepared from 18 benign thyroid nodules, 20 papillary thyroid cancers, and 23 normal thyroid samples from 38 subjects. Quantitative RT-PCR was used to measure NIS and thyroglobulin (TG) mRNA expression in normal thyroid tissue and in each nodular tissue sample. Papillary thyroid cancer samples had significantly lower NIS mRNA expression (72 +/- 41 picogram equivalents [pg Eq]), than did benign nodules (829 +/- 385 pg Eq), or normal tissues (1907 +/- 868 pg Eq, P = 0.04). Most important, in the paired samples, NIS gene expression was decreased in each papillary thyroid cancer compared with normal tissue (69% median decrease; range, 40-96%; P = .013). Eleven of the 12 benign nodules also demonstrated lower NIS gene expression than the normal tissue (49% decrease; range, 2-96%; P = .04). Analysis of the paired samples demonstrated that Tg mRNA expression was significantly lower in each of the thyroid cancer samples than in corresponding normal tissue (759 +/- 245 pg Eq vs. 1854 +/- 542 pg Eq, P = .03). We have demonstrated a significant decrement in NIS gene expression in all papillary thyroid cancers and in over 90% of benign nodules examined compared with adjacent normal thyroid tissue, using a highly accurate quantitative RT-PCR technique. Similarly, thyroid cancers demonstrated significantly lower TG mRNA expression than corresponding normal thyroid. Reduced NIS expression may be an important factor in the impairment of iodine-concentrating ability of neoplastic thyroid tissues.