MicroRNA miR-371a-3p - A Novel Serum Biomarker of Testicular Germ Cell Tumors: Evidence for Specificity from Measurements in Testicular Vein Blood and in Neoplastic Hydrocele Fluid.

BACKGROUND: microRNAs (miRs)-371-3 are suggested to be novel biomarkers of germ cell tumors (GCTs), but their specificity is unresolved. We aimed at clarifying the origin of miR 371a-3p by measuring this miR in peripheral vein blood, and in fluids present in the vicinity of GCTs. METHODS: miR-371a-3p levels were measured by quantitative PCR in 9 tumor surrounding hydroceles and in cubital vein blood (CVB) and testicular vein blood (TVB) of 64 GCT patients, 51 with clinical stage (CS) 1, 13 with CS2-3. Thirty three CS1 cases had also postoperative CVB measurement. TVB miR levels were compared with those of CVB. Associations with clinical factors were analyzed statistically. RESULTS: TVB miR levels were 294-fold, 80-fold and 4.6-fold higher than those in CVB of CS1 patients, CS2-3 patients and controls, respectively. Neoplastic hydrocele fluid comprised of very high miR levels. In CS1, miR levels dropped to normal postoperatively. Statistically, CVB miR levels are significantly associated with tumor size (p = 0.0211) and testis length (p = 0.0493). TVB miR levels are associated with testis length (p = 0.0129). CONCLUSIONS: This study provides evidence for the origin of circulating miR 371a-3p molecules from GCT cells. miR-371a-3p represents a specific serum biomarker for germ cell cancer.

Pretreatment oral hygiene habits and survival of head and neck squamous cell carcinoma (HNSCC) patients.

BACKGROUND: The survival time of patients with head and neck squamous cell carcinoma (HNSCC) is related to health behavior, such as tobacco smoking and alcohol consumption. Poor oral health (OH), dental care (DC) and the frequent use of mouthwash have been shown to represent independent risk factors for head and neck cancerogenesis, but their impact on the survival of HNSCC patients has not been systematically investigated. METHODS: Two hundred seventy-six incident HNSCC cases recruited for the ARCAGE study were followed through a period of 6-10 years. Interview-based information on wearing of dentures, gum bleeding, teeth brushing, use of floss and dentist visits were grouped into weighted composite scores, i.e. oral health (OH) and dental care (DH). Use of mouthwash was assessed as frequency per day. Also obtained were other types of health behavior, such as smoking, alcohol drinking and diet, appreciated as both confounding and study variables. Endpoints were progression-free survival, overall survival and tumor-specific survival. Prognostic values were estimated using Kaplan-Meier analysis and Cox proportional hazards regression models. RESULTS: A good dental care score, summarizing annual dental visits, daily teeth cleaning and use of floss was associated with longer overall survival time (p = .001). The results of the Cox regression models similarly suggested a higher risk of tumor progression and shortened overall survival in patients with poor dental care, but the results lost their statistical significance after other types of health behavior had been controlled for. Frequent use of mouthwash (≥ 2 times/day) significantly increased the risk of tumor-specific death (HR = 2.26; CI = 1.19-4.32). Alcohol consumption and tobacco smoking were dose-dependently associated with tumor progression and shorter overall survival. CONCLUSION: Frequent mouthwash use of ≥ 2 times/day seems to elevate the risk of tumor-specific death in HNSCC patients. Good dental care scores are associated with longer overall survival.

Cell cultures in uterine leiomyomas: rapid disappearance of cells carrying MED12 mutations.

Uterine leiomyomas (UL) are the most frequent symptomatic human tumors. Nevertheless, their molecular pathogenesis is not yet fully understood. To learn more about the biology of these common neoplasms and their response to treatment, cell cultures derived from UL are a frequently used model system, but until recently appropriate genetic markers confirming their origin from the tumor cell population were lacking for most UL, i.e., those not displaying karyotypic abnormalities. The identification of MED12 mutations in the majority of UL makes it possible to trace the tumor cell population during in vitro passaging in the absence of cytogenetic abnormalities. The present study is addressing the in vitro survival of cells carrying MED12 mutations and its association with karyotypic alterations. The results challenge numerous in vitro studies into the biology and behavior of leiomyomas. Cells of one genetic subtype of UL, i.e., those with rearrangements of the high mobility AT-hook 2 protein gene (HMGA2), seem to be able to proliferate in vitro for many passages whereas tumor cells from the much more frequent MED12-mutated lesions barely survive even the first passages. Apparently, for the most frequent type of human UL no good in vitro model seems to exist because cells do not survive culturing. On the other hand, this inability may point to an Achilles' heel of this type of UL.

The CD24hi smooth muscle subpopulation is the predominant fraction in uterine fibroids.

Uterine fibroids are the most common gynecological tumors affecting women in their reproductive age. Despite this high incidence the pathogenesis of fibroids is widely unsolved. Whereas formerly only imbalances in hormonal levels were considered to account for tumor development, the identification of genetic changes likely to affect myometrial stem cell reservoirs provided a novel approach to fibroid genesis. Here, we identified a certain subset of cells by the surface marker CD24 with increased abundance in fibroids compared with myometrial tissue. Fibroid cells expressing CD24 shared certain features of immature or progenitor-like cells such as quiescence, reduced expression of smooth muscle differentiation markers and elevated expression of genes involved in the wingless-type (WNT)-pathway such as beta-catenin. In addition, a positive correlation between CD24 and wingless-type family member 4 (WNT4) expression was observed in uterine fibroids with mediator subcomplex 12 gene (MED12) mutations. Our findings suggest that cells highly expressing CD24 represent a type of immature smooth muscle progenitor cells. Their accumulation might be driven by disturbed differentiation processes caused by genetic changes possibly involving MED12 mutations or high mobility group AT-hook (HMGA)2 rearrangements.

Uterine fibroids: do we deal with more than one disease?

Uterine fibroids rank among the most frequent symptomatic human tumors at all. Recent data suggest that mutations of the mediator subcomplex 12 gene (MED12) and rearrangements of the gene-encoding high-mobility group protein AT-hook 2 (HMGA2) characterize major genetic subtypes of these tumors, which, for example, differ by their average size. Herein, we have investigated a total of 289 fibroids from 120 patients. Of these fibroids, 256 were fully genetically analyzed. Of the latter group, 20 (7.8%) fibroids had a chromosomal rearrangement of 12q14-15 reflecting a rearranged allele of HMGA2 and 179 (69.9%) fibroids had a mutation of MED12. The remaining tumors had either another genetic abnormality or no detectable abnormality at all. We were able to demonstrate that tumors of both groups also display striking differences of their frequency in individual patients. Whereas 70.0% (14/20) HMGA2-mutated fibroids made their appearance as solitary nodules, 85.5% (153/179) MED12-mutated fibroids occurred as multiple nodules as a rule of independent clonal origin, as reflected by different MED12 mutations. These findings are likely to point to a different pathogenesis of both types of fibroids. In the predominant of these groups so far, an unknown "mutator" may cause independent mutations of MED12, resulting in an independent clonal outgrowth of nodules. Furthermore, the low but existing risk of MED12-mutated fibroids to undergo malignant transformation after a leiomyoma-STUMP (smooth muscle tumors of uncertain malignant potential)-leiomyosarcoma sequence excludes the latter mutation as a suitable stand-alone marker for benign growth.

MED12 mutations occurring in benign and malignant mammalian smooth muscle tumors.

Mutations of the mediator subcomplex 12 gene (MED12) recently have been described in a large group of uterine leiomyomas (UL) but only in a single malignant uterine smooth muscle tumor. To further address the occurrence of fibroid-type MED12 mutations in smooth muscle tumors, we have analyzed samples from 34 leiomyosarcomas (LMS), 21 UL, two extrauterine leiomyomas (EL), and 10 canine genital leiomyomas for the presence of MED12 mutations of the UL-type. Interestingly, besides UL MED12 mutations were found in one uterine LMS, one EL, and two canine vaginal leiomyomas. The results confirm the occurrence of fibroid-type MED12 mutations in malignant uterine smooth muscle tumors thus suggesting a rare but existing leiomyoma-LMS sequence. In addition, for the first time MED12 mutations are reported in smooth muscle tumors in a non-primate mammalian species.

The dark side of a success story: microRNAs of the C19MC cluster in human tumours.

MicroRNAs are a class of macromolecules of rapidly emerging significance for the pathogenesis of numerous human diseases, including cancer. Moreover, many of them hold great promise as valid biomarkers because of their high extracellular stability. Chromosome 19 harbours the largest cluster of microRNA genes known so far, which has developed in a very short time during mammalian evolution. Thus, in terms of evolution, gain of this cluster is an apparent success story. Nevertheless, we know very little about how functions of its microRNAs have contributed to this success and apparently, at least some of them can turn from Jekyll into Hyde and contribute to tumourigenesis. Recent work published in the Journal of Pathology by Fornari and colleagues, addressed here, reveals how members of that cluster are involved in the molecular pathogenesis of hepatocellular carcinomas.

Detection of PAX8-PPARG fusion transcripts in archival thyroid carcinoma samples by conventional RT-PCR.

The t(2;3)(q13;p25) occurs in a subgroup of follicular-patterned thyroid tumors and leads to a fusion of the genes encoding for the thyroid-specific transcription factor paired box 8 (PAX8) and the peroxisome proliferator-activated receptor gamma (PPARγ). Although initially discovered in follicular carcinomas (FTC), the fusion transcripts were also detected in a small fraction of follicular adenomas and rarely in follicular variants of papillary carcinomas (FV-PTC). In most RT-PCR based studies, fresh or snap-frozen tissue samples were used. The aim of the present study was to develop a method for the detection of chimeric PAX8-PPARG transcripts in formalin-fixed paraffin-embedded (FFPE) thyroid tumor samples by conventional RT-PCR. For this purpose, RNA from FFPE samples of 21 FTC, seven FV-PTC, and one bone metastasis derived from an FTC was subjected to RT-PCR with subsequent gel electrophoretic separation of the products. Fusion transcripts were detected in 2/21 primary FTC (9.5%) and in the bone metastasis, but they were undetectable in all seven FV-PTC under investigation. The RT-PCR approach described herein allows to detect all known variants of PAX8-PPARG fusion transcripts and is applicable to FFPE tissues. Thus, it can be used to screen archival thyroid tumor samples for the gene fusion.

MED12 mutations in uterine fibroids--their relationship to cytogenetic subgroups.

Recurrent chromosomal alterations are found in roughly 20% of all uterine fibroids but in the majority cytogenetic changes are lacking. Recently, mutations of the gene mediator subcomplex 12 (MED12) have been detected in a majority of fibroids but no information is available whether or not they co-occur with cytogenetic subtypes as, e.g., rearrangements of the genes encoding high mobility group AT-hook (HMGA) proteins. In a total of 80 cytogenetically characterized fibroids from 50 patients, we were not only able to confirm the frequent occurrence of MED12 mutations but also to stratify two mutually exclusive pathways of leiomyomagenesis with either rearrangements of HMGA2 reflected by clonal chromosome abnormalities affecting 12q14~15 or by mutations affecting exon 2 of MED12. On average the latter mutations were associated with a significantly smaller tumor size. However, G>A transitions of nucleotides c.130 or c.131 correlate with a significantly larger size of the fibroids compared to other MED12 mutations thus explaining the high prevalence of the former mutations among clinically detectable fibroids. Interestingly, fibroids with MED12 mutations expressed significantly higher levels of the gene encoding wingless-type MMTV integration site family, member 4 (WNT4). Based on these findings and data from the literature, we hypothesize that estrogen and the mutated MED12 cooperate in activating the Wnt pathway which in turn activates ß-catenin known to cause leiomyoma-like lesions in a mouse model. The occurrence of a "fibroid-type mutation" in a rare histologic subtype of endometrial polyps suggests that this mechanism is not confined to uterine leiomyomas.

Abundant expression and hemimethylation of C19MC in cell cultures from placenta-derived stromal cells.

MicroRNAs of the chromosome 19 microRNA cluster (C19MC) are known to be abundantly expressed in the placenta. Their genes are located on the long arm of chromosome 19 and seem to be part of a large imprinted region. Although the data available so far suggest important functions in the placenta, no data are available on their general expression patterns in cultures of placenta-derived mesenchymal stromal cells (PDMSC). Surprisingly, qRT-PCR on tissue cultures from first-trimester and term placenta mesenchymal stromal cells showed an abundant expression of the cluster members miR-517a-3p, miR-519a-3p, and miR-520c-3p. Accordingly, analyses of methylation patterns suggested that these cells had escaped methylation and epigenetic silencing, respectively, of the paternal allele. This was confirmed by the results of treatment of chorionic villous stromal cells by the demethylating agent 5-Aza-2'-deoxycytidine. Our results offer clear evidence that, in contrast to what is suggested in previous papers, members of C19MC are highly expressed in PDMSC indicating that their placenta-specific functions are not restricted to the trophoblast.

TNF-α induced secretion of HMGB1 from non-immune canine mammary epithelial cells (MTH53A).

BACKGROUND: Mammary neoplasias are one of the most frequent and spontaneously occurring malignancies in dogs and humans. Due to the similar anatomy of the mammary gland in both species, the dog has become an important animal model for this cancer entity. In human breast carcinomas, the overexpression of a protein named high-mobility group box 1 (HMGB1) was reported. Cells of the immune system were described to release HMGB1 actively exerting cytokine function. Thereby it is involved in the immune system activation, tissue repair, and cell migration. Passive release of HMGB1 by necrotic cells at sites of tissue damage or in necrotic hypoxic regions of tumors induces cellular responses e.g. release of proinflammatory cytokines leading to elevated inflammatory response and neo-vascularization of necrotic tumor areas. Herein we investigated if a time-dependent stimulation with the separately applied proinflammatory cytokines TNF-α and IFN-γ can cause secretion of HMGB1 in a non-immune related HMGB1-non-secreting epithelial canine mammary cell line (MTH53A) derived from non-neoplastic tissue. METHODS: The canine cell line was transfected with recombinant HMGB1 bicistronic expression vectors and stimulated after transfection with the respective cytokine independently for 6, 24 and 48 h. HMGB1 protein detection was performed by Western blot analysis and quantified a by enzyme-linked immunosorbent assay. Live cell laser scanning multiphoton microscopy of MTH53A cells expressing a HMGB1-GFP fusion protein was performed in order to examine, if secretion of HMGB1 under cytokine stimulating conditions is also visible by fluorescence imaging. RESULTS: The observed HMGB1 release kinetics showed a clearly time-dependent manner with a peak release 24h after TNF-α stimulation, while stimulation with IFN-γ had only small effects on the HMGB1 release. Multiphoton HMGB1 live cell microscopy showed diffuse cell membrane structure changes 29 h after cytokine-stimulation but no clear secretion of HMGB1-GFP after TNF-α stimulation was visible. CONCLUSION: Our results demonstrate that non-immune HMGB1-non-secreting cells of epithelial origin derived from mammary non-neoplastic tissue can be induced to release HMGB1 by single cytokine application. This indicates that tumor and surrounding tissue can be stimulated by tumor present inflammatory and necrotic cytokines to release HMGB1 acting as neo-vascularizing factor thus promoting tumor growth.

Longitudinal MRI contrast enhanced monitoring of early tumour development with manganese chloride (MnCl2) and superparamagnetic iron oxide nanoparticles (SPIOs) in a CT1258 based in vivo model of prostate cancer.

BACKGROUND: Cell lines represent a key tool in cancer research allowing the generation of neoplasias which resemble initial tumours in in-vivo animal models. The characterisation of early tumour development is of major interest in order to evaluate the efficacy of therapeutic agents. Magnetic resonance imaging (MRI) based in-vivo characterisation allows visualisation and characterisation of tumour development in early stages prior to manual palpation. Contrast agents for MRI such as superparamagnetic iron oxide nanoparticles (SPIOs) and manganese chloride (MnCl2) represent powerful tools for the in-vivo characterisation of early stage tumours. In this experimental study, we labelled prostate cancer cells with MnCl2 or SPIOs in vitro and used 1 T MRI for tracing labelled cells in-vitro and 7 T MRI for tracking in an in-vivo animal model. METHODS: Labelling of prostate cancer cells CT1258 was established in-vitro with MnCl2 and SPIOs. In-vitro detection of labelled cells in an agar phantom was carried out through 1 T MRI while in-vivo detection was performed using 7 T MRI after subcutaneous (s.c.) injection of labelled cells into NOD-Scid mice (n = 20). The animals were scanned in regular intervals until euthanization. The respective tumour volumes were analysed and corresponding tumour masses were subjected to histologic examination. RESULTS: MnCl2in-vitro labelling resulted in no significant metabolic effects on proliferation and cell vitality. In-vitro detection-limit accounted 105 cells for MnCl2 as well as for SPIOs labelling. In-vivo 7 T MRI scans allowed detection of 103 and 104 cells. In-vivo MnCl2 labelled cells were detectable from days 4-16 while SPIO labelling allowed detection until 4 days after s.c. injection. MnCl2 labelled cells were highly tumourigenic in NOD-Scid mice and the tumour volume development was characterised in a time dependent manner. The amount of injected cells correlated with tumour size development and disease progression. Histological analysis of the induced tumour masses demonstrated characteristic morphologies of prostate adenocarcinoma. CONCLUSIONS: To the best of our knowledge, this is the first study reporting direct in-vitro MnCl2 labelling and 7 T based in-vivo MRI tracing of cancer cells in a model of prostate cancer. MnCl2 labelling was found to be suitable for in-vivo tracing allowing long detection periods. The labelled cells kept their highly tumourigenic potential in-vivo. Tumour volume development was visualised prior to manual palpation allowing tumour characterisation in early stages of the disease.

Fibroid explants reveal a higher sensitivity against MDM2-inhibitor nutlin-3 than matching myometrium.

BACKGROUND: Spontaneous cessation of growth is a frequent finding in uterine fibroids. Increasing evidence suggests an important role of cellular senescence in this growth control. Deciphering the underlying mechanisms of growth control that can be expected not only to shed light on the biology of the tumors but also to identify novel therapeutic targets. METHODS: We have analyzed uterine leiomyomas and matching normal tissue for the expression of p14Arf and used explants to see if reducing the MDM2 activity using the small-molecule inhibitor nutlin-3 can induce p53 and activate genes involved in senescence and/or apoptosis. For these studies quantitative real-time RT-PCR, Western blots, and immunohistochemistry were used. Statistical analyses were performed using the student's t test. RESULTS: An in depth analysis of 52 fibroids along with matching myometrium from 31 patients revealed in almost all cases a higher expression of p14Arf in the tumors than in the matching normal tissue. In tissue explants, treatment with the MDM2 inhibitor nutlin-3 induced apoptosis as well as senescence as revealed by a dose-dependent increase of the expression of BAX as well as of p21, respectively. Simultaneously, the expression of the proliferation marker Ki-67 drastically decreased. Western-blot analysis identified an increase of the p53 level as the most likely reason for the increased activity of its downstream markers BAX and p21. Because as a rule fibroids express much higher levels of p14Arf, a major negative regulator of MDM2, than matching myometrium it was then analyzed if fibroids are more sensitive against nutlin-3 treatment than matching myometrium. We were able to show that in most fibroids analyzed a higher sensibility than that of matching myometrium was noted with a corresponding increase of the p53 immunopositivity of the fibroid samples compared to those from myometrium. CONCLUSIONS: The results show that uterine fibroids represent a cell population of advanced cellular age compared to matching myometrium. Moreover, the data point to members of the p53-network as to potential novel therapeutic targets for the treatment of uterine fibroids.

p14Arf acts as an antagonist of HMGA2 in senescence of mesenchymal stem cells-implications for benign tumorigenesis.

HMGA2 is a major regulator of benign tumorigenesis from mesenchyme-derived tissues and stem-cell self-renewal. It has been postulated that HMGA2 mediates its critical function by decreasing p16(Ink4a)/p14(Arf) expression and cellular senescence. To repress the oncogenic activity of HMGA2, the lin-28-let-7 axis is thought to increasingly repress the expression of HMGA2 with age. To understand the HMGA2-p14(Arf) -relationship in benign tumorigenesis, we performed a series of experiments on mesenchymal stem-cells, i.e., the proposed cells of origin of lipomas and uterine leiomyomas. The expression of both genes was inversely correlated during senescence in vitro but contrary to the expectations in adipose tissue derived stem cells (ADSCs) stimulation of HMGA2 by FGF1 increased the expression of p14(Arf) . Based on the assumption that in ADSCs p14(Arf) is repressing HMGA2, siRNA silencing of p14(Arf) was performed resulting in a significant upregulation of HMGA2. To see if p14(Arf) can repress HMGA2 by a TP53-dependent mechanism, nutlin-3, a known MDM2 antagonist, was used which not only increased the activity of the senescence, associated markers p21 and beta-galactosidase, but also decreased the expression of HMGA2, suggesting that p14(Arf) indeed influences HMGA2 by a p53-dependent mechanism because nutlin-3 stabilizes p53. Accordingly, the HMGA2 response triggered by serum was reduced by treatment of ADSCs with nutlin-3. As to the interaction between HMGA2 and p14(Arf) in benign tumorigenesis, we propose a model where akin to MSC self-renewal during tissue repair the simultaneous increase of p14(Arf) with HMGA2 ensures genomic stability, whereas in turn p14(Arf) can repress HMGA2 via TP53.

ABO blood groups and the risk of SARS-CoV-2 infection.

There is no doubt that genetic factors of the host play a role in susceptibility to infectious diseases. An association between ABO blood groups and SARS-CoV-2 infection as well as the severity of COVID-19 has been suggested relatively early during the pandemic and gained enormously high public interest. It was postulated that blood group A predisposes to a higher risk of infection as well as to a much higher risk of severe respiratory disease and that people with blood group O are less frequently and less severely affected by the disease. However, as to the severity of COVID-19, a thorough summary of the existing literature does not support these assumptions in general. Accordingly, at this time, there is no reason to suppose that knowledge of a patient's ABO phenotype should directly influence therapeutical decisions in any way. On the other hand, there are many data available supporting an association between the ABO blood groups and the risk of contracting SARS-CoV-2. To explain this association, several interactions between the virus and the host cell membrane have been proposed which will be discussed here.

HMGA proteins regulate the expression of FGF2 in uterine fibroids.

In human fibroids genes encoding the high-mobility proteins containing the 'AT-hook' DNA-binding motif (HMGA) are frequently affected by non-random chromosomal rearrangements. Thus, the different proteins and their derivatives resulting from these genomic rearrangements can be assumed to be involved in the genesis of these tumors by activation of largely identical downstream pathways. Constructs encoding HMGA proteins and their relevant derivatives were overexpressed in human myometrial cells, and RNA isolated from these cells was hybridized to filter arrays. Four genes were either up- or down-regulated at least 2-fold after overexpression of either of the HMGA genes and their derivatives. FGF2 (fibroblast growth factor 2) was one of these genes, and we were then able to show by microarray analyses that tumors with rearrangements of the HMGA2 locus (n = 8) expressed significantly higher levels of FGF2 than those with an apparently normal karyotype (n = 47). Accordingly, by quantitative real-time PCR uterine leiomyomas with rearrangements of the HMGA2 locus were found to express significantly higher levels of FGF2 than those with an apparently normal karyotype with a linear relationship between the expression of FGF2 and the level of HMGA2 overexpression as well as the tumor size. The results of western blot analyses confirmed these findings. Moreover, stimulation of myometrial tissue by FGF1, a strong inducer of HMGA2, leads to an increase of HMGA2 as well as FGF2 expression. In conclusion, the results contribute to the understanding of the association between the overexpression of HMGA proteins, the regulation of FGF2 expression and the size of fibroids.

BMP4 increases expression of HMGA2 in mesenchymal stem cells.

BMP4 has been linked to early steps of adipocyte lineage differentiation but only little is known about its corresponding downstream pathways. Herein, we have investigated whether or not the expression of high mobility group protein HMGA2, another protein linked to proliferation and differentiation within the process of adipogenesis, may be influenced by BMP4 signaling in adipose tissue derived stem cells. Compared to FGF1, a strong inducer of HMGA2 in immortalized pre-adipocytes, BMP4 was found moderately to induce the HMGA2 mRNA expression in serum starved adipose tissue derived stem cells and myometrial cells. In contrast, no such activity was noted in canine bone marrow derived mesenchymal stem cells. As to adipocyte lineage differentiation the functions of BMP4 and HMGA2 mechanistically overlap. Thus, we propose that in adipose tissue BMP4 acts in part by activating HMGA2 making this architectural transcription factor one of the major downstream players in that system.

Decrease in thyroid adenoma associated (THADA) expression is a marker of dedifferentiation of thyroid tissue.

BACKGROUND: Thyroid adenoma associated (THADA) has been identified as the target gene affected by chromosome 2p21 translocations in thyroid adenomas, but the role of THADA in the thyroid is still elusive. The aim of this study was to quantify THADA gene expression in normal tissues and in thyroid hyper- and neoplasias, using real-time PCR. METHODS: For the analysis THADA and 18S rRNA gene expression assays were performed on 34 normal tissue samples, including thyroid, salivary gland, heart, endometrium, myometrium, lung, blood, and adipose tissue as well as on 85 thyroid hyper- and neoplasias, including three adenomas with a 2p21 translocation. In addition, NIS (sodium-iodide symporter) gene expression was measured on 34 of the pathological thyroid samples. RESULTS: Results illustrated that THADA expression in normal thyroid tissue was significantly higher (p < 0.0001, exact Wilcoxon test) than in the other tissues. Significant differences were also found between non-malignant pathological thyroid samples (goiters and adenomas) and malignant tumors (p < 0.001, Wilcoxon test, t approximation), anaplastic carcinomas (ATCs) and all other samples and also between ATCs and all other malignant tumors (p < 0.05, Wilcoxon test, t approximation). Furthermore, in thyroid tumors THADA mRNA expression was found to be inversely correlated with HMGA2 mRNA. HMGA2 expression was recently identified as a marker revealing malignant transformation of thyroid follicular tumors. A correlation between THADA and NIS has also been found in thyroid normal tissue and malignant tumors. CONCLUSIONS: The results suggest THADA being a marker of dedifferentiation of thyroid tissue.