Human embryonic stem cells recover in vivo acute lung inflammation bleomycin-induced

Idiopathic pulmonary fibrosis (IPF) is characterized by alveolar epithelial cell injury, type II cell activation, apoptosis and bronchiolar epithelial cell proliferation, accumulation of extracellular matrix and fibroblasts. No current animal model recapitulates all of these cardinal manifestation of the human disease. However, bleomycin instillation in mice lung by intranasal way (ITN) represents the best experimental model of pulmonary fibrosis in which alveolar pneumocytes type II (ATII) are usually depleted. The aim of this study was to test the possibility to recover acute lung fibrosis after transplantation of human embryonic type II derived-pneumocytes in a murine model of bleomycin-induced damage. Our results indicate the striking "clinical" beneficial effect of differentiated HUES-3 cells into ATII in terms of lung function, weight loss and mortality in injured mice, suggesting this stem cell therapy as a promising, systemic and specific treatment of human pulmonary fibrosis.

Sunitinib therapy in metastatic papillary thyroid cancer

We present the case of a 51-year-old woman with a follicular variant of papillary thyroid carcinoma. After surgery she experienced a relapse. Chemotherapy treatment led only to disease stabilization. In August 2009, we decided to start therapy with sunitinib 50 mg daily in an intermittent schedule (4 weeks on/2 weeks off). A CT scan after 3 months of treatment showed partial remission of disease according to the RE-CIST criteria. The patient continued sunitinib until January 2011, when CT evidenced progression in the mediastinal lymph nodes and pleura. Genetic analyses were carried out to determine if the clinical response in our patient was correlated with the presence of RET or BRAF mutations. No RET/PTC rearrangements or BRAF-V600E mutation, which are the two most common genetic alterations detected in papillary thyroid carcinoma, were found. It can be hypothesized that the activity of sunitinib in this patient was due to its antiangiogenic properties.

Laparoscopic partial nephrectomy of thyroid cancer metastasis: case report and review of the literature

Background

Follicular cell thyroid carcinoma is a quite aggressive form of thyroid cancer. About 10% of follicular thyroid carcinoma shows multiple metastases: lung and bone are the most common sites of metastasis. Renal involvement from thyroid primary cancer is very rare with incidence of 4.5%–5.9%.

Purpose

We report the first laparoscopic conservative treatment of renal metastasis from thyroid cancer. This is a new and useful approach in order to delay malignant disease progression and to reduce the surgical discomfort of the patient.

Patients and methods

We present the case of a 67-year-old woman, undergoing total thyroidectomy for follicular thyroid cancer with bone and lung metastasis. During adjuvant radiometabolic treatment, renal metastasis was diagnosed. Renal metastasis showed high metabolic activity, reducing the effectiveness of radioiodine therapy for secondary lesions. For this reason, we performed a laparoscopic simple enucleation of the single renal metastasis using extraperitoneal access and a clampless procedure.

Results

The excision of the renal lesion improved the effectiveness of adjuvant radioiodine therapy: two months after surgery, the patient underwent adjuvant radiometabolic treatment with iodine-131 (150 mCi) and the following whole body scan showed only a small uptaking area at the level of the vertebral metastasis. The lung micrometastases were not detectable. At 36 months follow-up, malignant disease was clinically stable and well controlled.

Conclusion

Minimally invasive renal surgery with preservation of renal function and rapid recovery contributed to the success of radioiodine therapy and delayed the progression of the disease.

Association between BRAF V600E mutation and mortality in patients with papillary thyroid cancer

IMPORTANCE

BRAF V600E is a prominent oncogene in papillary thyroid cancer (PTC), but its role in PTC-related patient mortality has not been established.

OBJECTIVE

To investigate the relationship between BRAF V600E mutation and PTC-related mortality.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective study of 1849 patients (1411 women and 438 men) with a median age of 46 years (interquartile range, 34-58 years) and an overall median follow-up time of 33 months (interquartile range, 13-67 months) after initial treatment at 13 centers in 7 countries between 1978 and 2011.

MAIN OUTCOMES AND MEASURES

Patient deaths specifically caused by PTC.

RESULTS

Overall, mortality was 5.3% (45/845; 95% CI, 3.9%-7.1%) vs 1.1% (11/1004; 95% CI, 0.5%-2.0%) (P < .001) in BRAF V600E-positive vs mutation-negative patients. Deaths per 1000 person-years in the analysis of all PTC were 12.87 (95% CI, 9.61-17.24) vs 2.52 (95% CI, 1.40-4.55) in BRAF V600E-positive vs mutation-negative patients; the hazard ratio (HR) was 2.66 (95% CI, 1.30-5.43) after adjustment for age at diagnosis, sex, and medical center. Deaths per 1000 person-years in the analysis of the conventional variant of PTC were 11.80 (95% CI, 8.39-16.60) vs 2.25 (95% CI, 1.01-5.00) in BRAF V600E-positive vs mutation-negative patients; the adjusted HR was 3.53 (95% CI, 1.25-9.98). When lymph node metastasis, extrathyroidal invasion, and distant metastasis were also included in the model, the association of BRAF V600E with mortality for all PTC was no longer significant (HR, 1.21; 95% CI, 0.53-2.76). A higher BRAF V600E-associated patient mortality was also observed in several clinicopathological subcategories, but statistical significance was lost with adjustment for patient age, sex, and medical center. For example, in patients with lymph node metastasis, the deaths per 1000 person-years were 26.26 (95% CI, 19.18-35.94) vs 5.93 (95% CI, 2.96-11.86) in BRAF V600E-positive vs mutation-negative patients (unadjusted HR, 4.43 [95% CI, 2.06-9.51]; adjusted HR, 1.46 [95% CI, 0.62-3.47]). In patients with distant tumor metastasis, deaths per 1000 person-years were 87.72 (95% CI, 62.68-122.77) vs 32.28 (95% CI, 16.14-64.55) in BRAF V600E-positive vs mutation-negative patients (unadjusted HR, 2.63 [95% CI, 1.21-5.72]; adjusted HR, 0.84 [95% CI, 0.27-2.62]).

CONCLUSIONS AND RELEVANCE

In this retrospective multicenter study, the presence of the BRAF V600E mutation was significantly associated with increased cancer-related mortality among patients with PTC. Because overall mortality in PTC is low and the association was not independent of tumor features, how to use BRAF V600E to manage mortality risk in patients with PTC is unclear. These findings support further investigation of the prognostic and therapeutic implications of BRAF V600E status in PTC.

Gemcitabine-loaded biocompatible nanocapsules for the effective treatment of human cancer

Aim: To encapsulate the nucleoside gemcitabine (GEM) in novel PEGylated polymeric nanocapsules (NanoGEM). Materials & methods: The biological activity of NanoGEM was tested both in vitro and in vivo in comparison with the free drug. The NanoGEM was made of polylactic acid and allowed the entrapment of a great amount of GEM. Results & discussion: The NanoGEM showed mean sizes of approximately 200 nm, a polydispersity index of approximately 0.1 and a ζ-potential of -30 mV. It exerted a stronger, quicker effect on the reduction of HEK293 cell growth in vitro in comparison with free GEM and had an in vivo antitumoral effect on the proliferation of xenograft tumors at a drug dosage tenfold less than its saline solution. The employment of nanocapsules increased the plasmatic half-life of the drug and allowed a great accumulation of GEM inside the tumors. Conclusion: NanoGEM represents a promising new tool for the treatment of cancer.

Original submitted 16 November 2011; Revised submitted 21 June 2012; Published online 24 October 2012

Modifications in the papillary thyroid cancer gene profile over the last 15 years

BACKGROUND

Evidence for an increased prevalence of BRAF(V600E) mutations has been documented in recent decades. The aim of this study was to evaluate the prevalence of both RET/PTC rearrangements and BRAF(V600E) mutations in an Italian cohort of papillary thyroid carcinoma (PTC) patients followed at the Endocrine Units of Pisa, Milano, and Perugia from 1996-2010.

PATIENTS AND METHODS

In total, 401 PTC patients were examined and grouped according to the time of surgery: group 1, 1996-2000; group 2, 2001-2005; and group 3, 2006-2010. Patients were analyzed for clinical, pathological, and molecular features. In parallel, the molecular characteristics of 459 PTC from Sicily were studied.

RESULTS

The genetic profiles of the three groups were significantly different (P < 0.0001). In particular, the frequency of RET/PTC rearrangements decreased from 1996-2010, occurring in 33 of 100 (33%) of the patients in group 1, 26 of 148 (17%) in group 2, and 15 of 153 (9.8%) in group 3. The incidence of BRAF(V600E) mutations increased over the same period, from 28% in group 1 (28 of 100) to 48.9% in group 2 (73 of 148) and 58.1% in group 3 (89 of 153). A consistent increase in BRAF(V600E) prevalence was observed in the Sicilian group (P < 0.0001). Moreover, a statistically significant increase in the mean age at diagnosis and decrease in tumor size over the study period was observed.

CONCLUSION

The genetic profile of PTC changed over the last 15 yr, with a significant decrease in the prevalence of RET/PTC rearrangements and an increase in BRAF(V600E) mutations. In addition, the mean age at diagnosis increased and tumor size decreased over the study period.

Sunitinib exerts only limited effects on the proliferation and differentiation of anaplastic thyroid cancer cells

BACKGROUND

Novel molecularly targeted drugs are undergoing preclinical and clinical testing to assess their efficacy against refractory thyroid carcinomas. The multikinase inhibitor Sunitinib has been shown to inhibit the kinase activity of the RET oncogene and reduce proliferation in differentiated thyroid cancer cells harboring the RET/PTC rearrangement. In this study, we evaluated its effects in human cell lines derived from differentiated (TPC-1) and anaplastic (8505C, CAL-62, and C643) thyroid cancers.

METHODS

The cells exposed to various concentrations of Sunitinib were examined for: (1) cell viability and presence of apoptosis, analyzed by cell counts, MTT assay, trypan blue exclusion assay, western blotting, and immunofluorescence; (2) expression of cyclin D1 and phosphorylated and nonphosphorylated extracellular signal-regulated kinase (ERK) and Akt proteins, analyzed by western blotting; and (3) transcription of genes encoding thyrocyte differentiation markers (thyroid-stimulating hormone receptor, sodium/iodide symporter, thyroglobulin, and thyroperoxidase) and proangiogenic factors (vascular endothelial growth factor A, platelet-derived growth factors A and B), measured by quantitative reverse transcriptase-polymerase chain reaction.

RESULTS

Exposure to nanomolar concentrations of Sunitinib significantly reduced cell viability in only TPC-1 cells, and this effect was paralleled by reduction of cyclin D1 levels. Western blotting revealed reduced phosphorylation of ERK and Akt after 3 and 6 hours of drug exposure. In contrast, the growth of 8505C, CAL-62, and C-643 cells was significantly reduced only by micromolar concentrations of Sunitinib, mainly due to induced necrotic rather than apoptotic death. In these cells, Sunitinib exerted a few significant effects on the transcription of angiogenic factors or thyrocyte differentiation markers.

CONCLUSIONS

Sunitinib has little or no effect on the growth or differentiation of anaplastic thyroid cancer cells, thus suggesting that it is unlikely to be effective in the treatment of anaplastic thyroid cancer.

Intracellular signal transduction and modification of the tumor microenvironment induced by RET/PTCs in papillary thyroid carcinoma

RET gene rearrangements (RET/PTCs) represent together with BRAF point mutations the two major groups of mutations involved in papillary thyroid carcinoma (PTC) initiation and progression. In this review, we will examine the mechanisms involved in RET/PTC-induced thyroid cell transformation. In detail, we will summarize the data on the molecular mechanisms involved in RET/PTC formation and in its function as a dominant oncogene, on the activated signal transduction pathways and on the induced gene expression modifications. Moreover, we will report on the effects of RET/PTCs on the tumor microenvironment. Finally, a short review of the literature on RET/PTC prognostic significance will be presented.

BRAF(V600E) mutation and expression of proangiogenic molecular markers in papillary thyroid carcinomas

OBJECTIVE

Tyrosine kinase inhibitors (TKIs) are evaluated for treatment of radioiodine refractory thyroid cancer. Their effects in this setting are based on blockade of proangiogenic signaling mediated by receptors for vascular endothelial growth factors (VEGFs) and platelet-derived growth factors (PDGF). Most TKIs also block other cancer-relevant kinases, such as B-type Raf kinase (BRAF), which are constitutively activated in approximately half of papillary thyroid carcinomas (PTCs), but the impact of these effects is not clear.

DESIGN

The aim of our study was to investigate the impact of BRAF(V600E) on proangiogenic gene expression and microvascular features of PTCs.

METHODS

mRNA levels for VEGFA, VEGF receptors, and coreceptors (VEGFRs 1, 2, and 3, neuropilin-1), and PDGF receptor β (PDGFRβ or PDGFRB) were measured with real-time PCR in BRAF(V600E) (n=55) and wild-type BRAF (BRAF-wt; n=35) PTCs. VEGF and VEGFR protein expression and microvessel densities (MVD) and lymphatic vessel densities (LVDs) were assessed by immunohistochemistry in 22 of the 90 PTCs (including 11 BRAF(V600E) cases). Angiogenic gene expression was also studied in vitro after induction/silencing of the BRAF(V600E) mutation in thyrocyte lines.

RESULTS

Transcript levels of proangiogenic factors were significantly lower in BRAF(V600E) PTCs versus BRAF-wt PTCs (P<0.0001), but MVD and LVDs were not significantly different. VEGFA mRNA levels in thyroid cell lines decreased when BRAF(V600E) mutation was induced (P=0.01) and increased when it was silenced (P=0.01).

CONCLUSIONS

Compared with BRAF-wt PTCs, those harboring BRAF(V600E) exhibit downregulated VEGFA, VEGFR, and PDGFRβ expression, suggesting that the presence of BRAF mutation does not imply a stronger prediction of response to drugs targeting VEGF and PDGFB signaling pathways.

Sunitinib inhibits tumor vascularity and growth but does not affect Akt and ERK phosphorylation in xenograft tumors

Sunitinib is a multikinase inhibitor approved for use in some human solid malignancies, including renal clear cell and gastrointestinal stromal cancer, and under investigation for many other neoplasias. In many preclinical cancer models sunitinib has shown anti-angiogenic and antitumor effects, acting mainly by inhibiting the activity of pro-angiogenic growth factor receptors. However, a percentage of tumors develop resistance to this treatment. The aim of this study was to identify novel potential molecular targets for the non- responsive tumors. The effects of sunitinib were investigated in xenograft tumors obtained by injecting HEK293 cells into NOD-SCID mice, focusing on the activity of growth-regulating pathways involved in tumorigenesis. During 11 days of oral administration of sunitinib (40 mg/kg/day), the growth of tumors was monitored by measuring the mass volume by a caliper. At the end of the treatment, tumor specimens were histologically examined for microvessel density (MVD) and presence of necrosis, and the phosphorylation of ERK and Akt was analyzed in protein extracts by Western blotting. Moreover, the mRNA levels of VEGF and its receptor genes were measured by quantitative RT-PCR. Treatment with sunitinib elicited a clear reduction of the tumor growth, associated with a reduction of MVD, correlated with an increased number of necrotic cells. In contrast, the levels of phosphorylated Akt and ERK proteins were similar in treated and non-treated animals. The VEGF and VEGFR-1 and 2 transcripts were not affected by sunitinib treatment. In conclusion, these findings confirm the anti-angiogenic action as the major effect of sunitinib against tumor growth. In contrast, other important growth regulatory pathways involved in malignant trans-formation, such as the ERK-MAPK and Akt/mTOR pathways are not affected by such a treatment, suggesting the use of specific inhibitors of these pathways as valid candidates for combinatorial therapies in sunitinib-resistant malignancies.

Alternative strategies for targeting mouse double minute 2 activity with small molecules: novel patents on the horizon?

Most researchers have sought to restore the activity of p53 by identifying small molecules able to block the interaction of p53 with mouse double minute 2 (MDM2). To the same end, some scientists are pursuing the development of compounds that can inhibit the ubiquitin-ligase (E3) activity of MDM2. In this article, we provide a perspective review on what is known about MDM2 E3 inhibitors and what major questions remain to be addressed to boost this line of research. Recent studies provide the proof of concept that the inhibition of MDM2 E3 activity represents a viable strategy for rescuing p53 activity from MDM2 inhibitory functions. It is likely that settling some open issues such as the site of action of these compounds and their specificity towards E3 ligase enzymes will open in the near feature new horizons in cancer therapy.

Epigenetics of thyroid cancer and novel therapeutic targets

An increasing body of evidence suggests that epigenetic changes (DNA methylation, remodeling and post-translational modification of chromatin) play important roles in thyroid tumorigenesis, as a result of their effects on tumor-cell differentiation and proliferation. Epigenetic silencing of various thyroid-specific genes has been detected in thyroid tumors. These changes can diminish the tumor's ability to concentrate radioiodine, which dramatically reduces treatment options. Epigenetic changes in tumor-promoting and tumor-suppressor genes also contribute to the dysregulation of thyrocyte growth and other aspects of tumorigenesis, such as apoptosis, motility and invasiveness. We provide a brief overview of the mechanisms underlying epigenetic regulation of gene expression and the current methods used to investigate it. This is followed by a review of the principal epigenetic alterations detected in thyroid cancer cells, epigenetic strategies for treating thyroid cancers and data from preclinical and clinical studies (some still underway) on the use in this setting of demethylating agents and histone deacetylase inhibitors.

Regulation of MDM4 (MDMX) function by p76(MDM2): a new facet in the control of p53 activity

Under basal growth conditions, p53 function is tightly controlled by the members of MDM family, MDM2 and MDM4. The Mdm2 gene codes, in addition to the full-length p90(MDM2), for a short protein, p76(MDM2) that lacks the p53-binding domain. Despite this property and at variance with p90(MDM2), this protein acts positively toward p53, although the molecular mechanism remains elusive. Here, we report that p76(MDM2) antagonizes MDM4 inhibitory function. We show that p76(MDM2) possesses intrinsic ubiquitinating and degrading activity, and through these activities controls MDM4 levels. Furthermore, the presence of p76(MDM2) decreases the association of MDM4 with p53 and p90(MDM2), and antagonizes p53 degradation by the heterodimer MDM4/p90(MDM2). The p76(MDM2)-mediated regulation of MDM4 occurs in the cytoplasm, under basal growth conditions. Conversely, upon DNA damage, phosphorylation of MDM4Ser403 dissociates p76(MDM2) and prevents MDM4 degradation. The overall negative control of MDM4 by p76(MDM2) reflects on p53 function as p76(MDM2) impairs MDM4-mediated inhibition of p53 activity. In agreement with the positive role of p76(MDM2) toward p53, the p76(MDM2)/p90(MDM2) ratio significantly decreases in a group of thyroid tumor samples compared with normal counterparts. Overall, these findings reveal a new mechanism in the control of p53 basal activity that may account for the distinct sensitivity of tissues to stress signals depending on the balance among MDM proteins. Moreover, these data suggest an oncosuppressive function for a product of the Mdm2 gene.

Targeted molecular therapies in thyroid carcinoma

Thyroid cancer incidence has significantly increased in the last three decades and many patients seek medical attention for its treatment every year. Among follicular cell-derived tumors, the majority are differentiated thyroid carcinomas (DTC), whose prognosis is very good with only 15% of the cases presenting disease persistence or recurrence after initial treatment. Medullary thyroid carcinoma has a worse prognosis, especially in patients with diffused cancers at the time of initial surgery. Traditional treatment options for persistent or recurrent disease include additional surgery, radioiodine treatment and TSH-suppression in DTC patients; external beam radiotherapy, and cytotoxic chemotherapy, often have low efficacy and many patients with advanced disease ultimately die. In the last two decades many of the molecular events involved in cancer formation have been uncovered. This knowledge has prompted the development of novel therapeutic strategies mainly based on the inhibition of key molecular mediators of the tumorigenic process. In particular the class of small-molecule tyrosine kinase inhibitors was enriched by many compounds that have reached clinical trials and in some cases have had approval for clinical use in specific cancers. Many of these compounds entered clinical trials also for locally advanced or metastatic thyroid carcinomas showing very promising results.

Multiple endocrine neoplasia type 2 syndromes (MEN 2): results from the ItaMEN network analysis on the prevalence of different genotypes and phenotypes

OBJECTIVE

Multiple endocrine neoplasia type 2 (MEN 2) is a genetic disease characterized by medullary thyroid carcinoma (MTC) associated (MEN 2A and 2B) or not familial MTC (FMTC) with other endocrine neoplasia due to germline RET gene mutations. The prevalence of these rare genetic diseases and their corresponding RET mutations are unknown due to the small size of the study population.

METHODS

We collected data on germline RET mutations of 250 families with hereditary MTC followed in 20 different Italian centres.

RESULTS AND CONCLUSIONS

The most frequent RET amino acid substitution was Val804Met (19.6%) followed by Cys634Arg (13.6%). A total of 40 different germline RET mutations were present. Six families (2.4%) were negative for germline RET mutations. The comparison of the prevalence of RET germline mutations in the present study with those published by other European studies showed a higher prevalence of Val804Met and Ser891Ala mutations and a lower prevalence of Leu790Phe and Tyr791Phe (P<0.0001). A statistically significant higher prevalence of mutations affecting non-cysteine codons was also found (P<0.0001). Furthermore, the phenotype data collection showed an unexpected higher prevalence of FMTC (57.6%) with respect to other MEN 2 syndromes (34% MEN 2A and 6.8% of MEN 2B). In conclusion, we observed a statistically significant different pattern of RET mutations in Italian MEN 2 families with respect to other European studies and a higher prevalence of FMTC phenotype. The different ethnic origins of the patients and the particular attention given to analysing apparently sporadic MTC for RET germline mutations may explain these findings.

B-Raf(V600E) and thrombospondin-1 promote thyroid cancer progression

Although B-Raf(V600E) is the most common somatic mutation in papillary thyroid carcinoma (PTC), how it induces tumor aggressiveness is not fully understood. Using gene set enrichment analysis and in vitro and in vivo functional studies, we identified and validated a B-Raf(V600E) gene set signature associated with tumor progression in PTCs. An independent cohort of B-Raf(V600E)-positive PTCs showed significantly higher expression levels of many extracellular matrix genes compared with controls. We performed extensive in vitro and in vivo validations on thrombospondin-1 (TSP-1), because it has been previously shown to be important in the regulation of tumor angiogenesis and metastasis and is present in abundance in tumor stroma. Knockdown of B-Raf(V600E) resulted in TSP-1 down-regulation and a reduction of adhesion and migration/invasion of human thyroid cancer cells. Knockdown of TSP-1 resulted in a similar phenotype. B-Raf(V600E) cells in which either B-Raf(V600E) or TSP-1 were knocked down were implanted orthotopically into the thyroids of immunocompromised mice, resulting in significant reduction in tumor size and fewer pulmonary metastases from the primary carcinoma as compared with the control cells. Treatment of orthotopic thyroid tumors, initiated 1 week after tumor cell implantation with PLX4720, an orally available selective inhibitor of B-Raf(V600E), caused a significant tumor growth delay and decreased distant metastases, without evidence of toxicity. In conclusion, B-Raf(V600E) plays an important role in PTC progression through genes (i.e., TSP-1) important in tumor invasion and metastasis. Testing of a patient's thyroid cancer for B-Raf(V600E) will yield important information about potential tumor aggressiveness and also allow for future use of targeted therapies with selective B-Raf(V600E) inhibitors, such as PLX4720.

Nucleophosmin is overexpressed in thyroid tumors

Nucleophosmin (NPM) is a protein that contributes to several cell functions. Depending on the context, it can act as an oncogene or tumor suppressor. No data are available on NPM expression in thyroid cells. In this work, we analyzed both NPM mRNA and protein levels in a series of human thyroid tumor tissues and cell lines. By using immunohistochemistry, NPM overexpression was detected in papillary, follicular, undifferentiated thyroid cancer, and also in follicular benign adenomas, indicating it as an early event during thyroid tumorigenesis. In contrast, various levels of NPM mRNA levels as detected by quantitative RT-PCR were observed in tumor tissues, suggesting a dissociation between protein and transcript expression. The same behavior was observed in the normal thyroid FRTL5 cell lines. In these cells, a positive correlation between NPM protein levels, but not mRNA, and proliferation state was detected. By using thyroid tumor cell lines, we demonstrated that such a post-mRNA regulation may depend on NPM binding to p-Akt, whose levels were found to be increased in the tumor cells, in parallel with reduction of PTEN. In conclusion, our present data demonstrate for the first time that nucleophosmin is overexpressed in thyroid tumors, as an early event of thyroid tumorigenesis. It seems as a result of a dysregulation occurring at protein and not transcriptional level related to an increase of p-Akt levels of transformed thyrocytes.

Insights into the molecular function of the inactivating mutations of B-Raf involving the DFG motif

BRAF gene mutations have been associated with human cancers. Among the naturally occurring mutations, two that involve amino acids of the conserved DFG motif in the activation loop (D594V and G596R), appear to be inactivating. Aim of this study was to analyze the molecular mechanisms involved in the loss of function of B-Raf inactivating mutation G596R. Furthermore, the ability of the B-Raf DFG motif mutants to generate heterodimers with C-Raf and the possible functional consequences of the B-Raf/C-Raf heterodimer formation was examined. Wet molecular experiments in HEK293T cells demonstrate that B-Raf(G596R) is a kinase-impaired mutant. Molecular dynamics simulations show that the loss of function of B-Raf(G596R) depends on a restraining effect of Arg596 on the catalytic residue Asp594, which results in the loss of the appropriate spatial localization and/or conformation of the latter necessary for anchoring ATP to the enzyme. Exploration of B-Raf/C-Raf heterodimer formation indicates the occurrence of functioning heterodimers in the case of all the DFG B-Raf mutants, independently from the expected differences in spatial conformation of the activation loop, although the transforming activity of the mutants appear negligible. In conclusion, this study delivers novel information on the functional properties of the B-Raf DFG motif inactivating mutants and on the mechanisms driving B-Raf/C-Raf heterodimerization and consequent C-Raf transactivation.

A useful ultrasound score to select thyroid nodules requiring fine needle aspiration in an iodine-deficient area

BACKGROUND

The high prevalence of thyroid nodules in iodine-deficient areas is a practical problem because of the large number of patients requiring fine needle aspiration (FNA) to detect malignant nodules.

AIM

To obtain an ultrasound (US) score for predicting malignant nodules and reduce the number of unnecessary and expensive FNA.

SUBJECT AND METHOD

All nodules observed from September 2001 to March 2006 were evaluated by US: echostructure, echogenicity, halo, microcalcifications and ratio between antero-posterior and transversal diameters (AP/TR). Two thousand six hundred and forty-two consecutive patients underwent US-guided FNA for a total of 3645 nodules.

RESULTS

Logistic regression analysis showed a potent predictive role for solitary nodules and absence/ incomplete halo (p=0.000). A significant predictive role for microcalcifications and AP/TR ratio was also observed. A 10-point score was constructed using the standardized regression coefficient. Nodules with US score <or=2.4, those between 2.5-5.4 and >or=5.5 had a frequency of malignancy of 0.4, 1.1 and 5.6% (p<0.001), respectively. Nodules with >or=5.5 US score were characterized by a 66% sensitivity and a 76% specificity compared to the diagnostic values of single parameters which were either sensitive or specific.

CONCLUSIONS

According to our data, we suggest FNA for nodules reaching a >5.4 US score, whereas a clinical judgement should be used for the intermediate category nodules. When the score is lower than 2.5 we do not recommend FNA. The practical use of this US score can help reduce unnecessary and expensive FNA in iodine-deficient areas.

Germline BRAF mutations in Noonan, LEOPARD, and cardiofaciocutaneous syndromes: molecular diversity and associated phenotypic spectrum

Noonan, LEOPARD, and cardiofaciocutaneous syndromes (NS, LS, and CFCS) are developmental disorders with overlapping features including distinctive facial dysmorphia, reduced growth, cardiac defects, skeletal and ectodermal anomalies, and variable cognitive deficits. Dysregulated RAS-mitogen-activated protein kinase (MAPK) signal traffic has been established to represent the molecular pathogenic cause underlying these conditions. To investigate the phenotypic spectrum and molecular diversity of germline mutations affecting BRAF, which encodes a serine/threonine kinase functioning as a RAS effector frequently mutated in CFCS, subjects with a diagnosis of NS (N=270), LS (N=6), and CFCS (N=33), and no mutation in PTPN11, SOS1, KRAS, RAF1, MEK1, or MEK2, were screened for the entire coding sequence of the gene. Besides the expected high prevalence of mutations observed among CFCS patients (52%), a de novo heterozygous missense change was identified in one subject with LS (17%) and five individuals with NS (1.9%). Mutations mapped to multiple protein domains and largely did not overlap with cancer-associated defects. NS-causing mutations had not been documented in CFCS, suggesting that the phenotypes arising from germline BRAF defects might be allele specific. Selected mutant BRAF proteins promoted variable gain of function of the kinase, but appeared less activating compared to the recurrent cancer-associated p.Val600Glu mutant. Our findings provide evidence for a wide phenotypic diversity associated with mutations affecting BRAF, and occurrence of a clinical continuum associated with these molecular lesions.

Prohibitin is overexpressed in papillary thyroid carcinomas bearing the BRAF(V600E) mutation

BACKGROUND

Prohibitin (PHB) is a multifunctional protein that is localized in different intracellular sites. PHB may exert different roles in tumorigenesis, having either a permissive action on tumor growth or an oncosuppressor role, depending on the cellular context. The objective of this study was to evaluate PHB expression in normal thyroid tissues, thyroid follicular adenomas (FAs), and papillary thyroid carcinomas (PTCs).

METHODS

PHB expression was analyzed by immunohistochemistry, Western blot, and quantitative reverse transcription polymerase chain reaction (RT-PCR). Transfections in the BCPAP and TPC-1 thyroid cancer cell lines were used to evaluate the PHB promoter activity.

RESULTS

In terms of protein and mRNA levels, normal tissues from patients with serum thyrotropin (TSH) values >0.8mU/L had PHB levels that were significantly reduced compared to specimens from patients with serum TSH values <0.5mU/L, suggesting that TSH exerts an inhibitory effect on PHB expression. Consistent with this was the finding that the presence of TSH was associated with low PHB levels in normal FRTL5 thyroid cells. Immunohistochemical analysis showed relatively low and high PHB expression in FAs and PTCs, respectively. PHB mRNA and protein overexpression, as assessed by quantitative RT-PCR and Western blot, was noted only in PTCs bearing the BRAF(V600E) mutation. Notably, cell transfection experiments suggested that presence of the BRAF(V600E) mutation may be associated to increase of the PHB promoter activity.

CONCLUSIONS

PHB is overexpressed in PTCs bearing the BRAF(V600E) mutation. We postulate that the presence of the BRAF(V600E) mutation increases PHB promoter activity and therefore potentially mediates effects of this mutation on the behavior of BRAF(V600E) positive PTCs.

M. avium binding to HLA-DR expressed alleles in silico: a model of phenotypic susceptibility to sarcoidosis

Sarcoidosis is a systemic granulomatosis disease of unknown origin where a number of microbes, in particular M. tuberculosis and non-tuberculous mycobacteria, have been hypothesized to play a role in disease pathogenesis, possibly through bacterial antigen-driven hypersensitivity. To test this concept, we used bioinformatic tools allowing the identification of antigenic peptides in whole microbial genomes to analyze the interaction between the expressed HLA-DR gene allelic variants and the HLA-DR immunome of all pathogenic bacteria in a population of 149 sarcoidosis affected subjects and 447 controls, all HLA-typed at high resolution. We show here that patients with the Löfgren's syndrome, express HLA-DR alleles that recognize in silico a significantly higher number of bacterial antigen epitopes compared to the control population (18,496+9,114 vs 17,954+8,742; p<0.00001), and the chronic sarcoidosis affected population (17,954+8,742; p<0.00001 vs Löfgren's and controls). Further, the analysis of the ability of the HLA-DR allele combinations expressed by the Löfgren's and the chronic sarcoidosis affected subjects to recognize M. avium epitopes demonstrates that a significantly larger number of Löfgren's are capable of top affinity recognition, compared to chronic sarcoidosis (45% vs 17%, p<0.0037). Finally, both Löfgren's and chronic sarcoidosis subjects expressed HLA-DR allele combinations capable of M. tuberculosis and M. avium epitope recognition at higher affinity than tuberculosis affected subjects (p<0.01 all comparisons). In conclusion, we propose that - at least in a subgroup of affected subjects - sarcoidosis might be part of a spectrum of granulomatous responses to several agents where the Löfgren's syndrome represents the hyper-reactive end of the spectrum while pulmonary tuberculosis and atypical mycobacterial infections might represent the opposite end.

Functional characterization of the novel T599I-VKSRdel BRAF mutation in a follicular variant papillary thyroid carcinoma

CONTEXT

Mutations in BRAF are rare in the follicular variant of papillary thyroid carcinoma (FV-PTC).

OBJECTIVE

We identified and functionally characterized a novel T599I-VKSR(600-603)del BRAF mutation in a FV-PTC patient. We analyzed in vitro the effects of this novel mutation in comparison with other thyroid cancer-associated mutations.

DESIGN

Expression vectors for the BRAF mutants were generated and their in vitro kinase activity, signaling along the MAPK pathway, and capability of stimulating transcription from an AP1-responsive reporter evaluated.

RESULTS

BRAF kinase and signaling were increased to a similar extent by the T599I-VKSR (600-603)del, V600E, and K601E mutations. Instead, the G474R, a mutation previously found in a FV-PTC, knocked down the BRAF kinase and its intracellular signaling. Some cancer-associated low-activity BRAF mutants stimulate the MAPK cascade via CRAF; however, the G474R protein lacked also this property.

CONCLUSION

The T599I-VKSR(600-603)del is a novel gain-of-function mutation that targets BRAF in FV-PTC. Moreover, G474R is the first example of a mutation knocking down enzymatic BRAF activity in a FV-PTC. These findings underscore the importance of functional studies to characterize the role of BRAF mutations associated with thyroid cancer.

Surgical treatment of sporadic medullary thyroid carcinoma: strategy and outcome

BACKGROUND

Medullary Thyroid Carcinoma (MTC) originates from the thyroid C cells and accounts for approximately 5-9% of all thyroid cancers. Aim of this study was to retrospectively evaluate the outcomes of 41 patients with MTC who underwent treatment at our institution. PATIENTS AND METHODS. We reviewed the records of 41 patients who underwent surgery between 1995 and 2004. The patients were divided into two groups: A) patients (n 30) without any previous surgery. B) patients (n 11) previously thyroidectomized and high calcitonin levels with or without radiological evidence of local regional or distant metastases. We performed total thyroidectomy with central compartment lymphadenectomy and ipsilateral modified radical neck dissection in group A patients. Group B patients underwent re-excision of the central neck compartment and bilateral modified radical neck dissection if it had not been previously performed.

RESULTS

Most patients had major reduction in postoperative calcitonin levels. Compartmental dissection of the cervical node significantly improved the results of primary surgery and calcitonin returned to normal levels in approximately 60% of the patients in group A, but only the 30% of the patients in group B.

CONCLUSIONS

The extent of the primary surgical resection and the evidence of local or distant metastases significantly influence the outcome of MTC patients. An extensive lymphadenectomy performed early in the treatment and re-operative cervical lymphadenectomy in patients with persistently high calcitonin levels after thyroidectomy significantly improved the outcome, although re-operation rarely results in normalized calcitonin levels and is associated with a higher incidence of complications.

Surgical treatment of intrathyroid metastases: preliminary results of a multicentric study

BACKGROUND

Intrathyroid metastases (ITM) are rare and usually have a dismal prognosis. The aim of this study was to detect which neoplasms metastasize most often to the thyroid gland, their clinical features and treatment options.

MATERIALS AND METHODS

Retrospective analysis of clinical files of 17,122 patients submitted to surgery for thyroid disease between 1995 and 2005. Twenty-five patients (median age 61 years) were affected by ITM.

RESULTS

The site of the primary tumor was: kidney (15), lung (4), colon (3), breast (1), melanoma (1), and unknown in 1 patient. Ten patients (40%) complained of preoperative symptoms, in the others, thyroid involvement was incidentally discovered during the follow-up for the primary cancer. Twenty patients (80%) underwent total thyroidectomy, 3 received thyroid lobectomy and 2 palliative procedures. Morbidity was 16%, mortality was nil. The median follow-up was 24 months.

CONCLUSION

ITM should always be suspected in any patient with a previous history of malignancy. Fine-needle agobiopsy (FNAB) with immunohistochemical stains may help in preoperative workup. A long delay between the primary tumor and the recurrence warrants surgery and total thyroidectomy seems to be the treatment of choice because of the multifocality of metastasis to the thyroid gland.

Recurrences of thyroid well differentiated cancer: ultrasonography-guided surgical treatment

AIM

Differentiated thyroid carcinomas (DTC) have a favourable outlook overall. Cornerstone of treatment is total thyroidectomy (TT), followed, if needed, by radiometabolic therapy. Such lesions however show a definite tendency to recur (about 35% of cases), generally in the first decade of follow-up: in 70% of patients such recurrence is local. Surgical resection is the only curative treatment option for local recurrence of well-differentiated thyroid cancer. Intraoperative ultrasonography (US) can be of significant help in facilitating localization and complete resection of lesions. The aim of the study was to review the authors' own experience with the use of such diagnostic method in the clinical setting of thyroid neoplasm recurrence.

METHODS

Between January 2005 and March 2008 31 patients with DTC recurrences underwent intraoperative US exploration. Recurrences were easily identified and resected in all patients. Postoperative tireoglobuline (TG) was undetectable.

RESULTS

In all 31 patients preoperative US confirmed the presence of the lesion. In 26 patients digital exploration of the surgical field did not yield a definitively positive finding, whereas in 5 the lesion was easily palpable. Intraoperative US revealed the presence of pathologic tissue in all cases, with examination time ranging from 4 to 14 minutes (median 8 minutes). In all cases surgical resection was complete, with pathologic confirmation of the sample, and no necessity to extend ablation.

CONCLUSION

Intraoperative US can be of significant help in the identification of DTC recurrences, in particular when lesion dimensions are smaller than 10 mm in diameter and can facilitate a more radical excision of the tumor in a surgical field were anatomical landmarks can be altered by previous surgery and/or radiometabolic therapy.

Cytotoxic effects of a novel pyrazolopyrimidine derivative entrapped in liposomes in anaplastic thyroid cancer cells in vitro and in xenograft tumors in vivo

In this study, we evaluated the activity of two novel pyrazolopyrimidine derivatives (Si 34 and Si 35) against ARO cells, a human anaplastic thyroid cancer cell line. ARO cells exposed to different concentrations of the drugs showed a reduced growth rate and an increase of mortality. After 72 h incubation, doses of 5 and 10 microM Si 34 determined a decrease of cell counts by approximately 25% and approximately 75% compared with those of control cells respectively. Similar findings were observed using Si 35. Treatment with both Si 34 and Si 35 at 10 microM increased cell mortality also ( approximately 29% and approximately 18% respectively). At these concentrations, a decrease in cyclin D1 levels was observed. To improve the biopharmaceutical properties, a liposome formulation was prepared. When entrapped in unilamellar liposomes, Si 34 exerted its cytotoxic effects even at lower doses (maximal inhibition at 5 microM) and after shorter incubation time (48 h) either in ARO or other thyroid cancer cell lines. The effects were associated with weak apoptotic death. Inhibition of epidermal growth factor-stimulated src and ERK phosphorylation, as well as reduction of migration properties of ARO cells was also observed. Moreover, the growth of tumor xenografts induced in severe combined immunodeficiency (SCID) mice was inhibited by i.v. administration of 25-50 mg/kg of the drug liposomal formulation. In conclusion, the liposomal preparation of this novel pyrazolopyrimidine derivative appears to be a promising tool for the treatment of anaplasic thyroid cancer.

High periostin expression correlates with aggressiveness in papillary thyroid carcinomas

Periostin is a mesenchyme-specific gene product, which acts as an adhesion molecule during bone formation and supports osteoblastic cell line attachment and spreading. However, periostin expression is activated in a large variety of epithelial human tumors and correlates with their aggressiveness. Knowledge of expression of periostin in thyroid tumors is still scanty. The aim of the present work was to investigate periostin expression in differentiated neoplasms of the thyroid and to correlate it with several clinical and molecular features of these tumors. Periostin expression was evaluated by quantitative PCR and immunohistochemistry in normal thyroid tissues, papillary thyroid carcinomas (PTCs), follicular thyroid carcinomas (FTCs), and follicular adenomas (FAs). Periostin mRNA levels were also evaluated in several thyroid tumor cell lines. PTCs show mean periostin mRNA levels significantly higher than corresponding normal tissues. In five PTCs, periostin mRNA values were at least 30-fold higher than corresponding normal tissues. Conversely, mean periostin mRNA levels of FTCs and FAs were similar to those of normal tissues. Consistent with mRNA studies, periostin was detectable by immunohistochemistry in cancerous epithelial cells only in several cases of PTCs but not in normal tissue, FTCs, and FAs. In PTCs, periostin mRNA levels positively correlate with extrathyroidal invasion, distant metastasis, and higher grade staging. A negative correlation between periostin and expression of some markers of the thyroid-differentiated phenotype (thyroglobulin, thyrotropin receptor) was also present in the PTCs. These results indicate that an increase in periostin gene expression is present in several PTCs, in which it appears as a marker of aggressiveness. Experiments in thyroid tumor cell lines indicate that high levels of periostin mRNA are due, at least in part, to the increase in periostin promoter activity.

Clinical implications of BRAF mutation in thyroid carcinoma

Significant progress has recently been made in the clinical management of papillary thyroid carcinoma. The accuracy of diagnosis and prognostic stratification of this type of carcinoma are high but still fall below 100%. Lack of effective treatments for advanced stage papillary thyroid carcinoma leads to death in some patients. Approximately half of all such carcinomas harbor mutations in the gene encoding the serine/threonine-kinase B-type Raf kinase (BRAF), resulting in constitutive activation of the mitogen-activated protein kinase-extracellular-signal-regulated kinases signal transduction pathway. There is intriguing evidence that BRAF mutation testing of papillary thyroid carcinoma might improve the diagnosis, prognostic stratification and treatment of these tumors but large, prospective trials are needed to define the actual clinical impact of these approaches.

Surgical treatment of differentiated thyroid carcinoma: a retrospective study

INTRODUCTION

We carried out a retrospective analysis of our experience in the management of Differentiated Thyroid Carcinoma (DTC), in order to better define prognostic factors (age, gender, histological type, stage) and outline a standard procedure, where it's possible, for surgical treatment.

PATIENTS AND METHODS

Patient population consisted of 432 cases, operated from 1978 to 2003. We carried out 285 operations of total thyroidectomy of which 39 associated to some kind of lymphadenectomy, 66 totalization (21 pts had been operated in other institutes), 60 subtotal thyroidectomies and 21 lobo-isthmectomies. Survival and mortality curves for age, sex, histological type, grading and staging have been calculated. Kaplan-Meyer statistical elaboration for disease-free interval and Mann-Whitney test for the comparison of different clinical and pathological data have been employed.

RESULTS

The statistical analysis puts in evidence that on 432 cases examined, with a follow-up from 1 to 25 ys (median = 6.33 ys) and with a drop-out of 60 cases (13.8 %), total mortality for cancer has been of 24 cases (6,4%), with a median interval free by disease of 4.2 ys (range 5 months to 25 ys), and a probability to stay free by disease at 12 and 24 months respectively of 95.1% and 91.6%. The median survival is resulted of 5.8 ys (range 1 to 25 ys) with a probability of survival at 24 and 48 months respectively of 97.5% and 94.3%. The multivariate analysis evidences the most important variables, i.e. age > 45 ys, tumor of intermediate malignancy, with size 1.5 cm, operative M+, significantly condition the prognosis, noticeably getting worse it, independently by the kind of carried out operation.

CONCLUSION

Our present therapeutic choices are: 1. total thyroidectomy in the treatment of the apparently benign pathology when bilaterally with spread; the checking at the final histological exam of a cancer makes however think adequate the carried out operation; 2. lobo-isthmectomy in the treatment of unilateral benign pathology or with suspect FNAB for follicular neoplasm; the histological checking of a cancer makes think the operation adequate only in presence of favourable prognostic parameters, but in presence even of just one unfavourable variable, we consider necessary the totalization; 3. total thyroidectomy in presence of a certain or strongly suspected preoperative diagnosis of cancer.

Fine needle aspiration cytology of thyroid nodules: conventional vs thin layer technique

OBJECTIVE

Liquid-based cytology using the thin layer technique has recently been introduced in thyroid fine needle aspiration cytology together with or in substitution of direct smears, but its usefulness is still controversial and relatively few studies have been published in this field. The aim of the present study was to compare the results obtained from conventional smears with those from thin layer smears.

DESIGN

In 3875 thyroid nodules, a double cytologic sampling was taken in randomized order, to prepare conventional or thin layer smears.

MAIN OUTCOME

The diagnoses agreed in 2934 (75.7%) cases and disagreed in 941 (24.3%). The analysis of discordant data showed there were fewer non-diagnostic cases in the thin layer smears (377 vs 541, p<0.001) whereas in conventional smears there were more cases positive for carcinoma (27 vs 4, p<0.001). The cytohistologic correlation was available for 194 cases and showed that conventional smears had a greater capacity for revealing carcinomas (44 vs 31). Finally, diagnoses based on conventional smears were more sensitive than thin layer smears (93.6% vs 65.9%) whereas specificity was constant.

CONCLUSIONS

From our experience, the conventional smear offers a greater possibility of diagnosis when suspecting malignancy or diagnosing malignancy cases, whereas thin layer smears significantly reduce the number of non-diagnostic cases. For this reason, we suggest combining the two techniques in routine cytologic diagnosis.

[Molecular medicine in thyroid surgery]

Cancer originates from a single cell which, through the acquisition of mutations in genes for key growth and survival factors, undergoes clonal expansion. Study of the genome allowed the detection of genes whose mutation is involved in tumour formation. In detail, in most thyroid neoplasms we are now able to identify the genes which cause cancer initiation. Moreover, correlations between mutations and clinico-pathological features of the tumours have been revealed. Thus, the genetic study of tumours is not anymore only a scientific curiosity, but a useful tool for the formulation of the more efficacious therapeutic and follow-up strategies. In this review we will summarize the more recent molecular medicine acquisitions in the thyroid cancer field and will describe their present and eventually future impact on the activity of the endocrine surgeon.

Doping and respiratory system

Historically many different drugs have been used to enhance sporting performances. The magic elixir is still elusive and the drugs are still used despite the heavy adverse effects. The respiratory system is regularly involved in this research probably because of its central location in the body with several connections to the cardiovascular system. Moreover people are aware that O2 consumption and its delivery to mitochondria firstly depend on ventilation and on the respiratory exchanges. The second step consists in the tendency to increase V'O2 max and to prolong its availability with the aim of improving the endurance time and to relieve the fatigue. Many methods and substances had been used in order to gain an artificial success. Additional oxygen, autologous and homologous transfusion and erythropoietin, mainly the synthetic type, have been administered with the aim of increasing the amount of oxygen being delivered to the tissues. Some compounds like stimulants and caffeine are endowed of excitatory activity on the CNS and stimulate pulmonary ventilation. They did not prove to have any real activity in supporting the athletic performances. Beta-adrenergic drugs, particularly clenbuterol, when administered orally or parenterally develop a clear illicit activity on the myosin fibres and on the muscles as a whole. Salbutamol, terbutaline, salmeterol and formoterol are legally admitted when administrated by MDI in the treatment of asthma. The prevalence of asthma and bronchial hyperactivity is higher in athletes than amongst the general population. This implies that clear rules must be provided to set a correct diagnosis of asthma in the athletes and a correct therapy to align with the actual guidelines according to the same rights of the "other" asthmatic patients.

Clinical prognosis in BRAF-mutated PTC

BRAF mutation has recently emerged as a potential prognostic marker for papillary thyroid carcinoma (PTC) due to several studies suggesting that it may condition the development of tumors with aggressive behavior. A study of the phenotypes of thyroid follicular cell lines and transgenic mice characterized by targeted expression of BRAF mutation indicates that, at variance with RET/PTC rearrangement, it induces or facilitates genomic instability and higher invasiveness and eventually deeper tumor de-differentiation and more significant suppression of apoptosis. An analysis of differential gene expression of PTCs harboring BRAF mutation versus PTCs characterized by other genetic alterations shows an important impairment of the expression of genes related to intra-thyroidal iodine metabolism machinery, up-regulation of Glut-1 mRNA, methylation-induced gene silencing of tumor suppressor genes and up-regulation of pro-angiogenetic proteins such as VEGF. Correlation of BRAF mutation with PTC clinico-pathological features yields controversial results, with several studies showing the association with unfavourable clinico-pathological qualities, while others do not confirm the findings. This review will summarize the studies in favor of or in contrast with a role of BRAF mutation as a prognostic marker in PTC. We will also indicate what information we still need in order to routinely introduce this indicator in clinical practice.

BRAF mutations in papillary thyroid carcinomas inhibit genes involved in iodine metabolism

CONTEXT

BRAF mutations are common in papillary thyroid carcinomas (PTCs). By affecting the expression of genes critically related to the development and differentiation of thyroid cancer, they may influence the prognosis of these tumors.

OBJECTIVE

Our objective was to characterize the expression of thyroid-specific genes associated with BRAF mutation in PTCs. DESIGN/SETTING AND PATIENTS: We examined the expression of key markers of thyrocyte differentiation in 56 PTCs with BRAF mutations (BRAF-mut) and 37 with wild-type BRAF (BRAF-wt). Eight samples of normal thyroid tissue were analyzed as controls. Quantitative PCR was used to measure mRNA levels for the sodium/iodide symporter (NIS), apical iodide transporter (AIT-B), thyroglobulin (Tg), thyroperoxidase (TPO), TSH receptor (TSH-R), the transcription factor PAX8, and glucose transporter type 1 (Glut1). NIS protein expression and localization was also analyzed by immunohistochemistry.

RESULTS

mRNA levels for all thyroid-specific genes were reduced in all PTCs vs. normal thyroid tissues. NIS, AIT-B, Tg, and TPO expression was significantly lower in BRAF-mut tumors than in the BRAF-wt group. Glut-1 transcript levels were increased in all PTCs, and additional increases were noted in BRAF-mut tumors. In both tumor subsets, the NIS protein that was expressed was abnormally retained in the cytoplasm.

CONCLUSION

BRAF V600E mutation in PTCs is associated with reduced expression of key genes involved in iodine metabolism. This effect may alter the effectiveness of diagnostic and/or therapeutic use of radioiodine in BRAF-mut PTCs.

[Intraoperative ultrasonography in the surgery of recurrence of well differentiated thyroid cancer]

Surgical resection is the only curative treatment option for local recurrence of well differentiated thyroid cancer. In our experience, we found that intraoperative ultrasonography can be of significant help in facilitating the localisation and complete resection of lesions. From 2005 to 2006, 12 patients with well differentiated thyroid tumour recurrences underwent intraoperative ultrasonography. Recurrences were easily identified and resected in all patients. Postoperative thyreoglobulin was not detected. Intraoperative ulrasonography can be of significant help in the identification of well differeniated thyroid tumour recurrences, particularly when the cancer is smaller than 10 mm in diameter, and can facilitate a more radical excision of the tumour.

Radioiodine uptake in non-lactating mammary glands: evidence for a causative role of hyperprolactinemia

CONTEXT

Radioiodine uptake is rarely observed in normal non-lactating breast tissue. Investigation of the in vivo regulation of iodide uptake in breast tissue may be useful for the induction of radioiodine uptake in breast cancer tissue for diagnostic and therapeutic purposes.

CASE REPORTS

We report the cases of two post-menopausal women who underwent radioiodine therapy for papillary thyroid carcinoma and in whom breast uptake of radioiodine on post-therapy whole body scan (WBS) was observed.

METHODS AND RESULTS

In both patients, elevated serum prolactin levels (123 ng/mL in patient 1 and 48 ng/mL in patient 2) were documented at the time when radioiodine uptake in the breast was observed. The hyperprolactinemia was due to prolonged treatment with the anti-dopaminergic neuroleptic risperidone in Case 1, and chronic renal failure in Case 2. When prolactin levels were normalized (by withdrawal of risperidone in Case 1 and with cabergoline in Case 2), breast tissue uptake was no longer evident on WBS.

CONCLUSION

These cases provide the first documented correlation between serum levels of endogenous prolactin and radioiodine uptake by involuted breast tissue in humans.

Evaluation of goiter using ultrasound criteria: a survey in a middle schoolchildren population of a mountain area in Central Italy

Iodine deficiency is still an important health care problem in the world. In Italy, as in most European countries, it is responsible for the development of mild to moderate endemic goiter. In 1995 we conducted a goiter survey in the Gubbio township, an area of Umbria region in Italy, close to the Appenine mountain chain. This study demonstrated a high prevalence of goiter in the middle schoolchildren population, indicating the presence of moderate endemic goiter. Soon after, a goiter prevention campaign aimed at implementing the consumption of iodinated salt was started. In 2001, a second survey was conducted in the middle schoolchildren (age 11-14 yr old) of Gubbio and neighbour townships. Eight hundred thirteen subjects were studied. Data obtained in 240 age-matched children, studied in the same area in 1995, were used for comparison to monitor changes 5 yr after the beginning of iodine prophylaxis. Thyroid volume was measured by ultrasonography. Gland volume was expressed in ml. A large population living in a iodine-sufficient area, previously reported by others, was used as control. Urinary iodine excretion was measured randomly in 20% of the children. The overall prevalence of goiter decreased between 1995 and 2001 from 29 to 8%. Goiter odds ratio (OR), corrected for age, was 4.0 (95% CI 2.8-5.9) for 1995 compared to 2001 (p<0.000). Mean thyroid volume in the matched populations was 7.6+/-2.5 ml in 1995 and 5.7+/-2.1 ml in 2001. Median iodine urinary excretion increased from 72.6 to 93.5 mug/l, at the limit of statistical significance. Living in a rural area, no consumption of iodized salt and familiarity for goiter represented independent risk factors for goiter development. This study was the first conducted in Umbria region and confirmed that an implementation campaign for iodized salt consumption is a simple and useful instrument to prevent endemic goiter and related diseases. A new survey to evaluate goiter prevalence in the same area 10 yr after the beginning of iodine prophylaxis is already planned.

[Diagnostic-therapeutic pathways as instruments of clinical management: experience at the S. Maria Hospital in Terni]

Diagnostic-therapeutic itineraries and treatment profiles are instruments of clinical management. The authors report on their experience with the experimental creation of such itineraries in thyroid nodular pathology. These are the fruit of collaboration between the management team, endocrinological surgeons, and the hospital computer staff. The drawing-up of guidelines in the hospital setting allows the systematic organisation of clinical activities to be accomplished in the health-care facility, quantifying costs for all diseases in order to be able to plan and implement changes in resources and staff utilisation. Application of the method, in addition, helps to develop a common language among hospital doctors and nurses, facilitates proper communication with patients, and ensures adequate patient information regarding the clinical itinerary the patient will have to take for his or her condition.

Correlation between B-RAFV600E mutation and clinico-pathologic parameters in papillary thyroid carcinoma: data from a multicentric Italian study and review of the literature

Recently, a somatic point mutation of the B-RAF gene (V600E) has been identified as the most common genetic event in papillary thyroid carcinoma (PTC), with a prevalence variable among different series. Since discordant data on the clinico-pathologic features of B-RAF mutated PTC are present in the literature, the aim of the present co-operative study was to establish the prevalence of this genetic alteration and to perform a genotype-phenotype correlation in a large cohort of patients with PTC. To this purpose, a series of 260 sporadic PTCs with different histological variants were included in the study. The mutational analysis of the B-RAF gene was performed either by RT-PCR followed by single-stranded conformational polymorphism or by PCR and direct sequencing. Statistical analyses were obtained by means of chi2/Fisher's exact test and t-test. Overall, a heterozygous T > A transversion at nucleotide 1799 (V600E) was found in 99 out of 260 PTCs (38%). According to the histological type of the tumor, the B-RAF (V600E) mutation was present in 48.3% of cases of classic PTCs (85 out of 176), in 17.6% (nine out of 51) of follicular variants of PTCs, in 21.7% (five out of 23) in other PTC variants and in none of the ten poorly differentiated tumors. B-RAF (V600E) was significantly associated with the classic variant of PTC (P = 0.0001) and with an older age at diagnosis (P = 0.01). No statistically significant correlation was found among the presence of B-RAF (V600E) and gender, tumor node metastasis (TNM), multicentricity of the tumor, stage at diagnosis and outcome. In conclusion, the present study reports the prevalence of B-RAF (V600E) (38%) in the largest series of sporadic PTCs, including 260 cases from three different Italian referring centers. This prevalence is similar to that calculated by pooling together all data previously reported, 39.6% (759 out of 1914 cases), thus indicating that the prevalence of this genetic event lies around 38-40%. Furthermore, B-RAF (V600E) was confirmed to be associated with the papillary growth pattern, but not with poorer differentiated PTC variants. A significant association of B-RAF mutation was also found with an older age at diagnosis, the mutation being very rare in childhood and adolescent PTCs. Finally, no correlation was found with a poorer prognosis and a worse outcome after a median follow-up of 72 months.

Activating PTPN11 mutations play a minor role in pediatric and adult solid tumors

The PTPN11 gene encodes SHP-2, a widely expressed cytoplasmic protein tyrosine phosphatase functioning as a signaling transducer. Germ-line PTPN11 mutations cause Noonan syndrome (NS), a developmental disorder characterized by an increased risk of malignancies. Recently, a novel class of activating mutations in PTPN11 has been documented as a somatic event in a heterogeneous group of leukemias. Because of the relatively higher prevalence of certain solid tumors in children with NS and the positive modulatory function of SHP-2 in RAS signaling, a wider role for activating PTPN11 mutations in cancer has been hypothesized. Here, we screened a number of solid tumors, including those documented in NS or in which deregulated RAS signaling occurs at significant frequency, for PTPN11 mutations. No disease-associated mutation was identified in rhabdomyosarcoma (n = 13), neuroblastoma (n = 32), melanoma (n = 50), thyroid (n = 85), and colon (n = 48) tumors; a novel missense change, promoting an increased basal phosphatase activity of SHP-2, was observed in one glioma specimen. Our data document that deregulated SHP-2 function does not represent a major molecular event in pediatric and adult tumors, further supporting our previous evidence indicating that the oncogenic role of PTPN11 mutations is cell-context specific.

Biochemical and molecular characterization of the novel BRAFV599Ins mutation detected in a classic papillary thyroid carcinoma

Activating mutations of the BRAF gene are the most common genetic alterations in papillary thyroid carcinomas (PTCs) and the T1799A transversion, resulting in BRAFV600E, appeared virtually unique in this cancer type. Here, we report on the identification in a classic PTC of a novel BRAF mutation, namely a 1795GTT insertion, resulting in BRAFV599Ins, and describe its biochemical and molecular characterization. Kinase assays carried out on BRAFV599Ins and BRAFV600E revealed a three- to five-fold increase in the enzymatic activity of both mutants with respect to BRAFWT. Similarly, evaluation of BRAF-induced phosphorylation of MEK, MAPK and RSK revealed a significant MAPK cascade activation in cells expressing BRAFV599Ins or BRAFV600E, but not in cells expressing BRAFWT. Molecular dynamic simulations showed a destabilization of the inactive conformation of the enzyme in both BRAFV599Ins and BRAFV600E mutants, but not in BRAFWT. The analysis of the interaction energies inside the catalytic site allowed to demonstrate the presence of repulsive electrostatic forces acting on the activation loop and moving from inward to outward of the mutant enzymes. Finally, focus assays in NIH-3T3 cells confirmed a high transformation rate in the cells transfected either with BRAFV599Ins or BRAFV600E. In conclusion, this study demonstrated that BRAFV599Ins, as BRAFV600E, is a 'gain of function' mutation, characterized by a constitutive catalytic activation, which accounts for its causative role in the studied PTC.

Genotyping of an Italian papillary thyroid carcinoma cohort revealed high prevalence of BRAF mutations, absence of RAS mutations and allowed the detection of a new mutation of BRAF oncoprotein (BRAF(V599lns))

OBJECTIVES

The genes RET and RAS, and more recently BRAF, have been shown to be frequently mutated in human papillary thyroid carcinomas (PTC). The aim of this study was to genotype for these mutations a cohort of thyroid tumours collected at our institutions.

DESIGN AND PATIENTS

Thyroid tumours removed from 51 subjects were analysed, including 43 PTC and 8 non-PTC tumours [3 follicular adenomas (FA), 4 follicular carcinomas (FTC) and 1 anaplastic carcinoma (AC)].

MEASUREMENTS

RET/PTC1 and RET/PTC3 expression was evaluated by reverse transcriptase-polymerase chain reaction, whereas screening of BRAF (exon 15) and RAS (HRAS, KRAS2 and NRAS) mutations were performed, respectively, by single strand conformation polymorphism and denaturing high-pressure liquid chromatography.

RESULTS

RET/PTC expressions was positive in 5/43 (11.6%) PTC and in none of the non-PTC tumour. Similarly, BRAF mutations were positive only in PTC, but with a higher prevalence (24/43 positives, 55.8%). All but one BRAF mutation resulted in the prototypic substitution of valine 600 with a glutamic acid. In one case, a somatic in-frame insertion of three bases at codon 599 resulted in the insertion of an additional valine. RET/PTC expression and BRAF mutations were mutually exclusive. Screening of the RAS gene allowed identification of oncogenic mutations in 1/3 (33.3%) FA and 3/4 (75%) FTC. None of the PTCs was positive for RAS.

CONCLUSIONS

These data indicate that BRAF mutations are the most frequent genetic event in PTC and that RAS mutations, besides being a genetic hallmark of follicular tumours, are rare or completely absent in PTC from our area. Together, BRAF mutations and rarer RET rearrangements accounted for a genetic event in two-thirds of PTCs. This study showed a novel and presumably oncogenic mutation of BRAF, which is BRAF(V599Ins).

RET/PTC-induced gene expression in thyroid PCCL3 cells reveals early activation of genes involved in regulation of the immune response

RET/PTC rearrangements represent key genetic events involved in papillary thyroid carcinoma (PTC) initiation. The aim of the present study was to identify the early changes in gene expression induced by RET/PTC in thyroid cells. For this purpose, microarray analysis was conducted on PCCL3 cells conditionally expressing the RET/PTC3 oncogene. Gene expression profiling 48 h after activation of RET/PTC3 identified a statistically significant modification of expression of 270 genes. Quantitative PCR confirmation of 20 of these demonstrated 90% accuracy of the microarray. Functional clustering of genes with greater than or less than 1.75-fold expression change (86 genes) revealed RET/PTC3-induced regulation of genes with key functions in apoptosis (Ripk3, Tdga), cell-cell signaling (Cdh6, Fn1), cell cycle (Il24), immune and inflammation response (Cxcl10, Scya2, Il6, Gbp2, Oas1, Tap1, RT1Aw2, C2ta, Irf1, Lmp2, Psme2, Prkr), metabolism (Aldob, Ptges, Nd2, Gss, Gstt1), signal transduction (Socs3, Nf1, Jak2, Cpg21, Dusp6, Socs1, Stat1, Stat3, Cish) and transcription (Nr4a1, Junb, Hfh1, Runx1, Foxe1). Genes coding for proteins involved in the immune response and in intracellular signal transduction pathways activated by cytokines and chemokines were strongly represented, indicating a critical role of RET/PTC3 in the early modulation of the immune response.

Characterization of novel non-clonal intrachromosomal rearrangements between the H4 and PTEN genes (H4/PTEN) in human thyroid cell lines and papillary thyroid cancer specimens

The two main forms of RET rearrangement in papillary thyroid carcinomas (PTC) arise from intrachromosomal inversions fusing the tyrosine kinase domain of RET with either the H4 (RET/PTC1) or the ELE1/RFG genes (RET/PTC3). PTEN codes for a dual-specificity phosphatase and maps to chromosome 10q22-23. Germline mutations confer susceptibility to Cowden syndrome whereas somatic mutations or deletions are common in several sporadic human tumors. Decreased PTEN expression has been implicated in thyroid cancer development. We report the characterization of a new chromosome 10 rearrangement involving H4 and PTEN. The initial H4/PTEN rearrangement was discovered as a non-specific product of RT-PCR for RET/PTC1 in irradiated thyroid cell lines. Sequencing revealed a transcript consisting of exon 1 and 2 of H4 fused with exons 3-6 of PTEN. Nested RT-PCR with specific primers bracketing the breakpoints confirmed the H4/PTEN rearrangements in irradiated KAT-1 and KAT-50 cells. Additional H4/PTEN variants, generated by recombination of either exon 1 or exon 2 of H4 with exon 6 of PTEN, were found in non-irradiated KAK-1, KAT-50, ARO and NPA cells. Their origin through chromosomal recombination was confirmed by detection of the reciprocal PTEN/H4 product. H4/PTEN recombination was not a clonal event in any of the cell lines, as Southern blots with appropriate probes failed to demonstrate aberrant bands, and multicolor FISH of KAK1 cells with BAC probes for H4 and PTEN did not show a signal overlap in all cells. Based on PCR of serially diluted samples, the minimal frequency of spontaneous recombination between these loci was estimated to be approximately 1/10(6) cells. H4/PTEN products were found by nested RT-PCR in 4/14 normal thyroid tissues (28%) and 14/18 PTC (78%) (P<0.01). H4/PTEN is another example of recombination involving the H4 locus, and points to the high susceptibility of thyroid cells to intrachromosomal gene rearrangements. As this also represents a plausible mechanism for loss-of-function of PTEN, other thyroid neoplastic phenotypes and eventually other cancer types need to be screened for clonal H4/PTEN rearrangements.

BRAF(V599E) mutation is the leading genetic event in adult sporadic papillary thyroid carcinomas

Activating mutations of BRAF have been identified in a variety of human cancers, most notably melanomas and papillary thyroid carcinomas (PTCs). The aim of the present study was to disclose the role of BRAF mutations in thyroid carcinoma development. Seventy-two thyroid tumors, including 60 PTCs, six follicular adenomas, five follicular carcinomas, and one anaplastic carcinoma, were studied. BRAF mutation screening focused on exon 15 and exon 11 of the gene by single-stranded conformational polymorphism and sequence analysis. Search of RET/PTC expression was conducted with the RT-PCR technique. The molecular genetic study of the BRAF gene showed the presence of a missense thymine to adenine transversion at nucleotide 1796, resulting in the V599E substitution, in 24 of 60 PTCs (40%), none of six follicular adenomas, and none of five follicular carcinomas or one anaplastic carcinoma. Moreover, nine of 60 PTCs (15%) presented RET/PTC expression. A genetico-clinical association analysis showed a statistically significant correlation between BRAF mutation and development of PTCs of the classic papillary histotype (P = 0.038). On the contrary, no link could be detected between expression of BRAF(V599E) and age at diagnosis, gender, dimension, and local invasiveness of the primary cancer, presence of lymph node metastases, tumor stage, and multifocality of the disease. These data clearly confirm that BRAF(V599E) is the more common genetic alteration found to date in adult sporadic PTCs, that it is unique for this thyroid cancer histotype, and that it might drive the development of PTCs of the classic papillary subtype.

Microsomal Prostaglandin E2 Synthase-1 Is Induced by Conditional Expression of RET/PTC in Thyroid PCCL3 Cells through the Activation of the MEK-ERK Pathway

RET/PTC rearrangements are believed to be tumor-initiating events in papillary thyroid carcinomas. We identified microsomal prostaglandin E2 synthase-1 (mPGES-1) as a RET/PTC-inducible gene through subtraction hybridization cloning and expression profiling with custom microarrays. The inducible prostaglandin E2 (PGE2) biosynthetic enzymes cyclooxygenase-2 (COX-2) and mPGES-1 are up-regulated in many cancers. COX-2 is overexpressed in thyroid malignancies compared with benign nodules and normal thyroid tissues. Eicosanoids may promote tumorigenesis through effects on tumor cell growth, immune surveillance, and angiogenesis. Conditional RET/PTC1 or RET/PTC3 expression in PCCL3 thyroid cells markedly induced mPGES-1 and COX-2. PGE2 was the principal prostanoid and up-regulated (by approximately 60-fold), whereas hydroxyeicosatetraenoic acid metabolites were decreased, consistent with shunting of prostanoid biosynthesis toward PGE2 by coactivation of the two enzymes. RET/PTC activated mPGES-1 gene transcription. Based on experiments with kinase inhibitors, with PCCL3 cell lines with doxycycline-inducible expression of RET/PTC mutants with substitutions of critical tyrosine residues in the kinase domain, and lines with inducible expression of activated mutants of H-RAS and MEK1, RET/PTC was found to regulate mPGES-1 through Shc-RAS-MEK-ERK. These data show a direct relationship between activation of a tyrosine kinase receptor oncogene and regulation of PGE2 biosynthesis. As enzymes involved in prostanoid biosynthesis can be targeted with pharmacological inhibitors, these findings may have therapeutic implications.