Significance of Furin Expression in Thyroid Neoplastic Transformation

Angiotensin-Converting Enzyme 2 (ACE2), Transmembrane Serine Protease 2 (TMPRSS2), and Furin were known to be key players in the SARS-CoV-2 infection, and the thyroid gland was revealed to be one of the relevant targets of the virus. Regardless of the viral infection, the expression of these molecules in the thyroid gland and their putative role in the neoplastic transformation of the thyrocytes has not been thoroughly explored. In this work, we aimed to characterize the mRNA and protein expression pattern of ACE2, TMPRSS2, and Furin in a series of patients with thyroid lesions. Our main results revealed a significantly decreased expression of ACE2 mRNA in the thyroid neoplasms in comparison to normal adjacent tissue. Furin mRNA was significantly increased in thyroid neoplasms when compared to normal adjacent tissue. In addition, a higher Furin mRNA level in thyroid carcinomas was associated with the presence of lymph node metastasis. Furin mRNA expression revealed a high discriminatory power between adjacent tissue and neoplasms. Protein expression of these molecules did not correlate with mRNA expression. Our study shows the mRNA downregulation of ACE2 and overexpression of Furin in thyroid neoplasms. Further studies are required to clarify if Furin expression can be a potential diagnostic indicator in thyroid neoplasia.

Using a Dual CRISPR/Cas9 Approach to Gain Insight into the Role of LRP1B in Glioblastoma

LRP1B remains one of the most altered genes in cancer, although its relevance in cancer biology is still unclear. Recent advances in gene editing techniques, particularly CRISPR/Cas9 systems, offer new opportunities to evaluate the function of large genes, such as LRP1B. Using a dual sgRNA CRISPR/Cas9 gene editing approach, this study aimed to assess the impact of disrupting LRP1B in glioblastoma cell biology. Four sgRNAs were designed for the dual targeting of two LRP1B exons (1 and 85). The U87 glioblastoma (GB) cell line was transfected with CRISPR/Cas9 PX459 vectors. To assess LRP1B-gene-induced alterations and expression, PCR, Sanger DNA sequencing, and qRT-PCR were carried out. Three clones (clones B9, E6, and H7) were further evaluated. All clones presented altered cellular morphology, increased cellular and nuclear size, and changes in ploidy. Two clones (E6 and H7) showed a significant decrease in cell growth, both in vitro and in the in vivo CAM assay. Proteomic analysis of the clones' secretome identified differentially expressed proteins that had not been previously associated with LRP1B alterations. This study demonstrates that the dual sgRNA CRISPR/Cas9 strategy can effectively edit LRP1B in GB cells, providing new insights into the impact of LRP1B deletions in GBM biology.

Spotlight on hTERT Complex Regulation in Cutaneous T-Cell Lymphomas

As a major cancer hallmark, there is a sustained interest in understanding the telomerase contribution to carcinogenesis in order to therapeutically target this enzyme. This is particularly relevant in primary cutaneous T-cell lymphomas (CTCL), a malignancy showing telomerase dysregulation with few investigative data available. In CTCL, we examined the mechanisms involved in telomerase transcriptional activation and activity regulation. We analyzed 94 CTCL patients from a Franco-Portuguese cohort, as well as 8 cell lines, in comparison to 101 healthy controls. Our results showed that not only polymorphisms (SNPs) located at the promoter of human telomerase reverse transcriptase (hTERT) gene (rs2735940 and rs2853672) but also an SNP located within the coding region (rs2853676) could influence CTCL occurrence. Furthermore, our results sustained that the post-transcriptional regulation of hTERT contributes to CTCL lymphomagenesis. Indeed, CTCL cells present a different pattern of hTERT spliced transcripts distribution from the controls, mostly marked by an increase in the hTERT β+ variants proportion. This increase seems to be associated with CTCL development and progression. Through hTERT splicing transcriptome modulation with shRNAs, we observed that the decrease in the α-β+ transcript induced a decrease in the cell proliferation and tumorigenic capacities of T-MF cells in vitro. Taken together, our data highlight the major role of post-transcriptional mechanisms regulating telomerase non canonical functions in CTCL and suggest a new potential role for the α-β+ hTERT transcript variant.

Detection of SARS-CoV-2 infection in thyroid follicular cells from a COVID-19 autopsy series

OBJECTIVE

To understand whether thyroid cells can be directly infected by the SARS-CoV-2 virus and to establish a putative correlation with the expression of the host entry machinery: ACE-2, TMPRSS2, and furin.

METHODS

We assessed the presence of SARS-CoV-2 virus at the gene level by RT-PCR, viral RNA transcripts localization by in situ hybridization, and by detecting viral proteins by immunohistochemistry for the nucleocapsid and the spike proteins. Furthermore, we also described the immunoexpression of key host factors for virus entry in the COVID-19 thyroid samples.

RESULTS

We performed RT-PCR for SARS-CoV-2 in all autopsy specimens and detected viral genome positivity in 13 of 15 thyroid tissues and in a lung specimen. In 9 of the 14 positive samples, we were also able to confirm SARS-CoV-2 signal by in situ hybridization. Immunohistochemistry for the viral nucleocapsid and spike protein was also positive for ten and nine of the RT-PCR-positive cases, respectively, but revealed a lower sensitivity. We also described, for the first time in a COVID-19 series, the immunohistochemical expression of ACE-2, TMPRSS2, and furin in the thyroid.

CONCLUSIONS

Our results obtained in thyroid specimens from deceased COVID-19 patients indicate that thyrocytes can be directly infected by SARS-CoV-2 since we detected the presence of SARS-CoV-2 genome in follicular cells. Nevertheless, we did not find a clear correlation between the presence of viral genome and the expression of the host factors for virus entry, namely ACE-2, TMPRSS2, and furin.

Genetic Determinants for Prediction of Outcome of Patients with Papillary Thyroid Carcinoma

Papillary thyroid carcinoma (PTC) usually presents an excellent prognosis, but some patients present with aggressive metastatic disease. BRAF, RAS, and TERT promoter (TERTp) genes are altered in PTC, and their impact on patient outcomes remains controversial. We aimed to determine the role of genetic alterations in PTC patient outcomes (recurrent/persistent disease, structural disease, and disease-specific mortality (DSM)). The series included 241 PTC patients submitted to surgery, between 2002-2015, in a single hospital. DNA was extracted from tissue samples of 287 lesions (primary tumors and metastases). Molecular alterations were detected by Sanger sequencing. Primary tumors presented 143 BRAF, 16 TERTp, and 13 RAS mutations. Isolated TERTpmut showed increased risk of structural disease (HR = 7.0, p < 0.001) and DSM (HR = 10.1, p = 0.001). Combined genotypes, BRAFwt/TERTpmut (HR = 6.8, p = 0.003), BRAFmut/TERTpmut (HR = 3.2, p = 0.056) and BRAFmut/TERTpwt (HR = 2.2, p = 0.023) showed increased risk of recurrent/persistent disease. Patients with tumors BRAFwt/TERTpmut (HR = 24.2, p < 0.001) and BRAFmut/TERTpmut (HR = 11.5, p = 0.002) showed increased risk of structural disease. DSM was significantly increased in patients with TERTpmut regardless of BRAF status (BRAFmut/TERTpmut, log-rank p < 0.001; BRAFwt/TERTpmut, log-rank p < 0.001). Our results indicate that molecular markers may have a role in predicting PTC patients' outcome. BRAFmut/TERTpwt tumors were prone to associate with local aggressiveness (recurrent/persistent disease), whereas TERTpmut tumors were predisposed to recurrent structural disease and DSM.

Evaluation of the role of mitochondria in the non-targeted effects of ionizing radiation using cybrid cellular models

Radiobiology is moving towards a better understanding of the intercellular signaling that occurs upon radiation and how its effects relate to the dose applied. The mitochondrial role in orchestrating this biological response needs to be further explored. Cybrids (cytoplasmic hybrids) are useful cell models for studying the involvement of mitochondria in cellular processes. In the present study we used cybrid cell lines to investigate the role of mitochondria in the response to radiation exposure. Cybrid cell lines, derived from the osteosarcoma human cell line 143B, harboring, either wild-type mitochondrial DNA (Cy143Bwt), cells with mitochondria with mutated DNA that causes mitochondrial dysfunction (Cy143Bmut), as well as cells without mitochondrial DNA (mtDNA) (143B-Rho0), were irradiated with 0.2 Gy and 2.0 Gy. Evaluation of the non-targeted (or bystander) effects in non-irradiated cells were assessed by using conditioned media from the irradiated cells. DNA double stranded breaks were assessed with the γH2AX assay. Both directly irradiated cells and cells treated with the conditioned media, showed increased DNA damage. The effect of the irradiated cells media was different according to the cell line it derived from: from Cy143Bwt cells irradiated with 0.2 Gy (low dose) and from Cy143Bmut irradiated with 2.0 Gy (high dose) induced highest DNA damage. Notably, media obtained from cells without mtDNA, the143B-Rho0 cell line, produced no effect in DNA damage. These results point to a possible role of mitochondria in the radiation-induced non-targeted effects. Furthermore, it indicates that cybrid models are valuable tools for radiobiological studies.

Interaction of Genetic Variations in NFE2L2 and SELENOS Modulates the Risk of Hashimoto's Thyroiditis

Background: Several single-nucleotide polymorphisms (SNPs) are known to increase the risk of Hashimoto's thyroiditis (HT); such SNPs reside in thyroid-specific genes or in genes related to autoimmunity, inflammation, and/or cellular defense to stress. The transcription factor Nrf2, encoded by NFE2L2, is a master regulator of the cellular antioxidant response. This study aimed to evaluate the impact of genetic variation in NFE2L2 on the risk of developing HT. Methods: In a case-control candidate gene association study, functional SNPs in the NFE2L2 promoter (rs35652124, rs6706649, and rs6721961) were examined either as independent risk factors or in combination with a previously characterized HT risk allele (rs28665122) in the gene SELENOS, encoding selenoprotein S (SelS). A total of 997 individuals from the north of Portugal (Porto) were enrolled, comprising 481 HT patients and 516 unrelated healthy controls. SELENOS and NFE2L2 SNPs were genotyped using TaqMan^® assays and Sanger sequencing, respectively. Odds ratios (ORs) were calculated using logistic regression, with adjustment for sex and age. Expression of SelS was analyzed by immunohistochemistry in thyroid tissue from HT patients and control subjects. Molecular interactions between the Nrf2 and SelS pathways were investigated in thyroid tissues from mice and in rat PCCL3 thyroid follicular cells. Results: When all three NFE2L2 SNPs were considered together, the presence of one or more minor alleles was associated with a near-significant increased risk (OR = 1.43, p = 0.072). Among subjects harboring only major NFE2L2 alleles, there was no increased HT risk associated with heterozygosity or homozygosity for the SELENOS minor allele. Conversely, in subjects heterozygous or homozygous for the SELENOS risk allele, the presence of an NFE2L2 minor allele significantly increased HT risk by 2.8-fold (p = 0.003). Immunohistochemistry showed reduced expression of SelS in thyroid follicular cells of HT patients. In Nrf2 knockout mice, there was reduced expression of SelS in thyroid follicular cells; conversely, in PCCL3 cells, reducing SelS expression caused reduced activity of Nrf2 signaling. Conclusions: The NFE2L2 promoter genotype interacts with the SELENOS promoter genotype to modulate the risk of HT in a Portuguese population. This interaction may be due to a bidirectional positive feedback between the Nrf2 and SelS pathways.

OPNa Overexpression Is Associated with Matrix Calcification in Thyroid Cancer Cell Lines

Osteopontin (OPN) spliced variants (OPN-SV: OPNa, OPNb, and OPNc) are aberrantly expressed in tumors and frequently associated with cancer progression. This holds true for papillary thyroid carcinoma (PTC), which is the most common type of thyroid cancer (TC). PTC often presents with desmoplasia and dystrophic calcification, including psammoma bodies (PB). This work aimed to investigate total OPN (tOPN) and OPN-SV expression and their association with the presence of PB in the PTC classical variants (cPTC), as well as the involvement of OPN-SV in matrix calcification of TC cell lines. We found that cPTC samples presenting PB showed higher OPN expression levels. In TC cell lines, OPNa overexpression promotes higher matrix calcification and collagen synthesis when compared to that of clones overexpressing OPNb or OPNc. In response to OPN knockdown, calcification was inhibited, paralleled with the downregulation of calcification markers. In conclusion, our data evidenced that OPN expression is associated with the presence of PB in cPTC samples. Among the OPN-SV, OPNa is the main contributor to matrix calcification in tested TC cells, providing clues to a better understanding on the biology and ethiopathogenesis of the calcification process in TC cells.

TERTp mutation is associated with a shorter progression free survival in patients with aggressive histology subtypes of follicular-cell derived thyroid carcinoma

PURPOSE

Evaluate the impact of TERTp mutation on the outcomes after initial treatment of 45 patients with thyroid carcinomas derived from follicular cells (TCDFC) with aggressive histology, in which the role of this mutation is not yet well defined.

METHODS

Analysis of the presence of TERTp (-124C > T and -146C > T), BRAF (V600E), and NRAS (Q 61R) mutations by Sanger sequencing and analysis of their correlation with the patient's outcomes.

RESULTS

Forty-five patients with aggressive histopathologic variants were included in the study. Of these, 68.9% had aggressive variants of papillary thyroid cancer (PTC), 22.2% had poorly differentiated thyroid carcinoma (PDTC)/insular carcinoma, and 8.9% had invasive follicular thyroid cancer (FTC) with Hurthle cell features (Hurthle cell carcinoma). Lymph node metastases were present in 46.7% and distant metastases in 54.6%. The response to the initial therapy was excellent in 45.5% and structurally incomplete in 50%. During the follow-up period (median of 56 months; 5-360 months), 47.7% presented with disease progression and 17.8% experienced disease-related death. In 53.3% of the cases at least one molecular alteration (TERTp in 33.4%, BRAF in 24.5%, RAS in 8.9%) was detected. In the multivariate analysis, TERTp mutation was the factor associated with the highest risk (6 times) of having structural disease after initial therapy (p = 0.01), followed by vascular invasion (p = 0.02), gross extrathyroidal extension (ETE) (p = 0.02) and distant metastasis (p = 0.04). Regarding mutational status, only TERTp mutation was associated with disease progression, and diminished disease progression-free survival (PFS). The presence of distant metastasis, vascular invasion and gross ETE were significantly associated with the risk of disease progression.

CONCLUSIONS

TERTp mutation appears be an indicator of both persistence and progression of structural disease after initial therapy in aggressive variants of TCDFC, and associates with a shorter progression free survival regardless of the therapy employed.

TERT promoter mutations are associated with poor prognosis in cutaneous squamous cell carcinoma

BACKGROUND

Telomerase reverse transcriptase gene (TERT) promoter (TERTp) mutations have been reported as potential predictors of poor prognosis in several cancers, but the prognostic value of TERTp mutations for cutaneous squamous cell carcinoma (cSCC) has not been determined.

OBJECTIVE

To evaluate the frequency of TERTp mutations and correlate it with clinicopathologic features and patient outcome.

METHODS

We performed genetic profiling of TERTp mutations in a retrospective series of cSCCs. The predictive value of TERTp mutations and clinicopathologic parameters were assessed by using logistic regression models.

RESULTS

A total of 152 cSCCs from 122 patients were analyzed for TERTp mutations; the mutation rate was 31.6% (48 of 152), and it was higher in invasive cSCC (42 of 121 [34.7%]) than in in situ cSCC (6 of 31 [19.4%]). Age older than 75 years (odds ratio [OR], 14.84; P = .013] and TERTp mutation (OR, 8.11; P = .002) were independent predictors of local recurrence. TERTp mutation (OR, 15.89; P = .022) was independently associated with higher risk of lymph node metastasis.

LIMITATIONS

The restricted number of metastatic cases.

CONCLUSION

TERTp mutations may prove to be a molecular biomarker with prognostic significance in invasive cSCC, but larger studies are needed.

Abstract 180: OPNa variant expression is associated with matrix mineralization in thyroid cancer cell lines

Osteopontin (OPN) and its three spliced variants (OPN-SV: OPNa, OPNb and OPNc) are overexpressed in several tumors and frequently associated with cancer progression. This holds true for papillary thyroid carcinoma (PTC), which is the most common variety of thyroid cancer (TC), being the histologic type which often presents desmoplasia (collagen deposition) and dystrophic calcification, including a fairly typical feature, the psammoma bodies (PB). This study aims to investigate the OPN-SV expression in classical variant of PTC (cPTC) and the role of OPN in calcification and collagen deposition into the extracellular matrix of thyroid cancer cell lines. Total OPN and OPN-SV expression was analyzed by immunohistochemistry and real time PCR in a series of 48 cPTC cases and three diffuse sclerosing PTCs. The association of OPN expression and the presence of PB as well as between PB in cPTC and the clinicopathological features of the tumors were evaluated. TPC-1 and c643 TC cell lines overexpressing OPN-SV were tested for the ability to promote calcification and to synthesize collagen in vitro. We also evaluated the expression of calcification markers, including osteocalcin and collagen I. Overexpression of OPNa transcripts was significantly associated with the presence of PB in cPTC samples. The presence of PB in cPTC was associated with younger patients and lymph node metastasis. Moreover, OPNa overexpression displayed a strong capacity to promote calcification and substantial collagen deposition in thyroid cancer cell lines. Upon OPN knockdown, the mRNA expression levels of calcification markers (osteocalcin and collagen I) were downregulated, further evidencing the involvement of OPN on activating these processes. Our data suggest that OPNa plays a role in the extracellular matrix calcification associated with cPTC. Basic research on the interactions between OPNa overexpression by tumor cells and the surrounding microenvironment can give clues for a better understanding of cPTC biology and phenotype.

Citation Format: Luciana B. Ferreira, Raquel T. Lima, Ana Clara Santos da Fonseca Bastos, Andreia Machado Silva, Catarina Tavares, Ana Pestana, Elisabete Rios, Catarina Eloy, Manuel Sobrinho-Simões, Etel Rodrigues Pereira Gimba, Paula Soares. OPNa variant expression is associated with matrix mineralization in thyroid cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 180.

CRABP1, C1QL1 and LCN2 are biomarkers of differentiated thyroid carcinoma, and predict extrathyroidal extension

Background

The prognostic variability of thyroid carcinomas has led to the search for accurate biomarkers at the molecular level. Follicular thyroid carcinoma (FTC) is a typical example of differentiated thyroid carcinomas (DTC) in which challenges are faced in the differential diagnosis.

Methods

We used high-throughput paired-end RNA sequencing technology to study four cases of FTC with different degree of capsular invasion: two minimally invasive (mFTC) and two widely invasive FTC (wFTC). We searched by genes differentially expressed between mFTC and wFTC, in an attempt to find biomarkers of thyroid cancer diagnosis and/or progression. Selected biomarkers were validated by real-time quantitative PCR in 137 frozen thyroid samples and in an independent dataset (TCGA), evaluating the diagnostic and the prognostic performance of the candidate biomarkers.

Results

We identified 17 genes significantly differentially expressed between mFTC and wFTC. C1QL1, LCN2, CRABP1 and CILP were differentially expressed in DTC in comparison with normal thyroid tissues. LCN2 and CRABP1 were also differentially expressed in DTC when compared with follicular thyroid adenoma. Additionally, overexpression of LCN2 and C1QL1 were found to be independent predictors of extrathyroidal extension in DTC.

Conclusions

We conclude that the underexpression of CRABP1 and the overexpression of LCN2 may be useful diagnostic biomarkers in thyroid tumours with questionable malignity, and the overexpression of LCN2 and C1QL1 may be useful for prognostic purposes.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3948-3) contains supplementary material, which is available to authorized users.

NIS expression in thyroid tumors, relation with prognosis clinicopathological and molecular features

Thyroid cancer therapy is based on surgery followed by radioiodine treatment. The incorporation of radioiodine by cancer cells is mediated by sodium iodide symporter (NIS) (codified by the SLC5A5 gene), that is functional only when targeted to the cell membrane. We aimed to evaluate if NIS expression in thyroid primary tumors would be helpful in predicting tumor behavior, response to therapy and prognosis. NIS expression was addressed by qPCR and immunohistochemistry. In order to validate our data, we also studied SLC5A5 expression on 378 primary papillary thyroid carcinomas from The Cancer Genome Atlas (TCGA) database. In our series, SLC5A5 expression was lower in carcinomas with vascular invasion and with extrathyroidal extension and in those harboring BRAFV600E mutation. Analysis of SLC5A5 expression from TCGA database confirmed our results. Furthermore, it showed that larger tumors, with locoregional recurrences and/or distant metastases or harboring RAS, BRAF and/or TERT promoter (TERTp) mutations presented significantly less SLC5A5 expression. Regarding immunohistochemistry, 12/211 of the cases demonstrated NIS in the membrane of tumor cells, those cases showed variable outcomes concerning therapy success, prognosis and all but one were wild type for BRAF, NRAS and TERTp mutations. SLC5A5 mRNA lower expression is associated with features of aggressiveness and with key genetic alterations involving BRAF, RAS and TERTp. Mutations in these genes seem to decrease protein expression and its targeting to the cell membrane. SLC5A5 mRNA expression is more informative than NIS immunohistochemical expression regarding tumor aggressiveness and prognostic features.

TERT biology and function in cancer: beyond immortalisation

Evasion of replicative senescence and proliferation without restriction, sometimes designated as immortalisation, is one of the hallmarks of cancer that may be attained through reactivation of telomerase in somatic cells. In contrast to most normal cells in which there is lack of telomerase activity, upregulation of TERT transcription/activity is detected in 80-90% of malignant tumours. In several types of cancer, there is a relationship between the presence of TERT promoter mutations, TERT mRNA expression and clinicopathological features, but the biological bridge between the occurrence of TERT promoter mutations and the aggressive/invasive features displayed by the tumours remains unidentified. We and others have associated the presence of TERT promoter mutations with metastisation/survival in several types of cancer. In follicular cell-derived thyroid cancer, such mutations are associated with worse prognostic features (age of patients, tumour size and tumour stage) as well as with distant metastases, worse response to treatment and poorer survival. In this review, we analyse the data reported in several studies that imply TERT transcription reactivation/activity with cell proliferation, tumour invasion and metastisation. A particular attention is given to the putative connections between TERT transcriptional reactivation and signalling pathways frequently altered in cancer, such as c-MYC, NF-κB and B-Catenin.

TERT promoter mutations: a genetic signature of benign and malignant thyroid tumours occurring in the context of tinea capitis irradiation

OBJECTIVE

The aim of this study is to evaluate the frequency and molecular characteristics of TERTp mutations in thyroid adenomas and carcinomas occurring in the low-dose radiation exposure tinea capitis setting.

DESIGN AND METHODS

Twenty-seven patients with 34 well-differentiated thyroid carcinomas and 28 patients with 29 follicular adenomas diagnosed in a Portuguese tinea capitis cohort were studied. Blood samples were obtained from all the patients. Screening for TERTp mutations was performed by PCR amplification followed by Sanger sequencing. A series of 33 sporadic thyroid adenomas was used as control.

RESULTS

TERTp mutations were detected in six of the 28 patients with adenoma (21.4%) and in four of the 27 patients with carcinoma (14.8%). Three tumours (two carcinomas and one adenoma) had the tandem mutation -124/-125 GG>AA (30.0%), whereas the remaining seven had the -124G > A. The 20.7% frequency of TERTp mutations in adenomas contrasts with the absence of mutations in the adenomas from the control group and from most series on record, whereas the one found in carcinomas (11.8%) is similar to those reported in the literature for sporadic carcinomas.

CONCLUSION

TERTp mutations, including the tandem mutation -124/-125 GG>AA not described previously in thyroid tumours, appear to represent a genetic signature for thyroid tumours in patients submitted to low-dose X-ray irradiation. The high frequency of TERTp mutations in the adenomas of our cohort contrasts with their absence in sporadically occurring, as well as in adenomas of the Chernobyl series.

pmTOR is a marker of aggressiveness in papillary thyroid carcinomas

BACKGROUND

Activation of the mTOR pathway has been observed in thyroid cancer, but the biologic consequences regarding tumor behavior and patient prognosis remain poorly explored.

METHODS

We aimed to evaluate the associations of the mTOR pathway with clinicopathologic and molecular features and prognosis through the immunocharacterization of pmTOR and pS6 expression (as readouts of the pathway) in a series of 191 papillary thyroid carcinomas.

RESULTS

pmTOR expression was associated with distant metastases (P = .05) and persistence of disease (P = .05). Cases with greater expression of pmTOR were submitted to more ¹³¹I treatments (r[102] = 0.2; P = .02) and a greater cumulative dose of radioactive iodine (r[100] = 0.3; P = .01). Positive pmTOR expression showed to be an independent risk factor for distant metastases (odds ratio = 18.2; 95% confidence interval 2.1-157.9; P = .01). In contrast, pS6 expression was associated with absence of extrathyroid extension (P = .001), well-defined tumor margins (P = .05), and wild-type BRAF status (P = .01). There was no correlation between the expression of pmTOR and pS6 expression (r[140] = 0.1; P = .3).

CONCLUSION

pmTOR expression is an indicator of aggressive, metastatic papillary thyroid carcinoma, being possibly implicated in refractoriness to therapy, while pS6 expression is associated with less aggressive pathologic features. Further studies are needed to understand better the biologic consequences of activation of the mTOR pathway in the behavior of thyroid cancer, namely the contribution of other pmTOR downstream effectors.

TERT promoter mutations in pancreatic endocrine tumours are rare and mainly found in tumours from patients with hereditary syndromes

One of the hallmarks of cancer is its unlimited replicative potential that needs a compensatory mechanism for the consequential telomere erosion. Telomerase promoter (TERTp) mutations were recently reported as a novel mechanism for telomerase re-activation/expression in order to maintain telomere length. Pancreatic endocrine tumors (PETs) were so far recognized to rely mainly on the alternative lengthening of telomeres (ALT) mechanism. It was our objective to study if TERTp mutations were present in pancreatic endocrine tumors (PET) and could represent an alternative mechanism to ALT. TERTp mutations were detected in 7% of the cases studied and were mainly associated to patients harbouring hereditary syndromes. In vitro, using PET-derived cell lines and by luciferase reporter assay, these mutations confer a 2 to 4-fold increase in telomerase transcription activity. These novel alterations are able to recruit ETS transcription factor members, in particular GABP-α and ETV1, to the newly generated binding sites. We report for the first time TERTp mutations in PETs and PET-derived cell lines. Additionally, our data indicate that these mutations serve as an alternative mechanism and in an exclusive manner to ALT, in particular in patients with hereditary syndromes.

Osteopontin expression is correlated with differentiation and good prognosis in medullary thyroid carcinoma

BACKGROUND

Osteopontin (OPN) or secreted phosphoprotein 1 (SPP1) is a matricellular glycoprotein whose expression is elevated in various types of cancer and has been shown to be involved in tumourigenesis and metastasis in many malignancies, including follicular cell-derived thyroid carcinomas. Its role in C-cell-derived thyroid lesions and tumours remains to be established.

OBJECTIVE

The objective of this study is to clarify the role of OPN expression in the development of medullary thyroid carcinoma (MTC).

METHODS

OPN expression was analysed in a series of 116 MTCs by immunohistochemistry and by qPCR mRNA quantification of the 3 OPN isoforms (OPNa, OPNb and OPNc) in six cases from which fresh frozen tissue was available. Statistical tests were used to evaluate the relationship of OPN expression and the clinicopathological and molecular characteristics of patients and tumours.

RESULTS

OPN expression was detected in 91 of 116 (78.4%) of the MTC. We also observed high OPN expression in C-cell hyperplasia as well as in C-cells scattered in the thyroid parenchyma adjacent to the tumours. OPN expression was significantly associated with smaller tumour size, PTEN nuclear expression and RAS status, and suggestively associated with non-invasive tumours. OPNa isoform was expressed significantly at higher levels in tumours than in non-tumour samples. OPNb and OPNc presented similar levels of expression in all samples. Furthermore, OPNa isoform overexpression was significantly associated with reduced growth and viability in the MTC-derived cell line (TT).

CONCLUSION

The expression of OPN in normal C-cells and C-cell hyperplasia suggests that OPN is a differentiation marker of C-cells, rather than a marker of biological aggressiveness in this setting. At variance with other cancers, OPN expression is associated with good prognostic features in MTC.

Low frequency of TERT promoter mutations in gastrointestinal stromal tumors (GISTs)

Somatic mutations in the promoter region of telomerase reverse transcriptase (TERT) gene, mainly at positions c.-124 and c.-146 bp, are frequent in several human cancers; yet its presence in gastrointestinal stromal tumor (GIST) has not been reported to date. Herein, we searched for the presence and clinicopathological association of TERT promoter mutations in genomic DNA from 130 bona fide GISTs. We found TERT promoter mutations in 3.8% (5/130) of GISTs. The c.-124C>T mutation was the most common event, present in 2.3% (3/130), and the c.-146C>T mutation in 1.5% (2/130) of GISTs. No significant association was observed between TERT promoter mutation and patient's clinicopathological features. The present study establishes the low frequency (4%) of TERT promoter mutations in GISTs. Further studies are required to confirm our findings and to elucidate the hypothetical biological and clinical impact of TERT promoter mutation in GIST pathogenesis.

Molecular abnormalities of chromosome-19 in malignant gliomas - preferential involvement of the 19q13.2-q13.4 region

A deletion mapping analysis of chromosome 19 was performed on a series of 101 samples derived from malignant gliomas. A total of 35 tumors displayed different deletions for the loci studied (D19S21, D19S11, D19S74, D19S7, D19S8, CKM, and D19S22). In most instances, losses involving the long arm markers of chromosome 19 were observed, and only four samples were characterized by losses on the short arm. No tumor was found displaying loss of both short and long arm markers. The higher frequency of deletions was detected in tumors with a major oligodendroglial component: 76% of samples included in this group displayed losses at 19q. Among the astrocytic tumors, the frequency of 19q alterations varied as follows: 11% in pilocytic astrocytomas, 17% in astrocytomas grade II, 10% in anaplastic astrocytomas and 21% in glioblastoma multiforme. No ependymoma was found displaying allele loss on chromosome 19. The common region of overlap for the 19q deletions observed involves primarily the distal portion of the long arm, 19q13.2-q13.4. In agreement with previous reports, these data suggest the non-random involvement of a tumor suppressor gene located at 19q13 in the genesis or progression of malignant gliomas.

Linkage analysis and detection of somatic, postzygous RB1 mutations in Serbian retinoblastoma patients

PURPOSE

The etiology of retinoblastoma (RB) is mutational inactivation of two RB1 alleles, the prototype of tumor suppressor gene. The aim of this research was to reveal sporadic, postzygous RB1 gene mutations, in particular loss of heterozygosity (LOH), from formalin-fixed, paraffin-embedded tumor samples in RB patients, as well as tracking RB1 allele inheritance in 10 RB families.

METHODS

The mutational studies were carried out in the peripheral blood lymphocytes' DNA of 4 bilateral and 12 unilateral RB patients and DNAs from tumors from 3 bilateral and 10 unilateral patients. Tumor samples were collected from the same patients whose blood was analyzed. DNA was extracted and linkage analysis and microsatellite markers method were performed. LOH for two RB1 intragenic markers was analyzed.

RESULTS

Ten LOH were found in the area of two intragene microsatellite loci. Linkage analysis revealed inheritance of RB1 alleles in 10 families. LOH was found in 63.16% of tumors.

CONCLUSION

Peripheral blood lymphocytes' DNA gives better results as a control group for somatic mutations than DNA isolated from eye tissue outside the tumor. Linkage analysis is essential for identifying the individual risk, offering the possibility of an adequate genetic counseling in familial RB.

Allelic status of 1p, 14q, and 22q and NF2 gene mutations in sporadic schwannomas

Schwannomas are common benign tumours of schwann cell origin, frequently found in patients with neurofibromatosis type 2 (NF2). Inactivation of the NF2 tumour suppressor gene appears to be a molecular event responsible for the development of up to 60% of cases, but no data are available on other superimposed secondary or alternative molecular abnormalities in those schwannomas lacking NF2 gene inactivation. We analysed 23 sporadic schwannomas for mutations in the NF2 gene and for the allelic status at 1p, 14q and 22q, as alterations of these genomic regions appear to be related to tumour progression in meningiomas, another NF2-associated neoplasm. Nine samples displayed allelic losses for markers on chromosome 22, and deletions at 1p were detected in two. No case showed losses for 14q. Three tumours displayed NF2 gene mutations, at exons 2, 7 and 12. Our results confirm that inactivation of the NF2 gene is a primary event in schwannoma development, and provide data suggesting that allelic loss at 1p may contribute to the pathogenesis of a small subgroup of this histological tumour type.

Six novel mutations in the NF2 tumor suppressor gene

Six novel mutations were identified in the NF2 tumor suppressor gene in a panel of meningiomas and neurinomas. Screening was performed using a combination of single-strand conformation polymorphism and heteroduplex analyses on polymerase chain reaction-amplified DNA from tumors and matched peripheral blood lymphocytes. Mutations involved exons 2, 7, 11 and 12, and corresponded to three frameshift, one nonsense, one missense and one polymorphism.

Molecular analysis of chromosome 1 abnormalities in human gliomas reveals frequent loss of 1p in oligodendroglial tumors

Alterations of the short arm of chromosome 1 are recurrently found in cytogenetic analysis of malignant gliomas, and deletions of 1p36-p32 region characterize at least the higher-grade tumors, glioblastoma multiforme. Molecular analysis of tumor-derived and normal genomic DNA from 57 cases of gliomas, using a panel of chromosome 1-specific DNA probes showed LOH in 16 tumors. Allelic losses on 1p were primarily restricted to glioblastoma multiforme (2/11) and to tumors with a major oligodendroglial component: grade II oligodendrogliomas (6/6), grade III anaplastic oligodendrogliomas (5/6) and grade II-III mixed oligo-astrocytomas (2/3). Losses for 1q markers were detected in only 1 tumor (glioblastoma multiforme). Our data suggest that anomalies of 1p primarily characterize oligodendrogliomas, whereas they are rare events in astrocytic tumors and indicate that a tumor-suppressor gene on 1p36-p32 is involved in the development of brain tumors with oligodendroglial differentiation.

A clinical trial comparing the safety and efficacy of a topical erythromycin-zinc formulation with a topical clindamycin formulation

One hundred three patients with acne vulgaris were randomly designated to receive either a topical formulation of erythromycin plus zinc or a topical solution of 1% clindamycin phosphate (Cleocin-T). The patients treated themselves twice daily and were examined at 3, 6, 9, and 12 weeks after the start of therapy. By week 6 the overall severity grade was consistently lower and the percent reduction of severity, papules, pustules, and total comedones was higher in the erythromycin-zinc-treated group than in the clindamycin-treated group. In the 92 patients who completed this study (48 receiving erythromycin-zinc and 44 receiving clindamycin), no serious topical or systemic side effects were reported. Two patients, one from each treatment group, suffered mild irritation. One patient was withdrawn from the erythromycin-zinc-treated group. Results of patch tests were negative. The superiority of the erythromycin-zinc formulation may be due to the increased (4%) erythromycin concentration and/or the ability of 1.2% zinc acetate to enhance the product's activity.

Cutaneous segmental neurofibromatosis

A recent case of cutaneous segmental neurofibromatosis provided the opportunity to review the literature to better understand this rare disease. This cutaneous form of the disease usually appears only on the skin, without other systemic involvement; it is not inherited. Only 19 additional cases in the English literature could be found, three cases with extracutaneous manifestations; three cases were familial. The prognosis for this form of neurofibromatosis is excellent, but examination for evidence of systemic disease is indicated.

Effect of ultraviolet light on topical minoxidil-induced hair growth in advanced male pattern baldness

Nine healthy men with type IVa or Va male pattern baldness completed a 4-month single-blinded controlled pilot study designed to assess the effect of ultraviolet light (UVL) on topical minoxidil-induced hair growth. Subjects applied 2% topical minoxidil solution twice daily to their balding scalps and to one target area on the upper arm. These men, all of whom had either skin type II or III, were randomized to also receive either incremental doses of UVB or PUVA (topical psoralen) twice weekly to one side of their scalp and to a 2.5 cm target area on the nonminoxidil-treated upper ipsilateral arm. Vellus, nonvellus, and total hair counts were done in two 1-inch in diameter circular target areas in symmetric regions of the scalp and on each upper arm at regular intervals. All nine subjects had an increase in target nonvellus hair and a net loss of vellus hair in scalp target area treated with topical minoxidil. Concomitant UVL did not have a significant synergistic nor adverse effect on topical minoxidil-induced hair growth.

Predictive value of HLA antigen for methotrexate-induced liver damage in patients with psoriasis

For an investigation of a possible association between HLA antigens and postmethotrexate liver damage, the A, B, C, and Dr loci of the HLA antigens were determined in thirty-two patients with severe psoriasis who had been treated with methotrexate. There was no association between HLA antigens and increasing severity of liver disease in these patients. HLA-A3 was increased in frequency in the group of patients with the more severe liver damage but was not significant when corrected for the number of antigens tested. There appears to be no predictive value in HLA typing of psoriasis patients prior to starting methotrexate therapy.

Acetylation of ribosome-associated proteins in vitro by an acetyltransferanse bound to rat liver ribosomes

Incubation of rat liver ribosomes with [1-14-C]acetyl-coenzyme A results in the incorporation of [14-C]acetyl into a material insoluble in cold trichloroacetic acid. The acetyltransferase involved in the self-acetylation of ribosomes can be released by high salt washing of the ribosomes; the activity of the solubilized enzyme can be assayed using histones as acetyl acceptors. Electrophoretic analysis of acetylated risosomes or ribosomal proteins indicated that the acetyl radicals are associated with a group of relatively basic proteins, having molecular weights ranging from 10,000 to 45,000. Chromatographic analysis of the enzymatic hydrolsates of proteins extracted from acetylated ribosomes indicates that acetylation is mainly or exclusively NH2 terminal. Almost 80% of the acetyl proteins are released from the ribosomes by high salt treatment. Most of the acetyl radicals not solubilized by the high salt treatment were found in the 60S subunit, associated with a protein(s) having an apparent molecular weight of 43,000. This acetyl protein(s) was released from the 60S subunit by EDTA treatment and was found in a ribonucleoprotein complex having a bouyant density of 1.56.

Acetylation of nascent polypeptide chains on rat liver polyribosomes in vivo and in vitro

Rat liver polyribosomes may be acetylated in vivo utilizing [3-H]acetate as precursor and in vitro with [14-C]acetyl-CoA. The in vitro acetylation occurs almost completely in the amino terminal position while the in vivo acetylation (after correction for isotopic exchange and incorporation of tritium into nonacetyl positions of amino acids) was distributed equally between the amino terminal groups of a number of amino acids and the epsilon-amino groups of internal lysine residues. At least 50% of the labeled acetyl groups introduced in vivo as well as in vitro could be removed from polysomes as puromycin polypeptides or -peptidyl-tRNA. The acetylated polypeptides have been resolved by gel filtration into two components, one with an average molecular weight of 20,000 and the other of 4000-7000. The results presented indicate that the N-terminal acetylation of nascent growing polypeptides is a post initiation event that occurs on small peptides (40-70 amino acid residues) and depends on the presence of a polysome-bound acetyltransferase which differs from other cytoplasmic acetyltransferases which catalyze predominately the acetylation of internal amino groups of proteins.

Cyclic adenosine 3',5'-monophosphate during glucose repression in the rat liver

Intragastric administration of glucose inhibits the induction of serine dehydratase and tyrosine aminotransferase by glucagon in rat liver, but has no effect on the increase in hepatic adenosine 3',5'-monophosphate resulting from administration of glucagon. Thus, glucose repression in mammalian liver, unlike catabolite repression in microorganisms, appears to operate independently of the amounts of cyclic nucleotide in the cells.