Gene signature of the post-Chernobyl papillary thyroid cancer

Purpose: Following the nuclear accidents in Chernobyl and later in Fukushima, the nuclear community has been faced with important issues concerning how to search for and diagnose biological consequences of low-dose internal radiation contamination. Although after the Chernobyl accident an increase in childhood papillary thyroid cancer (PTC) was observed, it is still not clear whether the molecular biology of PTCs associated with low-dose radiation exposure differs from that of sporadic PTC. Methods: We investigated tissue samples from 65 children/young adults with PTC using DNA microarray (Affymetrix, Human Genome U133 2.0 Plus) with the aim of identifying molecular differences between radiation-induced (exposed to Chernobyl radiation, ECR) and sporadic PTC. All participants were resident in the same region so that confounding factors related to genetics or environment were minimized. Results: There were small but significant differences in the gene expression profiles between ECR and non-ECR PTC (global test, p < 0.01), with 300 differently expressed probe sets (p < 0.001) corresponding to 239 genes. Multifactorial analysis of variance showed that besides radiation exposure history, the BRAF mutation exhibited independent effects on the PTC expression profile; the histological subset and patient age at diagnosis had negligible effects. Ten genes (PPME1, HDAC11, SOCS7, CIC, THRA, ERBB2, PPP1R9A, HDGF, RAD51AP1, and CDK1) from the 19 investigated with quantitative RT-PCR were confirmed as being associated with radiation exposure in an independent, validation set of samples. Conclusion: Significant, but subtle, differences in gene expression in the post-Chernobyl PTC are associated with previous low-dose radiation exposure

Gene expression profiles for radiation-induced thyroid cancer.

The question whether radiation-induced thyroid cancer differs by its molecular biology from sporadic disease still remains. Studies on tissue from patients who developed thyroid cancer after the Chernobyl accident have provided a unique opportunity to look for biological consequences of low-dose irradiation by comparing the gene expression profile of sporadic papillary thyroid cancer (PTC), whose aetiology is unknown, and PTC induced by internal radiation. So far, four transcriptomic studies comparing radiation-induced and sporadic thyroid cancer have been reported. However, no final conclusion has been drawn regarding the presence of a radiation signature, as either no difference was noted or the reported differences were not sufficiently convincing due to the low number of cases analysed or to the presence of confounding factors. The list of putative biological and clinical factors that may influence the PTC gene expression profile is long, but there are sufficient data reported in the literature to link expression profiles with differing pathological variants of PTC. The comparison of expression profiles in the tumour samples allows the search for a radiation signature, whereas the comparison of expression profiles of the normal contralateral tissues offers a substantial opportunity for assessing the existence of a susceptibility to radiation that could be responsible for tumour development. We have undertaken this analysis as part of a European Union-funded project, GENRISK-T. Gene expression profiles were investigated in tumours that have arisen in the population exposed to fallout from Chernobyl (i.e. born before 26 April 1986) and were compared with profiles of tumours of similar pathology arising in an age-matched population, residing in the same geographical area (same ethnicity) and born after 1 January 1987. RNA samples from these tumours and their contralateral normal tissues were obtained from the Chernobyl Tissue Bank. Several lines of evidence suggest that the predisposition to developing cancer after radiation exposure is variable in the general population and may be measurable from gene expression.Journal ArticleResearch Support, Non-U.S. Gov'tReviewSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Efficacy and safety of radioiodine in the treatment of disseminated differentiated thyroid cancer (DTC) in children

10065 Background: Distant metastases, mainly to lung are diagnosed in about 20% of children with DTC. At present radioiodine is the treatment of choice in that case. However, it can results in massive lung fibrosis as was showed in historical groups of patients.The aim of this retrospective study was to evaluate results of radioiodine therapy in children and its long-term safety. Methods: From 235 children (median age 13.9) diagnosed either with papillary (82%) or follicular cancer (18%), 42 (17.9%) had lung, and 2 (9%) bone metastases (median time of observation 105 months). All were treated with radioiodine (accumulated activities 100 to 950 mCi). Treatment results were evaluated by means of scintigraphic, radiological, and biochemical examinations. 28 (67%) of the children were lately re-evaluated with high resolution CT, ultrasound, biochemistry, and spirometry. Results: In most children, 29/44 (66%), distant metastases were diagnosed in radioiodine scan while radiological examinations were normal. Complete scintigraphic and radiological remission was achieved in 38 (86%) children. In all children there was a decrease in thyroglobulin serum concentration after radioiodine therapy. However, it normalized at the last radioiodine treatment only in 13 (29%) cases. During follow-up Tg continued to decrease and at the last stimulated Tg evaluation it was &lt; 10 ng/ml in 28 (64%) patients. In 5/28 (18%) of the children with lung metastases some small foci of focal lung fibrosis were diagnosed with CT. However, comparable percentage of focal fibrosis was observed in DTC children without lung metastases. Also the preliminary results didn't show an increased rate of abnormal spirometry results. Conclusions: Complete remission of distant metastases can be achieved in about 85% of children with DTC treated with radioiodine. This therapy is safe and does not cause any increased risk of lung fibrosis even in children treated with repeated courses of radioiodine. No significant financial relationships to disclose. </jats:p

Papillary Thyroid Carcinoma in a Boy with Familial Tuberous Sclerosis Complex Attributable to a TSC2 Deletion—A Case Report

Tuberous sclerosis complex (TSC), a phacomatosis, is a rare genetic disease (autosomal dominant; incidence: 1 in 6,800–17,300) associated with mutations in the TSC1 and TSC2 genes, 70% of which are sporadic. The disease causes benign tumours in the brain, kidneys, heart, lungs, skin, and eyes; thyroid lesions are extremely rare. A 13-year-old euthyroid boy with a hereditary form of TSC (del 4730G in TSC2, also seen in 2 sisters and the father) was admitted to hospital with a thyroid nodule. Physical examination revealed a nodular left lobe with increased consistency. Thyroid ultrasonography revealed a heterogeneous left lobe, predominantly hypoechoic with multiple microcalcifications and the presence of suspicious cervical lymph nodes on the left side. A macrocalcification was observed on the right lobe. Fine-needle biopsy results showed a few groups of cells with discrete atypical characteristics, including abundant cytoplasm, nuclei with conspicuous nucleoli, intra-nuclear inclusions, and nuclear grooves. The patient underwent total thyroidectomy with lymphadenectomy. Histopathology examination confirmed papillary thyroid carcinoma. The coincidence of endocrine neoplasia including thyroid cancer and TSC is rare, and TSC with papillary thyroid carcinoma has never been described in a child. Studies of mutations in the tumour suppressor genes TSC1, TSC2, and STK11, activating the mtor (mammalian target of rapamycin) pathway, might support their role in the pathogenesis of thyroid cancer

Papillary thyroid carcinoma in a boy with familial tuberous sclerosis complex attributable to a TSC2 deletion—a case report

Tuberous sclerosis complex (TSC), a phacomatosis, is a rare genetic disease (autosomal dominant; incidence: 1 in 6,800–17,300) associated with mutations in the TSC1 and TSC2 genes, 70% of which are sporadic. The disease causes benign tumours in the brain, kidneys, heart, lungs, skin, and eyes; thyroid lesions are extremely rare. A 13-year-old euthyroid boy with a hereditary form of TSC (del 4730G in TSC2, also seen in 2 sisters and the father) was admitted to hospital with a thyroid nodule. Physical examination revealed a nodular left lobe with increased consistency. Thyroid ultrasonography revealed a heterogeneous left lobe, predominantly hypoechoic with multiple microcalcifications and the presence of suspicious cervical lymph nodes on the left side. A macrocalcification was observed on the right lobe. Fine-needle biopsy results showed a few groups of cells with discrete atypical characteristics, including abundant cytoplasm, nuclei with conspicuous nucleoli, intra-nuclear inclusions, and nuclear grooves. The patient underwent total thyroidectomy with lymphadenectomy. Histopathology examination confirmed papillary thyroid carcinoma. The coincidence of endocrine neoplasia including thyroid cancer and TSC is rare, and TSC with papillary thyroid carcinoma has never been described in a child. Studies of mutations in the tumour suppressor genes TSC1, TSC2, and STK11, activating the mtor (mammalian target of rapamycin) pathway, might support their role in the pathogenesis of thyroid cancer