Total thyroidectomy and central neck dissection are the procedures of choice in patients affected with medullary thyroid cancer. It is known that a medullary thyroid cancer with node metastases can be rarely cured, and therefore the utility of a modified radical neck dissection in the absence of suspicious node metastases still needs further evidence. The study aims to verify whether other epidemiological and pathological parameters could affect the prognosis of medullary thyroid cancer patients. We prospectively studied 70 medullary thyroid cancer patients consecutively operated on (from 2000 to 2004) at the same institution and analysed by the same pathologists. All patients underwent total thyroidectomy and central lymphadenectomy. In 27 cases, the ipsilateral (n=19) or bilateral (n=8) modified radical neck dissection was performed in the presence of suspicious lateral neck node metastases. After surgical treatment, basal and stimulated serum calcitonins (Cts) were measured in all patients. Follow-up ranged between 1 and 4 years. Patients were considered ‘cured’ when stimulated Ct was undetectable. Age, sex, tumour size, tumour capsule, multicentricity, nodes in the central neck and mean number of positive nodes were analysed in ‘cured’ and ‘not-cured’ patients. The presence of node metastases in the central compartment was significantly correlated with the outcome of the patients, being present in 9 and 72% of cured and not-cured patients respectively (P<0.000001). Tumour size was also significantly correlated with the outcome of the disease (P<0.00006). The presence of the tumour capsule correlated with better prognosis (P=0.0005) and absence of node metastases (P=0.0080). By multivariate analysis, the presence of node metastasis remained the most significant variable affecting the outcome of the disease (P=0.000014). Our results show that the outcome of encapsulated cancer is significantly better regardless of tumour size and node metastases. Although the early diagnosis and the extensive surgical treatment may favour the good outcome of medullary thyroid cancer, they do not always guarantee the definitive cure of the disease, being the capsular infiltration an independent bad prognostic factor.

Noninvasive encapsulated follicular variants of papillary thyroid carcinomas have been recently reclassified as noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTPs). NIFTPs exhibit a behavior that is very close to that of follicular adenomas but different from the infiltrative and invasive follicular variants of papillary thyroid carcinomas (FVPTCs). The importance of miRNAs to carcinogenesis has been reported in recent years. miRNAs seem to be promising diagnostic and prognostic molecular markers for thyroid cancer, and the combination of miRNA expression and mutational status might improve cytological diagnosis. The aim of the present study was to evaluate the miRNA expression profile in wild-type, RAS - or BRAF-mutated NIFTPs, infiltrative and invasive FVPTCs, and follicular adenomas using the nCounter miRNA Expression assay (NanoString Technologies). To identify the significant Kyoto Encyclopedia of Genes and Genomes (KEGG) molecular pathways associated with deregulated miRNAs, we used the union of pathways option in DNA Intelligent Analysis (DIANA) miRPath software. We have shown that the miRNA expression profiles of wild-type and mutated NIFTPs could be different. The expression profile of wild-type NIFTPs seems comparable to that of follicular adenomas, whereas mutated NIFTPs have an expression profile similar to that of infiltrative and invasive FVPTCs. The upregulation of 4 miRNAs (miR-221-5p, miR-221-3p, miR-222-3p, miR-146b-5p) and the downregulation of 8 miRNAs (miR-181a-3p, miR-28-5p, miR-363-3p, miR-342-3p, miR-1285-5p, miR-152-3p, miR-25-3p, miR-30e-3) in mutated NIFTPs compared to wild-type ones suggest a potential invasive-like phenotype by deregulating the specific pathways involved in cell adhesion and cell migration (Hippo signaling pathway, ECM-receptor interaction, adherens junction, regulation of actin cytoskeleton, fatty acid biosynthesis and metabolism).

The relevance of thyroid autoimmunity to the prognosis of papillary thyroid carcinoma is still unsettled. We decided to investigate the impact of thyroid autoimmunity on the prognosis of papillary thyroid carcinoma and the handling of TgAbs. We evaluated the clinical course of a large group of patients according to the presence (PTC-LT) or absence (PTC) of lymphocytic thyroiditis at histology. We studied 194 consecutive patients with a diagnosis of PTC and treated them with total thyroidectomy plus ¹³¹I ablation between 2007 and 2009. Median follow-up (with 25th–75th percentiles) was 84.0 (56.4–118.0) months. The remission criteria were: basal Tg < 0.2 ng/mL (or stimulated Tg: < 1), TgAbs < 8 IU/mL (otherwise ‘decreasing TgAb trend’, a decline of ≥20% in sequential TgAb measurements) and unremarkable imaging. PTC-LT and PTC patients had comparable treatment.TgAbs were detectable in 72.5% of PTC-LT and 16.5% of PTC patients. Time to remission was longer in the detectable than in the undetectable TgAb cohort (28.5 vs· 7.5 months (median); HR: 0.54, CI: 0.35–0.83, P = 0.005). When comparing PTC-LT to PTC patients, the difference was maintained in the detectable TgAb (29.3 vs 13.0 months; HR: 0.38, CI: 0.18–0.80; P = 0.01) but not in the undetectable TgAb cohort (7.7 vs 7.3 months; HR: 0.90, CI: 0.55–1.47; P = 0.68). Using the decreasing TgAb trend, the influence of detectable TgAbs on time to remission was abolished. Thyroid autoimmunity does not influence the prognosis of papillary thyroid carcinoma. A decreasing TgAb trend seems an appropriate criterion to establish the remission of papillary thyroid carcinoma.

Anaplastic thyroid carcinoma (ATC) is a very aggressive thyroid cancer. forkhead box protein M1 (FOXM1) is a member of the forkhead box family of transcription factors involved in control of cell proliferation, chromosomal stability, angiogenesis, and invasion. Here, we show that FOXM1 is significantly increased in ATCs compared with normal thyroid, well-differentiated thyroid carcinomas (papillary and/or follicular), and poorly differentiated thyroid carcinomas (P=0.000002). Upregulation of FOXM1 levels in ATC cells was mechanistically linked to loss-of-function of p53 and to the hyperactivation of the phosphatidylinositol-3-kinase/AKT/FOXO3a pathway. Knockdown of FOXM1 by RNA interference inhibited cell proliferation by arresting cells in G2/M and reduced cell invasion and motility. This phenotype was associated with decreased expression of FOXM1 target genes, like cyclin B1 (CCNB1), polo-like kinase 1 (PLK1), Aurora B (AURKB), S-phase kinase-associated protein 2 (SKP2), and plasminogen activator, urokinase: uPA (PLAU). Pharmacological inhibition of FOXM1 in an orthotopic mouse model of ATC reduced tumor burden and metastasization. All together, these findings suggest that FOXM1 represents an important player in thyroid cancer progression to the anaplastic phenotype and a potential therapeutic target for this fatal cancer.

For an identification of novel candidate genes in thyroid tumourigenesis, we have investigated gene copy number changes in a Trk-T1 transgenic mouse model of thyroid neoplasia. For this aim, 30 thyroid tumours from Trk-T1 transgenics were investigated by comparative genomic hybridisation. Recurrent gene copy number alterations were identified and genes located in the altered chromosomal regions were analysed by Gene Ontology term enrichment analysis in order to reveal gene functions potentially associated with thyroid tumourigenesis. In thyroid neoplasms from Trk-T1 mice, a recurrent gain on chromosomal bands 1C4–E2.3 (10.0% of cases), and losses on 3H1–H3 (13.3%), 4D2.3–E2 (43.3%) and 14E4–E5 (6.7%) were identified. The genes Twist2, Ptma, Pde6d, Bmpr1b, Pdlim5, Unc5c, Srm, Trp73, Ythdf2, Taf12 and Slitrk5 are located in these chromosomal bands. Copy number changes of these genes were studied by fluorescence in situ hybridisation on 30 human papillary thyroid carcinoma (PTC) samples and altered gene expression was studied by qRT-PCR analyses in 67 human PTC. Copy number gains were detected in 83% of cases for TWIST2 and in 100% of cases for PTMA and PDE6D. DNA losses of SLITRK1 and SLITRK5 were observed in 21% of cases and of SLITRK6 in 16% of cases. Gene expression was significantly up-regulated for UNC5C and TP73 and significantly down-regulated for SLITRK5 in tumours compared with normal tissue. In conclusion, a global genomic copy number analysis of thyroid tumours from Trk-T1 transgenic mice revealed a number of novel gene alterations in thyroid tumourigenesis that are also prevalent in human PTCs.

Somatic copy number alterations (SCNA) involving either a whole chromosome or just one of the arms, or even smaller parts, have been described in about 88% of human tumors. This study investigated the SCNA profile in 40 well-characterized sporadic medullary thyroid carcinomas by comparative genomic hybridization array. We found that 26/40 (65%) cases had at least one SCNA. The prevalence of SCNA, and in particular of chromosome 3 and 10, was significantly higher in cases with a RET somatic mutation. Similarly, SCNA of chromosomes 3, 9, 10 and 16 were more frequent in cases with a worse outcome and an advanced disease. By the pathway enrichment analysis, we found a mutually exclusive distribution of biological pathways in metastatic, biochemically persistent and cured patients. In particular, we found gain of regions involved in the intracellular signaling and loss of regions involved in DNA repair and TP53 pathways in the group of metastatic patients. Gain of regions involved in the cell cycle and senescence were observed in patients with biochemical disease. Finally, gain of regions associated with the immune system and loss of regions involved in the apoptosis pathway were observed in cured patients suggesting a role of specific SCNA and corresponding altered pathways in the outcome of sporadic MTC.