Leonardo Vicentini

BRAF mutations in an Italian cohort of thyroid cancers

objective  Recently, a somatic point mutation of the BRAF gene (V599E) has been identified as the most common genetic event in papillary thyroid carcinoma (PTC) with a variable frequency (about 25–70%) in different series from USA, Japan, Portugal and Ukraine.

Calcium-sensing receptor expression and signalling in human parathyroid adenomas and primary hyperplasia

Both in vivo and in vitro evidence indicates that primary hyperparathyroidism is characterized by a reduced sensitivity to extracellular calcium ([Ca2+]o). The existence of alterations in the expression and signalling of calcium sensing receptor (CaSR) in parathyroid neoplasia is still uncertain. In order to clarify the role of CaSR in the reduced [Ca2+]o sensing of parathyroid neoplasia we investigated PTH secretion and intracellular effectors triggered by CaSR activation as well as the levels of expression of CaSR and CaSR coupled G proteins (Gq/G11) in parathyroid adenomas and primary hyperplasia.

Clinical and molecular features of differentiated thyroid cancer diagnosed during pregnancy

OBJECTIVE Pregnancy represents a favorable condition for the development of thyroid nodules, likely due to the secretion of hormones with stimulatory activity. In particular, differentiated thyroid cancer (DTC) represents the second most frequent tumor among those diagnosed during pregnancy. However, few and discordant data are available about the impact of pregnancy on tumor outcome. METHODS A total of 123 women with DTC were divided into three groups according to the timing of tumor diagnosis (group 1, at least 1 year after the delivery; group 2, during pregnancy or in the first year after delivery; and group 3, before pregnancy or nulliparity) and evaluated according to the international guidelines. Furthermore, immunohistochemical studies of estrogen receptor alpha (ERalpha) were performed in 38 papillary thyroid cancer tissues from the three groups. RESULTS Thyroid cancer diagnosed during pregnancy was associated with a poorer prognosis compared to tumors developed in nongravidic periods (P<0.0001). Accordingly, at the stepwise logistic regression analysis, the diagnosis of DTC during pregnancy or in the first year post partum was the most significant indicator of persistent disease (P=0.001). Interestingly, ERalpha expression significantly differed among tumors of the three groups, being detected in 31% of group 1, in 87.5% of group 2, and in 0% of group 3 (P=0.01). CONCLUSIONS Present data indicate that pregnancy has a negative impact on the outcome of thyroid cancer. The presence of ERalpha in the majority of tumors diagnosed during pregnancy indicates that the poorer outcome of these cases could be related to the estrogen-mediated growth stimulus.

Comparison of Calcium and Pentagastrin Tests for the Diagnosis and Follow-Up of Medullary Thyroid Cancer

CONTEXT The evaluation of basal calcitonin (bCT) and stimulated calcitonin (sCT) can be used for the diagnosis and follow-up of medullary thyroid cancer (MTC). OBJECTIVE The aim of this study was to evaluate the reliability of high-calcium (Ca) test and to identify gender-specific thresholds for MTC diagnosis. PATIENTS Patients with MTC in remission (n=24) or in persistence (n=18), RET gene mutations carriers (n=14), patients with nodular goiter (n=69), and healthy volunteers (n=16) were submitted to pentagastrin and Ca (25 mg/kg) tests. RESULTS In all groups, the levels of calcitonin (CT) stimulated by either pentagastrin or Ca were significantly correlated. The prevalence of both C-cell hyperplasia (CCH) and MTC in women and men paralleled the increasing basal and peak CT levels in a gender-specific manner. Receiver operating characteristic plot analyses showed that the best levels of bCT to separate normal and CCH cases from MTC patients were above 18.7 pg/ml in females and above 68 pg/ml in males. Furthermore, Ca sCT above 184 pg/ml in females and above 1620 pg/ml in males had the highest accuracy to distinguish normal and CCH cases from patients with MTC. At the C-cell immunohistochemical examination, Ca sCT below 50 pg/ml corresponded to a mean number of 30 cells per 10 fields, whereas higher sCT associated with a mean number of 400 cells per 10 fields, often displaying a diffuse and nodular distribution pattern. CONCLUSIONS High-dose Ca test is a potent and well-tolerated procedure that can be applied worldwide at a low cost. Reference ranges for Ca sCT levels in different groups of patients and CT thresholds to diagnose CCH/MTC have been identified.

Post-surgical hypocortisolism after removal of an adrenal incidentaloma: is it predictable by an accurate endocrinological work-up before surgery?

OBJECTIVE Few data are available regarding the need of steroid substitutive therapy after unilateral adrenalectomy for adrenal incidentaloma (AI). It is unknown whether, before surgery, the hypothalamic-pituitary-adrenal (HPA) axis secretion parameters can predict post-surgical hypocortisolism. AIM This study aimed to evaluate whether, in AI patients undergoing unilateral adrenalectomy, post-surgical hypocortisolism could be predicted by the parameters of HPA axis function. DESIGN Prospective, multicenter. METHODS A total of 60 patients underwent surgical removal of AI (surgical indication: 29 subclinical hypercortisolism (SH); 31 AI dimension). Before surgery, SH was diagnosed in patients presenting at least three criteria out of urinary free cortisol (UFC) levels>60 microg/24 h, cortisol after 1-mg dexamethasone suppression test (1 mg-DST)>3.0 microg/dl, ACTH levels<10 pg/ml, midnight serum cortisol (MSC)>5.4 microg/dl. Two months after surgery, HPA axis function was assessed by low dose ACTH stimulation test or insulin tolerance test when needed: 39 patients were affected (Group B) and 21 were not affected (Group A) with hypocortisolism. The accuracy in predicting hypocortisolism of pre-surgical HPA axis parameters or their combinations was evaluated. RESULTS The presence of >2 alterations among 1 mg-DST>5.0 microg/dl, ACTH<10 pg/ml, elevated UFC and MSC has the highest odds ratio (OR) for predicting post-surgical hypocortisolism (OR 10.45, 95% confidence interval, CI 2.54-42.95, P=0.001). Post-surgical hypocortisolism was predicted with 100% probability by elevated UFC plus MSC levels, but not ruled out even in the presence of the normality of all HPA axis parameters. CONCLUSION Post-surgical hypocortisolism cannot be pre-surgically ruled out. A steroid substitutive therapy is indicated after unilateral adrenalectomy for SH or size of the adenoma.

Telomerase in differentiated thyroid cancer: Promoter mutations, expression and localization

Telomerase-reverse-transcriptase (TERT) promoter mutations have been recently described in tumors. In the present large series, TERT mutations were found in 12% of papillary thyroid cancers (PTCs) and in 14% of follicular thyroid cancers (FTCs), and were found to significantly correlate with older age at diagnosis and poorer outcome. Interestingly, the prognostic value of TERT mutations resulted to be significantly stronger than that of BRAF(V600E). Moreover, the outcome was not different among tumors with isolated TERT mutation and those with coexistent mutations (TERT/BRAF in PTCs or TERT/RAS in FTCs). TERT rs2853669 polymorphism was found in 44.4% of tumors. At WB, TERT was significantly more expressed in tumors than in normal samples, being the highest levels of expression recorded in TERT mutated cases. At IHC, in tumors and in metastatic lymph-nodes TERT staining was significantly higher in the cytoplasm than in the nucleus, whereas in normal tissue the degree of staining did not differ in the two cellular compartments. In conclusion, TERT mutations were shown to strongly correlate with a poorer outcome in differentiated thyroid tumors, and neither BRAF nor RAS mutation were found to confer an additional effect in the disease persistence. TERT protein was found to be more expressed in neoplastic than in normal tissues, and to display a different cellular localization, suggesting that it could contribute to thyroid cancer progression by mechanisms taking place in the cytoplasm.

Outcome predictors and impact of central node dissection and radiometabolic treatments in papillary thyroid cancers ≤2 cm

The incidence of papillary thyroid cancer (PTC) is rapidly growing, the recorded increase being mainly related to tumors < or =2 cm. The re-classification of tumors >1 and < or =2 cm limited to the thyroid from the T2 to the T1 category triggered some concerns about their best management. In order to identify possible predictors of disease outcome, several clinico-pathological features were analyzed by uni- and multivariate analyses in a retrospective consecutive series of 251 PTCs < or =2 cm. Moreover, since 37% of cases were submitted to prophylactic central compartment node dissection (CLND, VI-VII levels) and radioiodine ablation was performed only when the tumor had an extrathyroidal extension, the impact of these therapeutic tools on the final outcome was evaluated. Among all outcome predictors analyzed, only lymph node metastases and extracapsular invasion were strongly associated with persistence/recurrence. It is worth noting that neither age nor tumor size was a significant indicator of the outcome. Interestingly, as far as the therapeutic interventions are concerned, CLND was strongly associated with remission, whereas radioiodine ablation did not influence the outcome. In conclusion, present results confirm the prognostic influence of node metastases and extra-thyroidal invasion, indicating the need for aggressive treatment in tumors extending beyond the capsule. On the contrary, all pT1N0 tumors, regardless of the diameter, the number of intrathyroidal foci, and the age can be effectively treated only by surgery. The major impact of prophylactic CLND on prognosis suggests to routinely associate it to total thyroidectomy in cases with a preoperative diagnosis of malignancy.

The microRNA cluster C19MC is deregulated in parathyroid tumours.

A subset of over-expressed microRNAs (miRNAs) identified in parathyroid carcinomas (Ca) compared to normal glands belongs to C19MC, a cluster on chromosome 19q13.4 involved in stem cell biology and tumourigenesis. In this study, the expression of C19MC-MIR371-3 clusters and the molecular mechanisms presiding their modulation were investigated in a series of six normal parathyroids, 24 adenomas (Ad), 15 Ca and five matched metastases. The general expression levels of C19MC or MIR371-3 clusters in Ad lesions did not differ from normal glands, while they distinguished Ad from Ca at unsupervised hierarchical cluster analysis (P=0.0008). MIR517C showed the most significant difference in expression between Ca and Ad (P=0.0003) and it positively correlated with serum calcium, parathormone and tumour weight. In regard to the molecular mechanism determining C19MC cluster activation, we could detect C19MC copy number (CN) gain in ten Ca (67%) extending distal to the MIR371-3 cluster in almost all samples. Conversely, only four Ad (16%) showed C19MC amplification, with one case presenting distal genomic aberration to MIR371-3. Globally, CN variations of 19q13.4 loci were significantly associated with MIR517C up-regulation (P=0.006). Opposite to normal glands where C19MC promoter was methylated, hypomethylation occurred in 15 out of 30 analysed tumours. Though the epigenetic status did not correlate with C19MC miRNA expression levels, loss of C19MC promoter methylation was significantly associated with Ca and metastatic disease (P=0.01). In conclusion, C19MC cluster aberrations are a characteristic of Ca with respect to Ad. Altogether, these evidences point towards a role for 19q13.4 miRNA clusters as oncogenes in parathyroid tumourigenesis.

Fetal cell microchimerism in papillary thyroid cancer: studies in peripheral blood and tissues

Fetal cell microchimerism (FCM) is defined as the persistence, for decades after pregnancy, of fetal cells in maternal organs and circulation without any apparent rejection. We recently reported evidence, in papillary thyroid cancer (PTC) tissues, supporting a possible role of FCM in tumor damage and repair. To extend those data at the peripheral level, 106 women with a previous male pregnancy, comprising 57 with PTC and 49 healthy controls were enrolled. The presence of circulating male DNA was assessed by the amplification of the Y chromosome‐specific gene SRY, with a sensitivity of 1 male cell per 1 million female cells. Moreover, to compare the microchimeric status in blood and in tumors, the neoplastic tissues of 19 women were studied. At the blood level, a significantly lower frequency of FCM was found in parous women with PTC with respect to controls (49.1% vs. 77.6%; p = 0.002). By PCR, male DNA was identified in the tumor tissues of 6 patients, and FISH analyses confirmed the presence of microchimeric cells (range 2.1–6.9 cells/section). In some patients, FCM was negative in the blood, whereas microchimeric cells were identified in the tumor. In conclusion, the prevalence of FCM in peripheral blood was found to be significantly lower in patients than in healthy controls. The presence of microchimeric cells in the tumors, but not at the peripheral level, supports the hypothesis that fetal cells could reside in maternal niches and could be recruited to diseased areas, where they could differentiate to regenerate damaged tissues.

Refining Calcium Test for the Diagnosis of Medullary Thyroid Cancer: Cutoffs, Procedures, and Safety

CONTEXT Calcitonin (CT) measurement is crucial to the early diagnosis and the follow-up of medullary thyroid cancer (MTC). If the evaluation of stimulated CT levels is required, a provocative test can be performed, being the high-dose Ca test recently reintroduced in clinical practice. OBJECTIVE Our objective was to identify gender-specific thresholds for MTC diagnosis in a large series of patients who underwent the Ca test. PATIENTS AND METHODS A total of 91 patients (49 females and 42 males) underwent the Ca test (calcium gluconate, 25 mg/kg) before thyroidectomy and both basal CT (bCT) and stimulated CT (sCT) were compared with histological results by receiver operating characteristic plot analyses. To evaluate possible side effects of Ca administration, cardiac function has been extensively studied. RESULTS bCT levels were found to harbor the same accuracy as sCT in the preoperative diagnosis of MTC. The best Ca thresholds for the identification of MTC were >26 and >68 for bCT and >79 and >544 pg/mL for sCT in females and males, respectively. The high tolerability and safety of the Ca test was demonstrated and advice offered to be followed before and during the test. CONCLUSIONS Gender-specific bCT and sCT cutoffs for the identification of C-cell hyperplasia and/or MTC have been defined. The bCT and sCT were found to have a similar accuracy, indicating that serum CT assays with improved functional sensitivity may likely decrease the relevance of the stimulation test in several conditions. Finally, systematic cardiac monitoring confirms the safety of the Ca test.