Laura Fugazzola

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.

Association Between BRAF V600E Mutation and Recurrence of Papillary Thyroid Cancer

PURPOSE To investigate the prognostic value of BRAF V600E mutation for the recurrence of papillary thyroid cancer (PTC). PATIENTS AND METHODS This was a retrospective multicenter study of the relationship between BRAF V600E mutation and recurrence of PTC in 2,099 patients (1,615 women and 484 men), with a median age of 45 years (interquartile range [IQR], 34 to 58 years) and a median follow-up time of 36 months (IQR, 14 to 75 months). RESULTS The overall BRAF V600E mutation prevalence was 48.5% (1,017 of 2,099). PTC recurrence occurred in 20.9% (213 of 1,017) of BRAF V600E mutation-positive and 11.6% (125 of 1,082) of BRAF V600E mutation-negative patients. Recurrence rates were 47.71 (95% CI, 41.72 to 54.57) versus 26.03 (95% CI, 21.85 to 31.02) per 1,000 person-years in BRAF mutation-positive versus -negative patients (P < .001), with a hazard ratio (HR) of 1.82 (95% CI, 1.46 to 2.28), which remained significant in a multivariable model adjusting for patient sex and age at diagnosis, medical center, and various conventional pathologic factors. Significant association between BRAF mutation and PTC recurrence was also found in patients with conventionally low-risk disease stage I or II and micro-PTC and within various subtypes of PTC. For example, in BRAF mutation-positive versus -negative follicular-variant PTC, recurrence occurred in 21.3% (19 of 89) and 7.0% (24 of 342) of patients, respectively, with recurrence rates of 53.84 (95% CI, 34.34 to 84.40) versus 19.47 (95% CI, 13.05 to 29.04) per 1,000 person-years (P < .001) and an HR of 3.20 (95% CI, 1.46 to 7.02) after adjustment for clinicopathologic factors. BRAF mutation was associated with poorer recurrence-free probability in Kaplan-Meier survival analyses in various clinicopathologic categories. CONCLUSION This large multicenter study demonstrates an independent prognostic value of BRAF V600E mutation for PTC recurrence in various clinicopathologic categories.

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.

The Primary Occurrence of BRAFV600E Is a Rare Clonal Event in Papillary Thyroid Carcinoma

CONTEXT BRAF(V600E) is considered a primary event, a negative prognostic marker, and a site for pharmacological intervention in papillary thyroid carcinoma (PTC). We asked whether BRAF(V600E) can occur as a subclonal event in PTC and whether this and other oncogenes can coexist in the same tumor. STUDY DESIGN We determined by pyrosequencing the percentage of mutant BRAF, NRAS, and KRAS alleles in a series of conventional PTC. We also analyzed the BRAF mutation status in PTC cell clones in culture. RESULTS BRAF(V600E) alleles were present in 41 of 72 PTC (56.9%) in the range 44.7 to 5.1% of total BRAF alleles. In four PTC samples, mutant BRAF alleles were about 50%, being therefore compatible with a clonal heterozygous mutation. In 27 PTC samples, BRAF(V600E) alleles were in the range of 25 to 5.1%. This finding was confirmed after exclusion of the presence of a large contamination by lymphoreticular cells and by the analysis of PTC cells selected by laser capture. Analysis of clones derived from a single cell confirmed the presence of two distinct PTC populations with wild-type or mutated BRAF. Simultaneous subclonal BRAF and KRAS mutations were demonstrated in two PTC. CONCLUSIONS These data demonstrate that clonal BRAF(V600E) is a rare occurrence in PTC, although frequently this cancer consists of a mixture of tumor cells with wild-type and mutant BRAF. These results suggest that BRAF mutation in PTC is a later subclonal event, its intratumoral heterogeneity may hamper the efficacy of targeted pharmacotherapy, and its association with a more aggressive disease should be reevaluated.

A Meta-Analysis of Thyroid-Related Traits Reveals Novel Loci and Gender-Specific Differences in the Regulation of Thyroid Function

Thyroid hormone is essential for normal metabolism and development, and overt abnormalities in thyroid function lead to common endocrine disorders affecting approximately 10% of individuals over their life span. In addition, even mild alterations in thyroid function are associated with weight changes, atrial fibrillation, osteoporosis, and psychiatric disorders. To identify novel variants underlying thyroid function, we performed a large meta-analysis of genome-wide association studies for serum levels of the highly heritable thyroid function markers TSH and FT4, in up to 26,420 and 17,520 euthyroid subjects, respectively. Here we report 26 independent associations, including several novel loci for TSH (PDE10A, VEGFA, IGFBP5, NFIA, SOX9, PRDM11, FGF7, INSR, ABO, MIR1179, NRG1, MBIP, ITPK1, SASH1, GLIS3) and FT4 (LHX3, FOXE1, AADAT, NETO1/FBXO15, LPCAT2/CAPNS2). Notably, only limited overlap was detected between TSH and FT4 associated signals, in spite of the feedback regulation of their circulating levels by the hypothalamic-pituitary-thyroid axis. Five of the reported loci (PDE8B, PDE10A, MAF/LOC440389, NETO1/FBXO15, and LPCAT2/CAPNS2) show strong gender-specific differences, which offer clues for the known sexual dimorphism in thyroid function and related pathologies. Importantly, the TSH-associated loci contribute not only to variation within the normal range, but also to TSH values outside the reference range, suggesting that they may be involved in thyroid dysfunction. Overall, our findings explain, respectively, 5.64% and 2.30% of total TSH and FT4 trait variance, and they improve the current knowledge of the regulation of hypothalamic-pituitary-thyroid axis function and the consequences of genetic variation for hypo- or hyperthyroidism.

The tight relationship between papillary thyroid cancer, autoimmunity and inflammation: clinical and molecular studies

Objective  The recent concept that oncogenes responsible for thyroid neoplastic transformation are able to elicit an inflammatory protumourigenic microenvironment raises interest in further studies on papillary thyroid cancer (PTC) associated with thyroid autoimmunity.

A High Percentage of BRAFV600E Alleles in Papillary Thyroid Carcinoma Predicts a Poorer Outcome

CONTEXT BRAF(V600E) is considered a negative prognostic marker in papillary thyroid carcinoma (PTC), but unexplained conflicting results are present in the literature. In light of the new finding that most PTC consist of a mixture of tumor cells with wild-type and mutant BRAF, we examined the associations between the percentage of BRAF(V600E) alleles and both the clinicopathological parameters at time of diagnosis and the disease outcome in a large series of PTCs. STUDY DESIGN Tumors from 168 patients with PTC were genotyped for BRAF(V600E) using BigDye Terminator sequencing and pyrosequencing, and the clinical parameters were analyzed. The associations between clinicopathological characteristics, including disease recurrence at follow-up (median 5.1 yr) and the percentage of mutant BRAF alleles were assessed. RESULTS The observed prevalence of BRAF(V600E) was higher when using pyrosequencing then when using BigDye Terminator sequencing (53.6 vs. 36.9%). In the PTC positive for BRAF(V600E), the percentage of mutant alleles ranged from 5.1 to 44.7% of the total BRAF alleles, with a median of 20.6%. The presence or the percentage of BRAF(V600E) alleles did not correlate significantly with sex, multicentricity, lymph node metastasis, or tumor stage. The percentage of BRAF(V600E) alleles directly correlated with age at diagnosis and tumor volume (R(2) = 0.223, P = 0.039, and R(2) = 0.166, P < 0.001, respectively). The percentage of BRAF(V600E) alleles (P = 0.014), tumor volume (P = 0.012), and lymph node metastasis (P = 0.008) predicted the disease outcome. The odds ratio of recurrence for PTC with BRAF(V600E) alleles of 30% or greater, compared with that for PTC with BRAF(V600E) alleles of less than 30%, was 5.31 (P = 0.002). CONCLUSIONS A high percentage of BRAF(V600E) alleles defines a PTC molecular subtype and predicts a poorer disease outcome. The analysis of BRAF mutations by pyrosequencing is useful to refine the risk stratification of patients with PTC.

Frequent association between MEN 2A and cutaneous lichen amyloidosis.

objective Multiple endocrine neoplasia type 2A (MEN 2A) and familial medullary thyroid carcinoma (FMTC) are genetic diseases due to activating mutations of the RET proto‐oncogene. Affected patients develop medullary thyroid carcinoma (100%), in an isolated form (FMTC) or in association with phaeochromocytoma (30–50%), and primary hyperparathyroidism (10–20%) (MEN 2A). The presence of cutaneous lichen amyloidosis (CLA) has been anecdotally described in few families harbouring RET proto‐oncogene mutation in codon 634. The aim of the study was to evaluate the incidence of CLA in MEN 2A/FMTC families.

Evidence of a Low Prevalence of RAS Mutations in a Large Medullary Thyroid Cancer Series

BACKGROUND Approximately 60% of sporadic medullary thyroid carcinomas (sMTC) remain orphan of a recognized genetic cause. Recently, a high percentage of RAS point mutations have been described in RET-negative sMTC. The aim of this study was to assess the prevalence of RAS point mutations in a large series of MTC collected in four Italian centers. METHODS For this purpose, we studied codons 12, 13, and 61 of H-, K-, and N-RAS genes in 188 MTC samples, either hereditary or sporadic, by direct sequencing. Correlations between the RAS mutational status and the clinical-pathological features of MTC patients as well as a meta-analysis of all published data were performed. RESULTS The prevalence of RAS mutations in the present series of MTC was 10.1%, and 17.6% when considering only RET-negative cases. RAS mutations were found in MTC tumoral tissue, but not in peripheral blood indicating their somatic origin. A novel mutation in codon 72 (M72I) was found, but with a low or null transforming potential. No association was found between the presence of RAS mutations and the clinical-pathological features of the patients. Although not statistically significant, a positive association between the presence of RAS mutations and a better outcome was observed. The meta-analysis of all published studies confirmed a prevalence of 8.8% for RAS mutations in MTC. CONCLUSIONS The prevalence of RAS mutations in our MTC series was relatively low and consistent with the meta-analysis data. Only somatic RAS mutations were found and only in RET-negative sMTC. Likewise, MTCs that harbor a RAS mutation identify a subgroup of tumors with less aggressive behavior. To our knowledge, this is the largest series of MTCs studied for the presence of mutations in RAS genes and the first meta-analysis on this specific topic.

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.