Clinical case of familial medullary thyroid carcinoma

Medullary thyroid cancer (MTC) accounts for 5—10 % of all thyroid cancers. Most cases are sporadic (75 %), but the proportion of patients with MTC and familial medullary thyroid carcinoma (FMTC) is the highest among any hereditary cancer syndromes (appro­ximately 25 %), and this risk should be considered when evaluating a patient with MTC. In this clinical case study, case of FMTC has been elucidated. Diagnostic criteria of the disease, molecular-genetic aspects, treatment tactics and post-operative observation findings have been presented. The case study illustrates, the efficacy of genomic profiling for the identification of molecular genetic drivers of the disease and its role in ensuring proper and timely diagnosis and treatment of familial form of MTC. When planning prophylactic thyroidectomy, it is recommended to focus on the stratification of the level of RET gene mutation and the timing of prophylactic thyroidectomy as proposed by the American Thyroid Association. The use of molecular genetic investigations in clinical practice for diagnosing MTC makes it possible to objectify the genetic line of the disease in a particular biological family. The patient was found to have a pathogenic germline missense mutation c.2304 G> T (p.E768D, CM020961) in a heterozygous state, which refers to moderate risk of aggressiveness of MTC. In addition, molecular genetic test was performed for the patient's biological child, a 4-year-old girl. Pathogenic mutation was found in the CHEK2 gene, c.47OT> C (p.Ile 157 Thr) in a heterozygous state. These mutations increase the risk of developing breast cancer by 2-3 times, and by 4-5 times in the presence of family history of cancer. The presence of this mutation increases the risk of developing other types of cancers such as stomach, breast, intestinal, prostate and thyroid cancers. Timely diagnosis of FMTC allows to formulate adequate treatment strategy at the preclinical stage of the disease and can significantly improve the quality and duration of life.

Comparison Between Clinicopathological Characteristics, BRAF V600E and TERT Promoter Mutation of Familial Non-Medullary Thyroid Carcinomas, and Sporadic Case

BackgroundIt has been debated whether familial non-medullary thyroid carcinoma (FNMTC) is more aggressive and has a worse prognosis than sporadic non-medullary thyroid carcinoma (SNMTC). Our aim was to compare the invasiveness and prognosis of FNMTC and SNMTC by their biological behavior and molecular changes.Method and MaterialOur group mainly compared 106 patients with FNMTC whom have complete clinicopathological data during 2011–2019 in West China Hospital, Sichuan University, and 212 randomly selected cases with SNMTC were included to compare their biological behavior, recurrence and mortality, and molecular expression of BRAF V600E and TERT promoter. At the same time, FNMTC cases were divided into four subgroups, namely, two affected members group, three or more affected members, parent/offspring group, and sibling group, and they were compared with SNMTC separately to analyze the difference in their invasiveness and prognosis.ResultsWe found that the mean tumor size of FNMTC (0.96 ± 0.53cm) was smaller than that of SNMTC (1.15 ± 0.72 cm) (p = 0.020), while no significant difference in the incidence of other clinicopathological factors, including bilateral growth, capsular invasion, with thyroid nodular goiter or not, multifocality, lymph node metastasis, extrathyroidal extension, iodine 131 treatments, T stage, and American Joint Committee on Cancer (AJCC) stage, was observed between FNMTC and SNMTC (p > 0.05), between each FNMTC subgroup (p > 0.05), and between each FNMTC subgroup and SNMTC (p > 0.05). There was no significant difference in recurrence, mortality, and BRAF V600E and TERT promoter mutation between FNMTC and SNMTC, among which 50/60 (83.33%) of FNMTC patients had BRAF V600E mutation and 1/32 (3.13%) had TERT promoter mutation, while the mutation rates of SNMTC were 93/108 (86.11%) and 3/64 (4.69%) (p > 0.05).ConclusionThere was no significant difference in invasiveness and prognosis between FNMTC and SNMTC by biological behavior, patient survival, and molecular level comparison.

Preoperative calcitonin testing improves the diagnosis of medullary thyroid carcinoma in female and male patients

Calcitonin (Ctn) measurement in patients with thyroid disease could potentially increase the detection rates of medullary thyroid carcinoma (MTC) but remains a controversial issue. The aim of this study was to evaluate routine preoperative Ctn measurements. Methods: All patients with thyroid surgery documented in the prospective StuDoQ|Thyroid registry between 03/2017 and 09/2020 were included. Cutoff levels for Ctn were determined with ROC analyses to assess the preoperative diagnosis of MTC in subgroups for females and males. Findings: In 29.590 of 39.679 patients (75%) participating in the registry, routine preoperative Ctn testing was performed. In 357 patients (227 females, 130 males) histopathology confirmed MTC with a mean tumor size of 14.7 mm (± 12.43). Biochemical cure was achieved in 71.4% of the patients. Ctn levels between 11 and 20 pg/ml were seen in 2.6% of the patients, and only 0.7% of the patients had Ctn levels above 21 pg/ml. Cutoff levels for the diagnosis of MTC were 7.9 pg/ml for females and 15 pg/ml for males (p <0.001). The sensitivity and specificity for females were 95% and 98%, and 96% and 97% for males, respectively. Conclusion: Routine Ctn testing is a reliable predictor for MTC and provides the opportunity for earlier thyroidectomy before lymph node metastases occur, resulting in a better prognosis. Females with Ctn levels >7.9 pg/ml and males >15 pg/ml without any other extrathyroidal sources for an elevated Ctn should be monitored. Thyroid surgery should be considered if Ctn levels are increasing, or ultrasound detects suspicious thyroid lesions.

Identification of NID1 as a novel candidate susceptibility gene for familial non-medullary thyroid carcinoma using whole exome sequencing

The genetics underlying non-syndromic familial non-medullary thyroid carcinoma (FNMTC) is still poorly understood. To identify susceptibility genes for FNMTC, we performed whole exome sequencing (WES) in a Brazilian family affected by papillary thyroid carcinoma (PTC) in three consecutive generations. WES was performed in four affected and two unaffected family members. Manual inspection in over 100 previously reported susceptibility genes for FNMTC showed that no variants in known genes co-segregated with disease phenotype in this family. Novel candidate genes were investigated using PhenoDB and filtered using Genome Aggregation (gnomAD) and Online Archive of Brazilian Mutations (ABraOM) population databases. The missense variant p.Ile657Met in the NID1 gene was the only variant that co-segregated with the disease, while absent in unaffected family members and controls. The allele frequency for this variant was <0.0001 in the gnomAD and ABbraOM databases. In silico analysis predicted the variant to be deleterious or likely damaging to the protein function. Somatic mutations in NID1 gene were found in nearly 500 cases of different cancer subtypes in the intOGen platform. Immunohistochemistry analysis showed NID1 expression in PTC cells, while it was absent in normal thyroid tissue. Our findings were corroborated using data from the TCGA cohort. Moreover, higher expression of NID1 was associated with higher likelihood of relapse after treatment and N1b disease in PTCs from the TCGA cohort. Although replication studies are needed to better understand the role of this variant in the FNMTC susceptibility, the NID1 variant (c.1971T>G) identified in this study fulfills several criteria that suggest it as a new FNMTC predisposing gene.